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diff --git a/old/14504-h/14504-h.htm b/old/14504-h/14504-h.htm new file mode 100644 index 0000000..64ca690 --- /dev/null +++ b/old/14504-h/14504-h.htm @@ -0,0 +1,21982 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" +"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> +<meta http-equiv="Content-Type" content="text/html;charset=utf-8" /> +<meta http-equiv="Content-Style-Type" content="text/css" /> +<title>The Project Gutenberg eBook of Experiments and Considerations touching Colours, by Robert Boyle</title> + +<style type="text/css" xml:space="preserve"> + + body { margin-left: 10%; + margin-right: 10%; + } + + p { margin-top: .75em; + text-align: justify; + margin-bottom: .75em; + } + H1,H2,H3,H4,H5,H6 { + text-align: center; /* all headings centered */ + } + hr {text-align: center; width: 50%;} + hr.short {text-align: center; width: 20%;} + + p.i16 {margin-left: 8em;} + + .author {text-align: right; margin-top: -1em; margin-right: 5%;} + .center {text-align: center; } + .pagenum {position: absolute; left: 92%; font-size: smaller; text-align: right;} /* page numbers */ + .note {margin-left: 2em; margin-right: 2em; + font-size: small ;} /* footnote */F + + .figcenter + {padding: 1em; margin: 0; text-align: center; font-size: 0.8em;} + .figcenter img + {border: none;} + .figcenter {margin: auto;} + + </style> + </head> + <body> + +<div style='text-align:center; font-size:1.2em; font-weight:bold;'>The Project Gutenberg eBook of Experiments and Considerations Touching Colours, by Robert Boyle</div> +<div style='display:block; margin:1em 0'> +This eBook is for the use of anyone anywhere in the United States and +most other parts of the world at no cost and with almost no restrictions +whatsoever. You may copy it, give it away or re-use it under the terms +of the Project Gutenberg License included with this eBook or online +at <a href="https://www.gutenberg.org">www.gutenberg.org</a>. If you +are not located in the United States, you will have to check the laws of the +country where you are located before using this eBook. +</div> +<div style='display:block; margin-top:1em; margin-bottom:1em; margin-left:2em; text-indent:-2em'>Title: Experiments and Considerations Touching Colours</div> +<div style='display:block; margin-top:1em; margin-bottom:1em; margin-left:2em; text-indent:-2em'>Author: Robert Boyle</div> +<div style='display:block;margin:1em 0'>Release Date: December 28, 2004 [eBook #14504]<br /> +[Most recently updated: April 8, 2021]</div> +<div style='display:block;margin:1em 0'>Language: English</div> +<div style='display:block;margin:1em 0'>Character set encoding: UTF-8</div> +<div style='display:block; margin-left:2em; text-indent:-2em'>Produced by: Robert Shimmin, Keith Edkins, the PG Online Distributed Proofreading Team and David Widger</div> +<div style='margin-top:2em;margin-bottom:4em'>*** START OF THE PROJECT GUTENBERG EBOOK EXPERIMENTS AND CONSIDERATIONS TOUCHING COLOURS ***</div> + + <h1> + <span style="font-size:100%;">EXPERIMENTS</span><br /> <span + style="font-size:50%;">AND</span><br /> <span style="font-size:100%;">CONSIDERATIONS</span><br /> + <span style="font-size:50%;">Touching</span><br /> <span + style="font-size:150%; letter-spacing:6px">COLOURS.</span><br /> + </h1> + <p class="center"> + First occasionally Written, among some other<br /> <i>Essays</i>, to a + Friend; and now suffer'd to<br /> come abroad as + </p> + <h2> + <span style="font-size:50%;">THE</span><br /> <span style="font-size:50%;">BEGINNING</span><br /> + <span style="font-size:50%;">Of An</span><br /> <span style="font-size:75%;">Experimental + History</span><br /> <span style="font-size:50%;">OF</span><br /> <span + style="font-size:100%; letter-spacing:6px">COLOURS.</span><br /> + </h2> + <hr class="short" /> + <p class="center"> + By the Honourable <i>ROBERT BOYLE</i>,<br /> Fellow of the ROYAL SOCIETY. + </p> + <hr class="short" /> + <p class="center"> + <i>Non fingendum, aut excogitandum, sed inveniendum,<br /> quid Natura + faciat, aut ferat</i>. Bacon. + </p> + <hr class="short" /> + <h3> + <i>LONDON</i>. + </h3> + <p class="center"> + Printed for <i>Henry Herringman</i> at the<br /> <i>Anchor</i> on the Lower + walk of the <i>New<br /> Exchange</i>. MDCLXIV. + </p> + <div class="figcenter" style="width:50%;"> + <img width="100%" src="images/002a.png" alt="Decorative tile" /> + </div> + + <h2> + <span style="font-size:50%; letter-spacing:6px">THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">PREFACE.</span><br /> + </h2> + <p> + <img width="100" height="100" src="images/002b.png" + alt="Illuminated H in Having" /> <i>Aving in convenient places of the + following Treatise, mention'd the Motives, that induc'd me to write it, + and the Scope I propos'd to my self in it; I think it superfluous to + entertain the Reader now, with what he will meet with hereafter. And I + should judge it needless, to trouble others, or my self, with any thing of + Preface: were it not that I can scarce doubt, but this Book will fall into + the hands of some Readers, who being unacquainted with the difficulty of + attempts of this nature, will think itn strange that I should publish any + thing about Colours, without a particular Theory of them. But I dare + expect that Intelligent and Equitable Readers will consider on my behalf: + That the professed Design of this Treatise is to deliver things rather</i> + Historical <i>than</i> Dogmatical, <i>and consequently if I have added + divers new</i> speculative <i>Considerations and hints, which perhaps may + afford no despicable Assistance, towards the framing of a solid and + comprehensive Hypothesis, I have done at least as much as I promis'd, or + as the nature of my undertaking exacted. But another thing there is, which + if it should be objected, I fear I should not be able so easily to answer + it, and that is; That in the following treatise (especially in the Third + part of it) the Experiments might have been better Marshall'd, and some of + them deliver'd in fewer words. For I must confess that this Essay was + written to a private Friend, and that too, by snatches, at several times, + and places, and (after my manner) in loose sheets, of which I oftentimes + had not all by me that I had already written, when I was writing more, so + that it needs be no wonder if all the Experiments be not rang'd to the + best Advantage, and if some connections and consecutions of them might + easily have been mended. Especially since having carelessly laid by the + loose Papers, for several years after they were written, when I came to + put them together to dispatch them to the Press, I found some of those I + reckon'd upon, to be very unseasonably wanting. And to make any great + change in the order of the rest, was more than the Printers importunity, + and that, of my own avocations (and perhaps also considerabler + solicitations) would permit. But though some few preambles of the + particular Experiments might have (perchance) been spar'd, or shorten'd, + if I had had all my Papers under my View at once; Yet in the most of those + Introductory passages, the Reader will (I hope) find hints, or + Advertisements, as well as Transitions. If I sometimes seem to insist long + upon the circumstances of a Tryall, I hope I shall be easily excused by + those that both know, how nice divers experiments of Colours are, and + consider that I was not barely to</i> relate <i>them, but so as to teach a + young Gentleman to make them. And if I was not sollicitous, to make a + nicer division of the whole Treatise, than into three parts, whereof the + One contains some Considerations about Colours in general. The Other + exhibits a specimen of an Account of particular Colours, Exemplifi'd in + Whiteness and Blackness. And the Third promiscuous Experiments about the + remaining Colours (especially Red) in order to a Theory of them. If, I + say, I contented my self with this easie Division of my Discourse, it was + perhaps because I did not think it so necessary to be Curious about the + Method or Contrivance of a Treatise, wherein I do not pretend to present + my Reader with a compleat Fabrick, or so much as Modell; but only to bring + in Materials proper for the Building; And if I did not well know how + Ingenious the Curiosity and Civility of Friends makes them, to perswade + Men by specious allegations, to gratifie their desires; I should have been + made to believe by persons very well qualify'd to judge of matters of this + nature, that the following Experiments will not need the addition of + accurate Method and speculative Notions to procure Acceptance for the + Treatise that contains them: For it hath been represented, That in most of + them, as the Novelty will make them surprizing, and the Quickness of + performance, keep them from being tedious; so the sensible changes, that + are effected by them, are so manifest, so great, and so sudden, that + scarce any will be displeased to see them, and those that are any thing + Curious will scarce be able to see them, without finding themselves + excited, to make Reflexions upon Them. But though with me, who love to + measure Physical things by their</i> use, <i>not their</i> strangeness, <i>or</i> + prettiness, <i>the partiality of others prevails not to make me over value + these, or look upon them in themselves as other than Trifles: Yet I + confess, that ever since I did divers years ago shew some of them to a + Learned Company of</i> Virtuosi: <i>so many persons of differing + Conditions, and ev'n Sexes, have been Curious to see them, and pleas'd not + to Dislike them, that I cannot Despair, but that by complying with those + that urge the Publication of them, I may both gratifie and excite the + Curious, and lay perhaps a Foundation whereon either others or my self may + in time superstruct a substantial theory of Colours. And if</i> Aristotle, + <i>after his Master</i> Plato, <i>have rightly observ'd Admiration to be + the</i> Parent of Philosophy, <i>the wonder, some of these Trifles have + been wont to produce in all sorts of Beholders, and the access they have + sometimes gain'd ev'n to the Closets of Ladies, seem to promise, that + since the subject is so pleasing, that the Speculation appears as + Delightful! as Difficult, such easie and recreative Experiments, which + require but little time, or charge, or trouble in the making, and when + made are sensible and surprizing enough, may contribute more than others, + (far more important but as much more difficult) to recommend those parts + of Learning (Chymistry and Corpuscular Philosophy) by which they have been + produc'd, and to which they give Testimony ev'n to such kind of persons, + as value a pretty Trick more than a true Notion, and would scarce admit + Philosophy, if it approach'd them in another Dress: without the + strangeness or endearments of pleasantness to recommend it. I know that I + do but ill consult my own Advantage in the consenting to the Publication + of the following Treatise: For those things, which, whilst men knew not + how they were perform'd, appear'd so strange, will, when the way of making + them, and the Grounds on which I devis'd them, shall be Publick, quickly + lose all that their being</i> Rarityes, <i>and their</i> being thought + Mysteries, <i>contributed to recommend them. But 'tis fitter for + Mountebancks than Naturalis to desire to have their discoverys rather + admir'd than understood, and for my part I had much rather deserve the + thanks of the Ingenious, than enjoy the Applause of the Ignorant. And if I + can so farr contribute to the discovery of the nature of Colours, as to + help the Curious to it, I shall have reach'd my End, and sav'd my self + some Labour which else I may chance be tempted to undergo in prosecuting + that subect, and Adding to this Treatise, which I therefore call a</i> + History, <i>because it chiefly contains matters of fact, and which History + the Title declares me to look upon but as</i> Begun: <i>Because though + that above a hundred, not to say a hundred and fifty Experiments, (some + loose, and others interwoven amongst the discourses themselves) may + suffice to give a</i> Beginning <i>to a History not hitherto, that I know, + begun, by any; yet the subject is so fruitfull, and so worthy, that those + that are Curious of these Matters will be farr more wanting to themselves + than I can suspect, if what I now publish prove any more than a</i> + Beginning. <i>For, as I hope my Endeavours may afford them some assistance + towards this work, so those Endeavours are much too Vnfinish'd to give + them any discouragement, as if there were little left for others to do + towards the History of Colours.</i> + </p> + <p> + <i>For (first) I have been willing to leave unmention'd the</i> most part + <i>of those Phænomena of Colours, that Nature presents us of her own + accord, (that is, without being guided or over-ruld by man) such as the + different Colours that several sorts of Fruites pass through before they + are perfectly ripe, and those that appear upon the fading of flowers and + leaves, and the putrifaction (and its several degrees) of fruits, &c. + together with a thousand other obvious Instances of the changes of + colours. Nor have I</i> much <i>medled with those familiar Phænomena + wherein man is not an Idle spectator; such as the Greenness produc'd by + salt in Beef much powder'd, and the Redness produc'd in the shells of + Lobsters upon the boyling of those fishes; For I was willing to leave the</i> + gathering <i>of</i> Observations <i>to those that have not the Opportunity + to</i> make Experiments. <i>And for the same Reasons, among others, I did + purposly omit the Lucriferous practise of Trades-men about colours; as the + ways of making Pigments, of Bleanching wax, of dying Scarlet, &c. + though to divers of them I be not a stranger, and of some I have myself + made Tryall.</i> + </p> + <p> + <i>Next; I did purposely pass by divers Experiments of other Writers that + I had made Tryall of (and that not without registring some of their + Events) unless I could some way or other improve them, because I wanted + leasure to insert them, and had thoughts of prosecuting the work once + begun of laying together those I had examin'd by themselves in case of my + not being prevented by others diligence. So that there remains not a + little, among the things that are already published, to imploy those that + have a mind to exercise themselves in repeating and examining them. And I + will not undertake, that</i> none <i>of the things deliver'd, ev'n in this + Treatise, though never so faithfully set down, may not prove to be thus + farr of this Sort, as to afford the Curious somewhat to add about them. + For I remember that I have somewhere in the Book it self acknowledged, + that having written it by snatches, partly in the Counntrey, and partly at + unseasonable times of the year, when the want of fit Instruments, and of a + competent variety of flowers, salts, Pigments, and other materials made me + leave some of the following Experiments, (especialy those about Emphatical + Colours) far more unfinish'd than they should have been, if it had been as + easie for me to</i> supply <i>what was wanting to compleat them, as to</i> + discern<i>. Thirdly to avoyd discouraging the young Gentleman I call + Pyrophilus, whom the less Familiar, and more Laborious operations of + Chymistry would probably have frighted, I purposely declin'd in what I + writ to him, the setting down any Number of such Chymicall Experiments, + as, by being very elaborate or tedious, would either require much skill, + or exercise his patience. And yet that this sort of Experiments is + exceedingly Numerous, and might more than a little inrich the History of + Colours, those that are vers'd in Chymical processes, will, I presume, + easily allow me.</i> + </p> + <p> + <i>And (Lastly) for as much as I have occasion more than once in my + several Writings to treat either porposely or incidentally of matters + relating to Colours; I did not, perhaps, conceive my self oblig'd, to + deliver in one Treatise</i> all <i>that I would say concerning that + subject.</i> + </p> + <p> + <i>But to conclude, by summing up what I would say concerning what I</i> + have <i>and what I</i> have not <i>done, in the following Papers; I shall + not</i> (on the one side) <i>deny, that considering that I pretended not + to write an accurate Treatise of Colours, but an Occasional Essay to + acquaint a private friend with what then occurrd to me of the things I had + thought or try'd concerning them; I might presume I did enough for once, + if I did clearly and faithfully set down, though not</i> all <i>the + Experiments I could, yet at least such a variety of them, that an + attentive Reader that shall consider the Grounds on which they have been + made, and the hints that are purposely (though dispersedly) couched in + them, may easily</i> compound <i>them, and otherwise</i> vary <i>them, so + as very much to increase their Number. And yet</i> (on the other side) <i>I + am so sensible both of how much I have, either out of necessity or choice, + left undone, and of the fruitfullness of the subject I have begun to + handle; that though I had performed far more then 'tis like many Readers + will judge I have, I should yet be very free to let them apply to my + Attempts that of</i> Seneca, <i>where having spoken of the Study of + Natures Mysteries, and Particularly of the Cause of Earth-Quakes, he + subjoins.<a name="NtA_1" id="NtA_1"></a><a href="#Nt_1"><sup>1</sup></a></i> + Nulla res consummata est dum incipit. Nec in hac tantum re omnium maxima + ac involutissimá, in quâ etiam cum multum actum erit, omnis ætas, quod + agat inveniet; sed in omni alio Negotio, longè semper à perfecto fuere + Principia. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/012a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:100%;"><i>The Publisher to the</i></span><br /> + <span style="font-size:100%; letter-spacing:10px">READER.</span><br /> + </h2> + <p> + <i>Friendly Reader,</i> + </p> + <p> + <img width="80" height="80" src="images/012b.png" + alt="Illuminated H in Here" />Ere is presented to thy view one of the + Abstrusest as well as the Gentilest Subjects of Natural Philosophy, the <i>Experimentall + History of Colours</i>; which though the Noble Author be pleased to think + but <i>Begun</i>, yet I must take leave to say, that I think it so well + begun, that the work is more than half dispatcht. Concerning which I + cannot but give this advertisement to the Reader, that I have heard the + Author express himself, that it would not surprise him, if it should + happen to be objected, that some of these Experiments have been already + published, partly by Chymists, and partly by two or three very fresh + Writers upon other Subjects. And though the number of these Experiments be + but very small, and though they be none of the considerablest, yet it may + on this occasion be further represented, that it is easie for our Author + to name several men, (of whose number I can truly name my self) who + remember either their having seen him make, or their having read, his + Accounts of the Experiments delivered in the following Tract several years + since, and long before the publication of the Books, wherein they are + mentioned. Nay in divers passages (where he could do it without any great + inconvenience) he hath struck out Experiments, which he had tryed many + years ago, because he since found them divulged by persons from whom he + had not the least hint of them; which yet is not touched, with design to + reflect upon any Ingenious Man, as if he were a Plagiary: For, though our + Generous Author were not reserved enough in showing his Experiments to + those that expressed a Curiosity to see them (amongst whom a very Learned + Man hath been pleased publickly to acknowledge it several years ago<a + name="NtA_2" id="NtA_2"></a><a href="#Nt_2"><sup>2</sup></a>; yet the same + thing may be well enough lighted on by persons that know nothing of one + another. And especially Chymical Laboratories may many times afford the + same <i>Phænomenon</i> about Colours to several persons at the same or + differing times. And as for the few <i>Phænomena</i> mentioned in the same + Chymical writers, as well as in the following Treatise, our Author hath + given an account, why he did not decline rejecting them, in the Anotations + upon the 47<sup>th</sup> Experiment of the third part. Not here to + mention, what he elsewhere saith, to shew what use may be Justifiably made + of Experiments not of his own devising by a writer of Natural History, if, + what he employes of others mens, be well examined or verified by himself. + </p> + <p> + In the mean time, this Treatise is such, that there needs no other + invitation to peruse it, but that tis composed by one of the Deepest & + Most indefatigable searchers of Nature, which, I think the World, as far + as I know it, affords. For mine own part, I feel a Secret Joy within me, + to see such beginings upon such <i>Themes</i>, it being demonstratively + true, <i>Mota facilius moveri</i>, which causeth me to entertain strong + hopes, that this Illustrious <i>Virtuoso</i> and Restless Inquirer into + Nature's Secrets will not stop here, but go on and prosper in the + Disquisition or the other principal Colours, <i>Green, Red</i>, and <i>Yellow</i>. + The Reasoning faculty set once afloat, will be carried on, and that with + ease, especially, when the productions thereof meet, as they do here, with + so greedy an Entertainment at home and abroad. I am confident, that the <b>ROYAL + SOCIETY</b>, lately constituted by his <b>MOST EXCELLENT MAJESTY</b> <i>for + improving Natural knowledge</i>, will Judge it their interest to exhort + our Author to the prosecution of this Argument, considering, how much it + is their design and business to accumulate a good stock of such accurate + Observations and Experiments, as may afford them and their Offpring + genuine Matter to raise a Masculine Philosophy upon, whereby the Mind of + Man may be enobled with the Knowledge of solid Truths, and the Life of Man + benefited with ampler accommodations, than it hath been hitherto. + </p> + <p> + Our Great Author, one of the Pillars of that Illustrious Corporation, is + constantly furnishing large <i>Symbola</i>'s to this work, and is now + falln, as you see, upon so comprehensive and important a theme, as will, + if insisted on and compleated, prove one of the considerablest peeces of + that structure. To which, if he shall please to add his Treatise of <i>Heat</i> + and <i>Flame</i>, as he is ready to publish his Experimental Accounts of + <i>Cold</i>, I esteem, the World will be obliged to Him for having shewed + them both the <i>Right</i> and <i>Left Hand</i> of Nature, and the + Operations thereof. + </p> + <p> + The considering Reader will by this very Treatise see abundant cause to + sollicit the Author for more; sure I am, that of whatever of the + Productions of his Ingeny comes into <i>Forein parts</i> (where I am happy + in the acquaintance of many intelligent friends) is highly valued; And to + my knowledge, there are those among the French, that have lately begun to + learn English, on purpose to enable themselves to read his Books, being + impatient of their Traduction into Latin. If I durst say all, I know of + the Elogies received by me from abroad concerning Him, I should perhaps + make this Preamble too prolix, and certainly offend the modesty of our + Author. + </p> + <p> + Wherefore I shall leave this, and conclude with desiring the Reader, that + if he meet with other faults besides those, that the Errata take notice of + (as I believe he may) he will please to consider both the weakness of the + Authors eyes, for not reviewing, and the manifold Avocations of the + Publisher for not doing his part; who taketh his leave with inviting + those, that have also considered this Nice subject experimentally, to + follow the Example of our Noble Author, and impart such and the like + performances to the now very inquisitive world. <i>Farewell.</i> + </p> + <p class="author"> + <i>H. O.</i> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/018.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:50%;">THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">CONTENTS.</span><br /> + </h2> + <hr /> + <h3> + CHAP. I. + </h3> + <p> + <i>The Author shews the Reason, first of his Writing on this Subject</i> (<a + href="#Page_1">1</a>.) <i>Next of his present manner of Handling it, and + why he partly declines a Methodical way</i> (<a href="#Page_2">2</a>.) <i>and + why he has partly made use of it in the History of</i> Whiteness <i>and</i> + Blackness. (<a href="#Page_3">3</a>.) + </p> + <p> + Chap. 2. <i>Some general Considerations are premis'd, first of the + Insignificancy of the Observasion of Colours in many Bodies</i> (<a + href="#Page_4">4</a>, <a href="#Page_5">5</a>.) <i>and the Importance of + it in others</i> (<a href="#Page_5">5</a>.) <i>as particularly in the + Tempering of Steel</i> (<a href="#Page_6">6</a>, <a href="#Page_7">7</a>, + <a href="#Page_8">8</a>.) <i>The reason why other particular Instances are + in that place omitted</i> (<a href="#Page_9">9</a>) <i>A necessary + distinction about Colour premis'd</i> (<a href="#Page_10">10</a>, <a + href="#Page_11">11</a>.) <i>That Colour is not Inherent in the Object</i> + (<a href="#Page_11">11</a>.) <i>prov'd first by the Phantasms of Colours + to</i> Dreaming <i>men, and</i> Lunaticks; <i>Secondly by the sensation or + apparition of Light upon a Blow given the Eye or the Distemper of the + Brain from internal Vapours</i> (<a href="#Page_12">12</a>.) <i>The Author + recites a particular Instance in himself; another that hapn'd to an + Excellent Person related to him</i> (<a href="#Page_13">13</a>.) <i>and a + third told him by an Ingenious Physician</i> (<a href="#Page_14">14</a>, + <a href="#Page_15">15</a>.) <i>Thirdly, from the change of Colours made by + the Sensory Disaffected</i> (<a href="#Page_15">15</a>, <a href="#Page_16">16</a>.) + <i>Some Instances of this are related by the Author, observ'd in himself</i> + (<a href="#Page_16">16</a>, <a href="#Page_17">17</a>.) <i>others told him + by a Lady of known Veracity</i> (<a href="#Page_18">18</a>.) <i>And others + told him by a very Eminent Man</i> (<a href="#Page_19">19</a>.) <i>But the + strange Instances afforded by such as are Bit by the</i> Tarantula <i>are + omitted, as more properly deliver'd in another place</i>. (<a + href="#Page_20">20</a>.) + </p> + <p> + Chap. 3. <i>That the Colour of Bodies depends chiefly on the disposition + of the Superficial parts, and partly upon the Variety of the Texture of + the Object</i> (<a href="#Page_21">21</a>.) <i>The former of these are + confirm'd by several Persons</i> (<a href="#Page_22">22</a>.) <i>and two + Instances, the first of the Steel mention'd before, the second of melted + Lead</i> (<a href="#Page_23">23</a>, <a href="#Page_24">24</a>.) <i>of + which last several Observables are noted</i> (<a href="#Page_25">25</a>.) + <i>A third Instance is added of the Porousness of the appearing smooth + Surface of Cork</i> (<a href="#Page_26">26</a>, <a href="#Page_27">27</a>.) + <i>And that the same kind of Porousness may be also in the other Colour'd + Bodies; And of what kind of Figures, the Superficial reflecting Particles + of them may be</i> (<a href="#Page_28">28</a>.) <i>and of what Bulks, and + closeness of Position</i> (<a href="#Page_29">29</a>.) <i>How much these + may conduce to the Generation of Colour instanc'd in the Whiteness of + Froth, and in the mixtures of Dry colour'd Powders</i> (<a href="#Page_30">30</a>.) + <i>A further explication of the Variety that may be in the Superficial + parts of Colour'd Bodies, that may cause that Effect, by an example drawn + from the Surface of the Earth</i> (<a href="#Page_31">31</a>.) <i>An + Apology for that gross Comparison</i> (<a href="#Page_32">32</a>.) <i>That + the appearances of the Superficial asperities may be Varied from the + position of the Eye, and several Instances given of such appearances</i> (<a + href="#Page_33">33</a>, <a href="#Page_34">34</a>, <a href="#Page_35">35</a>.) + <i>That the appearance of the Superficial particles may be Varied also by + their Motion, confirm'd by an Instance of the smoaking Liquor</i> (<a + href="#Page_35">35</a>.) <i>especially if the Superficial parts be of such + a Nature as to appear divers in several Postures, explain'd by the variety + of Colours exhibited by the shaken Leaves of some Plants</i> (<a + href="#Page_36">36</a>.) <i>and by changeable Taffities</i> (<a + href="#Page_37">37</a>, <a href="#Page_38">38</a>, <a href="#Page_39">39</a>.) + <i>The Authors wish that the Variety of Colours in Mother of Pearl were + examin'd with a</i> Microscope (<a href="#Page_40">40</a>.) <i>And his + Conjectures, that possibly good</i> Microscopes <i>might discover those + Superficial inequalities to be Real, which we now only imagine with his + reasons drawn partly from the Discoveries of the</i> Telescope, <i>and</i> + Microscope (<a href="#Page_41">41</a>.) <i>And partly also from the + Prodigiously strange example of a Blind man that could feel Colours</i> (<a + href="#Page_42">42</a>.) <i>whose History is Related</i> (<a + href="#Page_43">43</a>, <a href="#Page_44">44</a>, <a href="#Page_45">45</a>.) + <i>The Authors conjecture and thoughts of it</i> (<a href="#Page_46">46</a>, + <a href="#Page_47">47</a>, <a href="#Page_48">48</a>, <a href="#Page_49">49</a>.) + <i>and several Conclusions and Corollaries drawn from it about the Nature + of Blackness and Black Bodies</i> (<a href="#Page_50">50</a>, <a + href="#Page_51">51</a>, <a href="#Page_52">52</a>.) <i>and about the + Asperities of several other Colour'd Bodies</i> (<a href="#Page_53">53</a>.) + <i>And from these, and some premis'd Considerations, are propos'd some + Conjectures; That the reason of the several Phænomena of Colours, + afterwards to be met with, depends upon the Disposition of the Seen parts + of the Object</i> (<a href="#Page_54">54</a>.) <i>That Liquors may alter + the Colours of each other, and of other Bodies, first by their Insinuating + themselves into the Pores, and filling them, whence the Asperity of the + Surface of a Body becomes alter'd, explicated with some Instances</i> (<a + href="#Page_55">55</a>, <a href="#Page_56">56</a>.) <i>Next by removing + those Bodies, which before hindred the appearance of the Genuine Colour, + confirm'd by several examples</i> (<a href="#Page_57">57</a>) <i>Thirdly, + by making a Fissure or Separation either in the Contiguous or Continued + Particles of a Body</i> (<a href="#Page_58">58</a>.) <i>Fourthly, by a + Union or Conjunction of the formerly separated Particles; Illustrated with + divers Instances of precipitated Bodies</i> (<a href="#Page_59">59</a>.) + <i>Fifthly, by Dislocating the parts, and putting them both into other + Orders and Postures, which is Illustrated with Instances</i> (<a + href="#Page_60">60</a>, <a href="#Page_61">61</a>.) <i>Sixthly, by Motion, + which is explain'd</i> (<a href="#Page_62">62</a>.) <i>And lastly, and + chiefly, by the Union of the Saline Bodies, with the Superficial parts of + another Body, whereby both their Bigness and Shape must necessarily be + alter'd</i> (<a href="#Page_63">63</a>, <a href="#Page_64">64</a>.) <i>Explain'd + by Experiments</i> (<a href="#Page_65">65</a>, <a href="#Page_66">66</a>.) + <i>That the Colour of Bodies may be Chang'd by the concurrence of two or + more of these ways</i> (<a href="#Page_67">67</a>.) <i>And besides all + these, Eight Reflective causes of Colours, there may be in Transparent + Bodies several Refractive</i> (<a href="#Page_68">68</a>, <a + href="#Page_69">69</a>) <i>Why the Author thinks the Nature of Colours + deserves yet a further Inquiry</i> (<a href="#Page_69">69</a>.) <i>First + for that the little Motes of Dust exhibited very lovely Colours in a + darkned Room, whilst in a convenient posture to the Eye, which in other + Postures and Lights they did not</i> (<a href="#Page_70">70</a>.) <i>And + that though the smaller Parts of some Colour'd Bodies are Transparent, yet + of others they are not, so that the first Doubt's, whether the Superficial + parts create those Colours, and the second, whether there be any + Refraction at all in the later</i> (<a href="#Page_71">71</a>, <a + href="#Page_72">72</a>, <a href="#Page_73">73</a>.) <i>A famous + Controversie among Philosophers, about the Nature of Colour decided</i>. (<a + href="#Page_74">74</a>. <a href="#Page_75">75</a>.) + </p> + <p> + Chap. 4. <i>The controversie stated about Real and Emphatical Colours</i> + (<a href="#Page_75">75</a>, <a href="#Page_76">76</a>.) <i>That the great + Disparity between them seems to be, partly their Duration in the same + state, and partly, that Genuine Colours are produc'd in Opacous Bodies by + Reflection, and Emphatical in Transparent by Refraction</i> (<a + href="#Page_78">78</a>.) <i>but that this is not to be taken in too large + a Sense, the Cautionary instance of Froth is alleged and insisted on</i> (<a + href="#Page_78">78</a>, <a href="#Page_79">79</a>.) <i>That the Duration + is not a sufficient Characteristick, exemplify'd by the duration of Froth, + and other Emphatical Colours, and the suddain fading of Flowers, and other + Bodies of Real ones</i> (<a href="#Page_80">80</a>.) <i>That the position + of the Eye is not necessary to the discerning Emphatical Colours, shew'd + by the seeing white Froth, or an Iris cast on the Wall by a Prism, in what + place of the Room soever the Eye be</i> (<a href="#Page_81">81</a>.) <i>which + proceeds from the specular Reflection of the Wall</i> (<a href="#Page_82">82</a>.) + <i>that Emphatical Colours may be Compounded, and that the present + Discourse is not much concern'd, whether there be, or be not made a + distinction between Real and Emphatical Colours</i>. (<a href="#Page_83">83</a>.) + </p> + <p> + Chap. 5. <i>Six Hypotheses about Colour recited</i> (<a href="#Page_84">84</a>, + <a href="#Page_85">85</a>) <i>Why the Author cannot more fully Speak of + any of these</i> (<a href="#Page_86">86</a>.) <i>nor Acquiesce in them</i> + (<a href="#Page_87">87</a>, <a href="#Page_88">88</a>.) <i>What</i> + Pyrophilus <i>is to expect in this Treatise</i> (<a href="#Page_88">88</a>, + <a href="#Page_89">89</a>.) <i>What Hypothesis of Light and Colour the + Author most inclines too</i> (<a href="#Page_90">90</a>.) <i>Why he thinks + neither that nor any other sufficient; and what his Difficulties are, that + make him decline all Hypotheses, and to think it very difficult to stick + to any.</i> (<a href="#Page_91">91</a>, <a href="#Page_92">92</a>.) + </p> + <hr /> + <h2> + Part the Second. + </h2> + <p class="center"> + <i>Of the Nature of Whiteness and Blackness.</i> + </p> + <h3> + CHAP. I. + </h3> + <p> + <i>The reason why the Author chose the Explication of Whiteness and + Blackness</i> (<a href="#Page_93">93</a>.) <i>Wherein</i> Democritus <i>thought + amiss of these</i> (<a href="#Page_94">94</a>.) Gassendus <i>his Opinion + about them</i> (<a href="#Page_95">95</a>.) <i>What the Author approves, + and a more full Explication of White, makinig it a Multiplicity of Light + or Reflections</i> (<a href="#Page_96">96</a>, <a href="#Page_97">97</a>.) + <i>Confirm'd first by the Whiteness of the</i> Meridian <i>Sun, observ'd + in Water</i> (<a href="#Page_98">98</a>.) <i>and of a piece of Iron + glowing Hot</i> (<a href="#Page_99">99</a>.) <i>Secondly, by the + Offensiveness of Snow to the Travellers eyes, confirm'd by an example of a + Person that has Travell'd much in Russia</i> (<a href="#Page_100">100</a>.) + <i>and by an Observation out of</i> Olaus Magnus (<a href="#Page_100">100</a>.) + <i>and that the Snow does inlighten and clear the Air in the Night, + confirm'd by the Mosco Physician, and Captain</i> James (<a + href="#Page_101">101</a>.) <i>But that Snow has no inherent Light, prov'd + by Experience</i> (<a href="#Page_102">102</a>.) <i>Thirdly, by the great + store of Reflections, from white Bodies observ'd in a darkned Room, and by + their unaptness to be Kindled by a Burning-glass</i> (<a href="#Page_103">103</a>.) + <i>Fourthly, the Specularness of White Bodies is confirm'd by the + Reflections in a dark Room from other Bodies</i> (<a href="#Page_104">104</a>.) + <i>and by the appearance of a River, which both to the Eye and in a + darkned Room appear'd White</i> (<a href="#Page_105">105</a>, <a + href="#Page_106">106</a>.) <i>Fifthly, by the Whiteness of distill'd</i> + Mercury, <i>and that of the</i> Galaxie (<a href="#Page_107">107</a>, <a + href="#Page_108">108</a>.) <i>and by the Whiteness of Froth, rais'd from + whites of Eggs beaten; that this Whiteness comes not from the Air, shew'd + by Experiments</i> (<a href="#Page_109">109</a>, <a href="#Page_110">110</a>.) + <i>where occasionally the Whiteness of Distill'd Oyls, Hot water, &c. + are shew'd</i> (<a href="#Page_111">111</a>.) <i>That it seems not + necessary the Reflecting Surfaces should be Sphærical, confirm'd by + Experiments</i> (<a href="#Page_112">112</a>, <a href="#Page_113">113</a>.) + <i>Sixthly, by the Whiteness of the Powders of transparent Bodies</i> (<a + href="#Page_114">114</a>.) <i>Seventhly, by the Experiment of Whitening + and Burnishing Silver.</i> (<a href="#Page_115">115</a>, <a + href="#Page_116">116</a>.) + </p> + <p> + Chap. 2. <i>A Recital of some Opinions about Blackness, and which the + Author inclines to</i> (<a href="#Page_117">117</a>.) <i>which he further + insists on and explicates</i> (<a href="#Page_118">118</a>, <a + href="#Page_119">119</a>.) <i>and shews for what reasons he imbrac'd that + Hypothesis</i> (<a href="#Page_120">120</a>.) <i>First, from the contrary + Nature of Whiteness and Blackness, White reflecting most Beams outwards, + Black should reflect most inward</i> (<a href="#Page_120">120</a>.) <i>Next, + from the Black appearance of all Bodies, when Shadow'd; And the manner how + this paucity of Reflection outwards is caus'd, is further explicated, by + shewing that the Superficial parts may be Conical and Pyramical</i> (<a + href="#Page_121">121</a>.) <i>This and other Considerations formerly + deliver'd, Illustrated by Experiments with black and white Marble</i> (<a + href="#Page_122">122</a>, <a href="#Page_123">123</a>.) <i>Thirdly, from + the Black appearance of Holes in white Linnen, and from the appearance of + Velvet stroak'd several ways, and from an Observation of Carrots</i> (<a + href="#Page_124">124</a>, <a href="#Page_125">125</a>.) <i>Fourthly, from + the small Reflection from Black in a darkned Room</i> (<a href="#Page_125">125</a>, + <a href="#Page_126">126</a>.) <i>Fifthly, from the Experiment of a + Checker'd Tile expos'd to the Sun-beams</i> (<a href="#Page_127">127</a>.) + <i>which is to be preferr'd before a Similar Experiment try'd in</i> + Italy, <i>with black and white Marble</i> (<a href="#Page_128">128</a>.) + <i>Some other congruous Observations</i> (<a href="#Page_129">129</a>.) <i>Sixthly, + from the Roasting black'd Eggs in the Sun</i> (<a href="#Page_130">130</a>.) + <i>Seventhly, by the Observation of the Blind man lately mention'd, and of + another mention'd by</i> Bartholine (<a href="#Page_130">130</a>.) <i>That + notwithstanding all these Reasons, the Author is not absolutely Positive, + but remains yet a Seeker after the true Nature of Whiteness and Blackness.</i> + (<a href="#Page_131">131</a>, <a href="#Page_132">132</a>.) + </p> + <p> + Experiments <i>in Consort, touching</i> Whiteness <i>and</i> Blackness. + </p> + <p> + <i>The first</i> Experiment, <i>with a Solution of Sublimate, made White + with Spirit of Urine</i>, &c. (<a href="#Page_133">133</a>, <a + href="#Page_134">134</a>.) + </p> + <p> + <i>The second</i> Experiment, <i>with an Infusion of Galls, made Black + with Vitriol</i>, &c. (<a href="#Page_135">135</a>, <a href="#Page_136">136</a>.) + <i>further Discours'd of</i> (<a href="#Page_137">137</a>.) + </p> + <p> + <i>The third</i> Experiment, <i>of the Blacking of Hartshorn, and Ivory, + and Tartar, and by a further Calcination making them White</i> (<a + href="#Page_138">138</a>, <a href="#Page_139">139</a>.) + </p> + <p> + <i>The fourth</i> Experiment, <i>limiting the</i> Chymist's <i>principle</i>, + Adusta nigra sed perusta alba, <i>by several Instances of Calcin'd + Alabaster, Lead, Antimony, Vitriol, and by the Testimony of</i> Bellonius, + <i>about the white Charcoles of</i> Oxy-cædar, <i>and by that of</i> + Camphire. (<a href="#Page_140">140</a>, <a href="#Page_141">141</a>, <a + href="#Page_142">142</a>.) <i>That which follows about Inks was misplac'd + by an Errour of the Printer, for it belongs to what has been formerly said + of Galls</i> (<a href="#Page_142">142</a>, <a href="#Page_143">143</a>.) + </p> + <p> + <i>The fifth</i> Experiment, <i>of the black Smoak of Camphire</i> (<a + href="#Page_144">144</a>.) + </p> + <p> + <i>The sixth</i> Experiment, <i>of a black</i> Caput Mortuum, <i>of Oyl of + Vitriol, with Oyl of Worm-word, and also with Oyl of Winter-Savory</i> (<a + href="#Page_145">145</a>.) + </p> + <p> + <i>The seventh</i> Experiment, <i>of whitening Wax</i> (<a href="#Page_146">146</a>.) + </p> + <p> + <i>The eighth</i> Experiment, <i>with Tin-glass, and Sublimate</i> (<a + href="#Page_147">147</a>, <a href="#Page_148">148</a>.) + </p> + <p> + <i>The ninth</i> Experiment, <i>of a Black powder of Gold in the bottom of</i> + Aqua-fortis, <i>and of the Blacking of Refin'd Gold and Silver</i> (<a + href="#Page_148">148</a>, <a href="#Page_149">149</a>.) + </p> + <p> + <i>The tenth</i> Experiment, <i>of the staining Hair, Skin, Ivory</i>, + &c. <i>Black, with Crystals of Silver</i> (<a href="#Page_150">150</a>, + <a href="#Page_151">151</a>.) + </p> + <p> + <i>The eleventh</i> Experiment, <i>about the Blackness of the Skin, and + Hair of</i> Negroes, <i>and Inhabitants of Hot Climates. Several + Objections are made, and the whole Matter more fully discours'd and stated + from several notable Histories and Observations</i> (from the <a + href="#Page_151">151</a> to the <a href="#Page_167">167</a>.) + </p> + <p> + <i>The twelfth</i> Experiment, <i>of the white Powders, afforded by + Precipitating several Bodies, as Crabs Eyes, Minium, Coral, Silver, Lead, + Tin, Quick-silver, Tin-glass, Antimony, Benzoin, and Resinous Gumms out of + Spirit of Wine</i>, &c. <i>but this is not Universal, since other + Bodies, as Gold, Antimony, Quick-silver</i>, &c. <i>may be + Precipitated of other Colours</i> (<a href="#Page_168">168</a>, <a + href="#Page_169">169</a>, <a href="#Page_170">170</a>.) + </p> + <p> + <i>The thirteenth</i> Experiment, <i>of Changing the Blackness of some + Bodies into other Colours</i> (<a href="#Page_171">171</a>, <a + href="#Page_172">172</a>.) <i>and of Whitening what would be Minium, and + Copper, with Tin, and of Copper with Arsnick, which with Coppilling again + Vanishes; of covering the Colour of that of</i> 1/3 <i>of Gold with</i> + 2/3 <i>of Silver melted in a Mass together</i> (<a href="#Page_173">173</a>, + <a href="#Page_174">174</a>) + </p> + <p> + <i>The fourteenth</i> Experiment, <i>of turning the black Body of Horn + into a White immediately with Scraping, without changing the Substantial + form, or without the Intervention of Salt, Sulphur, or Mercury</i> (<a + href="#Page_176">176</a>.) + </p> + <p> + <i>The fifteenth</i> Experiment, <i>contains several Instances against the + Opinion of the</i> Chymists <i>that Sulphur</i> Adust <i>is the cause of + Blackness, and the whole Matter is fully discuss'd and stated</i> (from <a + href="#Page_176">176</a> to <a href="#Page_184">184</a>) + </p> + <hr /> + <h2> + Part the Third. + </h2> + <p class="center"> + <i>Concerning Promiscuous Experiments about Colours.</i> + </p> + <h3> + Experiment the First. + </h3> + <p> + <i>IN confirmation of a former Conjecture about the Generation of Colours + from diversity of Reflections are set down several Observations made in a + Darkned room</i> (<a href="#Page_186">186</a>, <a href="#Page_187">187</a>.) + </p> + <p> + Experiment <i>the second, That white Linnen seem'd Ting'd with the Red of + Silk plac'd near it in a light Room</i> (<a href="#Page_188">188</a>,<a + href="#Page_189">189</a>.) + </p> + <p> + Experiment <i>the third, Of the Trajection of Light through Colour'd + Papers</i> (<a href="#Page_189">189</a>, <a href="#Page_190">190</a>.) + </p> + <p> + Experiment <i>the fourth, Observations of a Prism in a dark Room</i> (<a + href="#Page_191">191</a>, <a href="#Page_192">192</a>.) + </p> + <p> + Experiment <i>the fifth, Of the Refracting and Reflecting Prismatical + Colours in a light Room</i> (<a href="#Page_193">193</a>.) + </p> + <p> + Experiment <i>the sixth, On the Vanishing of the</i> Iris <i>of the Prism, + upon the access of a greater adventitious Light</i> (<a href="#Page_194">194</a>.) + </p> + <p> + Experiment <i>the seventh, Of the appearances of the same Colour'd Papers + by Candle-light</i> (<a href="#Page_195">195</a>, <a href="#Page_196">196</a>). + </p> + <p> + Experiment <i>the eighth, Of the Yellowness of the Flame of a Candle</i> (<a + href="#Page_197">197</a>). + </p> + <p> + Experiment <i>the ninth, Of the Greenish Blew transparency of Leaf Gold</i> + (<a href="#Page_198">198</a>). + </p> + <p> + Experiment <i>the tenth, Of the curious Tinctures afforded by</i> Lignum + Nephriticum (from <a href="#Page_199">199</a> to <a href="#Page_203">203</a>). + <i>Several trials for the Investigation of the Nature of it</i> (from <a + href="#Page_204">204</a> to <a href="#Page_206">206</a>.) Kircher's <i>relation + of this Wood set down, and examin'd</i> (from <a href="#Page_206">206</a> + to <a href="#Page_212">212</a>). <i>A Corollary on this tenth</i> + Experiment, <i>shewing how it may be applicable for the Discovering, + whether any Salt be of an Acid, or a Sulphureous, and Alcalizate Nature</i> + (from <a href="#Page_213">213</a> to <a href="#Page_216">216</a>). + </p> + <p> + <i>The eleventh</i> Experiment, <i>Of certain pieces of Glass that + afforded this Variety of Colours; And of the way of so Tinging any Plate + of Glass with Silver</i> (from <a href="#Page_216">216</a> to <a + href="#Page_219">219</a>). + </p> + <p> + <i>The twelfth</i> Experiment, <i>Of the Mixing and Tempering of Painters + Pigments</i> (<a href="#Page_219">219</a>, <a href="#Page_220">220</a>, <a + href="#Page_221">221</a>). + </p> + <p> + <i>The thirteenth</i> Experiment, <i>Of compounding several Colours by + Trajecting the Sun-beams through Ting'd Glasses</i> (from <a + href="#Page_221">221</a> to <a href="#Page_224">224</a>). + </p> + <p> + <i>The fourteenth</i> Experiment, <i>Of the Compounding of Real and + Phantastical Colours, and the Results</i> (<a href="#Page_224">224</a>, <a + href="#Page_225">225</a>, <a href="#Page_226">226</a>.) <i>as also the + same of Phantastical Colours</i> (<a href="#Page_226">226</a>, <a + href="#Page_227">227</a>.) + </p> + <p> + <i>The fifteenth</i> Experiment, <i>Of Varying the Trajected</i> Iris <i>by + a Colour'd Prism</i> (<a href="#Page_228">228</a>, <a href="#Page_229">229</a>.) + </p> + <p> + <i>The sixteenth</i> Experiment, <i>Of the Red fumes of Spirit of</i> + Nitre, <i>and, the resembling Redness of the Horizontal Sun-beams</i> (<a + href="#Page_230">230</a>, <a href="#Page_231">231</a>.) + </p> + <p> + <i>The seventeenth</i> Experiment, <i>Of making a Green by nine Kinds of + Compositions</i> (from <a href="#Page_231">231</a> to <a href="#Page_236">236</a>.) + <i>And some Deductions from them against the necessity of recurring to + Substantial forms and Hypostatical principles for the production of + Colours</i> (from <a href="#Page_237">237</a> to <a href="#Page_240">240</a>.) + </p> + <p> + <i>The eighteenth</i> Experiment, <i>Of several Compositions of Blew and + Yellow which produce not a Green, and of the production of a Green by + other Colours</i> (<a href="#Page_241">241</a>, <a href="#Page_242">242</a>.) + </p> + <p> + <i>The nineteenth</i> Experiment, <i>contains several instances of + producing Colours, without the alteration of any Hypostatical principle, + by the Prism, Bubbles, and Feathers</i> ( from <a href="#Page_242">242</a> + to <a href="#Page_245">245</a>.) + </p> + <p> + <i>The twentieth</i> Experiment <i>Of turning the Blew of Violets into a + Red by Acid Salts, and to a Green by Alcalizate (<a href="#Page_245">245</a>, + <a href="#Page_246">246</a>.) and the use of it for Investigating the + Nature of Salts</i> (<a href="#Page_247">247</a>, <a href="#Page_248">248</a>.) + </p> + <p> + <i>The one and twentieth</i> Experiment, <i>of the same Changes effected + by the same means on the Blew Tinctures of Corn-flowers</i> (<a + href="#Page_249">249</a>, <a href="#Page_250">250</a>.) <i>And some + Restrictions to shew it not to be so general a propriety as one might + imagine</i> (<a href="#Page_251">251</a>.) + </p> + <p> + <i>The twenty second</i> Experiment, <i>of turning a Solution of + Verdigrease into a Blew, with Alcalizate and Urinous Salts</i> (<a + href="#Page_252">252</a>, <a href="#Page_253">253</a>, <a href="#Page_254">254</a>.) + </p> + <p> + <i>The twenty third</i> Experiment, <i>of taking away the Colour of Roses + with the Steams of Sulphur, and heightning them with the Steams Condens'd + into Oyl of Sulphur</i> per Campanam (<a href="#Page_254">254</a>, <a + href="#Page_255">255</a>.) + </p> + <p> + <i>The twenty fourth</i> Experiment, <i>of Tinging a great quantity of + Liquor with a very little Ting'd Substance, Instanced in</i> Cochineel + (from <a href="#Page_255">255</a> to <a href="#Page_257">257</a>.) + </p> + <p> + <i>The twenty fifth</i> Experiment, <i>of the more general use of + Alcalizate and Sulphureous Salts in the Tinctures of Vegetables, further + Instanced in the Tincture of Privet Berries, and of the Flowers of + Mesereon and Pease</i> (from <a href="#Page_257">257</a> to <a + href="#Page_259">259</a>.) <i>An</i> Annotation, <i>shewing that of the + three Hypostatical principles, Salt according to</i> Paracelsus <i>is the + most active about Colours</i> (from <a href="#Page_259">259</a> to <a + href="#Page_261">261</a>.) <i>Some things Precursory premis'd to three + several Instances next following, against the fore-mention'd Operations of + Salts</i> (<a href="#Page_261">261</a>, <a href="#Page_262">262</a>.) + </p> + <p> + <i>The twenty sixth</i> Experiment, <i>containing Trials with Acid and + Sulphureous Salts on the Red Tinctures of Clove-july-flowers, Buckthorn + Berries, Red-Roses, Brasil</i>, &c. (<a href="#Page_262">262</a>, <a + href="#Page_263">263</a>.) + </p> + <p> + <i>The twenty seventh</i> Experiment, <i>of the changes of the Colour of + Jasmin flowers, and Snow drops, by Alcalizate and Sulphureous Salts</i> (<a + href="#Page_263">263</a>, <a href="#Page_264">264</a>.) + </p> + <p> + <i>The twenty eighth</i> Experiment, <i>of other differing Effects on + Mary-golds, Prim-roses, and fresh Madder</i> (<a href="#Page_265">265</a>.) + <i>with an Admonition, that these Salts may have differing Effects in the + changing of the tinctures of divers other Vegetables</i> (<a + href="#Page_266">266</a>, <a href="#Page_267">267</a>.) + </p> + <p> + <i>The twenty ninth</i> Experiment, <i>of the differing Effects of these + Salts on Ripe and Unripe Juices, instanced in Black-berries, and the + Juices of Roses</i> (from <a href="#Page_267">267</a> to <a + href="#Page_270">270</a>.) <i>Two reasons, why the Author added this + twenty ninth</i> Experiment, <i>the last of which is confirm'd by an + Instance of Mr.</i> Parkinson, <i>consonant to the Confession of the + Makers of such Colours</i> (<a href="#Page_272">272</a>.) + </p> + <p> + <i>The thirtieth</i> Experiment, <i>of several changes in Colours by + Digestion, exemplify'd by an</i> Amalgam <i>of</i> <img + src="images/gold.png" class="noborder" width="16" height="18" alt="Gold" /> + <i>and</i> <img src="images/mercury.png" class="noborder" width="16" + height="18" alt="Mercury" /> <i>and by Spirit of Harts-horn. And (to such + as believe it) by the changes of the</i> Elixir. + </p> + <p> + <i>The thirty first</i> Experiment, <i>shewing that most Tinctures drawn + by Digestion Incline to a Red, instanc'd in</i> Jalap, Guaicum, <i>Amber, + Benzoin, Sulphur, Antimony</i>, &c. (<a href="#Page_276">276</a>, <a + href="#Page_277">277</a>.) + </p> + <p> + <i>The thirty second</i> Experiment, <i>That some Reds with Diluting turn + Yellow, others not, exemplify'd by the Tincture of</i> Cochineel, <i>and + by Balsam of</i> Sulphur, <i>Tinctures of</i> Amber, &c. (<a + href="#Page_277">277</a>, <a href="#Page_278">278</a>, <a href="#Page_279">279</a>.) + </p> + <p> + <i>The thirty third</i> Experiment, <i>of a Red Tincture of</i> Saccarum + <img src="images/lead.png" class="noborder" width="16" height="20" + alt="Saturni" /> <i>and Oyl of</i> Turpentine <i>made by Digestion</i> (<a + href="#Page_279">279</a>.) + </p> + <p> + <i>The thirty fourth</i> Experiment, <i>of drawing a Volatile red Tincture + of Mercury</i>, <i>whose Steams were white, but it would Tinge the Skin + black </i> (<a href="#Page_279">279</a>, <a href="#Page_280">280</a>.) + </p> + <p> + <i>The thirty fifth</i> Experiment, <i>of a suddain way of making a Blood + red Colour with Oyl of</i> Vitriol, <i>and Oyl of</i> Anniseeds, <i>two + transparent Liquors </i> (<a href="#Page_280">280</a>, <a href="#Page_281">281</a>.) + </p> + <p> + <i>The thirty sixth</i> Experiment, <i>of the Degenerating of several + Colours exemplify'd in the last mention'd Blood red, and by Mr.</i> + Parkinsons <i>relation of</i> Turnsol, <i>by some Trials with the Juice of + Buck-thorn Berries, and other Vegetables, to which several notable + Considerations and Advertisements back'd with</i> Experiments <i>are + adjoyn'd</i> (from <a href="#Page_281">281</a> to <a href="#Page_288">288</a>.) + </p> + <p> + <i>The thirty seventh</i> Experiment, <i>Of Varying the Colour of the + Tinctures of</i> Cochineel, <i>Red-cherries, and Brasil, with Acid and + Sulphureous Salts, and divers Considerations thereon</i> (from <a + href="#Page_288">288</a> to <a href="#Page_290">290</a>.) + </p> + <p> + <i>The thirty eighth</i> Experiment, <i>About the Red fumes of some, and + White of other distill'd Bodies, and of their Coalition for the most part + into a transparent Liquor</i> (<a href="#Page_290">290</a>, <a + href="#Page_291">291</a>.) <i>And of the various Colours of dry + Sublimations, exemplify'd with several</i> Experiments (<a href="#Page_292">292</a>, + <a href="#Page_293">293</a>, <a href="#Page_294">294</a>.) + </p> + <p> + <i>The thirty ninth</i> Experiment, <i>Of Varying the Decoction of</i> + Balaustiums <i>with Acid and Urinous Salts</i> (<a href="#Page_294">294</a>, + <a href="#Page_295">295</a>.) <i>Some</i> Annotations <i>wherein two</i> + Experiments <i>of</i> Gassendus <i>are Related, Examined, and Improv'd</i> + (from <a href="#Page_295">295</a> to <a href="#Page_302">302</a>.) + </p> + <p> + <i>The fortieth</i> Experiment, <i>Of the no less Strange than Pleasant + changes made with a Solution of Sublimate</i> (from <a href="#Page_301">301</a> + to <a href="#Page_306">306</a>.) <i>The difference between a Chymical axd + Philosophical Solution of a</i> Phænomenon (<a href="#Page_307">307</a>, + <a href="#Page_308">308</a>.) <i>The Authors Chymical Explication of the</i> + Phænomena, <i>confirm d by several</i> Experiments <i>made on</i> Mercury, + <i>with several Saline Liquors</i> (from <a href="#Page_308">308</a> to <a + href="#Page_310">310</a>.) <i>An Improvement of the fortieth</i> + Experiment, <i>by a fresh Decoction of</i> Antimony <i>in a</i> Lixivium (<a + href="#Page_311">311</a>, <a href="#Page_312">312</a>, <a href="#Page_313">313</a>.) + <i>Reflections on the tenth, twentieth, and fortieth</i> Experiments, <i>compar'd + together, shewing a way with this Tincture of Sublimate to distinguish + whether any Saline Body to be examin'd be of a Urinous or Alcalizate + Nature</i> (from <a href="#Page_314">314</a> to <a href="#Page_317">317</a>.) + <i>The Examination of Spirit of</i> Sal-armoniack, <i>and Spirit of</i> + Oak <i>by these Principles</i> (from <a href="#Page_316">316</a> to <a + href="#Page_319">319</a>.) <i>That the Author knows ways of making highly + Operative Saline bodies, that produce none of the before mention'd effects</i> + (<a href="#Page_319">319</a>, <a href="#Page_320">320</a>.) <i>Some + notable</i> Experiments <i>about Solutions and Precipitations of Gold and + Silver</i> (<a href="#Page_320">320</a>, <a href="#Page_321">321</a>.) + </p> + <p> + <i>The one and fortieth</i> Experiment, <i>Of Depriving a deep Blew + Solution of Copper of its Colour</i> (<a href="#Page_322">322</a>.) <i>to + which is adjoyn'd the Discolouring or making Transparent a Solution of + Verdigrease, &c. and another of Restoring or Increasing it</i> (<a + href="#Page_322">322</a>, <a href="#Page_323">323</a>.) + </p> + <p> + <i>The forty second</i> Experiment, <i>Of changing a Milk white + Precipitate of</i> Mercury <i>into a Yellow, by Affusion of fair Water, + with several Considerations thereon</i> (from <a href="#Page_323">323</a> + to <a href="#Page_326">326</a>.) + </p> + <p> + <i>The forty third</i> Experiment, <i>Of Extracting a Green Solution with + fair Water out of imperfectly Calcin'd Vitriol</i> (<a href="#Page_327">327</a>.) + </p> + <p> + <i>The forty fourth</i> Experiment, <i>Of the Deepning and Diluting of + several Tinctures, by the Affusions of Liquors, and by Conical Glasses + that contain'd them, Exemplify'd in the Tinctures of</i> Cochineel, + Brasil, Verdigrease, Glass, Litmus, <i>of which last on this occasion + several pleasant</i> Phænomena <i>are related</i> (from <a href="#Page_328">328</a> + to <a href="#Page_335">335</a>.) <i>To which are adjoyn'd certain + Cautional Corollaries </i> (<a href="#Page_335">335</a>, <a + href="#Page_336">336</a>.) <i>The Waterdrinker and some of his Legerdemain + tricks related.</i>(<a href="#Page_337">337</a>.) + </p> + <p> + <i>The forty fifth</i> Experiment, <i>Of the turning Rhenish and White + Wine into a lovely Green, with a preparation of Steel </i>(<a + href="#Page_338">338</a>, <a href="#Page_339">339</a>.) <i>Some further + Trial made about these Tinctures, and a Similar</i> Experiment <i>of</i> + Olaus Wormius (<a href="#Page_340">340</a>.) + </p> + <p> + <i>The forty sixth</i> Experiment, <i>Of the Internal Colour of Metalls + exhibited by Calcination</i> (<a href="#Page_341">341</a>, <a + href="#Page_342">342</a>, <a href="#Page_343">343</a>.) Annotation <i>the + first, That several degrees of Fire may disclose a differing Colour</i> (<a + href="#Page_343">343</a>.) Annotation <i>the second, That the Glasses of + Metalls may exhibit also other Kinds of Colours</i> (<a href="#Page_344">344</a>.) + Annotation <i>the third, That Minerals by several degrees of Fire may + disclose several Colours</i>(<a href="#Page_345">345</a>). + </p> + <p> + Experiment <i>the forty seventh, Of the Internal Colours of Metalls + disclos'd by their Dissolutions in several</i> Menstruums (from <a + href="#Page_345">345</a> to <a href="#Page_350">350</a>.) Annotation <i>the + first, The Authors Apology for Recording some already known</i> + Experiments, <i>without mentioning their Authors</i> (from <a + href="#Page_350">350</a> to <a href="#Page_352">352</a>.) Annotation <i>the + second, That some Minerals also by Dissolutions in</i> Menstruums <i>may + exhibit divers Colours</i>. Annotation <i>the third, That Metalls disclose + other Colours by Precipitations, instanc'd in</i> Mercury (from <a + href="#Page_353">353</a> to <a href="#Page_355">355</a>.) + </p> + <p> + <i>The forty eighth</i> Experiment, <i>Of Tinging Glass Blew with Leaf + Silver, and with Calcin'd Copper, and White with Putty</i> (from <a + href="#Page_355">355</a> to <a href="#Page_358">358</a>.) Annotation <i>the + first, That this white Glass is the Basis of Ammels</i> (<a + href="#Page_358">358</a>.) Annotion <i>the second, That Colour'd Glasses + may be Compounded like Colour'd Liquors in Dying Fats</i> (<a + href="#Page_359">359</a>.) Annotation <i>the third, Of Tinging Glass with + Minerel Substances, and of trying what Metalls they contain by this means</i> + (from <a href="#Page_360">360</a> to <a href="#Page_362">362</a>.) + Annotation <i>the fourth, That Metalls may be Ting'd by Mineralls</i> (<a + href="#Page_362">362</a>, <a href="#Page_363">363</a>.) Annotation <i>the + fifth, Of making several Kinds of Amauses or Counterfeit Stones</i> (from + <a href="#Page_363">363</a> to <a href="#Page_365">365</a>.) Annotation <i>the + sixth, Of the Scarlet Dye, of the Stains of dissolv'd Gold and Silver</i> + (<a href="#Page_366">366</a>, <a href="#Page_367">367</a>) <i>Of the + Greenness of Salt Beef, and Redness of Neats Tongues from Salts; of + Gilding Silver with Bathe Water</i> (<a href="#Page_368">368</a>, <a + href="#Page_369">369</a>.) <i>And Tinging the Nails and Skin with</i> + Alcanna (<a href="#Page_369">369</a>) + </p> + <p> + <i>The forty ninth</i> Experiment, <i>Of making Lakes</i> (<a + href="#Page_369">369</a>.) <i>A particular example in Turmerick</i> (<a + href="#Page_370">370</a>, <a href="#Page_371">371</a>.) Annotation <i>the + first, That in Precipitations wherein Allum is a Coefficient, a great part + of them may consist of the Stony particles of that Compound Body</i> (from + <a href="#Page_372">372</a> to <a href="#Page_375">375</a>.) Annotation <i>the + second, That Lakes may be made of other Substances, as Madder, Rue,</i> + &c. <i>but that Alcalizate Salts do not Always Extract the same Colour + of which the Vegetable appears</i> (from <a href="#Page_376">376</a> to <a + href="#Page_378">378</a>.) Annotation <i>the third, That the</i> + Experiments <i>related may Hint divers others</i> (<a href="#Page_378">378</a>) + Annotation <i>the fourth, That Alum is usefull for the preparing other + than Vegetable Pigments</i> (<a href="#Page_379">379</a>.) + </p> + <p> + <i>The fiftieth</i> Experiment, <i>Of the Similar effects of</i> Saccarum + <img src="images/lead.png" class="noborder" width="16" height="20" + alt="Saturni" /> <i>and</i> Alkalies, <i>of Precipitating with Oyl of</i> + Vitriol <i>out of</i> Aqua-fortis, <i>and Spirit of</i> Vinegar; <i>and of + divers Varyings of the Colours, with these Compounded</i> (from <a + href="#Page_380">380</a> to <a href="#Page_384">384</a>.) <i>Another very + pretty</i> Experiment, <i>with a Solution of</i> Minium (<a + href="#Page_384">384</a>, <a href="#Page_385">385</a>.) <i>That these</i> + Experiments <i>Skilfully digested may hint divers matters about Colours</i> + (<a href="#Page_386">386</a>.) <i>The Authors Apologetick conclusion, in + which is Cursorily hinted the Bow or Scarlet Dye</i> (<a href="#Page_387">387</a>.) + <i>The Authors Letter to Sir</i> Robert Moray, <i>concerning his + Observations on the Shining Diamond</i> (<a href="#Page_391">391</a>. + &c.) <i>And the Observations themselves</i>. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/039b.png" alt="Decorative rule" /> + </div> + <!-- Page 1 --> + <p> + <span class="pagenum"><a name="Page_1" id="Page_1"></a>[pg 1]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/040a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>EXPERIMENTAL HISTORY</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>OF COLOURS BEGUN.</i></span><br /> + </h2> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE FIRST PART.</i></span><br /> + </h2> + <h2> + <span style="font-size:75%; letter-spacing:6px">CHAP. I.</span><br /> + </h2> + <table> + <tr> + <td valign="top"> + 1 + </td> + <td> + <img width="80" height="80" src="images/040b.png" alt="Illuminated I" /> + </td> + </tr> + </table> + <p> + have seen you so passionately addicted, <i>Pyrophilus</i> to the + delightful Art of Limning and Painting, that I cannot but think my self + obliged to acquaint you with some of those things that have occurred to + mee concerning the changes of Colours. And I may expect that I shall as + well serve the <i>Virtuosi</i> in general, as gratifie you in particular, + by furnishing a person, who, I hope, will both improve my Communications, + and communicate his Improvements, with such Experiments and Observations + as may both invite you to enquire seriously into the Nature of Colours, + and assist you in the Investigation of it. This being the principal scope + of the following Tract, I should do that which might prevent my own + design, + <!-- Page 2 --> <span class="pagenum"><a name="Page_2" id="Page_2"></a>[pg + 2]</span> if I should here attempt to deliver you an accurate and + particular Theory of Colours; for that were to present you with what I + desire to receive from you; and, as farr as in mee lay, to make that study + needless, to which I would engage you. + </p> + <p> + 2 Wherefore my present work shall be but to divert and recreate, as well + as excite you by the delivery of matters of fact, such as you may for the + most part try with much <i>ease</i>, and possibly not without some <i>delight</i>: + And lest you should expect any thing of Elaborate or Methodical in what + you will meet with here, I must confess to you before-hand, that the + seasons I was wont to chuse to devise and try Experiments about Colours, + were those daies, wherein having taken Physick, and finding my self as + unfit to speculate, as unwilling to be altogether idle, I chose this + diversion, as a kind of Mean betwixt the one and the other. And I have the + less scrupled to set down the following Experiments, as some of them came + to my mind, and as the Notes wherein I had set down the rest, occurr'd to + my hands, that by declining a Methodical way of delivering them, I might + leave you and my self the greater liberty and convenience to add to them, + and transpose them as shall appear expedient. + <!-- Page 3 --> <span class="pagenum"><a name="Page_3" id="Page_3"></a>[pg + 3]</span> + </p> + <p> + 3 Yea, that you may not think mee too reserv'd, or look upon an Enquiry + made up of meer Narratives, as somewhat jejune, am content to <i>premise</i> + a few considerations, that now offer themselves to my thoughts, which + relate in a more general way, either to the Nature of Colours, or to the + study of it. And I shall <i>insert</i> an <i>Essay</i>, as well + Speculative as Historical, of the Nature of Whiteness and Blackness, that + you may have a <i>Specimen</i> of the History of Colours, I have sometimes + had thoughts of; and if you dislike not the Method I have made use of, I + hope, you, and some of the <i>Virtuosi</i>, your friends, may be thereby + invited to go thorow with <i>Red, Blew, Yellow</i>, and the rest of the + particular Colours, as I have done with <i>White</i> and <i>Black</i>, but + with farr more sagacity and success. And if I can invite Ingenious men to + undertake such Tasks, I doubt not but the Curious will quickly obtain a + better Account of Colours, than as yet we have, since in our Method the + Theorical part of the Enquiry being attended, and as it were interwoven + with the Historical, whatever becomes of the disputable Conjectures, the + Philosophy of Colours will be promoted by the indisputable Experiments. + </p> + <!-- Page 4 --> + <p> + <span class="pagenum"><a name="Page_4" id="Page_4"></a>[pg 4]</span> + </p> + <hr /> + <h3> + CHAP. II. + </h3> + <p> + 1 To come then in the first place to our more general Considerations, I + shall begin with saying something as to the Importance of examining the + Colours of Bodies. For there are some, especially <i>Chymists</i>, who + think, that a considerable diversity of Colours does constantly argue an + equal diversity of Nature, in the Bodies wherein it is conspicuous; but I + confess I am not altogether of their mind; for not to mention changeable + Taffaties, the blew and golden necks of Pidgeons, and divers Water-fowl, + Rainbows Natural and Artificial, and other Bodies, whose Colours the + Philosophers have been pleased to call not Real, but Apparent and + Phantastical; not to insist on these, I say, (for fear of needlesly + engaging in a Controversie) we see in Parrots, Goldfinches, and divers + other Birds, not only that the contiguous feathers which are probably as + near in properties as place, are some of them Red, and others White, some + of them Blew, & others Yellow, <i>&c.</i> but that in the several + parts of the self-same feather there may often be seen the greatest + disparity of Colours; and so in the leaves of Tulips, July-flowers, and + some other Vegetables + <!-- Page 5 --> <span class="pagenum"><a name="Page_5" id="Page_5"></a>[pg + 5]</span> the several leaves, and even the several parts of the same leaf, + although no difference have been observed in their other properties, are + frequently found painted with very different Colours. And such a variety + we have much more admired in that lovely plant which is commonly, and not + unjustly call'd the <i>Marvayl of Peru</i>; for of divers scores of fine + Flowers, which in its season that gaudy Plant does almost daily produce, I + have scarce taken notice of any two that were dyed perfectly alike. But + though <i>Pyro</i>: such things as these, among others, keep mee from + daring to affirm, that the Diversity and change of Colours does <i>alwaies</i> + argue any great difference or alteration, betwixt, or in, the Bodies, + wherein it is to be discerned, yet that <i>oftentimes</i> the Alteration + of Colours does signifie considerable Alterations in the disposition of + parts of Bodies, may appear in the Extraction of Tinctures, and divers + other Chymical Operations, wherein the change of Colours is the chief, and + sometimes the only thing, by which the Artist regulates his proceeding, + and is taught to know when 'tis seasonable for him to leave off. Instances + of this sort are more obvious in divers sorts of fruits, as Cherries, + Plums, &c. wherein, according as the Vegetable sap is sweetned, or + otherwise + <!-- Page 6 --> <span class="pagenum"><a name="Page_6" id="Page_6"></a>[pg + 6]</span> ripened, by passing from one degree to another of Maturation, + the external part of the fruit passes likewise from one to another Colour. + But one of the noblest Instances I have met with of this kind, is not so + obvious; and that is the way of tempering Steel to make Gravers, Drills, + Springs, and other Mechanical Instruments, which we have divers times both + made Artificers practise in our presence, and tryed our selves, after the + following manner, First, the slender Steel to be tempered is to be + hardened by heating as much of it as is requisite among glowing Coals, + till it be glowing hot, but it must not be quenched assoon as it is taken + from the fire (for that would make it too brittle, and spoil it) but must + be held over a bason of water, till it descend from a White heat to a Red + one, which assoon as ever you perceive, you must immediately quench as + much as you desire to harden in the cold water. The Steel thus hardened, + will, if it be good, look somewhat White and must be made bright at the + end, that its change of Colours may be there conspicuous; and then holding + it so in the flame of a Candle, that the bright end may be, for about half + an inch, or more, out of the flame, that the smoak do not stain or sully + the brightness of it, you shall after a + <!-- Page 7 --> <span class="pagenum"><a name="Page_7" id="Page_7"></a>[pg + 7]</span> while see that clean end, which is almost contiguous to the + flame, pass very nimbly from one Colour to another, as from a brighter + Yellow, to a deeper and reddish Yellow, which Artificers call a <i>sanguine</i>, + and from that to a fainter first, and then a a deeper Blew. And to bring + home this Experiment to our present purpose, it is found by daily + Experience, that each of these succeeding Colours argue such a change made + in the texture of the Steel, that if it be taken from the flame, and + immediately quenched in the tallow (whereby it is setled in whatever + temper it had before) when it is Yellow, it is of such a hardness as makes + it fit for Gravers Drills, and such like tools; but if it be kept a few + minutes longer in the flame till it grow Blew, it becomes much softer, and + unfit to make Gravers for Metalls, but fit to make Springs for Watches, + and such like Instruments, which are therefore commonly of that Colour; + and if the Steel be kept in the flame, after that this deep Blew hath + disclosed it self, it will grow so soft, as to need to be new hardened + again, before it can be brought to a temper, fit for Drills or Penknives. + And I confess <i>Pyro.</i> I have taken much pleasure to see the Colours + run along from the parts of the Steel contiguous to the flame, to the end + of the Instrument, + <!-- Page 8 --> <span class="pagenum"><a name="Page_8" id="Page_8"></a>[pg + 8]</span> and succeed one another so fast, that if a man be not vigilant, + to thrust the Steel into the tallow at the very nick of time, at which it + has attain'd its due Colour, he shall miss of giving his tool the right + temper. But because the flame of a Candle is offensive to my weak eyes, + and because it is apt to either black or sully the contiguous part of the + Steel which is held in it, and thereby hinder the change of Colours from + being so long and clearly discern'd, I have sometimes made this Experiment + by laying the Steel to be tempered upon a heated bar of Iron, which we + finde also to be employ'd by some Artificers in the tempering of such + great Instruments, as are too big to be soon heated sufficiently by the + flame of a Candle. And you may easily satisfie your self <i>Pyro</i>: of + the differing hardness and toughness, which is ascribed to Steel temper'd + at different Colours, if you break but some slender wires of Steel so + temper'd, and observe how they differ in brittleness, and if with a file + you also make tryal of their various degrees of hardness. + </p> + <p> + 2 But <i>Pyrophilus</i>, I must not at present any further prosecute the + Consideration of the importance of Experiments about Colours, not only + because you will in the following papers finde some instances, that would + here + <!-- Page 9 --> <span class="pagenum"><a name="Page_9" id="Page_9"></a>[pg + 9]</span> be presented you out of their due place, of the use that may be + made of such Experiments, in discovering in divers bodies, what kind the + salt is, that is predominant in them; but also because a speculative + Naturalist might justly enough allege, that as Light is so pleasing an + object, as to be well worth our looking on, though it discover'd to us + nothing but its self; so modifi'd Light called Colour, were worth our + contemplation, though by understanding its Nature we should be taught + nothing else. And however, I need not make either you or my self excuses + for entertaining you on the subject I am now about to treat of, since the + pleasure <i>Pyro</i>: takes in mixing and laying on of Colours, will I + presume keep him, and will (I am sure) keep mee from thinking it + troublesome to set down, especially after the tedious processes (about + other matters) wherewith I fear I may have tyr'd him, some easie, and not + unpleasant Experiments relating to that subject. + </p> + <p> + 3 But, before we descend to the more particular considerations, we are to + present you concerning Colours, I presume it will be seasonable to propose + at the very entrance a Distinction; the ignorance or neglect of which, + seems to mee to have frequently enough occasioned either mistakes or + confusion + <!-- Page 10 --> <span class="pagenum"><a name="Page_10" id="Page_10"></a>[pg + 10]</span> in the Writings of divers Modern Philosophers; for Colour may + be considered, either as it is a quality residing in the body that is said + to be coloured, or to modifie the light after such or such a manner; or + else as the Light it self, which so modifi'd, strikes upon the organ of + sight, and so causes that Sensation which we call Colour; and that this + latter may be look'd upon as the more proper, though not the usual + acception of the word Colour, will be made probable by divers passages in + the insuing part of our discourse; and indeed it is the Light it self, + which after a certain manner, either mingled with shades, or some other + waies troubled, strikes our eyes, that does more immediately produce that + motion in the organ, upon whose account men say they see such or such a + Colour in the object; yet, because there is in the body that is said to be + coloured, a certain disposition of the superficial particles, whereby it + sends the Light reflected, or refracted, to our eyes thus and thus + alter'd, and not otherwise, it may also in some sense be said, that Colour + depends upon the visible body; and therefore we shall not be against that + way of speaking of Colours that is most used among the Modern Naturalists, + provided we be allowed to have recourse when occasion shall + <!-- Page 11 --> <span class="pagenum"><a name="Page_11" id="Page_11"></a>[pg + 11]</span> require to the premis'd distinction, and to take the more + immediate cause of Colour to be the modifi'd Light it self, as it affects + the Sensory; though the disposition also of the colour'd body, as that + modifies the Light, may be call'd by that name Metonimically (to borrow a + School term) or Efficiently, that is in regard of its turning the Light, + that rebounds from it, or passes thorow it, into this or that particular + Colour. + </p> + <p> + 4 I know not whether I may not on this occasion add, that Colour is so far + from being an Inherent quality of the object in the sense that is wont to + be declar'd by the Schools, or even in the sense of some Modern Atomists, + that, if we consider the matter more attentively, we shall see cause to + suspect, if not to conclude, that though Light do more immediately affect + the organ of sight, than do the bodies that send it thither, yet Light it + self produces the sensation of a Colour, but as it produces such a + determinate kind of local motion in some part of the brain; which, though + it happen most commonly from the motion whereinto the slender strings of + the <i>Retina</i> are put, by the appulse of Light, yet if the like motion + happen to be produc'd by any other cause, wherein the Light concurrs not + at + <!-- Page 12 --> <span class="pagenum"><a name="Page_12" id="Page_12"></a>[pg + 12]</span> all, a man shall think he sees the same Colour. For proof of + this, I might put you in mind, that 'tis usual for dreaming men to think + they see the Images that appear to them in their sleep, adorn'd some with + this, and some with that lively Colour, whilst yet, both the curtains of + their bed, and those of their eyes are close drawn. And I might add the + confidence with which distracted persons do oftentimes, when they are + awake, think, they see black fiends in places, where there is no black + object in sight without them. But I will rather observe, that not only + when a man receives a great stroak upon his eye, or a very great one upon + some other part of his head, he is wont to see, as it were, flashes of + lightning, and little vivid, but vanishing flames, though perhaps his eyes + be shut: But the like apparitions may happen, when the motion proceeds not + from something without, but from something within the body, provided the + unwonted fumes that wander up and down in the head, or the propagated + concussion of any internal part in the body, do cause about the inward + extremities of the Optick Nerve, such a motion as is wont to be there + produc'd, when the stroak of the Light upon the <i>Retina</i> makes us + conclude, that we see either Light, or such and such a + <!-- Page 13 --> <span class="pagenum"><a name="Page_13" id="Page_13"></a>[pg + 13]</span> Colour: This the most ingenious <i>Des Cartes</i> hath very + well observ'd, but because he seems not to have exemplifi'd it by any + unobvious or peculiar observation, I shall indeavour to illustrate this + doctrine by a few Instances. + </p> + <p> + 5 And first, I remember, that having, through Gods goodness, been free for + several years, from troublesome Coughs, being afterwards, by an accident, + suddenly cast into a violent one, I did often, when I was awaked in the + night by my distempers, observe, that upon coughing strongly, it would + seem to mee, that I saw very vivid, but immediately disappearing flames, + which I took particular notice of, because of the conjecture I am now + mentioning. + </p> + <p> + 6 An excellent and very discreet person, very near ally'd both to you and + mee, was relating to mee, that some time since, whilst she was talking + with some other Ladies, upon a sudden, all the objects, she looked upon, + appeared to her dyed with unusual Colours, some of one kind, and some of + another, but all so bright and vivid, that she should have been as much + delighted, as surpriz'd with them, but that finding the apparition to + continue, she fear'd it portended some very great alteration as to her + health: As indeed the day after she was assaulted + <!-- Page 14 --> <span class="pagenum"><a name="Page_14" id="Page_14"></a>[pg + 14]</span> with such violence by Hysterical and Hypocondrical Distempers, + as both made her rave for some daies, and gave her, during that time, a + Bastard Palsey. + </p> + <p> + 7 Being a while since in a Town, where the Plague had made great havock, + and inquiring of an ingenious man, that was so bold, as without much + scruple to visit those that were sick of it, about the odd symptomes of a + Disease that had swept away so many there; he told mee, among other + things, that he was able to tell divers Patients, to whom he was called, + before they took their beds, or had any evident symptomes of the Plague, + that they were indeed infected upon peculiar observations, that being + asked, they would tell him that the neighbouring objects, and particularly + his cloths, appear'd to them beautifi'd with most glorious Colours, like + those of the Rainbow, oftentimes succeeding one another; and this he + affirm'd to be one of the most usual, as well as the most early symptomes, + by which this odd Pestilence disclos'd it self: And when I asked how long + the Patients were wont to be thus affected, he answered, that it was most + commonly for about a day; and when I further inquired whether or no + Vomits, which in that Pestilence were usually given, did not remove this + symptome + <!-- Page 15 --> <span class="pagenum"><a name="Page_15" id="Page_15"></a>[pg + 15]</span> (For some used the taking of a Vomit, when they came ashore, to + cure themselves of the obstinate and troublesome giddiness caus'd by the + motion of the ship) reply'd, that generally, upon the evacuation made by + the Vomit, that strange apparition of Colours ceased, though the other + symptomes were not so soon abated, yet he added (to take notice of that + upon the by, because the observation may perchance do good) that an + excellent Physician, in whose company he was wont to visit the sick, did + give to almost all those to whom he was called, in the beginning before + Nature was much weakened, a pretty odd Vomit consisting of eight or ten + dramms of Infusion of <i>Crocus Metallorum</i>, and about half a dramm, or + much more, of White Vitriol, with such success, that scarce one of ten to + whom it was seasonably administred, miscarried. + </p> + <p> + 8 But to return to the consideration of Colours: As an apparition of them + may be produced by motions from within, without the assistance of an + outward object, so I have observed, that 'tis sometimes possible that the + Colour that would otherwise be produced by an outward object, may be + chang'd by some motion, or new texture already produced in the Sensory, as + long as that unusual motion, or new disposition + <!-- Page 16 --> <span class="pagenum"><a name="Page_16" id="Page_16"></a>[pg + 16]</span> lasts; for I have divers times try'd, that after I have through + a Telescope look'd upon the Sun, though thorow a thick, red, or blew + glass, to make its splendor supportable to the eye, the impression upon + the <i>Retina</i>, would be not only so vivid, but so permanent, that if + afterwards I turned my eye towards a flame, it would appear to mee of a + Colour very differing from its usual one. And if I did divers times + successively shut and open the same eye, I should see the adventitious + Colour, (if I may so call it) changed or impair'd by degrees, till at + length (for this unusual motion of the eye would not presently cease) the + flame would appear to mee, of the same hew that it did to other beholders; + a not unlike effect I found by looking upon the Moon, when she was near + full, thorow an excellent Telescope, without colour'd Glass to screen my + eye with; But that which I desire may be taken notice of, because we may + elsewhere have occasion to reflect upon it, and because it seems not + agreeable to what Anatomists and Optical Writers deliver, touching the + relation of the two eyes to each other, is this circumstance, that though + my Right eye, with which I looked thorow the Telescope, were thus affected + by the over-strong impression of the light, yet when the flame + <!-- Page 17 --> <span class="pagenum"><a name="Page_17" id="Page_17"></a>[pg + 17]</span> of a Candle, or some other bright object appear'd to me of a + very unusual Colour, whilst look'd upon with the Discompos'd Eye, or + (though not so notably) with both eyes at once; yet if I shut that Eye, + and looked upon the same object with the other, it would appear with no + other than its usual Colour, though if I again opened, and made use of the + Dazled eye, the vivid adventitious Colour would again appear. And on this + occasion I must not pretermit an Observation which may perswade us, that + an over-vehement stroak upon the Sensory, especially if it be naturally of + a weak constitution, may make a more lasting impression than one would + imagine, which impression may in some cases, as it were, mingle with, and + vitiate the action of vivid objects for a long time after. + </p> + <p> + For I know a Lady of unquestionable Veracity, who having lately, by a + desperate fall, receiv'd several hurts, and particularly a considerable + one upon a part of her face near her Eye, had her sight so troubl'd and + disorder'd, that, as she hath more than once related to me, not only when + the next morning one of her servants came to her bed side, to ask how she + did, his cloaths appear'd adorn'd with such variety of dazling Colours, + that she was fain presently to + <!-- Page 18 --> <span class="pagenum"><a name="Page_18" id="Page_18"></a>[pg + 18]</span> command him to withdraw, but the Images in her Hangings, did, + for many daies after, appear to her, if the Room were not extraordinarily + darken'd, embellish'd with several offensively vivid Colours, which no + body else could see in them; And when I enquir'd whether or no White + Objects did not appear to her adorn'd with more luminous Colours than + others, and whether she saw not some which she could not now well describe + to any, whose eyes had never been distemper'd, she answer'd mee, that + sometimes she thought she saw Colours so new and glorious, that they were + of a peculiar kind, and such as she could not describe by their likeness + to any she had beheld either before or since, and that White Objects did + so much disorder her sight, that if several daies after her fall, she + look'd upon the inside of a Book, she fanci'd she saw there Colours like + those of the Rain-bow, and even when she thought her self pretty well + recover'd, and made bold to leave her Chamber, the coming into a place + where the Walls and Ceeling were whited over, made those Objects appear to + her cloath'd with such glorious and dazling Colours, as much offended her + sight, and made her repent her venturousness, and she added, that this + Distemper of her Eyes lasted no less + <!-- Page 19 --> <span class="pagenum"><a name="Page_19" id="Page_19"></a>[pg + 19]</span> than five or six weeks, though, since that, she hath been able + to read and write much without finding the least Inconvenience in doing + so. I would gladly have known, whether if she had shut the Injur'd Eye, + the <i>Phænomena</i> would have been the same, when she employ'd only the + other, but I heard not of this accident early enough to satisfie that + Enquiry. + </p> + <p> + 9 Wherefore, I shall now add, that some years before, a person exceedingly + eminent for his profound Skil in almost all kinds of Philological + Learning, coming to advise with mee about a Distemper in his Eyes, told + me, among other Circumstances of it, that, having upon a time looked too + fixedly upon the Sun, thorow a Telescope, without any coloured Glass, to + take off from the dazling splendour of the Object, the excess of Light did + so strongly affect his Eye, that ever since, when he turns it towards a + Window, or any White Object, he fancies, he seeth a Globe of Light, of + about the bigness the Sun then appeared of to him, to pass before his + Eyes: And having Inquir'd of him, how long he had been troubled with this + Indisposition, he reply'd, that it was already nine or ten years, since + the Accident, that occasioned it, first befel him. + </p> + <!-- Page 20 --> + <p> + <span class="pagenum"><a name="Page_20" id="Page_20"></a>[pg 20]</span> + </p> + <p> + I could here subjoyn, <i>Pyrophilus</i>, some memorable Relations that I + have met with in the Account given us by the experienc'd <i>Epiphanius + Ferdinandus</i>, of the Symptomes he observ'd to be incident to those that + are bitten with the Tarantula, by which (Relations) I could probably shew, + that without any change in the Object, a change in the Instruments of + Vision may for a great while make some Colours appear Charming, and make + others Provoking, and both to a high degree, though neither of them + produc'd any such Effects before. These things, I say, I could here + subjoyn in confirmation of what I have been saying, to shew, that the + Disposition of the Organ is of great Importance in the Dijudications we + make of Colours, were it not that these strange Stories belonging more + properly to another Discourse, I had rather, (contenting my self to have + given you an Intimation of them here) that you should meet with them fully + deliver'd there. + </p> + <hr /> + <h3> + CHAP. III. + </h3> + <p> + But, <i>Pyrophilus</i>, I would not by all that I have hitherto + discours'd, be thought to have forgotten the Distinction + <!-- Page 21 --> <span class="pagenum"><a name="Page_21" id="Page_21"></a>[pg + 21]</span> (of Colour) that I mentioned to you about the beginning of the + third Section of the former Chapter; and therefore, after all I have said + of Colour, as it is modifi'd Light, and immediately affects the Sensory, I + shall now re-mind you, that I did not deny, but that Colour might in some + sense be consider'd as a Quality residing in the body that is said to be + Colour'd, and indeed the greatest part of the following Experiments referr + to Colour principally under that Notion, for there is in the bodyes we + call Colour'd, and chiefly in their Superficial parts, a certain + disposition, whereby they do so trouble the Light that comes from them to + our Eye, as that it there makes that distinct Impression, upon whose + Account we say, that the Seen body is either White or Black, or Red or + Yellow, or of any one determinate Colour. But because we shall (God + permiting) by the Experiments that are to follow some Pages hence, more + fully and particularly shew, that the Changes, and consequently in divers + places the Production and the appearance of Colours depends upon the + continuing or alter'd Texture of the Object, we shall in this place + intimate (and that too but as by the way) two or three things about this + Matter. + </p> + <p> + 2. And first it is not without some Reason, + <!-- Page 22 --> <span class="pagenum"><a name="Page_22" id="Page_22"></a>[pg + 22]</span> that I ascribe Colour (in the sense formerly explan'd) <i>chiefly</i> + to the Superficial parts of Bodies, for not to question how much Opacous + Corpuscles may abound even in those Bodies we call Diaphanous, it seems + plain that of Opacous bodies we do indeed see little else than the + Superficies, for if we found the beams of Light that rebound from the + Object to the Eye, to peirce deep into the Colour'd body, we should not + judge it Opacous, but either Translucid, or at least Semi-diaphanous, and + though the Schools seem to teach us that Colour is a Penetrative Quality, + that reaches to the Innermost parts of the Object, as if a piece of + Sealing-wax be broken into never so many pieces, the Internal fragments + will be as Red as the External surface did appear, yet that is but a + Particular Example that will not overthrow the Reason lately offer'd, + especially since I can alleage other Examples of a contrary Import, and + two or three Negative Instances are sufficient to overthrow the Generality + of a Positive Rule, especially if that be built but upon One or a Few + Examples. Not (then) to mention Cherries, Plums, and I know not how many + other Bodies, wherein the skin is of one Colour, and what it hides of + another, I shall name a couple of Instances drawn from the Colours + <!-- Page 23 --> <span class="pagenum"><a name="Page_23" id="Page_23"></a>[pg + 23]</span> of Durable bodies that are thought far more Homogeneous, and + have not parts that are either Organical, or of a Nature approaching + thereunto. + </p> + <p> + 3 To give you the first Instance, I shall need but to remind you of what I + told you a little after the beginning of this Essay, touching the Blew and + Red and Yellow, that may be produc'd upon a piece of temper'd Steel, for + these Colours though they be very Vivid, yet if you break the Steel they + adorn, they will appear to be but Superficial; not only the innermost + parts of the Metall, but those that are within a hairs breadth of the + Superficies, having not any of these Colours, but retaining that of the + Steel it self. Besides that, we may as well confirm this Observation, as + some other particulars we elsewhere deliver concerning Colours, by the + following Experiment which we purposely made. + </p> + <p> + 4 We took a good quantity of clean Lead, and melted it with a strong Fire, + and then immediately pouring it out into a clean Vessel of a convenient + shape and matter, (we us'd one of Iron, that the great and sudden Heat + might not injure it) and then carefully and nimbly taking off the Scum + that floated on the top, we perceiv'd, as we expected, the smooth and + <!-- Page 24 --> <span class="pagenum"><a name="Page_24" id="Page_24"></a>[pg + 24]</span> glossie Surface of the melted matter, to be adorn'd with a very + glorious Colour, which being as Transitory as Delightfull, did almost + immediately give place to another vivid Colour, and that was as quickly + succeeded by a third, and this as it were chas'd away by a fourth, and so + these wonderfully vivid Colours successively appear'd and vanish'd, (yet + the same now and then appearing the second time) till the Metall ceasing + to be hot enough to afford any longer this pleasing Spectacle, the Colours + that chanc'd to adorn the Surface, when the Lead thus began to cool, + remain'd upon it; but were so Superficial, that how little soever we + scrap'd off the Surface of the Lead, we did in such places scrape off all + the Colour, and discover only that which is natural to the Metall it self, + which receiving its adventitious Colours, only when the heat was very + Intense, and in that part which was expos'd to the comparatively very cold + Air, (which by other Experiments seems to abound with subtil Saline parts, + perhaps not uncapable of working upon Lead so dispos'd:) These things I + say, together with my observing that whatever parts of the so strongly + melted Lead were expos'd a while to the Air, turn'd into a kind of Scum or + Litharge, + <!-- Page 25 --> <span class="pagenum"><a name="Page_25" id="Page_25"></a>[pg + 25]</span> how bright and clean soever they appear'd before, suggested to + me some Thoughts or Ravings, which I have not now time to acquaint You + with. One that did not know me, <i>Pyrophilus</i>, would perchance think I + endeavour'd to impose upon You by relating this Experiment, which I have + several times try'd, but the Reason why the <i>Phænomena</i> mention'd + have not been taken notice of, may be, that unless Lead be brought to a + much higher degree of Fusion or Fluidity than is usual, or than is indeed + requisite to make it melt, the <i>Phænomena</i> I mention'd will scarce at + all disclose themselves; And we have also observ'd that this successive + appearing and vanishing of vivid Colours, was wont to be impair'd or + determin'd whilst the Metal expos'd to the Air remain'd yet hotter than + one would readily suspect. And one thing I must further Note, of which I + leave You to search after the Reason, namely, that the same Colours did + not always and regularly succeed one another, as is usually in Steel, but + in the diversify'd Order mention'd in this following Note, which I was + scarce able to write down, the succession of the Colours was so very + quick, whether that proceeded from the differing degrees of Heat in the + Lead expos'd to the cool Air, or from some + <!-- Page 26 --> <span class="pagenum"><a name="Page_26" id="Page_26"></a>[pg + 26]</span> other Reason, I leave you to examine. + </p> + <blockquote> + <p> + [<i>Blew, Yellow, Purple, Blew; Green, Purple, Blew, Yellow, Red; + Purple, Blew, Yellow and Blew, Yellow, Blew, Purple, Green mixt, Yellow, + Red, Blew, Green, Yellow, Red, Purple, Green</i>.] + </p> + </blockquote> + <p> + 5. The <i>Atomists</i> of Old, and some Learned men of late, have + attempted to explicate the variety of Colours in Opacous bodies from the + various Figures of their Superficial parts; the attempt is Ingenious, and + the Doctrine seems partly True, but I confess I think there are divers + other things that must be taken in as concurrent to produce those + differing forms of Asperity, whereon the Colours of Opacous bodies seem to + depend. To declare this a little, we must assume, that the Surfaces of all + such Bodies how Smooth or polite soever they may appear to our Dull Sight + and Touch, are exactly smooth only in a popular, or at most in a Physical + sense, but not in a strict and rigid sense. + </p> + <p> + 6. This, excellent <i>Microscopes</i> shew us in many Bodies, that seem + Smooth to our naked Eyes; and this not only as to the little Hillocks or + Protuberancies that swell + <!-- Page 27 --> <span class="pagenum"><a name="Page_27" id="Page_27"></a>[pg + 27]</span> above that which may be conceiv'd to be the Plain or Level of + the consider'd Surface, for it is obvious enough to those that are any + thing conversant with such Glasses, but as to numerous Depressions beneath + that Level, of which sort of Cavities by the help of a <i>Microscope</i>, + which the greatest Artificer that makes them, judges to be the greatest + Magnifying Glass in <i>Europe</i>, except one that equals it, we have on + the Surface of a thin piece of Cork that appear'd smooth to the Eye, + observ'd about sixty in a Row, within the length of less then an 31 and 32 + part of an Inch, (for the Glass takes in no longer a space at one view) + and these Cavities (which made that little piece of Cork look almost like + an empty Honey-comb) were not only very distinct, and figur'd like one + another, but of a considerable bigness, and a scarce credible depth; + insomuch that their distinct shadows as well as sides were plainly + discern'd and easiy to be reckon'd, and might have been well + distinguish'd, though they had been ten times lesser than they were; which + I thought it not amiss to mention to you <i>Pyrophilus</i> upon the by, + that you may thence make some Estimate, what a strange Inequality, and + what a multitude of little Shades, there may really be, in a + <!-- Page 28 --> <span class="pagenum"><a name="Page_28" id="Page_28"></a>[pg + 28]</span> scarce sensible part of the Physical superficies, though the + naked Eye sees no such matter. And as Excellent <i>Microscopes</i> shew us + this Ruggedness in many Bodies that pass for Smooth, so there are divers + Experiments, though we must not now stay to urge them, which seem to + perswade us of the same thing as to the rest of such Bodies as we are now + treating off; So, that there is no sensible part of an Opacous body, that + may not be conceiv'd to be made up of a multitude of singly insensible + Corpuscles, but in the giving these surfaces that disposition, which makes + them alter the Light that reflects thence to the Eye after the manner + requisite to make the Object appear Green, Blew, &c. the Figures of + these Particles have <i>a great</i>, but not <i>the only</i> stroak. 'Tis + true indeed that the protuberant Particles may be of very great variety of + Figures, Sphærical, Elliptical, Conical, Cylindrical, Polyedrical, and + some very irregular, and that according to the Nature of these, and the + situation of the Lucid body, the Light must be variously affected, after + one manner from Surfaces (I now speak of Physical Surfaces) consisting of + Sphaerical, and in another from those that are made up of Conical or + Cylindrical Corpuscles; some + <!-- Page 29 --> <span class="pagenum"><a name="Page_29" id="Page_29"></a>[pg + 29]</span> being fitted to reflect more of the incident Beams of Light, + others less, and some towards one part, others towards another. But + besides this difference of Shape, there may be divers other things that + may eminently concurr to vary the forms of Asperity that Colours so much + depend on. For, willingly allowing the Figure of the Particles in the + first place, I consider secondly, that the superficial Corpuscles, if I + may so call them, may be bigger in one Body, and less in another, and + consequently fitted to allay the Light falling on them with greater + shades. Next, the protuberant Particles may be set more or less close + together, that is, there may be a greater or a smaller number of them + within the compass of one, than within the compass of another small part + of the Surface of the same Extent, and how much these Qualities may serve + to produce Colour may be somewhat guess'd at, by that which happens in the + Agitation of Water; for if the Bubbles that are thereby made be Great, and + but Few, the Water will scarce acquire a sensible Colour, but if it be + reduc'd to a Froth, consisting of Bubbles, which being very Minute and + Contiguous to each other, are a multitude of them crowded into a narrow + Room, the Water (turned to + <!-- Page 30 --> <span class="pagenum"><a name="Page_30" id="Page_30"></a>[pg + 30]</span> Froth) does then exhibit a very manifest White Colour,<a + name="NtA_3" id="NtA_3"></a><a href="#Nt_3"><sup>3</sup></a> (to which + these last nam'd Conditions of the Bubbles do as well as their Convex + figure contribute) and that for Reasons to be mention'd anon. Besides, it + is not necessary that the Superficial particles that exhibit one Colour, + should be all of them Round, or all Conical, or all of any one Shape, but + Corpuscles of differing Figures may be mingled on the Surface of the + Opacous Body, as when the Corpuscles that make a Blew colour, and those + that make a Yellow, come to be Accurately and Skilfully mix'd, they make + up a Green, which though it seem one simple Colour, yet in this case + appears to be made by Corpuscles of very differing Kinds, duely commix'd. + Moreover the Figure and Bigness of the little Depressions, Cavities, + Furrows or Pores intercepted betwixt these protuberant Corpuscles, are as + well to be consider'd as the Sizes and Shapes of the Corpuscles + themselves: For we may conceive the Physical superficies of a Body, where + (as we said) its Colour does as it were reside, to be cut Transversly by a + Mathematical plain, which you know is conceiv'd to be without any Depth or + Thickness at all, and then as + <!-- Page 31 --> <span class="pagenum"><a name="Page_31" id="Page_31"></a>[pg + 31]</span> some parts of the Physical Superficies will be Protuberant; or + swell above this last plain, so others may be depress'd beneath it; as (to + explane my self by a gross Comparison) in divers places of the Surface of + the Earth, there are not only Neighbouring Hills, Trees, &c. that are + rais'd above the Horizontal Level of the Valley, but Rivers, Wells, Pits + and other Cavities that are depress'd beneath it, and that such + Protuberant and Concave parts of a Surface may remit the Light so + differingly, as much to vary a Colour, some examples and other things, + that we shall hereafter have occasion to take notice off in this Tract, + will sufficiently declare, till when, it may suffice to put you in mind, + that of two Flat-sides of the same piece of, for example, red Marble, the + one being diligently Polished, and the other left to its former Roughness, + the differing degrees or sorts of Asperity, for the side that is smooth to + the Touch wants not its Roughness, will so diversifie the Light reflected + from the several Plains to the Eye, that a Painter would employ two + differing Colours to represent them. + </p> + <p> + 7. And I hope, <i>Pyrophilus</i>, you will not think it strange or + impertinent, that I employ in divers passages of these Papers, + <!-- Page 32 --> <span class="pagenum"><a name="Page_32" id="Page_32"></a>[pg + 32]</span> examples drawn from Bodies and Shadows far more Gross, than + those minute Protuberances and shady Pores on which in most cases the + Colour of a Body as 'tis an Inherent Quality or Disposition of its + Surface, seems to depend. For sometimes I employ such Examples, rather to + declare my Meaning, than prove my Conjecture; things, whom their Smallness + makes Insensible, being better represented to the Imagination by such + familiar Objects, as being like them enough in other respects, are of a + Visible bulk. And next, though the Beams of Light are such subtil Bodies, + that in respect of them, even Surfaces that are sensibly Smooth, are not + exactly so, but have their own degree of Roughness, consisting of little + Protuberances and Depressions; and though consequently such Inequalities + may suffice to give Bodies differing Colours, as we see in Marble that + appears White or Black, or Red or Blew, even when the most carefully + Polish'd, yet 'tis plain by the late Instance of Red Marble, and many + others, that even bigger Protuberances and greater Shades may likewise so + Diversifie the Roughness of a Bodies Superficies, as manifestly to concurr + to the varying of its Colour, whereby such Examples appear to be proper + enough + <!-- Page 33 --> <span class="pagenum"><a name="Page_33" id="Page_33"></a>[pg + 33]</span> to be employ'd in such a Subject as we have now in hand. And + having hinted thus much on this Occasion, I now proceed. + </p> + <p> + 8. The Situation also of the Superficial particles is considerable, which + I distinguish into the Posture of the single Corpuscles, in respect of the + Light, and of the Eye, and the Order of them in reference also to one + another; for a Body may otherwise reflect the Light, when its Superficial + particles are more erected upon the Plain that may be conceiv'd to pass + along their Basis, and when the Points or Extremes of such Particles are + Obverted to the Eye, than when those Particles are so Inclin'd, that their + Sides are in great part Discernable, as the Colour of Plush or Velvet will + appear Vary'd to you, if you carefully stroak part of it one way, and part + of it another, the posture of the particular Thrids, in reference to the + Light, or the Eye, becoming thereby different. And you may observe in a + Field of ripe Corn blown upon by the Wind, that there will appear as it + were Waves of a Colour (at least Gradually) differing from that of the + rest of the Field, the Wind by Depressing some of the Ears, and not at the + same time others, making the one Reflect more from + <!-- Page 34 --> <span class="pagenum"><a name="Page_34" id="Page_34"></a>[pg + 34]</span> the Lateral and Strawy parts, than do the rest. And so, when + Doggs are so angry, as to Erect the Hairs upon their Necks, and upon some + other parts of their Bodies, those Parts seem to acquire a Colour vary'd + from that which the same Hairs made, when in their usual Posture they did + farr more stoop. And that the Order wherein the Superficial Corpuscles are + Rang'd is not to be neglected, we may guess by turning of Water into + Froth, the beating of Glass, and the scraping of Horns, in which cases the + Corpuscles that were before so marshall'd as to be Perspicuous, do by the + troubling of that Order become Dispos'd to terminate and reflect more + Light, and thereby to appear Whitish. And there are other ways in which + the Order of the Protuberant parts, in reference to the Eye, may much + contribute to the appearing of a particular Colour, for I have often + observ'd, that when Pease are Planted, or Set in Parallel Lines, and are + Shot up about half a Foot above the Surface of the Ground, by looking on + the Field or Plot of Ground from that part towards which the Parallel + Lines tended, the greater part of the Ground by farr would appear of its + own dirty Colour, but if I look'd upon it Transversly, the Plot + <!-- Page 35 --> <span class="pagenum"><a name="Page_35" id="Page_35"></a>[pg + 35]</span> would appear very Green, the upper parts of the Pease hindering + the intercepted parts of the Ground, which as I said retain'd their wonted + Colour, from being discover'd by the Eye. And I know not, <i>Pyrophilus</i>, + whether I might not add, that even the Motion of the Small Parts of a + Visible Object may in some cases contribute, though it be not so easie to + say how, to the Producing or the Varying of a Colour; for I have several + times made a Liquor, which when it has well settled in a close Vial, is + Transparent and Colourless, but as soon as the Glass is unstopp'd, begins + to fly away very plentifully in a White and Opacous fume; and there are + other Bodies, whose Fumes, when they fill a Receiver, would make one + suspect it contains Milk, and yet when these Fumes settle into a Liquor, + that Liquor is not White, but Transparent; And such White Fumes I have + seen afforded by unstopping a Liquor I know, which yet is it self + Diaphanous and Red; Nor are these the only Instances of this Kind, that + our Tryals can supply us with. And if the Superficial Corpuscles be of the + Grosser sort, and be so Framed, that their differing Sides or Faces may + exhibit differing Colours, then the Motion or Rest of those Corpuscles may + be + <!-- Page 36 --> <span class="pagenum"><a name="Page_36" id="Page_36"></a>[pg + 36]</span> considerable, as to the Colour of the Superficies they compose, + upon this account, that sometimes more, sometimes fewer of the Sides + dispos'd to exhibit such a Colour may by this means become or continue + more Obverted to the Eye than the rest, and compose a Physical Surface, + that will be more or less sensibly interrupted; As, to explane my meaning, + by proposing a gross Example, I remember, that in some sorts of Leavy + Plants thick set by one another, the two sides of whose Leaves were of + somewhat differing Colours, there would be a notable Disparity as to + Colour, if you look'd upon them both when the Leaves being at Rest had + their upper and commonly expos'd sides Obverted to the Eye, and when a + breath of Wind passing thorow them, made great Numbers of the usually + Hidden sides of the Leaves become conspicuous. And though the Little + Bodies, we were lately speaking of, may Singly and Apart seem almost + Colourless, yet when Many of them are plac'd by one another, so near, that + the Eye does not easily discern an Interruption, within a sensible space, + they may exhibit a Colour; as we see, that though a Slenderest Thrid of + Dy'd Silk do's, whilst look'd on Single, seem almost quite Devoyd of + Redness, (for instance) + <!-- Page 37 --> <span class="pagenum"><a name="Page_37" id="Page_37"></a>[pg + 37]</span> yet when numbers of these Thrids are brought together into one + Skein, their Colour becomes notorious. + </p> + <p> + 9. But the same Occasion that invited me to say what I have mention'd + concerning the Leaves of Trees, invites me also to give you some account + of what happens in Changeable Taffities, where we see differing Colours, + as it were, Emerge and Vanish upon the Ruffling of the same piece of Silk: + As I have divers times with Pleasure observ'd, by the help of such a <i>Microscope</i>, + as, though it do not very much Magnifie the Object, has in recompence this + great Conveniency, that you may easily, as fast as you please, remove it + from one part to another of a Large Object, of which the Glass taking a + great part at once, you may thereby presently Survey the Whole. Now by the + help of such a <i>Microscope</i> I could easily (as I began to say) + discern, that in a piece of Changeable Taffity, (that appear'd, for + Instance, sometimes Red, and sometimes Green) the Stuff was compos'd of + Red thrids and Green, passing under and over each other, and crossing one + another in almost innumerable points; and if I look'd through the Glass + upon any considerable portion of the Stuff, that (for example sake) to the + <!-- Page 38 --> <span class="pagenum"><a name="Page_38" id="Page_38"></a>[pg + 38]</span> naked Eye appear'd to be Red, I could plainly see, that in that + Position, the Red thrids were Conspicuous, and reflected a vivid Light; + and though I could also perceive, that there were Green ones, yet by + reason of their disadvantagious Position in the <i>Physical Surface</i> of + the Taffity, they were in part hid by the more Protuberant Thrids of the + other Colour; and for the same cause, the Reflection from as much of the + Green as was discover'd, was comparatively but Dim and Faint. And if, on + the contrary, I look'd through the <i>Microscope</i> upon any part that + appear'd Green, I could plainly see that the Red thrids were less fully + expos'd to the Eye, and obscur'd by the Green ones, which therefore made + up the Predominant Colour. And by observing the Texture of the Silken + Stuff, I could easisy so expose the Thrids either of the one Colour or of + the other to my Eye, as at pleasure to exhibit an apparition of Red or + Green, or make those Colours succeed one another: So that, when I observ'd + their Succession by the help of the Glass, I could mark how the + Predominant Colour did as it were start out, when the Thrids that + exhibited it came to be advanagiously plac'd; And by making little Folds + in the Stuff after a certain manner, + <!-- Page 39 --> <span class="pagenum"><a name="Page_39" id="Page_39"></a>[pg + 39]</span> the Sides that met and terminated in those Folds, would appear + to the naked Eye, one of them Red, and the other Green. When Thrids of + more than two differing Colours chance to be Interwoven, the resulting + changeableness of the Taffity may be also somewhat different. But I choose + to give an Instance in the Stuff I have been speaking off, because the + mixture being more Simple, the way whereby the Changeableness is produc'd, + may be the more easily apprehended: and though Reason alone might readily + enough lead a considering Man to guess at the Explication, in case he knew + how Changeable Taffities are made: yet I thought it not impertinent to + mention it, because both Scholars and Gentlemen are wont to look upon the + Inquiry into Manufactures, as a <i>Mechanick</i> imployment, and + consequently below Them; and because also with such a <i>Microscope</i> as + I have been mentioning, the discovery is as well Pleasant as Satisfactory, + and may afford Hints of the Solution of other <i>Phænomena</i> of Colours. + And it were not amiss, that some diligent Inquiry were made, whether the + <i>Microscope</i> would give us an account of the Variableness of Colour, + that is so Conspicuous and so Delightfull in Mother of Pearl, in Opalls, + and some + <!-- Page 40 --> <span class="pagenum"><a name="Page_40" id="Page_40"></a>[pg + 40]</span> other resembling Bodies: For though I remember I did formerly + attempt something of that Kind (fruitlesly enough) upon Mother of Pearl, + yet not having then the advantage of my best <i>Microscope</i>, nor some + Conveniences that might have been wish'd, I leave it to you, who have + better Eyes, to try what you can do further; since 'twill be <i>Some</i> + discovery to find, that, in this case, the best Eyes and <i>Microscopes</i> + themselves can make <i>None</i>. + </p> + <p> + 10. I confess, <i>Pyrophilus</i>, that a great part of what I have + deliver'd, (or propos'd rather) concerning the differing forms of Asperity + in Bodies, by which Differences the incident Light either comes to be + Reflected with more or less of Shade, and with that Shade more or less + Interrupted, or else happens to be also otherwise Modify'd or Troubl'd, is + but Conjectural. But I am not sure, that if it were not for the Dullness + of our Senses, either these or some other Notions of Kin to them, might be + better Countenanc'd; for I am apt to suspect, that if we were Sharp + sighted enough, or had such perfect <i>Microscopes</i>, as I fear are more + to be wish'd than hop'd for, our promoted Sense might discern in the + Physical Surfaces of Bodies, both a great many latent Ruggidnesses, and + the particular + <!-- Page 41 --> <span class="pagenum"><a name="Page_41" id="Page_41"></a>[pg + 41]</span> Sizes, Shapes, and Situations of the extremely little Bodies + that cause them, and perhaps might perceive among other Varieties that we + now can but imagine, how those little Protuberances and Cavities do + Interrupt and Dilate the Light, by mingling with it a multitude of little + and singly undiscernable Shades, though some of them more, and some of + them less Minute, some less, and some more Numerous; according to the + Nature and Degree of the particular Colour we attribute to the Visible + Object; as we see, that in the Moon we can with Excellent <i>Telescopes</i> + discern many Hills and Vallies, and as it were Pits and other Parts, + whereof some are more, and some less Vividly illustrated, and others have + a fainter, others a deeper Shade, though the naked Eye can discern no such + matter in that Planet. And with an Excellent <i>Microscope</i>, where the + <i>Naked</i> Eye did see but a Green powder, the <i>Assisted</i> Eye as we + noted above, could discern particular Granules, some of them of a Blew, + and some of them of a Yellow colour, which Corpuscles we had beforehand + caus'd to be exquisitly mix'd to compound the Green. + </p> + <p> + 11. And, <i>Pyrophilus</i>, that you may not think me altogether + extravagant in what I + <!-- Page 42 --> <span class="pagenum"><a name="Page_42" id="Page_42"></a>[pg + 42]</span> have said of the Possibility, (for I speak of no more) of + discerning the differing forms of Asperity in the Surfaces of Bodies of + several Colours, I'l here set down a Memorable particular that chanc'd to + come to my Knowledge, since I writ a good part of this <i>Essay</i>; and + it is this. Meeting casually the other Day with the deservedly Famous<a + name="NtA_4" id="NtA_4"></a><a href="#Nt_4"><sup>4</sup></a> Dr. <i>J. + Finch</i>, Extraordinary <i>Anatomist</i> to that Great Patron of the <i>Virtuosi</i>, + the now Great Duke of <i>Toscany</i>, and enquiring of this Ingenious + Person, what might be the chief Rarity he had seen in his late return out + of <i>Italy</i> into <i>England</i>, he told me, it was a Man at <i>Maestricht</i> + in the Low-Countrys, who at certain times can discern and <i>distinguish + Colours by the Touch</i> with his Fingers. You'l easily Conclude, that + this is farr more strange, than what I propos'd but as <i>not Impossible</i>; + since the Sense of the <i>Retina</i> seeming to be much more Tender and + quick than that of those Grosser Filaments, Nerves or Membranes of our + Fingers, wherewith we use to handle Gross and Hard Bodies, it seems scarce + credible, that any Accustomance, or Diet, or peculiarity of Constitution, + should enable a Man to distinguish + <!-- Page 43 --> <span class="pagenum"><a name="Page_43" id="Page_43"></a>[pg + 43]</span> with such Gross and Unsuitable Organs, such Nice and Subtile + Differences as those of the forms of Asperity, that belong to differing + Colours, to receive whose Languid and Delicate Impressions by the + Intervention of Light, Nature seems to have appointed and contexed into + the <i>Retina</i> the tender and delicate Pith of the Optick Nerve. + Wherefore I confess, I propos'd divers Scruples, and particularly whether + the Doctor had taken care to bind a Napkin or Hankerchief over his Eyes so + carefully, as to be sure he could make no use of his Sight, though he had + but Counterfeited the want of it, to which I added divers other Questions, + to satisfie my Self, whether there were any Likelihood of Collusion or + other Tricks. But I found that the Judicious Doctor having gone farr out + of his way, purposely to satisfie Himself and his Learned Prince about + this Wonder, had been very Watchfull and Circumspect to keep <i>Himself</i> + from being Impos'd upon. And that he might not through any mistake in + point of Memory mis-inform <i>Me</i>, he did me the Favour at my Request, + to look out the Notes he had Written for his Own and his Princes + Information, the summ of which Memorials, as far as we shall mention them + here, was this, That the Doctor + <!-- Page 44 --> <span class="pagenum"><a name="Page_44" id="Page_44"></a>[pg + 44]</span> having been inform'd at <i>Utrecht</i>, that there Lived one at + some Miles distance from <i>Maestricht</i>, who could distinguish Colours + by the Touch, when he came to the last nam'd Town, he sent a Messenger for + him, and having Examin'd him, was told upon Enquiry these Particulars: + </p> + <p> + That the Man's name was <i>John Vermaasen</i>, at that time about 33 Years + of Age; that when he was but two years Old, he had the Small Pox, which + rendred him absolutely Blind: That at this present he is an <i>Organist</i>, + and serves that Office in a publick Quire. + </p> + <p> + That the Doctor discoursing with him over Night, the Blind man affirm'd, + that he could distinguish Colours by the Touch, but that he could not do + it, unless he were Fasting; Any quantity of Drink taking from him that + Exquisitness of Touch, which is requisite to so Nice a Sensation. + </p> + <p> + That hereupon the Doctor provided against the next Morning seven pieces of + Ribbon, of these seven Colours, Black, White, Red, Blew, Green, Yellow, + and Gray, but as for <i>mingled</i> Colours, this <i>Vermaasen</i> would + not undertake to discern them, though if offer'd, he would tell that they + were <i>Mix'd</i>. + </p> + <p> + That to discern the Colour of the Ribbon, + <!-- Page 45 --> <span class="pagenum"><a name="Page_45" id="Page_45"></a>[pg + 45]</span> he places it betwixt the Thumb and the Fore-finger, but his + most exquisite perception was in his Thumb, and much better in the right + Thumb than in the left. + </p> + <p> + That after the Blind man had four or five times told the Doctor the + several Colours, (though Blinded with a Napkin for fear he might have some + Sight) the Doctor found he was twice mistaken, for he call'd the White + Black, and the Red Blew, but still, he, before his Errour, would lay them + by in Pairs, saying, that though he could easily distinguish them from all + others, yet those two Pairs were not easily distinguish'd amongst + themselves, whereupon the Doctor desir'd to be told by him what kind of + Discrimination he had of Colours by his Touch, to which he gave a reply, + for whose sake chiefly I insert all this Narrative in this place, namely, + That all the difference was more or less Asperity, for says he, (I give + you the Doctor's own words) Black feels as if you were feeling Needles + points, or some harsh Sand, and Red feels very Smooth. + </p> + <p> + That the Doctor having desir'd him to tell in Order the difference of + Colours to his Touch, he did as follows; + </p> + <p> + Black and White are the most asperous + <!-- Page 46 --> <span class="pagenum"><a name="Page_46" id="Page_46"></a>[pg + 46]</span> or unequal of all Colours, and so like, that 'tis very hard to + distinguish them, but Black is the most Rough of the two, Green is next in + Asperity, Gray next to Green in Asperity, Yellow is the fifth in degree of + Asperity, Red and Blew are so like, that they are as hard to distinguish + as Black and White, but Red is somewhat more Asperous than Blew, so that + Red has the sixth place, and Blew the seventh in Asperity. + </p> + <p> + 12. To these Informations the Obliging Doctor was pleas'd to add the + welcome present of three of those very pieces of Ribbon, whose Colours in + his presence the Blind man had distinguished, pronouncing the one Gray, + the other Red, and the third Green, which I keep by me as Rarities, and + the rather, because he fear'd the rest were miscarry'd. + </p> + <p> + 13. Before I saw the Notes that afforded me the precedent Narrative, I + confess I suspected this man might have thus discriminated Colours, rather + by the Smell than by the Touch; for some of the Ingredients imployed by + Dyers to Colour things, have Sents, that are not so Languid, nor so near + of Kin, but that I thought it not impossible that a very Critical Nose + might distinguish them, and this I the rather suspected, because he + requir'd, that the Ribbons, + <!-- Page 47 --> <span class="pagenum"><a name="Page_47" id="Page_47"></a>[pg + 47]</span> whose Colours he was to Name, should be offer'd him Fasting in + the morning; for I have observ'd in Setting Doggs, that the feeding of + them (especially with some sorts of Aliments) does very much impair the + exquisite sent of their Noses. And though some of the foregoing + particulars would have prevented that Conjecture, yet I confess to you (<i>Pyrophilus</i>) + that I would gladly have had the Opportunity of Examining this Man my + self, and of Questioning him about divers particulars which I do not find + to have been yet thought upon. And though it be not incredible to me, that + since the Liquors that Dyers imploy to tinge, are qualifi'd to do so by + multitudes of little Corpuscles of the Pigment or Dying stuff, which are + dissolved and extracted by the Liquor, and swim to and fro in it, those + Corpuscles of Colour (as the <i>Atomists</i> call them) insinuating + themselves into, and filling all the Pores of the Body to be Dyed, may + Asperate its Superficies more or less according to the Bigness and Texture + of the Corpuscles of the Pigment; yet I can scarce believe, that our Blind + man could distinguish all the Colours he did, meerly by the Ribbons having + more or less of Asperity, so that I cannot but think, notwithstanding this + History, that the Blind man + <!-- Page 48 --> <span class="pagenum"><a name="Page_48" id="Page_48"></a>[pg + 48]</span> distinguish'd Colours not only by the <i>Degrees</i> of + Asperity in the Bodies offer'd to him, but by <i>Forms</i> of it, though + this (latter) would perhaps have been very difficult for him to make an + Intelligible mention of, because those Minute disparities having not been + taken notice of by men for want of touch as Exquisite as our Blind Mans, + are things he could not have Intelligibly express'd, which will easily + seem Probable, if you consider, that under the name of Sharp, and Sweet, + and Sour, there are abundance of, as it were, immediate peculiar Relishes + or Tasts in differing sorts of Wine, which though Critical and Experienc'd + Palats can easily discern themselves cannot make them be understood by + others, such Minute differences not having hitherto any Distinct names + assign'd them. And it seems that there was somthing in the Forms of + Asperity that was requisite to the Distinction of Colours, besides the + Degree of it, since he found it so difficult to distingush Black and White + from one another, though not from other Colours. For I might urge, that he + seems not consonant to himself about the <i>Red</i>, which as you have + seen in one place, he represents as somewhat more Asperous than the <i>Blew</i>; + and in another, very Smooth: But because he speaks of this Smoothness in + that place, + <!-- Page 49 --> <span class="pagenum"><a name="Page_49" id="Page_49"></a>[pg + 49]</span> where he mentions the Roughness of <i>Black</i>, we may + favourably presume that he might mean but a <i>comparative Smoothness</i>; + and therefore I shall not Insist on this, but rather Countenance my + Conjecture by this, that he found it so Difficult, not only, to + Discriminate Red and Blew, (though the first of our promiscuous + Experiments will inform you, that the Red reflects by great Odds more + Light than the other) but also to distinguish Black and White from one + another, though not from other Colours. And indeed, though in the Ribbonds + that were offer'd him, they might be almost equally Rough, yet in such + slender Corpuscles as those of Colour, there may easily enough be + Conceiv'd, not only a greater Closeness of Parts, or else Paucity of + Protuberant Corpuscles, and the little extant Particles may be otherwise + Figur'd, and Rang'd in the White than in the Black, but the Cavities may + be much Deeper in the one than the other. + </p> + <p> + 14. And perhaps, (<i>Pyrophilus</i>) it may prove some <i>Illustration of + what I mean</i>, and help you to conceive how <i>this may</i> be, if I + Represent, that where the Particles are so exceeding Slender, we may allow + the Parts expos'd to the Sight and Touch to be a little Convex in + comparison of the Erected + <!-- Page 50 --> <span class="pagenum"><a name="Page_50" id="Page_50"></a>[pg + 50]</span> Particle of Black Bodies, as if there were Wyres I know not how + many times Slenderer than a Hair: whether you suppose them to be Figur'd + like Needles, or Cylindrically, like the Hairs of a Brush, with + Hemisphærical (or at least Convex) Tops, they will be so very Slender, and + consequently the Points both of the one sort and the other so very Sharp, + that even an exquisite Touch will be able to distinguish no greater + Difference between them, than that which our Blind man allow'd, when + comparing Black and White Bodies, he said, that the latter was the less + Rough of the two. Nor is every Kind of Roughness, though Sensible enough, + Inconsistent with Whiteness, there being Cases, wherein the Physical + Superficies of a Body is made by the same Operation both <i>Rough</i> and + <i>white</i>, as when the Level Surface of clear Water being by agitation + Asperated with a multitude of Unequal Bubbles, do's thereby acquire a + Whiteness; and as a Smooth piece of Glass, by being Scratch'd with a + Diamond, do's in the Asperated part of its Surface disclose the same + Colour. But more (perchance) of this elsewhere. + </p> + <p> + 15. And therefore, we shall here pass by the Question, whether any thing + might + <!-- Page 51 --> <span class="pagenum"><a name="Page_51" id="Page_51"></a>[pg + 51]</span> be consider'd about the Opacity of the Corpuscles of Black + Pigments, and the <i>Comparative</i> Diaphaneity of those of many White + Bodies, apply'd to our present Case; and proceed, to represent, That the + newly mention'd Exiguity and Shape of the extant Particles being suppos'd, + it will then be considerable what we lately but Hinted, (and therefore + must now somewhat Explane) That the Depth of the little Cavities, + intercepted between the extant Particles, without being so much greater in + Black Bodies than in White ones, as to be perceptibly so to the Gross + Organs of Touch, may be very much greater in reference to their + Disposition of Reflecting the imaginary subtile Beams of Light. For in + Black Bodies, those Little intercepted Cavities, and other Depressions, + may be so Figur'd, so Narrow and so Deep, that the incident Beams of + Light, which the more extant Parts of the Physical Superficies are + dispos'd to Reflect inwards, may be Detain'd there, and prove unable to + Emerge; whilst in a White Body, the Slender Particles may not only by + their Figure be fitted to Reflect the Light copiously outwards, but the + intercepted Cavities being not Deep, nor perhaps very Narrow, the Bottoms + of them may be so Constituted, as to + <!-- Page 52 --> <span class="pagenum"><a name="Page_52" id="Page_52"></a>[pg + 52]</span> be fit to Reflect outwards much of the Light that falls even + upon Them; as you may possibly better apprehend, when we shall come to + treat of Whiteness and Blackness. In the mean time it may suffice, that + you take Notice with me, that the Blind mans Relations import no necessity + of Concluding, that, though, because, according to the Judgment of his + Touch, Black was the Roughest, as it is the Darkest of Colours, therefore + White, which (according to us) is the Lightest, should be also the + Smoothest: since I observe, that he makes Yellow to be two Degrees more + Asperous than Blew, and as much less Asperous than Green; whereas indeed, + Yellow do's not only appear to the Eye a Lighter Colour than Blew, but (by + our first Experiment hereafter to be mention'd) it will appear, that + Yellow reflected much more Light than Blew, and manifestly more than + Green, (which we need not much wonder at, since in this Colour and the two + others (Blew and Yellow) 'tis not <i>only</i> the <i>Reflected Light</i> + that is to be considered, since to produce both these, <i>Refraction</i> + seems to Intervene, which by its Varieties may much alter the Case:) which + both seems to strengthen the Conjecture I was formerly proposing, that + there was something else + <!-- Page 53 --> <span class="pagenum"><a name="Page_53" id="Page_53"></a>[pg + 53]</span> in the <i>Kinds</i> of Asperity, as well as in the <i>Degrees</i> + of it, which enabled our Blind man to Discriminate Colours, and do's at + least show, that we cannot in all Cases from the bare Difference in the + Degrees of Asperity betwixt Colours, safely conclude, that the Rougher of + any two always Reflects the least Light. + </p> + <p> + 16. But this notwithstanding, (<i>Pyrophilus</i>) and what ever Curiosity + I may have had to move some Questions to our Sagacious Blind man, yet thus + much I think you will admit us to have gain'd by his Testimony, that since + many Colours may be felt with the Circumstances above related, the + Surfaces of such Coloured Bodies must certainly have differing <i>Degrees</i>, + and in all probability have differing <i>Forms</i> or Kinds of Asperity + belonging to them, which is all the Use that my present attempt obliges me + to make of the History above deliver'd, that being sufficient to prove, <i>that</i> + Colour do's much depend upon the Disposition of the Superficial parts of + Bodies, and to shew in general, <i>wherein</i> 'tis probable that such a + Disposition do's (principally at least) consist. + </p> + <p> + 17. But to return to what I was saying before I began to make mention of + our Blind <i>Organist</i>, what we have deliver'd + <!-- Page 54 --> <span class="pagenum"><a name="Page_54" id="Page_54"></a>[pg + 54]</span> touching the causes of the several Forms or Asperity that may + Diversifie the Surfaces of Colour'd Bodies, may perchance somewhat assist + us to make some Conjectures in the general, at several of the ways whereby + 'tis possible for the Experiments hereafter to be mention'd, to produce + the suddain changes of Colours that are wont to be Consequent upon them; + for most of these <i>Phænomena</i> being produc'd by the Intervention of + Liquors, and these for the most part abounding with very Minute, Active, + and Variously Figur'd Saline Corpuscles, Liquors so Qualify'd may well + enough very Nimbly after the Texture of the Body they are imploy'd to Work + upon, and so may change the form of Asperity, and thereby make them Remit + to the Eye the Light that falls on them, after another manner than they + did before, and by that means Vary the Colour, so farr forth as it depends + upon the Texture or Disposition of the Seen Parts of the Object, which I + say, <i>Pyrophilus</i>, that you may not think I would absolutely exclude + all other ways of Modifying the Beams of Light between their Parting from + the Lucid Body, and their Reception into the common Sensory. + </p> + <p> + 18. Now there seem to me divers ways, + <!-- Page 55 --> <span class="pagenum"><a name="Page_55" id="Page_55"></a>[pg + 55]</span> by which we may conceive that Liquors may Nimbly alter the + Colour of one another, and of other Bodies, upon which they Act, but my + present haste will allow me to mention but some of them, without Insisting + so much as upon those I shall name. + </p> + <p> + 19. And first, the Minute Corpuscles that compose a Liquor may early + insinuate themselves into those Pores of Bodies, whereto their Size and + Figure makes them Congruous, and these Pores they may either exactly Fill, + or but Inadequately, and in this latter Case they will for the most part + alter the Number and Figure, and always the Bigness of the former Pores. + And in what capacity soever these Corpuscles of a Liquor come to be Lodg'd + or Harbour'd in the Pores that admit them, the Surface of the Body will + for the most part have its Asperity alter'd, and the Incident Light that + meets with a Grosser Liquor in the little Cavities that before contain'd + nothing but Air, or some yet Subtiler Fluid, will have its Beams either + Refracted, or Imbib'd, or else Reflected more or less Interruptedly, than + they would be, if the Body had been Unmoistned, as we see, that even fair + Water falling on white Paper, or Linnen, and divers other Bodies + <!-- Page 56 --> <span class="pagenum"><a name="Page_56" id="Page_56"></a>[pg + 56]</span> apt to soak it in, will for some such Reasons as those newly + mention'd, immediately alter the Colour of them, and for the most part + make it Sadder than that of the Unwetted Parts of the same Bodies. And so + you may see, that when in the Summer the High-ways are Dry and Dusty, if + there falls store of Rain, they will quickly appear of a much Darker + Colour than they did before, and if a Drop of Oyl be let fall upon a Sheet + of White Paper, that part of it, which by the Imbibition of the Liquor + acquires a greater Continuity, and some Transparency, will appear much + Darker than the rest, many of the Incident Beams of Light being now + Transmitted, that otherwise would be Reflected towards the Beholders Eyes. + </p> + <p> + 20. Secondly, A Liquor may alter the Colour of a Body by freeing it from + those things that hindred it from appearing in its Genuine Colour; and + though this may be said to be rather a Restauration of a Body to its own + Colour, or a Retection of its native Colour, than a Change, yet still + there Intervenes in it a change of the Colour which the Body appear'd to + be of before this Operation. And such a change a Liquor may work, either + by Dissolving, or Corroding, or by some such way of + <!-- Page 57 --> <span class="pagenum"><a name="Page_57" id="Page_57"></a>[pg + 57]</span> carrying off that Matter, which either Veil'd or Disguis'd the + Colour that afterwards appears. Thus we restore Old pieces of Dirty Gold + to a clean and nitid Yellow, by putting them into the Fire, and into <i>Aqua-fortis</i>, + which take off the adventitious Filth that made that pure Metall look of a + Dirty Colour. And there is also an easie way to restore Silver Coyns to + their due Lustre, by fetching off that which Discolour'd them. And I know + a <i>Chymical</i> Liquor, which I employ'd to restore pieces of Cloath + spotted with Grease to their proper Colour, by Imbibing the Spotted part + with this Liquor, which Incorporating with the Grease, and yet being of a + very Volatile Nature, does easily carry it away with it Self. And I have + sometimes try'd, that by Rubbing upon a good Touch-stone a certain <i>Metalline</i> + mixture so Compounded, that the Impression it left upon the Stone appear'd + of a very differing Colour from that of Gold, yet a little of <i>Aqua-fortis</i> + would in a Trice make the Golden Colour disclose it self, by Dissolving + the other <i>Metalline</i> Corpuscles that conceal'd those of the Gold, + which you know that <i>Menstruum</i> will leave Untouch'd. + </p> + <p> + 21. Thirdly, A Liquor may alter the + <!-- Page 58 --> <span class="pagenum"><a name="Page_58" id="Page_58"></a>[pg + 58]</span> Colour of a Body by making a Comminution of its Parts, and that + principally two ways, the first by Disjoyning and Dissipating those + Clusters of Particles, if I may so call them, which stuck more Loosely + together, being fastned only by some more easily Dissoluble Ciment, which + seems to be the Case of some of the following Experiments, where you'l + find the Colour of many Corpuscles brought to cohere by having been + Precipitated together, Destroy'd by the Affusion of very peircing and + incisive Liquors. The other of the two ways I was speaking of, is, by + Dividing the Grosser and more Solid Particles into Minute ones, which will + be always Lesser, and for the most part otherwise Shap'd than the Entire + Corpuscle so Divided, as it will happen in a piece of Wood reduc'd into + Splinters or Chips, or as when a piece of Chrystal heated red Hot and + quench'd in Cold water is crack'd into a multitude of little Fragments, + which though they fall not asunder, alter the Disposition of the Body of + the Chrystal, as to its manner of Reflecting the Light, as we shall have + Occasion to shew hereafter. + </p> + <p> + 22. There is a fourth way contrary to the third, whereby a Liquor may + change the Colour of another Body, especially of + <!-- Page 59 --> <span class="pagenum"><a name="Page_59" id="Page_59"></a>[pg + 59]</span> another Fluid, and that is, by procuring the Coalition of + several Particles that before lay too Scatter'd and Dispers'd to exhibit + the Colour that afterwards appears. Thus sometimes when I have had a + Solution of Gold so Dilated, that I doubted whether the Liquor had really + Imbib'd any true Gold or no, by pouring in a little <i>Mercury</i>, I have + been quickly able to satisfie my Self, that the Liquor contain'd Gold, + that Mettall after a little while Cloathing the Surface of the <i>Quick-silver</i>, + with a Thin Film of its own Livery. And chiefly, though not only by this + way of bringing the Minute parts of Bodies together in such Numbers as to + make them become Notorious to the Eye, many of these Colours seem to be + Generated which are produc'd by Precipitations, especially by such as are + wont to be made with fair Water, as when Resinous Gumms dissolv'd in + Spirit of Wine, are let fall again, if the Spirit be Copiously diluted + with that weakning Liquor. And so out of the Rectify'd and Transparent + Butter of <i>Antimony</i>, by the bare Mixture of fair Water, there will + be plentifully Precipitated that Milk-white Substance, which by having its + Looser Salts well wash'd off, is turn'd into that Medicine, which Vulgar + <i>Chymists</i> are pleas'd to call <i>Mercurius Vitæ.</i> + </p> + <!-- Page 60 --> + <p> + <span class="pagenum"><a name="Page_60" id="Page_60"></a>[pg 60]</span> + </p> + <p> + 23. A fifth way, by which a Liquor may change the Colour of a Body, is, by + Dislocating the Parts, and putting them out of their former Order into + another, and perhaps also altering the Posture of the single Corpuscles as + well as their Order or Situation in respect of one another. What certain + Kinds of Commotion or Dislocation of the Parts of a Body may do towards + the Changing its Colour, is not only evident in the Mutations of Colour + observable in <i>Quick-silver</i>, and some other Concretes long kept by + <i>Chymists</i> in a Convenient Heat, though in close Vessels, but in the + Obvious Degenerations of Colour, which every Body may take notice of in + Bruis'd Cherries, and other Fruit, by comparing after a while the Colour + of the Injur'd with that of the Sound part of the same Fruit. And that + also such Liquors, as we have been speaking of, may greatly Discompose the + Textures of many Bodies, and thereby alter the Disposition of their + Superficial parts, the great Commotion made in Metalls, and several other + Bodies by <i>Aqua-fortis</i>, Oyl of <i>Vitriol</i>, and other Saline <i>Menstruums</i>, + may easily perswade us, and what such Vary'd Situations of Parts may do + towards the Diversifying of the manner of their Reflecting the Light, may + <!-- Page 61 --> <span class="pagenum"><a name="Page_61" id="Page_61"></a>[pg + 61]</span> be Guess'd in some Measure by the Beating of Transparent Glass + into a White Powder, but farr better by the Experiments lately Pointed at, + and hereafter Deliver'd, as the Producing and Destroying Colours by the + means of subtil Saline Liquors, by whose Affusion the Parts of other + Liquors are manifestly both Agitated, and likewise Dispos'd after another + manner than they were before such Affusion. And in some <i>Chymical</i> + Oyls, as particularly that of Lemmon Pills, by barely Shaking the Glass, + that holds it, into Bubbles, that Transposition of the Parts which is + consequent to the Shaking, will shew you on the Surfaces of the Bubbles + exceeding Orient and Lively Colours, which when the Bubbles relapse into + the rest of the Oyl, do immediately Vanish. + </p> + <p> + 24. I know not, <i>Pyrophilus</i>, whether I should mention as a Distinct + way, because it is of a somewhat more General Nature, that Power, whereby + a Liquor may alter the Colour of another Body, by putting the Parts of it + into Motion; For though possibly the Motion so produc'd, does, as such, + seldome suddenly change the Colour of the Body whose Parts are Agitated, + yet this seems to be one of the most General, however not Immediate causes + of + <!-- Page 62 --> <span class="pagenum"><a name="Page_62" id="Page_62"></a>[pg + 62]</span> the Quick change of Colours in Bodies. For the Parts being put + into Motion by the adventitious Liquor, divers of them that were before + United, may become thereby Disjoyn'd, and when that Motion ceases or + decays others of them may stick together, and that in a new Order, by + which means the Motion may sometimes produce Permanent changes of Colours, + as in the Experiment you will meet with hereafter, of presently turning a + Snowy White Body into a Yellow, by the bare Affusion of fair Water, which + probably so Dissolves the Saline Corpuscles that remain'd in the <i>Calx</i>, + and sets them at Liberty to Act upon one another, and the Metall, far more + Powerfully than the Water without the Assistance of such Saline Corpuscles + could do. And though you rubb Blew <i>Vitriol</i>, how Venereal and + Unsophisticated soever it be, upon the Whetted Blade of a Knife, it will + not impart to the Iron its Latent Colour, but if you moisten the <i>Vitriol</i> + with your Spittle, or common Water, the Particles of the Liquor disjoyning + those of the <i>Vitriol</i>, and thereby giving them the Various Agitation + requisite to Fluid Bodies, the Metalline Corpuscles of the thus Dissolv'd + <i>Vitriol</i> will Lodge themselves in Throngs in the Small and Congruous + <!-- Page 63 --> <span class="pagenum"><a name="Page_63" id="Page_63"></a>[pg + 63]</span> Pores of the Iron they are Rubb'd on, and so give the Surface + of it the Genuine Colour of the Copper. + </p> + <p> + 25. There remains yet a way, <i>Pyrophilus</i> to be mention'd, by which a + Liquor may alter the Colour of another Body, and this seems the most + Important of all, because though it be nam'd but as One, yet it may indeed + comprehend Many, and that is, by Associating the Saline Corpuscles, or any + other Sort of the more Rigid ones of the Liquor, with the Particles of the + Body that it is employ'd to Work upon. For these Adventitious Corpuscles + Associating themselves with the Protuberant Particles of the Surface of a + Colour'd Body, must necessarily alter their Bigness, and will most + commonly alter their Shape. And how much the Colours of Bodies depend upon + the Bulk and Figure of their Superficial Particles, you may Guess by this, + that eminent antient <i>Philosophers</i> and divers <i>Moderns</i>, have + thought that all Colours might in a general way be made out by these two; + whose being Diversify'd, will in our Case be attended with these two + Circumstances, the One, that the Protuberant Particles being Increas'd in + Bulk, they will oftentimes be Vary'd as to the Closness or Laxity of + <!-- Page 64 --> <span class="pagenum"><a name="Page_64" id="Page_64"></a>[pg + 64]</span> their Order, fewer of them being contain'd within the same + Sensible (though Minute) space than before; or else by approaching to one + another, they must Straighten the Pores, and it may be too, they will by + their manner of Associating themselves with the Protuberant Particles, + intercept new Pores. And this invites me to consider farther, that the + Adventitious Corpuscles, I have been speaking of, may likewise produce a + great Change as well in the Little Cavities or Pores as in the + Protuberances of a Colour'd Body; for besides what we have just now taken + notice of, they may by Lodging themselves in those little Cavities, fill + them up, and it may well happen, that they may not only fill the Pores + they Insinuate themselves into, but likewise have their Upper Parts extant + above them; and partly by these new Protuberances, partly by Increasing + the Bulk of the former, these Extraneous Corpuscles may much alter the + Number and Bigness of the Surfaces Pores, changing the Old and + Intercepting new ones. And then 'tis Odds, but the Order of the Little + Extancies, and consequently that of the Little Depressions in point of + Situation will be alter'd likewise: as if you dissolve <i>Quick-silver</i> + in some kind of <i>Aqua-fortis</i>, + <!-- Page 65 --> <span class="pagenum"><a name="Page_65" id="Page_65"></a>[pg + 65]</span> the Saline Particles of the <i>Menstruum</i> Associating + themselves with the Mercurial Corpuscles, will make a Green Solution, + which afterwards easily enough Degenerates. And Red Lead or <i>Minium</i> + being Dissolv'd in Spirit of Vinegar, yields not a Red, but a Clear + Solution, the Redness of the Lead being by the Liquor Destroy'd. But a + better Instance may be taken from Copper, for I have try'd, that if upon a + Copper-plate you let some Drops of weak <i>Aqua-fortis</i> rest for a + while, the Corpuscles of the <i>Menstruum</i>, joyning with those of the + Metall, will produce a very sensible Asperity upon the Surface of the + Plate, and will Concoagulate that way into very minute Grains of a Pale + Blew <i>Vitriol</i>; whereas if upon another part of the same Plate you + suffer a little strong Spirit of Urine to rest a competent time, you shall + find the Asperated Surface adorn'd with a Deeper and Richer Blew. And the + same <i>Aqua-fortis</i>, that will quickly change the Redness of Red Lead + into a Darker Colour, will, being put upon Crude Lead, produce a Whitish + Substance, as with Copper it did a Blewish. And as with Iron it will + produce a Reddish, and on White Quills a Yellowish, so much may the + Coalition of the Parts of the same + <!-- Page 66 --> <span class="pagenum"><a name="Page_66" id="Page_66"></a>[pg + 66]</span> Liquor, with the differingly Figur'd Particles of Stable + Bodies, divers ways Asperate the differingly Dispos'd Surfaces, and to + Diversifie the Colour of those Bodies. And you'l easily believe, that in + many changes of Colour, that happen upon the Dissolutions of Metalls, and + Precipitations made with Oyl of <i>Tartar</i>, and the like Fix'd Salts, + there may Intervene a Coalition of Saline Corpuscles with the Particles of + the Body Dissolv'd or Precipitated, if you examine how much the <i>Vitriol</i> + of a Metall may be Heavier than the Metalline part of it alone, upon the + Score of the Saline parts Concoagulated therewith, and, that in Several + Precipitations the weight of the <i>Calx</i> does for the same Reason much + exceed that of the Metall, when it was first put in to be Dissolv'd. + </p> + <p> + 26. But, <i>Pyrophilus</i>, to consider these Matters more particularly + would be to forget that I declar'd against Adventuring, at least for this + time, at particular Theories of Colours, and that accordingly you may + justly expect from me rather Experiments than Speculations, and therefore + I shall Dismiss this Subject of the Forms of Superficial Asperity in + Colour'd Bodies, as soon as I shall but have nam'd to you by way of + Supplement to what we have + <!-- Page 67 --> <span class="pagenum"><a name="Page_67" id="Page_67"></a>[pg + 67]</span> hitherto Discours'd in this Section, a Couple of Particulars, + (which you'l easily grant me) The one, That there are divers other ways + for the speedy Production even of True and Permanent Colours in Bodies, + besides those Practicable by the help of Liquors; for proof of which + Advertisement, though several Examples might be alleged, yet I shall need + but Re-mind you of what I mention'd to you above, touching the change of + Colours suddenly made on Temper'd Steel, and on Lead, by the Operation of + Heat, without the Intervention of a Liquor. But the other particular I am + to observe to you is of more Importance to our present Subject and it is, + That though Nature and Art may in some cases so change the Asperity of the + Superficial parts of a Body, as to change its Colour by either of the ways + I have propos'd Single or Unassisted, yet for the most part 'tis by two or + three, or perhaps by more of the fore-mention'd ways Associated together, + that the Effect is produc'd, and if you consider how Variously those + several ways and some others Ally'd unto them, which I have left + unmention'd, may be Compounded and Apply'd, you will not much wonder that + such fruitfull, whether Principles (or Manners of Diversification) + <!-- Page 68 --> <span class="pagenum"><a name="Page_68" id="Page_68"></a>[pg + 68]</span> should be fitted to Change or Generate no small store of + Differing Colours. + </p> + <p> + 27. Hitherto, <i>Pyrophilus</i>, we have in discoursing of the Asperity of + Bodies consider'd the little Protuberances of other Superficial particles + which make up that Roughness, as if we took it for granted, that they must + be perfectly Opacous and Impenetrable by the Beams of Light, and so, must + contribute to the Variety of Colours as they terminate more or less Light, + and reflect it to the Eye mix'd with more or less of thus or thus mingl'd + Shades. But to deal Ingenuously with you, <i>Pyrophilus</i>, before I + proceed any further, I must not conceal from you, that I have often + thought it worth a Serious Enquiry, whether or no Particles of Matter, + each of them sing'y Insensible, and therefore small enough to be capable + of being such Minute Particles as the <i>Atomists</i> both of old and of + late have (not absurdly) called <i>Corpuscula Coloris</i>, may not yet + consist each of them of divers yet Minuter Particles, betwixt which we may + conceive little Commissures where they Adhere to one another, and, + however, may not be Porous enough to be, at least in some degree, Pervious + to the unimaginably subtile Corpuscles that make up the Beams of + <!-- Page 69 --> <span class="pagenum"><a name="Page_69" id="Page_69"></a>[pg + 69]</span> Light, and consequently to be in such a degree Diaphanous. For, + <i>Pyrophilus</i>, that the proposed Enquiry may be of moment to him that + searches after the Nature of Colour, you'l easily grant, if you consider, + that whereas Perfectly Opacous bodies can but reflect the incident Beams + of Light, those that are Diaphanous are qualified to refract them too, and + that Refraction has such a stroak in the Production of Colours, as you + cannot but have taken notice of, and perhaps admir'd in the Colours + generated by the Trajection of Light through Drops of Water that exhibit a + Rain-bow, through Prismatical glasses, and through divers other + Transparent bodies. But 'tis like, <i>Pyrophilus</i>, you'l more easily + allow that about this matter 'tis rather Important to have a Certainty, + than that 'tis Rational to entertain a Doubt; wherefore I must mention to + you some of the Reasons that make me think it may need a further Enquiry, + for I find that in a Darkned Room, where the Light is permitted to enter + but at One hole, the little wandering Particles of Dust, that are commonly + called Motes, and, unless in the Sunbeams, are not taken notice of by the + unassisted Sight, I have, I say, often observ'd, that these roving + Corpuscles being look'd on by an Eye plac'd on one side of the + <!-- Page 70 --> <span class="pagenum"><a name="Page_70" id="Page_70"></a>[pg + 70]</span> Beams that enter'd the Little hole, and by the Darkness having + its Pupill much Enlarg'd, I could discern that these Motes as soon as they + came within the compass of the Luminous, whether Cylinder or Inverted + Cone, if I may so call it, that was made up by the Unclouded Beams of the + Sun, did in certain positions appear adorn'd with very vivid Colours, like + those of the Rain-bow, or rather like those of very Minute, but Sparkling + fragments of Diamonds; and as soon as the Continuance of their Motion had + brought them to an Inconvenient position in reference to the Light and the + Eye, they were only visible without Darting any lively Colours as before, + which seems to argue that these little Motes, or minute Fragments, of + several sorts of bodies reputed Opacous, and only crumbled as to their + Exteriour and Looser parts into Dust, did not barely Reflect the Beams + that fell upon them, but remit them to the Eye Refracted too. We may also + observe, that several Bodies, (as well some of a Vegetable, as others of + an Animal nature) which are wont to pass for Opacous, appear in great part + Transparent, when they are reduc'd into Thin parts, and held against a + powerful Light. This I have not only taken notice of in pieces of Ivory + reduc'd but into Thick leaves, as also in divers considerable + <!-- Page 71 --> <span class="pagenum"><a name="Page_71" id="Page_71"></a>[pg + 71]</span> Thick shells of Fishes, and in shaving of Wood, but I have also + found that a piece of Deal, far thicker than one would easily imagine, + being purposly interposed betwixt my Eye plac'd in a Room, and the clear + Daylight, was not only somewhat Transparent, but (perhaps by reason of its + Gummous nature) appear'd quite through of a lovely Red. And in the Darkned + Room above mention'd, Bodies held against the hole at which the Light + enter'd, appear'd far less Opacous then they would elsewhere have done, + insomuch that I could easily and plainly see through the whole Thickness + of my Hand, the Motions of a Body plac'd (at a very near distance indeed, + but yet) beyond it. And even in Minerals, the Opacity is not always so + great as many think, if the Body be made Thin, for White Marble though of + a pretty Thickness, being within a Due distance plac'd betwixt the Eye and + a Convenient Light, will Suffer the Motions of ones Finger to be well + discern'd through it, and so will pieces, Thick enough, of many common + Flints. But above all, that Instance is remarkable, that is afforded us by + <i>Muscovie</i> glass, (which some call <i>Selenites</i>, others <i>Lapis + Specularis</i>) for though plates of this Mineral, though but of a + moderate Thickness, do often appear Opacous, yet if + <!-- Page 72 --> <span class="pagenum"><a name="Page_72" id="Page_72"></a>[pg + 72]</span> one of these be Dextrously split into the thinnest Leaves 'tis + made up of, it will yield such a number of them, as scarce any thing but + Experience could have perswaded me, and these Leaves will afford the most + Transparent sort of consistent Bodies, that, for ought I have observ'd, + are yet known; and a single Leaf or Plate will be so far from being + Opacous, that 'twill scarce be so much as Visible. And multitudes of + Bodies there are, whose Fragments seem Opacous to the naked Eye, which + yet, when I have included them in good <i>Microscopes</i>, appear'd + Transparent; but, <i>Pyrophilus</i>, on the other side I am not yet sure + that there are no Bodies, whose Minute Particles even in such a <i>Microscope</i> + as that of mine, which I was lately mentioning, will not appear + Diaphanous. For having consider'd <i>Mercury</i> Precipitated <i>per se</i>, + the little Granules that made up the powder, look'd like little fragments + of Coral beheld by the naked Eye at a Distance (for very Near at hand + Coral will sometimes, especially if it be Good, shew some Transparency.) + Filings likewise of Steel and Copper, though in an excellent <i>Microscope</i>, + and a fair Day, they show'd like pretty Big Fragments of those Metalls, + and had considerable Brightness on some of their Surfaces, yet I was not + satisfi'd, that I perceiv'd + <!-- Page 73 --> <span class="pagenum"><a name="Page_73" id="Page_73"></a>[pg + 73]</span> any Reflection from the Inner parts of any of the Filings. Nay, + having look'd in my best <i>Microscope</i> upon the Red <i>Calx</i> of + Lead, (commonly call'd <i>Minium</i>) neither I, nor any I shew'd it to, + could discern it to be other than Opacous, though the Day were Clear, and + the Object strongly Enlightned. And the deeply Red Colour of <i>Vitriol</i> + appear'd in the same <i>Microscope</i> (notwithstanding the great + Comminution effected by the Fire) but like Grossy beaten Brick. So that, + <i>Pyrophilus</i>, I shall willingly resign you the care of making some + further Enquiries into the Subject we have now been considering; for I + confess, as I told you before, that I think that the Matter may need a + further Scrutiny, nor would I be forward to Determine how far or in what + cases the Transparency or Semi-diaphaniety of the Superficial Corpuscles + of Bigger Bodies, may have an Interest in the Production of their Colours, + especially because that even in divers White bodies, as Beaten Glass, Snow + and Froth, where it seems manifest that the Superficial parts are singly + Diaphanous, (being either Water, or Air, or Glass) we see not that such + Variety of Colours are produc'd as usually are by the Refraction of Light, + even in those Bodies, when by their Bigness, Shape, &c. they are + conveniently + <!-- Page 74 --> <span class="pagenum"><a name="Page_74" id="Page_74"></a>[pg + 74]</span> qualify'd to exhibit such Various and Lively Colours as those + of the Rain-bow, and of Prismatical Glasses. + </p> + <p> + 28. By what has been hitherto discours'd, <i>Pyrophilus</i>, we may be + assisted to judge of that famous Controversie which was of Old disputed + betwixt the <i>Epicureans</i> and other <i>Atomists</i> on the one side, + and most other <i>Philosophers</i> on the other side. The former Denying + Bodies to be Colour'd in the Dark, and the Latter making Colour to be an + Inherent quality, as well as Figure, Hardness; Weight, or the like. For + though this Controversie be Reviv'd, and hotly Agitated among the <i>Moderns</i>, + yet I doubt whether it be not in great part a Nominal dispute, and + therefore let us, according to the Doctrine formerly deliver'd, + Distinguish the Acceptions of the word Colour, and say, that if it be + taken in the Stricter Sense, the <i>Epicureans</i> seem to be in the + Right, for if Colour be indeed, though not according to them, but Light + Modify'd, how can we conceive that it can Subsist in the Dark, that is, + where it must be suppos'd there is no Light; but on the other side, if + Colour be consider'd as a certain Constant Disposition of the Superficial + parts of the Object to Trouble the Light they Reflect after such and such + a Determinate manner, + <!-- Page 75 --> <span class="pagenum"><a name="Page_75" id="Page_75"></a>[pg + 75]</span> this Constant, and, if I may so speak, Modifying disposition + persevering in the Object, whether it be Shin'd upon or no, there seems no + just reason to deny, but that in this Sense, Bodies retain their Colour as + well in the Night as Day; or, to Speak a little otherwise, it may be said, + that Bodies are Potentially Colour'd in the Dark, and Actually in the + Light. But of this Matter discoursing more fully elsewhere, as 'tis a + difficulty that concerns Qualities in general, I shall forbear to insist + on it here. + </p> + <hr /> + <h3> + CHAP. IV + </h3> + <p> + 1. Of greater Moment in the Investigation of the Nature of Colours is the + Controversie, Whether those of the Rain-bow, and those that are often seen + in Clouds, before the Rising, or after the Setting of the Sun; and in a + word, Whether those other Colours, that are wont to be call'd Emphatical, + ought or ought not to be accounted True Colours. I need not tell you that + the Negative is the Common Opinion, especially in the Schools, as may + appear by that Vulgar distinction of Colours, whereby these under + Consideration are term'd Apparent, by way of Opposition + <!-- Page 76 --> <span class="pagenum"><a name="Page_76" id="Page_76"></a>[pg + 76]</span> to those that in the other Member of the Distinction are call'd + True or Genuine. This question I say seems to me of Importance, upon this + Account, that it being commonly Granted, (or however, easie enough to be + Prov'd) that Emphatical Colours are Light it self Modify'd by Refractions + chiefly, with a concurrence sometimes of Reflections, and perhaps some + other Accidents depending on these two; if these Emphatical Colours be + resolv'd to be Genuine, it will seem consequent, that Colours, or at least + divers of them, are but Diversify'd Light, and not such Real and Inherent + qualities as they are commonly thought to be. + </p> + <p> + 2. Now since we are wont to esteem the Echoes and other Sounds of Bodies, + to be True Sounds, all their Odours to be True Odours, and (to be short) + since we judge other Sensible Qualities to be True ones, because they are + the proper Objects of some or other of our Senses, I see not why + Emphatical Colours, being the proper and peculiar Objects of the Organ of + Sight, and capable to Affect it as Truly and as Powerfully as other + Colours, should be reputed but Imaginary ones. + </p> + <p> + And if we have (which perchance you'l allow) formerly evinc'd Colour, + (when + <!-- Page 77 --> <span class="pagenum"><a name="Page_77" id="Page_77"></a>[pg + 77]</span> the word is taken in its more Proper sense) to be but Modify'd + Light, there will be small Reason to deny these to be true Colours, which + more manifestly than others disclose themselves to be produc'd by + Diversifications of the Light. + </p> + <p> + 3. There is indeed taken notice of a Difference betwixt these Apparent + colours, and those that are wont to be esteem'd Genuine, as to the + Duration, which has induc'd some Learned Men to call the former rather + Evanid than Fantastical. But as the Ingenious <i>Gassendus</i> does + somewhere Judiciously observe, if this way of Arguing were Good, the + Greeness of a Leaf ought to pass for Apparent, because, soon Fading into a + Yellow, it Scarce lasts at all, in comparison of the Greeness of an + Emerauld. I shall add, that if the Sun-beams be in a convenient manner + trajected through a Glass-prism, and thrown upon some well-shaded Object + within a Room, the Rain-bow thereby Painted on the Surface of the Body + that Terminates the Beams, may oftentimes last longer than Some Colours I + have produc'd in certain Bodies, which would justly, and without scruple + be accounted Genuine Colours, and yet suddenly Degenerate, and lose their + Nature. + </p> + <p> + 4. A greater Disparity betwixt Emphatical + <!-- Page 78 --> <span class="pagenum"><a name="Page_78" id="Page_78"></a>[pg + 78]</span> Colours, and others, may perhaps be taken from this, that + Genuine Colours seem to be produc'd in Opacous Bodies by Reflection, but + Apparent ones in Diaphanous Bodies, and principally by Refraction, I say + Principally rather than Solely, because in some cases Reflection also may + concurr, but still this seems not to conclude these Latter Colours not to + be True ones. Nor must what has been newly said of the Differences of True + and Apparent Colours, be interpreted in too Unlimited a Sense, and + therefore it may perhaps somewhat Assist you, both to Reflect upon the two + fore-going Objections, and to judge of some other Passages which you'l + meet with in this Tract, if I take this Occasion to observe to you, that + if Water be Agitated into Froth, it exhibits you know a White colour, + which soon after it Loses upon the Resolution of the Bubbles into Air and + Water, now in this case either the Whiteness of the Froth is a True Colour + or not, if it be, then True Colours, supposing the Water pure and free + from Mixtures of any thing Tenacious, may be as Short-liv'd as those of + the Rain-bow; also the Matter, wherein the Whiteness did Reside, may in a + few moments perfectly Lose all foot-steps or remains of it. And + <!-- Page 79 --> <span class="pagenum"><a name="Page_79" id="Page_79"></a>[pg + 79]</span> besides, even Diaphanous Bodies may be capable of exhibiting + True Colours by Reflection, for that Whiteness is so produc'd, we shall + anon make it probable. But if on the other side it be said, that the + Whiteness of Froth is an Emphatical Colour, then it must no longer be + said, that Fantastical Colours require a certain Position of the Luminary + and the Eye, and must be Vary'd or Destroy'd by the Change thereof, since + Froth appears White, whether the Sun be Rising or Setting, or in the + Meridian, or any where between it and the Horizon, and from what + (Neighbouring) place soever the Beholders Eye looks upon it. And since by + making a Liquor Tenacious enough, yet without Destroying its Transparency, + or Staining it with any Colour, you may give the Little Films, whereof the + Bubbles consist, such a Texture, as may make the Froth last very many + Hours, if not some Days, or even Weeks, it will render it somewhat + Improper to assign Duration for the Distinguishing Character to + Discriminate Genuine from Fantastical Colours. For such Froth may much + outlast the Undoubtedly true Colours of some of Nature's Productions, as + in that Gaudy Plant not undeservedly call'd the Mervail of <i>Peru</i>, + the Flowers do often Fade, the + <!-- Page 80 --> <span class="pagenum"><a name="Page_80" id="Page_80"></a>[pg + 80]</span> same Day they are Blown; And I have often seen a <i>Virginian</i> + Flower, which usually Withers within the compass of a Day; and I am + credibly Inform'd, that not far from hence a curious Herborist has a + Plant, whose Flowers perish in about an Hour. But if the Whiteness of + Water turn'd into Froth must therefore be reputed Emphatical, because it + appears not that the Nature of the Body is Alter'd, but only that the + Disposition of its Parts in reference to the Incident Light is Chang'd, + why may not the Whiteness be accounted Emphatical too, which I shall shew + anon to be Producible, barely by such another change in Black Horn? and + yet this so easily acquir'd Whiteness seems to be as truly its Colour as + the Blackness was before, and at least is more Permanent than the + Greenness of Leaves, the Redness of Roses, and, in short, than the Genuine + Colours of the most part of Nature's Productions. It may indeed be further + Objected, that according as the Sun or other Luminous Body changes place, + these Emphatical Colours alter or vanish. But not to repeat what I have + just now said, I shall add, that if a piece of Cloath in a Drapers Shop + (in such the Light being seldome Primary) be variously Folded, it will + appear of differing + <!-- Page 81 --> <span class="pagenum"><a name="Page_81" id="Page_81"></a>[pg + 81]</span> Colours, as the Parts happen to be more Illuminated or more + Shaded, and if you stretch it Flat, it will commonly exhibit some one + Uniform Colour, and yet these are not wont to be reputed Emphatical, so + that the Difference seems to be chiefly this, that in the Case of the + Rain-bow, and the like, the Position of the Luminary Varies the Colour, + and in the Cloath I have been mentioning, the Position of the Object does + it. Nor am I forward to allow that in all Cases the Apparition of + Emphatical Colours requires a Determinate position of the Eye, for if Men + will have the Whiteness of Froth Emphatical, you know what we have already + Inferr'd from thence. Besides, the Sun-beams trajected through a + Triangular Glass, after the manner lately mention'd, will, upon the Body + that Terminates them, Paint a Rain-bow, that may be seen whether the Eye + be plac'd on the Right Hand of it or the Left, or Above or Beneath it, or + Before or Behind it; and though there may appear some Little Variation in + the Colours of the Rain-bow, beheld from Differing parts of the Room, yet + such a Diversity may be also observ'd by an Attentive Eye in Real Colours, + look'd upon under the like Circumstances, Nor will it follow, + <!-- Page 82 --> <span class="pagenum"><a name="Page_82" id="Page_82"></a>[pg + 82]</span> that because there remains no Footsteps of the Colour upon the + Object, when the Prism is Remov'd, that therefore the Colour was not Real, + since the Light was truly Modify'd by the Refraction and Reflection it + Suffer'd in its Trajection through the Prism; and the Object in our case + serv'd for a Specular Body, to Reflect that Colour to the Eye. And that + you may not be Startled, <i>Pyrophilus</i>, that I should Venture to say, + that a Rough and Coiour'd Object may serve for a <i>Speculum</i> to + Reflect the Artificial Rain-bow I have been mentioning, consider what + usually happens in Darkned Rooms, where a Wall, or other Body conveniently + Situated within, may so Reflect the Colours of Bodies, without the Room, + that they may very clearly be Discern'd and Distinguish'd, and yet 'tis + taken for granted, that the Colours seen in a Darkned Room, though they + leave no Traces of themselves upon the Wall or Body that Receives them, + are the True Colours of the External Objects, together with which the + Colours of the Images are Mov'd or do Rest. And the Errour is not in the + Eye, whose Office is only to perceive the Appearances of things, and which + does Truly so, but in the Judging or Estimative faculty, which Mistakingly + <!-- Page 83 --> <span class="pagenum"><a name="Page_83" id="Page_83"></a>[pg + 83]</span> concludes that Colour to belong to the Wall, which does indeed + belong to the Object, because the Wall is that from whence the Beams of + Light that carry the Visible <i>Species</i>, do come in Straight Lines + directly to the Eye, as for the same Reason we are wont at a certain + Distance from Concave Sphærical Glasses, to perswade our Selves that we + see the Image come forth to Meet us, and Hang in the Air betwixt the Glass + and Us, because the Reflected Beams that Compose the image cross in that + place, where the Image seems to be, and thence, and not from the Glass, do + in Direct Lines take their Course to the Eye, and upon the like Cause it + is, that divers Deceptions in Sounds and other Sensible Objects do depend, + as we elsewhere declare. + </p> + <p> + 5. I know not, whether I need add, that I have purposely Try'd, (as you'l + find some Pages hence, and will perhaps think somewhat strange) that + Colours that are call'd Emphatical, because not Inherent in, the Bodies in + which they Appear, may be Compounded with one another, as those that are + confessedly Genuine may. But when all this is said, <i>Pyrophilus</i>, I + must Advertise you, that it is but Problematically Spoken, and that though + I think the Opinion + <!-- Page 84 --> <span class="pagenum"><a name="Page_84" id="Page_84"></a>[pg + 84]</span> I have endeavour'd to fortifie Probable, yet a great part of + our Discourse concerning Colours may be True, whether that Opinion be so + or not. + </p> + <hr /> + <h3> + CHAP. V. + </h3> + <p> + 1. There are you know, <i>Pyrophilus</i>, besides those Obsolete Opinions + about Colours which have been long since Rejected, very Various Theories + that have each of them, even at this day, Eminent Men for its Abetters; + for the Peripatetick Schools, though they dispute amongst themselves + divers particulars concerning Colours, yet in this they seem Unanimously + enough to Agree, that Colours are Inherent and Real Qualities, which the + Light doth but Disclose, and not concurr to Produce. Besides there are <i>Moderns</i>, + who with a slight Variation adopt the Opinion of <i>Plato</i>, and as he + would have Colour to be nothing but a Kind of Flame consisting of Minute + Corpuscles as it were Darted by the Object against the Eye, to whose Pores + their Littleness and Figure made them congruous, so these would have + Colour to be an Internal Light of the more Lucid parts of the Object, + Darkned and consequently Alter'd by the Various Mixtures of the less + Luminous + <!-- Page 85 --> <span class="pagenum"><a name="Page_85" id="Page_85"></a>[pg + 85]</span> parts. There are also others, who in imitation of some of the + Ancient <i>Atomists</i>, make Colour not to be Lucid steam, but yet a + Corporeal <i>Effluvium</i> issuing out of the Colour'd Body, but the + Knowingst of these have of late Reform'd their Hypothesis, by + acknowledging and adding that some External Light is necessary to Excite, + and as <i>they</i> speak, Sollicit these Corpuscles of Colour as <i>they</i> + call them, and Bring them to the Eye. Another and more principal Opinion + of the <i>Modern</i> Philosophers, to which this last nam'd may by a + Favourable explication be reconcil'd, is that which derives Colours from + the Mixture of Light and Darkness, or rather Light and Shadows. And as for + the <i>Chymists</i> 'tis known, that the generality of them ascribes the + Origine of Colours to the Sulphureous Principle in Bodies, though I find, + as I elsewhere largely shew, that some of the Chiefest of them derive + Colours rather from Salt than Sulphur, and others, from the third + Hypostatical Principle, <i>Mercury</i>. And as for the <i>Cartesians</i> I + need not tell you, that they, supposing the Sensation of Light to bee + produc'd by the Impulse made upon the Organs of Sight, by certain + extremely Minute and Solid Globules, to which the Pores of the Air and + other Diaphanous + <!-- Page 86 --> <span class="pagenum"><a name="Page_86" id="Page_86"></a>[pg + 86]</span> bodies are pervious, endeavour to derive the Varieties of + Colours from the Various Proportion of the Direct Progress or Motion of + these Globules to their Circumvolution or Motion about their own Centre, + by which Varying Proportion they are by this Hypothesis suppos'd qualify'd + to strike the Optick Nerve after several Distinct manners, so to produce + the perception of Differing Colours. + </p> + <p> + 2. Besides these six principal Hypotheses, <i>Pyrophilus</i>, there may be + some others, which though Less known, may perhaps as well as thesc deserve + to be taken into consideration by you; but that I should copiously debate + any of them at present, I presume you will not expect, if you consider the + Scope of these Papers, and the Brevity I have design'd in them, and + therefore I shall at this time only take notice to you in the general of + two or three things that do more peculiarly concern the Treatise you have + now in your hands. + </p> + <p> + 3. And first, though the Embracers of the Several Hypotheses I have been + naming to you, by undertaking each Sect of them to explicate Colours + indefinitely, by the particular Hypotheses they maintain, seem to hold it + forth as the only Needful Theory about that Subject, yet for my part I + doubt + <!-- Page 87 --> <span class="pagenum"><a name="Page_87" id="Page_87"></a>[pg + 87]</span> whether any one of all these Hypotheses have a right to be + admitted Exclusively to all others, for I think it Probable, that + Whiteness and Blackness may be explicated by Reflection alone without + Refraction, as you'l find endeavour'd in the Discourse you'l meet with + e're long Of the Origine of Whiteness and Blackness, and on the other + side, since I have not found that by any Mixture of White and True Black, + (for there is a Blewish Black which many mistake for a Genuine) there can + be a Blew, a Yellow, or a Red, to name no other Colours, produced, and + since we do find that these Colours may be produc'd in the Glass-prism and + other Transparent bodies, by the help of Refractions, it seems that + Refraction is to be taken in into the Explication of some Colours, to + whose Generation they seem to concurr, either by making a further or other + Commixture of Shades with the Refracted Light, or by some other way not + now to be discours'd. And as it seems not improbable, that in case the + Pores of the Air, and other Diaphanous bodies be every where almost fill'd + with such <i>Globuli</i> as the <i>Cartesians</i> suppose, the Various + kind of Motion of these <i>Globuli</i>, may in many cases have no small + stroak in Varying our Perception of Colour, so + <!-- Page 88 --> <span class="pagenum"><a name="Page_88" id="Page_88"></a>[pg + 88]</span> without the Supposition of these <i>Globuli</i>, which 'tis not + so easie to evince, I think we may probably enough conceive in general, + that the Eye may be Variously affected, not only by the Entire Beams of + Light that fall upon it as they are such, but by the Order, and by the + Degree of Swiftness, and in a word by the Manner according to which the + Particles that compose each Particular Beam arrive at the Sensory, so that + whatever be the Figure of the Little Corpuscles, of which the Beams of + Light consist, not only the Celerity or Slowness of their Revolution or + Rotation in reference to their Progressive Motion, but their more Absolute + Celerity, their Direct or Undulating Motion, and other Accidents, which + may attend their Appulse to the Eye, may fit them to make Differing + Impressions on it. + </p> + <p> + 4. Secondly, For these and the like Considerations, <i>Pyrophilus</i>, I + must desire that you would look upon this little Treatise, not as a + Discourse written Principally to maintain any of the fore-mention'd + Theories, Exclusively to all others, or substitute a New one of my Own, + but as the beginning of a History of Colours, upon which, when you and + your Ingenious friends shall have Enrich'd it, a Solid Theory may be + <!-- Page 89 --> <span class="pagenum"><a name="Page_89" id="Page_89"></a>[pg + 89]</span> safely built. But yet because this History is not meant barely + for a Register of the things recorded in it, but for an <i>Apparatus</i> + to a sound and comprehensitive Hypothesis, I thought fit, so to temper the + whole Discourse, as to make it as conducible, as conveniently I can to + that End, and therefore I have not scrupled to let you see that I was + willing, as to save you the labour of Cultivating some Theories that I + thought would never enable you to reach the Ends you aim at, so to + contract your Enquiries into a Narrow compass, for both which purposes I + thought it requisite to do these two things, the <i>One</i>, to set down + some Experiments which by the help of the Reflections and Insinuations + that attend them, may assist you to discover the Infirmness and + Insufficiency both of the common Peripatetick Doctrine, and of the now + more applauded Theory of the <i>Chymists</i> about Colour, because those + two Doctrines having Possess'd themselves, the one of the most part of the + Schools, and the other of the Esteem of the Generality ef Physicians and + other Learned Men, whose Professions and Ways of Study do not exact that + they should Scrupulously examine the very First and Simplest Principles of + Nature, I fear'd it would be to + <!-- Page 90 --> <span class="pagenum"><a name="Page_90" id="Page_90"></a>[pg + 90]</span> little purpose, without doing something to discover the + Insufficiency of these Hypotheses, that I should, (which was the <i>Other</i> + thing I thought requisite for me to do) set down among my other + Experiments those in the greatest Number, that may let you see, that, till + I shall be Better Inform'd, I encline to take Colour to be a Modification + of Light, and would invite you chiefly to Cultivate that Hypothesis, and + Improve it to the making out of the Generation of Particular Colours, as I + have Endeavour'd to apply it to the Explication of Whiteness and + Blackness. + </p> + <p> + 5. Thirdly. But, <i>Pyrophilus</i>, though this be at present the + Hypothesis I preferr, yet I propose it but in a General Sense, teaching + only that the Beams of Light, Modify'd by the Bodies whence they are sent + (Reflected or Refracted) to the Eye, produce there that Kind of Sensation, + Men commonly call Colour; But whether I think this Modification of the + Light to be perform'd by Mixing it with Shades, or by Varying the + Proportion of the Progress and Rotation of the <i>Cartesian Globuli + Cælestes</i>, or by some other way which I am not now to mention, I + pretend not here to Declare. Much less do I pretend to Determine, or + scarce so much as to Hope to + <!-- Page 91 --> <span class="pagenum"><a name="Page_91" id="Page_91"></a>[pg + 91]</span> know all that were requisite to be Known, to give You, or even + my Self, a perfect account of the Theory of Vision and Colours, for in + Order to such an undertaking I would first Know what Light is, and if it + be a Body (as a Body or the Motion of a Body it seems to be) what Kind of + Corpuscles for Size and Shape it consists of, with what Swiftness they + move Forwards, and Whirl about their own Centres. Then I would Know the + Nature of Refraction, which I take to be one of the Abstrusest things (not + to explicate Plausibly, but to explicate Satisfactorily) that I have met + with in Physicks; I would further Know what Kind and what Degree of + Commixture of Darkness or Shades is made by Refractions or Reflections, or + both, in the Superficial particles of those Bodies, that being Shin'd + upon, constantly exhibit the one, for Instance, a Blew, the other a + Yellow, the third a Red Colour; I would further Know why this + Contemperation of Light and Shade, that is made, for Example, by the Skin + of a Ripe Cherry, should exhibit a Red, and not a Green, and the Leaf of + the same Tree should exhibit a Green rather than a Red; and indeed, + Lastly, why since the Light that is Modify'd into these Colours consists + but of Corpuscles + <!-- Page 92 --> <span class="pagenum"><a name="Page_92" id="Page_92"></a>[pg + 92]</span> moved against the <i>Retina</i> or Pith of the Optick Nerve, it + should there not barely give a Stroak, but produce a Colour, whereas a + Needle wounding likewise the Eye, would not produce Colour but Pain. + These, and perhaps other things I should think requisite to be Known, + before I should judge my Self to have fully Comprehended the True and + Whole Nature of Colours; and therefore, though by making the Experiments + and Reflections deliver'd in this Paper, I have endeavour'd somewhat to + Lessen my Ignorance in this Matter, and think it far more Desireable to + discover a Little, than to discover Nothing, yet I pretend but to make it + Probable by the Experiments I mention, that some Colours may be Plausibly + enough Explicated in the General by the Doctrine here propos'd; For + whensoever I would Descend to the Minute and Accurate Explication of + Particulars, I find my Self very Sensible of the great Obscurity of + things, without excepting those which we never see but when they are + Enlightned, and confess with <i>Scaliger</i><a name="NtA_5" id="NtA_5"></a><a + href="#Nt_5"><sup>5</sup></a>, <i>Latet natura hæc</i>, (says he, Speaking + of that of Colour) <i>& sicut aliarum rerum species in profundissima + caligine inscitiæ humanæ.</i> + </p> + <!-- Page 93 --> + <p> + <span class="pagenum"><a name="Page_93" id="Page_93"></a>[pg 93]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/132a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>EXPERIMENTAL HISTORY</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>OF COLOURS.</i></span><br /> + </h2> + <hr /> + <h2> + <span style="font-size:75%; letter-spacing:6px">PART. II.</span><br /> + </h2> + <p class="center"> + <i>Of the Nature of Whiteness and Blackness</i>. + </p> + <h2> + <span style="font-size:75%; letter-spacing:6px">CHAP. I.</span><br /> + </h2> + <table> + <tr> + <td valign="top"> + 1. + </td> + <td> + <img width="80" height="80" src="images/132b.png" + alt="Illuminated T in Though" /> + </td> + </tr> + </table> + <p> + Hough after what I have acknowledged, <i>Pyrophilus</i>, of the Abstruse + Nature of Colours in <i>particular</i>, you will easily believe, that I + pretend not to give you a Satisfactory account of Whiteness and Blackness; + Yet not wholly to frustrate your Expectation of my offering something by + way of Specimen towards the Explication of some Colours in particular, + <!-- Page 94 --> <span class="pagenum"><a name="Page_94" id="Page_94"></a>[pg + 94]</span> I shall make choice of These as the most Simple Ones, (and by + reason of their mutual Opposition the Least hardly explicable) about which + to present you my Thoughts, upon condition you will take them at most to + be my Conjectures, not my Opinions. + </p> + <p> + 2. When I apply'd my Self to consider, how the cause of Whiteness might be + explan'd by Intelligible and Mechanical Principles, I remembred not to + have met with any thing among the Antient <i>Corpuscularian</i> + Philosophers, touching the Quality we call Whiteness, save that <i>Democritus</i> + is by <i>Aristotle</i> said to have ascrib'd the Whiteness of Bodies to + their Smoothness, and on the contrary their Blackness to their Asperity.<a + name="NtA_6" id="NtA_6"></a><a href="#Nt_6"><sup>6</sup></a> But though + about the Latter of those Qualities his Opinion be allowable, as we shall + see anon, yet that he heeds a Favourable Interpretation in what is + Deliver'd concerning the First, (at least if his Doctrine be not + Mis-represented in this point, as it has been in many others) we shall + quickly have Occasion to manifest. But amongst the <i>Moderns</i>, the + most Learned <i>Gassendus</i> in his Ingenious Epistle publish'd in the + Year 1642. <i>De apparente + <!-- Page 95 --> <span class="pagenum"><a name="Page_95" id="Page_95"></a>[pg + 95]</span> Magnitudine solis humilis & sublimis</i>, reviving the <i>Atomical</i> + Philosophy, has, though but Incidentally, deliver'd something towards the + Explication of Whiteness upon Mechanical Principles: And because no Man + that I know of, has done so before him, I shall, to be sure to do him + Right, give you his Sense in his own Words:<a name="NtA_7" id="NtA_7"></a><a + href="#Nt_7"><sup>7</sup></a> <i>Cogites velim</i> (says he) <i>lucem + quidem in Diaphano nullius coloris videri, sed in Opaco tamen terminante + Candicare, ac tantò magis, quantò densior seu collectior fuerit. Deinde + aquam non esse quidem coloris ex se candidi & radium tamen ex eâ + reflexum versus oculum candicare. Rursus cum plana aquæ Superficies non + nisi ex una parte eam reflexionem faciat: si contigerit tamen illam in + aliquot bullas intumescere, bullam unamquamque reflectionem facere, & + candoris speciem creare certa Superficiei parte. Ad hæc Spumam ex aqua + pura non alia ratione videri candescere & albescerere quam quod sit + congeries confertissima minutissimarum bullarum, quarum unaquæque suum + radium reflectit, unde continens candor alborve apparet. Denique Nivem + nihil aliud videri quam speciem purissimæ spumæ ex bullulis quam + minutissimis & confertissimis cohærentis. Sed ridiculam me exhibeam, + si tales meas nugas uberius proponem.</i> + </p> + <!-- Page 96 --> + <p> + <span class="pagenum"><a name="Page_96" id="Page_96"></a>[pg 96]</span> + </p> + <p> + 3. But though in this passage, that very Ingenous Person has Anticipated + part of what I should say; Yet I presume you will for all that expect, + that I should give you a fuller Account of that Notion of Whiteness, which + I have the least Exceptions to, and of the Particulars whence I deduce it, + which to do, I must mention to you the following Experiments and + Observations. + </p> + <p> + Whiteness then consider'd as a Quality in the Object, seems chiefly to + depend upon this, That the Superficies of the Body that is call'd White, + is Asperated by almost innumerable Small Surfaces, which being of an + almost Specular Nature, are also so Plac'd, that some Looking this way, + and some that way, they yet Reflect the Rays of Light that fall on them, + not towards one another, but outwards towards the Spectators Eye. In this + Rude and General account of Whiteness, it seems that besides those + Qualities, which are common to Bodies of other Colours, as for instance + the Minuteness and Number of the Superficial parts, the two chief things + attributed to Bodies as White are made to be, First, that its Little + Protuberances and Superficial parts be of somewhat a Specular Nature, that + they may as little Looking-glasses each of them Reflect the Beams it + <!-- Page 97 --> <span class="pagenum"><a name="Page_97" id="Page_97"></a>[pg + 97]</span> receives, (or the little Picture of the Sun made on it) without + otherwise considerably Altering them; whereas in most other Colours, they + are wont to be much Chang'd, by being also Refracted, or by being Return'd + to the Eye, mixt with Shades or otherwise. And next, that its Superficial + parts be so Situated, that they Retain not the Incident Rays of Light by + Reflecting them Inwards, but Send them almost all Back, so that the + Outermost Corpuscles of a White Body, having their Various Little Surfaces + of a Specular Nature, a Man can from no place Behold the Body, but that + there will be among those Innumerable <i>Superficieculæ</i>, that Look + some one way, and some another, enough of them Obverted to his Eye, to + afford like a broken Looking-glass, a confused Idæa, or Representation of + Light, and make such an Impression on the Organ, as that for which Men are + wont to call a Body White. But this Notion will perhaps be best Explan'd + by the same Experiments and Observations, on which it is Built, And + therefore I shall now advance to <i>Them</i>. + </p> + <p> + 4. And in the first place I consider, that the Sun and other Powerfully + Lucid Bodies, are not only wont to Offend, which we call to Dazle our + Eyes, but that if any + <!-- Page 98 --> <span class="pagenum"><a name="Page_98" id="Page_98"></a>[pg + 98]</span> Colour be to be Ascrib'd to them as they are Lucid, it seems it + should be Whiteness: For the Sun at Noon-day, and in Clear weather, and + when his Face is less Troubled, and as it were Stained by the Steams of + Sublunary Bodies, and when his Beams have much less of the Atmosphere to + Traject in their Passage to our Eyes, appears of a Colour more approaching + to White, than when nearer the Horizon, the Interposition of certain Sorts + of Fumes and Vapours make him oftentimes appear either Red, or at least + more Yellow. And when the Sun Shines upon that Natural Looking-glass, a + Smooth water, that part of it, which appears to this or that particular + Beholder, the most Shin'd on, does to his Eye seem far Whiter than the + rest. And here I shall add, that I have sometimes had the Opportunity to + observe a thing, that may make to my present purpose, namely, that when + the Sun was Veil'd over as it were, with a Thin White Cloud, and yet was + too Bright to be Look'd upon Directly without Dazling, by casting my Eyes + upon a Smooth water, as we sometimes do to observe Eclipses without + prejudice to our Eyes, the Sun then not far from the Meridian, appear'd to + me not Red, but so White, that 'twas + <!-- Page 99 --> <span class="pagenum"><a name="Page_99" id="Page_99"></a>[pg + 99]</span> not without some Wonder, that I made the Observation. Besides, + though we in <i>English</i> are wont to say, a thing is Red hot, as an + Expression of its being Superlatively <i>Ignitum</i>, (if I may so Speak + for want of a proper <i>English</i> word) yet in the Forges of Smiths, and + the Furnaces of other Artificers, by that which they call a White heat, + they mean a further Degree of <i>Ignition</i>, than by that which both + they and we call a Red heat. + </p> + <p> + 5. Secondly, I consider, that common Experience informs us, that as much + Light Over-powers the Eye, so when the Ground is covered with Snow, (a + Body extremely White) those that have Weak Eyes are wont to complain of + too much Light: And even those that have not, are generally Sensible of an + Extraordinary measure of Light in the Air; and if they are fain to Look + very long upon the Snow, find their Sight Offended by it. On which + occasion we may call to mind what <i>Xenophon</i> relates, that his <i>Cyrus</i> + marching his Army for divers days through Mountains covered with Snow, the + Dazling splendor of its Whiteness prejudic'd the Sight of very many of his + Souldiers, and Blinded some of them; and other Stories of that Nature be + met with in Writers of good + <!-- Page 100 --> <span class="pagenum"><a name="Page_100" id="Page_100"></a>[pg + 100]</span> Note. And the like has been affirm'd to me by credible Persons + of my own Acquaintance, and especially by one who though Skill'd in + Physick and not Ancient confess'd to me when I purposely ask'd him, that + not only during his stay in <i>Muscovy</i>, he found his Eyes much + Impair'd, by being reduc'd frequently to Travel in the Snow, but that the + Weakness of his Eyes did not Leave him when he left that Country, but has + follow'd him into these Parts, and yet continues to Trouble him. And to + this doth agree what I as well as others have observ'd, namely, that when + I Travell'd by Night, when the Ground was all cover'd with Snow, though + the Night otherwise would not have been Lightsome, yet I could very well + see to Choose my way. But much more Remarkable to my present purpose is + that, which I have met with in <i>Olaus Magnus</i>,<a name="NtA_8" + id="NtA_8"></a><a href="#Nt_8"><sup>8</sup></a> concerning the way of + Travelling in Winter in the <i>Northern</i> Regions, where the Days of + that Season are so very Short; for after other things not needfull to be + here Transcribed: <i>Iter</i>, says he, <i>Diurnum duo scilicet montana + milliaria (quæ 12 Italica sunt) consiciunt. Nocte verò sub splendissima + luna, duplatum iter consumunt aut triplatum. Neque id incommodè fit, + <!-- Page 101 --> <span class="pagenum"><a name="Page_101" id="Page_101"></a>[pg + 101]</span> cum nivium reverberatione lunaris splendo<sup>ris</sup> + sublimes & declives campos illustret, ac etiam montium præcipitia ac + noxias feras à lorgè prospiciant evitandas</i>. Which Testimony I the less + Scruple to allege, because that it agrees very well with what has been + Affirm'd to me by a Physician of <i>Mosco</i>, whom the Notion I have been + Treating of concerning Whiteness invited me to ask whether he could not + See much farther when he Travell'd by Night in <i>Russia</i> than he could + do in <i>England</i>, or elsewhere, when there was no Snow upon the + Ground; For this Ingenious Person inform'd me, that he could See Things at + a farr greater Distance, and with more Clearness, when he Travell'd by + Night on the <i>Russian</i> Snow, though without the Assistance of + Moon-shine, than we in these Parts would easily be perswaded. Though it + seems not unlikely to me, that the Intenseness of the Cold may contribute + something to the considerableness of the Effect, by much Clearing the Air + of Darkish Steams, which in these more Temperate Climates are wont to + Thicken it in Snowy weather: For having purposely inquir'd of this Doctor, + and consulted that Ingenious Navigator Captain <i>James</i>'s Voyage + hereafter to be further mention'd, I find both their Relations + <!-- Page 102 --> <span class="pagenum"><a name="Page_102" id="Page_102"></a>[pg + 102]</span> agree in this, that in Dark Frosty Nights they could Discover + more Stars, and See the rest Clearer than we in <i>England</i> are wont to + do. + </p> + <p> + 6. I know indeed that divers Learned Men think, that Snow so strongly + Affects our Eye, not by a Borrow'd, but a Native Light; But I venture to + give it as a Proof, that White Bodies reflect more Light than Others, + because having once purposely plac'd a parcel of Snow in a Room carefully + Darkned, that no Celestial Light might come to fall upon it; neither I, + nor an ingenous Person, (Skill'd in Opticks) whom I desir'd for a Witness, + could find, that it had any other Light than what it receiv'd. And + however, 'tis usual among those that Travel in Dark Nights, that the + Guides wear something of White to be Discern'd by, there being scarce any + Night so Dark, but that in the Free Air there remains some Light, though + Broken and Debilitated perhaps by a thousand Reflections from the Opacous + Corpuscles that Swim in the Air, and lend it to one another before it + comes to arrive at the Eye. + </p> + <p> + 7. Thirdly, And the better to shew that White Bodies reflect store of + Light, in comparson of those that are otherwise Colour'd, I did in the + Darkn'd Room, + <!-- Page 103 --> <span class="pagenum"><a name="Page_103" id="Page_103"></a>[pg + 103]</span> formerly mention'd, hold not far from the Hole, at which the + Light was admitted, a Sheet only of White Paper, from whence casting the + Sun-beams upon a White Wall, whereunto it was Obverted, it manifestly + appear'd both to Me, and to the Person I took for a Witness of the + Experiment, that it Reflected a far greater Light, than any of the other + Colours formerly mention'd, the Light so thrown upon one Wall notably + Enlightning it, and by it a good part of the Room. And yet further to show + you, that White Bodies Reflect the Beams From them, and not Towards + themselves, Let me add, that Ordinary Burning-glasses, such as are wont to + be employ'd to light Tobacco, will not in a great while Burn, or so much + as Discolour a Sheet of White Paper. Insomuch that even when I was a Boy, + and Lov'd to make Tryals with Burning-glasses, I could not but wonder at + this Odd <i>Phænomenon</i>, which set me very Early upon Guessing at the + Nature of Whiteness, especially because I took notice, that the Image of + the Sun upon a White Paper was not so well Defin'd (the Light seeming too + Diffus'd) as upon Black, and because I try'd, that Blacking over the Paper + with Ink, not only the Ink would be quickly Dry'd up, but the + <!-- Page 104 --> <span class="pagenum"><a name="Page_104" id="Page_104"></a>[pg + 104]</span> Paper that I could not Burn before, would be quickly set on + Fire. I have also try'd, that by exposing my Hand with a Thin Black Glove + over it to the Warm Sun, it was thereby very quickly and considerably more + Heated, than if I took off the Glove, and held my Hand Naked, or put on it + another Glove of Thin but White Leather. And having thus shewn you, <i>Pyrophilus</i>, + that White Bodies reflect the most Light of any, let us now proceed, to + consider what is further to be taken notice of in them, in order to our + present Enquiry. + </p> + <p> + 8. And Fourthly, whereas among the Dispositions we attributed to White + Bodies, we also intimated this, That such Bodies are apt, like <i>Speculums</i>, + though but Imperfect ones, to Reflect the Light that falls on them + Untroubled or Unstain'd, we shall besides other particulars to be met with + in these Papers, offer you this in favour of the Conjecture; That in the + Darkned Room several times mention'd in this Treatse, we try'd that the + Sun-beams being cast from a Coloured Body upon a neighbouring White Wall, + the Determinate Colour of the Body was from the Wall reflected to the Eye; + whereas we could in divers cases manifestly Alter the Colour arriving at + the Eye, by Substituting + <!-- Page 105 --> <span class="pagenum"><a name="Page_105" id="Page_105"></a>[pg + 105]</span> at a convenient Distance, a (conveniently) Colour'd (and + Glossy) Body instead of the White Wall. As by throwing the Beams from a + Yellow Body upon a Blew, there would be Exhibited a kind of Green, as in + the Experiments about Colours is more fully Declar'd. + </p> + <p> + 9. I know not whether I should on this Occasion take notice, that when, as + when looking upon the Calm and Smooth Surface of a River betwixt my Eye + and the Sun, it appear'd to be a natural <i>Speculum</i>, wherein that + Part which Reflected to my Eye the Entire and defin'd Image of the Sun, + and the Beams less remote from those which exhibited That Image, appear'd + indeed of a great and Whitish Brightness, but the rest Comparatively Dark + enough: if afterwards the Superficies chanc'd to be a little, but not much + troubled, by a gentle Breath of Wind, and thereby reduc'd into a Multitude + of Small and Smooth <i>Speculums</i>, the Surface of the River would + suitably to the Doctrine lately deliver'd, at a Distance appear very much + of Kin to White, though it would lose that Brightness or Whiteness upon + the Return of the Surface to Calmness and an Uniform Level. And I have + sometimes for Tryals sake brought in by a Lenticular Glass, the Image of a + River, Shin'd upon + <!-- Page 106 --> <span class="pagenum"><a name="Page_106" id="Page_106"></a>[pg + 106]</span> by the Sun, into an Upper Room Darkn'd, and Distant about a + Quarter of a Mile from the River, by which means the Numerous Declining + Surfaces of the Water appear'd so Contracted, that upon the Body that + receiv'd the Images, the whole River appear'd a very White Object at two + or three paces distance. But if we drew Near it, this Whiteness appear'd + to proceed from an Innumerable company of Lucid Reflections, from the + several Gently wav'd Superficies of the Water, which look'd Near at hand + like a Multitude of very Little, but Shining Scales of Fish, of which many + did every moment Disappear, and as many were by the Sun, Wind and River + generated anew. But though this Observation seem'd Sufficiently to + discover, how the Appearing Whiteness in that case was Produc'd, yet in + some other cases Water may have the Same, though not so Vivid a Colour + upon other Accounts; for oftentimes it happens that the Smooth Surface of + the Water does appear Bright or Whitish, by reason of the Reflection not + immediatly of the Images of the Sun, but of the Brightness of the Sky; and + in such cases a Convenient Wind may where it passes along make the Surface + look Black, by causing many such Furrows and Cavities, as may make the + Inflected Superficies + <!-- Page 107 --> <span class="pagenum"><a name="Page_107" id="Page_107"></a>[pg + 107]</span> of the Water reflect the Brightness of the Sky rather Inward + than Outward. And again if the Wind increase into a Storm, the Water may + appear White, especially near the Shore and the Ship, namely because the + Rude Agitation Breaks it into Fome or Froth. So much do Whiteness and + Blackness depend upon the Disposition of the Superficial parts of a Body + to Reflect the Beams of Light Inward or Outward. But that as White Bodies + reflect the most Light of any, so there Superficial Particles are, in the + Sense newly Deliver'd, of a Specular Nature, I shall now further endeavour + to shew both by the making of Specular bodies White, and the making of a + White body Specular. + </p> + <p> + 10. In the Fifth place then, I will inform You, that (not to repeat what + <i>Gassendus</i> observes concerning Water) I have for Curiosity sake + Distill'd Quicksilver in a Cucurbit, fitted with a Capacious Glass-head, + and observ'd that when the Operation was perform'd by the Degrees of Fire + requisite for my purpose, there would stick to the Inside of the Alembick + a multitude of Little round drops of <i>Mercury</i>. And as you know that + <i>Mercury</i> is a Specular Body, so each of these Little drops was a + small round Looking-glass, + <!-- Page 108 --> <span class="pagenum"><a name="Page_108" id="Page_108"></a>[pg + 108]</span> and a Multitude of them lying Thick and Near one another, they + did both in my Judgment, and that of those I Invited to see it, make the + Glass they were fastened to, appear manifestly a White Body. And yet as I + said, this Whiteness depended upon the Minuteness and Nearness of the + Little Mercurial <i>Globuli</i>, the Convexity of whose Surfaces fitted + them to represent in a Narrow compass a Multitude of Little Lucid Images + to differingly situated Beholders. And here let me observe a thing that + seems much to countenance the Notion I have been recommending: namely, + that whereas divers parts of the Sky, and especially the Milky-way, do to + the naked Eye appear White, (as the name it self imports) yet the Galaxie + look'd upon through the Telescope, does not shew White, but appears to be + made up of a Vast multitude of Little Starrs; so that a Multitude of Lucid + Bodies, if they be so Small that they cannot Singly or apart be discern'd + by the Eye, and if they be sufficiently Thick set by one another, may by + their confus'd beams appear to the Eye One White Body. And why it is not + possible, that the like may be done, when a Multitude of Bright and Little + Corpuscles being crowded together, are made to send together Vivid beams + to the Eye, + <!-- Page 109 --> <span class="pagenum"><a name="Page_109" id="Page_109"></a>[pg + 109]</span> though they Shine but as the Planets by a Borrow'd Light? + </p> + <p> + 11. But to return to our Experiments. We may take notice, That the White + of an Egg, though in part Transparent, yet by its power of Reflecting some + Incident Rays of Light, is in some measure a Natural <i>Speculum</i>, + being long agitated with a Whisk or Spoon, loses its Transparency, and + becomes very White, by being turn'd into Froth, that is into an Aggregate + of Numerous small Bubbles, whose Convex Superficies fits them to Reflect + the Light every way Outwards. And 'tis worth Noting, that when Water, for + instance, is Agitated into Froth, if the Bubbles be Great and Few, the + Whiteness will be but Faint, because the number of <i>Specula</i> within a + Narrow compass is but Small, and they are not Thick set enough to Reflect + so Many Little Images or Beams of the Lucid Body, as are requisite to + produce a Vigorous sensation of Whiteness: And partly least it should be + said, that the Whiteness of such Globulous Particles proceeds from the Air + Included in the Froth; (which to make good, it should be prov'd that the + Air it self is White) and partly to illustrate the better the Notion we + have propos'd of Whiteness, I shall add, that I purposely made this + Experiment, I took a quantity + <!-- Page 110 --> <span class="pagenum"><a name="Page_110" id="Page_110"></a>[pg + 110]</span> Fair water, & put to it in a clear Glass phial, a + convenient quantity of Oyl or Spirit of Turpentine, because that Liquor + will not incorporate with Water, and yet is almost as Clear and Colourless + as it; these being Gently Shaken together, the Agitation breaks the Oyl + (which as I said, is Indispos'd to Mix like Wine or Milk <i>per minima</i> + with the Water) into a Multitude of Little Globes, which each of them + Reflecting Outwards a Lucid Image, make the Imperfect Mixture of the two + Liquors appear Whitish; but if by Vehemently Shaking the Glass for a + competent time you make a further Comminution of the Oyl into far more + Numerous and Smaller <i>Globuli</i>, and thereby confound it also better + with the Water, the Mixture will appear of a Much greater Whiteness, and + almost like Milk; whereas if the Glass be a while let alone, the Colour + will by degrees Impair, as the Oyly globes grow Fewer and Bigger, and at + length will quite Vanish, leaving both the Liquors Distinct and Diaphanous + as before. And such a Tryal hath not ill succeeded, when insteed of the + Colourless Oyl of Turpentine I took a Yellow Mixture made of a good + Proportion of Crude Turpentine dissolv'd in that Liquor; and (if I + mis-remember not) it also Succeeded better than one would + <!-- Page 111 --> <span class="pagenum"><a name="Page_111" id="Page_111"></a>[pg + 111]</span> expect, when I employ'd an Oyl brought by Filings of Copper + infused in it, to a deep Green. And this (by the way) may be the Reason, + why often times when the Oyls of some Spices and of Anniseeds &c. are + Distilled in a Limbec with Water, the Water (as I have several times + observ'd) comes over Whitish, and will perhaps continue so for a good + while, because if the Fire be made too Strong, the subtile Chymical Oyl is + thereby much Agitated and Broken, and Blended with the Water in such + Numerous and Minute Globules, as cannot easily in a short time Emerge to + the Top of the Water, and whilst they Remain in it, make it, for the + Reason newly intimated, look Whitish; and perhaps upon the same Ground a + cause may be rendred, why Hot water is observ'd to be usually more Opacous + and Whitish, than the same Water Cold, the Agitation turning the more + Spirituous or otherwise Conveniently Dispos'd Particles of the Water into + Vapours, thereby Producing in the Body of the Liquor a Multitude of Small + Bubbles, which interrupt the Free passage, that the Beams of Light would + else have Every way, and from the Innermost parts of the Water Reflect + many of them Outwards. These and the like Examples, <i>Pyrophilus</i>, + <!-- Page 112 --> <span class="pagenum"><a name="Page_112" id="Page_112"></a>[pg + 112]</span> have induc'd me to Suspect, that the Superficial Particles of + White bodies, may for the Most part be as well Convex as Smooth; I content + my self to say <i>Suspect</i> and <i>for the most part</i>, because it + seems not Easie to prove, that when Diaphanous bodies, as we shall see by + and by, are reduc'd into White Powders, each Corpuscle must needs be of a + Convex Superficies, since perhaps it may Suffice that Specular Surfaces + look severally ways. For (as we have seen) when a Diaphanous Body comes to + be reduc'd to very Minute parts, it thereby requires a Multitude of Little + Surfaces within a Narrow compass. And though each of these should not be + of a Figure Convenient to Reflect a Round Image of the Sun, yet even from + such an Inconveniently Figur'd body, there may be Reflected some (either + Streight or Crooked) Physical Line of Light, which Line I call Physical, + because it has some Breadth in it, and in which Line in many cases some + Refraction of the Light falling upon the Body it depends on, may + contribute to the Brightness, as if a Slender Wire, or Solid Cylinder of + Glass be expos'd to the Light, you shall see in some part of it a vivid + Line of Light, and if we were able to draw out and lay together a + Multitude of these Little + <!-- Page 113 --> <span class="pagenum"><a name="Page_113" id="Page_113"></a>[pg + 113]</span> Wires or Thrids of Glass, so Slender, that the Eye could not + discern a Distance betwixt the Luminous Lines, there is little doubt (as + far as I can guess by a Tryal purposely made with very Slender, but far + less Slender Thrids of Glass, whose Aggregate was Look'd upon one way + White) but the whole Physical Superficies compos'd of them, would to the + Eye appear White, and if so, it will not be always necessary that the + Figure of those Corpuscles, that make a Body appear White, should be <i>Globulous</i>. + And as for Snow it self, though the Learned <i>Gassendus</i> (as we have + seen above) makes it to seem nothing else but a pure Frozen Froth, + consisting of exceedingly Minute and Thickset Bubbles; yet I see no + necessity of Admitting that, since not only by the Variously and Curiously + Figur'd Snow, that I have divers times had the Opportunity with Pleasure + to observe, but also by the Common Snow, it rather doth appear both to the + Naked Eye, and in a <i>Microscope</i>, often, if not most commonly, to + consist principally of Little Slender Icicles of several Shapes, which + afford such Numerous Lines of Light, as we have been newly Speaking of. + </p> + <p> + 12. Sixthly, If you take a Diaphanous Body, as for instance a Piece of + Glass, and + <!-- Page 114 --> <span class="pagenum"><a name="Page_114" id="Page_114"></a>[pg + 114]</span> reduce it to Powder, the same Body, which when it was Entire, + freely Transmitted the Beams of Light, acquiring by Contusion a multitude + of Minute Surfaces, each of which is as it were a Little, but Imperfect <i>Speculum</i>, + is qualify'd to Reflect in a Confus'd manner, so many either Beams, or + Little and Singly Unobservable Images of the Lucid Body, that from a + Diaphanous it Degenerates into a White Body. And I remember, I have for + Trials sake taken Lumps of Rock Crystal, and Heating them Red hot in a + Crucible, I found according to my Expectation, that being Quench'd in Fair + water, even those that remain'd in seemingly entire Lumps exchang'd their + Translucency for Whiteness, the Ignition and Extinction having as it were + Crack'd each Lump into a multitude of Minute Bodies, and thereby given it + a great multitude of new Surfaces. And ev'n with Diaphanous Bodies, that + are Colour'd, there may be this way a Greater Degree of Whiteness + produced, than one would lightly think; as I remember, I have by Contusion + obtain'd Whitish Powders of <i>Granates</i>, Glass of <i>Antimony</i>, and + <i>Emeralds</i> finely Beaten, and you may more easily make the + Experiment, by taking Good Venereal <i>Vitriol</i> of a Deep Blew, + <!-- Page 115 --> <span class="pagenum"><a name="Page_115" id="Page_115"></a>[pg + 115]</span> and comparing with some of the Entire Crystalls purposely + reserv'd, some of the Subtile Powder of the same Salt, which will + Comparatively exhibit a very considerable degree of Whitishness. + </p> + <p> + 13. Seventhly, And as by a Change of Position in the Parts, a Body that is + not White, may be made White, so by a Slight change of the Texture of its + Surface, a White Body may be Depriv'd of its Whiteness. For if, (as I have + try'd in Gold-smiths Shops) you take a piece of Silver that has been + freshly Boyl'd, as the Artificers call it, (which is done by, first + Brushing, and then Decocting it with Salt and Tartar, and perhaps some + other Ingredients) you shall find it to be of a Lovely White. But if you + take a piece of Smooth Steel, and therewith Burnish a part of it, which + may be presently done, you shall find that Part will Lose its Whiteness, + and turn a <i>Speculum</i>, looking almost every where Dark, as other + Looking-glasses do, which may not a little confirm our Doctrine. For by + this we may guess, what it is chiefly that made the Body White before, by + considering that all that was done to deprive it of that Whiteness, was + only to Depress the Little Protuberances that were before on the Surface + of the Silver + <!-- Page 116 --> <span class="pagenum"><a name="Page_116" id="Page_116"></a>[pg + 116]</span> into one Continu'd Superficies, and thereby effect this, that + now the Image of the Lucid Body, and consequently a Kind of Whiteness + shall appear to your Eye, but in some place of the greater Silver + Looking-glass (whence the Beams reflected at an Angle Equal to that + wherewith they fall on it, may reach your Eye) whilst the Asperity + remain'd Undestroy'd, the Light falling on innumerable Little <i>Specula</i> + Obverted some one way, and some another, did from all Sensibly + Distinguishable parts of the Superficies reflect confus'd Beams or + Representations of Light to the Beholders Eye, from whence soever he + chance to Look upon it. And among the Experiments annex'd to this + Discourse, you will find One, wherein by the Change of Texture in Bodies, + Whiteness is in a Trice both Generated and Destroy'd. + </p> + <hr /> + <h3> + CHAP. II. + </h3> + <p> + 1. What we have Discours'd of Whiteness, may somewhat Assist us to form a + Notion of Blackness, those two Qualities being Contrary enough to + Illustrate each other. Yet among the Antient <i>Philosophers</i> I find + less Assistance + <!-- Page 117 --> <span class="pagenum"><a name="Page_117" id="Page_117"></a>[pg + 117]</span> to form a Notion of Blackness than of Whiteness, only <i>Democritus</i> + in the passage above Recited out of <i>Aristotle</i> has given a General + Hint of the Cause of this Colour, by referring the Blackness of Bodies to + their Asperity. But this I call but a General Hint, because those Bodies + that are Green, and Purple, and Blew, seem to be so as well as Black ones, + upon the Account of their Superficial Asperity. But among the <i>Moderns</i>, + the formerly mention'd <i>Gassendus</i>, perhaps invited by this Hint of + <i>Democritus</i>, has Incidentally in another Epistle given us, though a + very Short, yet a somewhat Clearer account of the Nature of Blackness in + these words: <i>Existimare par est corpora suâpte Naturâ nigra constare ex + particulis, quarum Superficieculæ scabræ sint, nec facilè lucem extrorsum + reflectant.</i> I wish this Ingenious Man had enlarg'd himself upon this + Subject; For indeed it seems, that as that which makes a Body White, is + chiefly such a Disposition of its Parts, that it Reflects (I mean without + much Interruption) more of the Light that falls on it, than Bodies of any + other Colour do, so that which makes a Body Black is principally a + Peculiar kind of Texture, chiefly of its Superficial Particle, whereby it + does as it were Dead the Light + <!-- Page 118 --> <span class="pagenum"><a name="Page_118" id="Page_118"></a>[pg + 118]</span> that falls on it, so that very little is Reflected Outwards to + the Eye. + </p> + <p> + 2. And this Texture may be Explicated two, and perhaps more than two + several ways, whereof the first is by Supposing in the Superficies of the + Black Body a Particular kind of Asperity, whereby the Superficial + Particles reflect but Few of the Incident Beams Outwards, and the rest + Inwards towards the Body it self. As if for Instance, we should conceive + the Surface of a Black Body to be Asperated by an almost Numberless throng + of Little Cylinders, Pyramids, Cones, and other such Corpuscles, which by + their being Thick Set and <i>Erected</i>, reflect the Beams of Light from + one to another Inwards, and send them too and fro so often, that at length + they are Lost before they can come to Rebound out again to the Eye. And + this is the first of the two mention'd ways of Explicating Blackness. The + other way is by Supposing the Texture of Black Bodies to be such, that + either by their Yielding to the Beams of Light, or upon some other + Account, they do as it were Dead the Beams of Light, and keep them from + being Reflected in any Plenty, or with any Considerable Vigour of Motion, + Outwards. According to this Notion it may be said, that + <!-- Page 119 --> <span class="pagenum"><a name="Page_119" id="Page_119"></a>[pg + 119]</span> the Corpuscles that make up the Beams of Light, whether they + be Solary <i>Effluviums</i>, or Minute Particles of some Ætherial + Substance, Thrusting on one another from the Lucid Body, do, falling on + Black Bodies, meet with such a Texture, that such Bodies receive Into + themselves, and Retain almost all the Motion communicated to them by the + Corpuscles that make up the Beams of Light, and consequently Reflect but + Few of them, or those but Languidly, towards the Eye, it happening here + almost in like manner as to a ball, which thrown against a Stone or Floor, + would Rebound a great way Upwards, but Rebounds very Little or not at all, + when it is thrown against Water, or Mud, or a Loose Net, because the Parts + yield, and receive into themselves the Motion, on whose Account the Ball + should be Reflected Outwards. But this Last way of Explicating Blackness, + I shall content my Self to have Propos'd, without either Adopting it, or + absolutely Rejecting it. For the Hardness of Touchstones, Black Marble and + other Bodies, that being Black are Solid, seem to make it somewhat + Improbable, that such Bodies should be of so Yielding a Texture, unless we + should say, that some Bodies may be more Dispos'd to Yield to the Impulses + of + <!-- Page 120 --> <span class="pagenum"><a name="Page_120" id="Page_120"></a>[pg + 120]</span> the Corpuscles of Light by reason of a Peculiar Texture, than + other Bodies, that in other Tryals appear to be Softer than they. But + though the Former of these two Explications of Blackness be that, by which + we shall Endeavour to give an Account of it, yet as we said, we shall not + Absolutely Reject this Latter, partly because they both Agree in this, + that Black Bodies Reflect but Little of the Light that falls on them, and + partly because it is not Impossible, that in some Cases both the + Disposition of the Superficial particles, as to Figure and Position, and + the Yielding of the Body, or some of its Parts, may joyntly, though not in + an Equal measure concurr to the rendring of a Body Black. The + Considerations that induc'd me to propose this Notion of Blackness, as I + Explan'd it, are principally these: + </p> + <p> + 3. First, That as I lately said, Whiteness and Blackness being generally + reputed to be Contrary Qualities, Whiteness depending as I said upon the + Disposition of the Parts of a Body to Reflect much Light, it seems likely, + that Blackness may depend upon a Contrary Disposition of the Black Bodies + Surface; But upon this I shall not Insist. + </p> + <p> + 4. Next then we see, that if a Body of + <!-- Page 121 --> <span class="pagenum"><a name="Page_121" id="Page_121"></a>[pg + 121]</span> One and the same Colour be plac'd, part in the Sun-beams, and + part in the Shade, that part which is not Shin'd on will appear more of + Kin to Blackness than the other, from which more Light Rebounds to the + Eye; And Dark Colours seem the Blacker, the less Light they are Look'd + upon in, and we think all Things Black in the Dark, when they send no + Beams to make Impressions on our Organs of Sight, so that Shadows and + Darkness are near of Kin, and Shaddow we know is but a Privation of Light; + and accordingly Blackness seems to proceed from the Paucity of Beams + Reflected from the Black Body to the Eye, I say the Paucity of Beams, + because those Bodies that we call Black, as Marble, Jeat, &c. are + Short of being perfectly so, else we should not See them at all. But + though the Beams that fall on the Sides of those Erected Particles that we + have been mentioning, do Few of them return Outwards, yet those that fall + upon the Points of those Cylinders, Cones, or Pyramids, may thence Rebound + to the Eye, though they make there but a Faint Impression, because they + Arrive not there, but Mingl'd with a great Proportion of Little Shades. + This may be Confirm'd by my having procur'd a Large piece of Black + <!-- Page 122 --> <span class="pagenum"><a name="Page_122" id="Page_122"></a>[pg + 122]</span> Marble well Polish'd, and brought to the Form of a Large + Sphærical and Concave <i>Speculum</i>; For on the Inside this Marble being + well Polish'd, was a kind of Dark Looking-glass, wherein I could plainly + see a Little Image of the Sun, when that Shin'd upon it. But this Image + was very far from Offending and Dazling my Eyes, as it would have done + from another <i>Speculum</i>; Nor, though the <i>Speculum</i> were Large, + could I in a Long time, or in a Hot Sun set a piece of Wood on Fire, + though a far less <i>Speculum</i> of the same Form, and of a more + Reflecting Matter, would have made it Flame in a Trice. + </p> + <p> + 5. And on this Occasion we may as well in Reference to something formerly + deliver'd concerning Whiteness, as in Reference to what has been newly + said, Subjoyn what we further observ'd touching the Differing Reflections + of Light from White and Black Marble, namely, that having taking a pretty + Large Mortar of White Marble, New and Polish'd in the Inside, and Expos'd + it to the Sun, we found that it Reflected a great deal of Glaring Light, + but so Dispers'd, that we could not make the Reflected Beams concurr in + any such Conspicuous <i>Focus</i>, as that newly taken notice of in the + Black Marble, though + <!-- Page 123 --> <span class="pagenum"><a name="Page_123" id="Page_123"></a>[pg + 123]</span> perhaps there may enough of them be made to meet near the + Bottom, to make some Kind of <i>Focus</i>, especially since by holding in + the Night-time a Candle at a convenient Distance, we were able to procure + a Concourse of some, though not many of the Reflected Beams, at about two + Inches distant from the Bottom of the Mortar: But we found the Heat even + of the Sunbeams so Dispersedly Reflected to be very Languid, even in + Comparison of the Black Marbles <i>Focus</i>. And the Little Picture of + the Sun, that appear'd upon the White Marble as a <i>Speculum</i>, was but + very Faint and exceeding ill Defin'd. Secondly, That taking two pieces of + Plain and Polish'd Surfaces, and casting on them Successively the Beams of + the Same Candle, In such manner, as that the Neighbouring Superficies + being Shaded by an Opacous and Perforated Body, the Incident Beams were + permitted to pass but through a Round Hole of about Half an Inch Diameter, + the Circle of Light that appear'd on the White Marble was in Comparison + very Bright, but very ill Defin'd; whereas that on the Black Marble was + far less Luminous, but much more precisely Defin'd. + </p> + <p> + 6. Thirdly, When you Look upon a piece of Linnen that has Small Holes in + it, + <!-- Page 124 --> <span class="pagenum"><a name="Page_124" id="Page_124"></a>[pg + 124]</span> those Holes appear very Black, and Men are often deceiv'd in + taking Holes for Spots of Ink; And Painters to represent Holes, make use + of Black, the Reason of which seems to be, that the Beams that fall on + those Holes, fall into them So Deep, that none of them is Reflected back + to the Eye. And in narrow Wells part of the Mouth seems Black, because the + Incident Beams are Reflected Downwards from one side to another, till they + can no more Rebound to the Eye. + </p> + <p> + We may consider too, that if Differing parts of the same piece of Black + Velvet be stroak'd Opposite ways, the piece of Velvet will appear of two + Distinct kinds of Blackness, the one far Darker than the other, of which + Disparity the Reason Seems to be, that in the Less obscure part of the + Velvet, the Little Silken Piles whereof 'tis made up, being Inclin'd, + there is a Greater part of each of them Obverted to the Eye, whereas in + the other part the Piles of Silk being more Erected, there are far Fewer + Beams Reflected Outwards from the Lateral parts of each Pile, So that most + of those that Rebound to the Eye, come from the Tops of the Piles, which + make but a small part of the whole Superficies, that may be cover'd by the + piece of Velvet. + <!-- Page 125 --> <span class="pagenum"><a name="Page_125" id="Page_125"></a>[pg + 125]</span> Which Explication I propose, not that I think the Blackness of + the Velvet proceeds from the Cause assign'd, since each Single Pile of + Silk is Black by reason of its Texture, in what Position soever you Look + upon it; But that the Greater Blackness of one of these Tuffts seems to + proceed from the Greater Paucity of Beams Reflected from it, and that from + the Fewness of those Parts of a Surface that Reflect Beams, and the + Multitude of those Shaded Parts that Reflect none. And I remember, that I + have oftentimes observ'd, that the Position of Particular Bodies far + greater than Piles of Silk in reference to the Eye, may notwithstanding + their having each of them a Colour of its own, make one part of their + Aggregate appear far Darker than the other; For I have near Great Towns + often taken notice, that a Cart-load of Carrots pack'd up, appear'd of a + much Darker Colour when Look'd upon, where the Points of the Carrots were + Obverted to the Eye, than where the Sides of them were so. + </p> + <p> + 7. Fourthly, In a Darkned Room, I purposely observ'd, that if the + Sun-beams, which came in at the Hole were receiv'd upon White or any other + Colour, and directed to a Convenient place of the Room, + <!-- Page 126 --> <span class="pagenum"><a name="Page_126" id="Page_126"></a>[pg + 126]</span> they would Manifestly, though not all Equally, Encrease the + Light of that Part; whereas if we Substituted, either a piece of Black + Cloth or Black Velvet, it would so Dead the Incident Beams, that the place + (newly mention'd) whereto I Obverted the Black Body, would be Less + Enlightned than it was before, when it received its Light but from the + Weak and Oblique Reflections of the Floor and Walls of a pretty Large + Room, through which the Beams that came in at the Hole were Confusedly and + Brokenly Dispers'd. + </p> + <p> + 8. Fifthly, And to shew that the Beams that fall on Black Bodies, as they + do not Rebound Outwards to the Eye, so they are Reflected towards the Body + it self, as the Nature of those Erected Particles to which we have imputed + Blackness, requires, we will add an Experiment that will also confirm our + Doctrine touching Whiteness; Namely, that we took a Broad and Large Tile, + and having Whitened over one half of the Superficies of it, and Black'd + the other, we expos'd it to the Summer Sun; And having let it lye there a + convenient time (for the Difference is more Apparent, if it have not lain + there too long) we found, as we expected, that whilst the Whited part of + the Tile remained Cool enough, the + <!-- Page 127 --> <span class="pagenum"><a name="Page_127" id="Page_127"></a>[pg + 127]</span> Black'd part of the same Tile was grown not only Sensible, but + very Hot, (sometimes to a strong Degree.) And to satisfie some of our + Friends the more, we have sometimes left upon the Surface of the Tile, + besides the White and Black parts thereof, a part that Retain'd the native + Red of the Tile it self, and Exposing them to the Sun, we observ'd this + Last mention'd to have Contracted a Heat in comparison of the White, but a + Heat Inferiour to that of the Black, of which the Reason seems to be, that + the Superficial Particles of Black Bodies, being, as we said, more + Erected, than those of White or Red ones, the Corpuscles of Light falling + on their sides, being for the most part Reflected Inwards from one + Particle to another, and thereby engag'd as it were and kept from + Rebounding Upwards, they communicate their brisk Motion, wherewith they + were impell'd against the Black Body, (upon whose account had they fallen + upon a White Body, they would have been Reflected Outwards) to the Small + parts of the Black Body, and thereby Produce in those Small parts such an + Agitation, as (when we feel it) we are wont to call Heat. I have been + lately inform'd, that an Observation near of Kin to Ours, has been made by + some Learned Men in <i>France</i> and + <!-- Page 128 --> <span class="pagenum"><a name="Page_128" id="Page_128"></a>[pg + 128]</span> <i>Italy</i>, by long Exposing to a very Hot Sun, two pieces + of Marble, the one White, the other Black; But though the Observation be + worthy of them, and may confirm the same Truth with Our Experiment, yet + besides that our Tryal needs not the Summer, nor any Great Heat to + succeed, It seems to have this Advantage above the other, that whereas + Bodies more Solid, and of a Closer Texture, though they use to be more + Slowly Heated, are wont to receive a Greater Degree of Heat from the Sun + or Fire, than (<i>Cæteris paribus</i>) Bodies of a Slightest Texture; I + have found by the Information of Stone-cutters, and by other ways of + Enquiry, that Black Marble is much Solider and Harder than White, so that + possibly the Difference betwixt the Degrees of Heat they receive from the + Sunbeams will by many be ascrib'd to the Difference of their Texture, + rather than to that of their Colour, though I think our Experiment will + make it Probable enough that the greater part of that Difference may well + be ascrib'd to that Disposition of Parts, which makes the one Reflect the + Sunbeams Inward; and the other Outwards. And with this Doctrine accords + very well, that Rooms hung with Black, are not only Darker than else they + would be, but are + <!-- Page 129 --> <span class="pagenum"><a name="Page_129" id="Page_129"></a>[pg + 129]</span> wont to be Warmer too; Insomuch that I have known a great + Lady, whose Constitution was somewhat Tender, complain that she was wont + to catch Cold, when she went out into the Air, after having made any long + Visits to Persons, whose Rooms were hung with Black. And this is not the + only Lady I have heard complain of the Warmth of such Rooms, which though + perhaps it may be partly imputed to the <i>Effluvia</i> of those Materials + wherewith the hangings were Dy'd, yet probably the Warmth of such Rooms + depends chiefly upon the same Cause that the Darkness does; As (not to + repeat what I formerly Noted touching my Gloves,) to satisfie some Curious + Persons of that Sex, I have convinc'd them, by Tryall, that of two Pieces + of Silken Stuff given me by themselves, and expos'd in their Presence, to + the same Window, Shin'd on by that Sun, the White was <i>considerably</i> + Heated, when the Black was not so much as <i>Sensibly</i> so. + </p> + <p> + 9. Sixthly, I remember, that Acquainting one Day a <i>Virtuoso</i> of + Unsuspected Credit, that had Visited Hot Countries, with part of what I + have here Deliver'd concerning Blackness, he Related to me by way of + Confirmation of it, a very notable + <!-- Page 130 --> <span class="pagenum"><a name="Page_130" id="Page_130"></a>[pg + 130]</span> Experiment, which he had both others make, and Made himself in + a Warm Climate, namely, that having carefully Black'd over Eggs, and + Expos'd them to the Hot Sun, they were thereby in no very Long time well + Roasted, to which Effect I conceive the Heat of the Climate must have + Concurr'd with the Disposition of the Black Surface to Reflect the + Sunbeams Inward, for I remember, that having made that among other Tryals + in <i>England</i>, though in Summer-time, the Eggs I Expos'd, acquir'd + indeed a considerable Degree of Heat, but yet not so Intense a One, as + prov'd Sufficient to Roast them. + </p> + <p> + 10. Seventhly, and Lastly, Our Conjectures at the Nature of Blackness may + be somewhat Confirm'd by the (formerly mention'd) Observation of the Blind + <i>Dutch-man</i>, that Discerns Colours with his Fingers; for he Says, + that he Feels a greater Roughness upon the Surfaces of Black Bodies, than + upon those of Red, or Yellow, or Green. And I remember, that the Diligent + <i>Bartholinus</i> says,<a name="NtA_9" id="NtA_9"></a><a href="#Nt_9"><sup>9</sup></a> + that a Blind Earl of <i>Mansfield</i> could Distinguish White from Black + only by the Touch, which would Sufficiently Argue a great Disparity in the + Asperities, or other + <!-- Page 131 --> <span class="pagenum"><a name="Page_131" id="Page_131"></a>[pg + 131]</span> Superficial Textures of Bodies of those two Colours, if the + Learn'd Relator had Affirm'd the Matter upon his own Knowledge. + </p> + <p> + II. These, <i>Pyrophilus</i>, are the chief things that Occurr to me at + present, about the Nature of Whiteness and Blackness, which it they have + Rendred it so much as Probable, that in <i>Most</i>; or at least <i>Many</i> + Cases, the Causes of these Qualities may be such as I have Adventur'd to + Deliver, it is as much as I Pretend to; for till I have Opportunity to + Examine the Matter by some further Tryals, I am not sure, but that in some + White and Black Bodies, there may Concurr to the Colour some peculiar + Texture or Disposition of the Body, whereby the Motion of the Small + Corpuscles that make up the Incident Beams of Light, may be Differingly + Modify'd, before they reach the Eye, especially in this, that White Bodies + do not only Copiously Reflect those Incident Corpuscles Outwards, but + Reflect them Briskly, and do not otherwise Alter them in the manner of + their Motion. Nor shall I now stay to Enquire, whether some of those other + ways, (as a Disposition to Alter the Velocity, the Rotation, or the Order + and Manner of Appulse so the Eye of the Reflected Corpuscles + <!-- Page 132 --> <span class="pagenum"><a name="Page_132" id="Page_132"></a>[pg + 132]</span> that Compos'd the Incident Beams of Light) which we mention'd + when we consider'd the Production of Colours in General, may not in some + Cases be Applicable to those of White and Black Bodies: For I am yet so + much a <i>Seeker</i> in this Matter, and so little Wedded to the Opinions + I have propos'd, that what I am to add shall be but the Beginning of a + Collection of Experiments and Observation towards the History of Whiteness + and Blackness, without at present interposing my Explications of them, + that so, I may assist your Enquires without much Fore-stalling or Biassing + your Judgment. + </p> + <hr /> + <!-- Page 133 --> + <p> + <span class="pagenum"><a name="Page_133" id="Page_133"></a>[pg 133]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/172a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:100%; letter-spacing:10px">EXPERIMENT</span><br /> + <span style="font-size:75%; letter-spacing:6px">IN</span><br /> <span + style="font-size:100%; letter-spacing:10px">CONSORT,</span><br /> <span + style="font-size:50%;">Touching</span><br /> <span style="font-size:100%;">Whiteness + & Blackness.</span><br /> + </h2> + <hr /> + <h3> + EXPERIMENT I. + </h3> + <p> + <img width="80" height="80" src="images/172b.png" + alt="Illuminated H in Having" /> Aving promis'd in the <a href="#Page_114">114</a>, + and <a href="#Page_115">115</a>. Pages of the foregoing Discourse of + Whiteness and Blackness, to shew, that those two Colours may by a change + of Texture in bodies, each of them apart Diaphanous and Colourless, be at + pleasure and in a trice as well Generated as Destroy'd, We shall begin + with Experiments that may acquit us of that promise. + </p> + <p> + Take then what Quantity you please of Fair Water, and having Heated it, + put into it as much good Common Sublimate, as it is able to Dissolve, and + (to be sure of having + <!-- Page 134 --> <span class="pagenum"><a name="Page_134" id="Page_134"></a>[pg + 134]</span> it well glutted:) continue putting in the Sublimate, till some + of it lye Untouch'd in the bottom of the Liquor, Filter this Solution + through Cap-paper, to have it cleer and limpid, and into a spoonfull or + two thereof, (put into a clean glass vessel,) shake about four or five + drops (according as you took more or less of this Solution) of good limpid + Spirits of Urine, and immediately the whole mixture will appear White like + Milk, to which mixture if you presently add a convenient proportion of + Rectifi'd <i>Aqua Fortis</i> (for the number of drops is hard to + determine, because of the Differing Strength of the liquor, but easily + found by tryal) the Whiteness will presently disappear, and the whole + mixture become Transparent, which you may, if you please, again reduce to + a good degree of Whiteness (though inferiour to the first) onely by a more + copious affusion of fresh Spirit of Urine. <i>N</i>. First, That it is not + so necessary to employ either <i>Aqua Fortis</i> or Spirit of Urine about + this Experiment, but that we have made it with other liquors instead of + these, of which perhaps more elsewhere. Secondly, That this Experiment, + though not made with the same <i>Menstruums</i>, nor producing the same + Colour is yet much of Kin to that other to be + <!-- Page 135 --> <span class="pagenum"><a name="Page_135" id="Page_135"></a>[pg + 135]</span> mentioned in this Tract among our other Experiments of + Colours, about turning a Solution of Præcipitate into an Orange-colour, + and the Chymical Reason being much alike in both, the annexing it to one + of them may suffice FOR both. + </p> + <h3> + <i>EXPERIMENT II.</i> + </h3> + <p> + Make a strong Infusion of broken Galls in Fair Water, and having Filtred + it into a clean Vial, add more of the same liquor to it, till you have + made it somewhat Transparent, and sufficiently diluted the Colour, for the + credit of the Experiment, lest otherwise the Darkness of the liquor might + make it be objected, that 'twas already almost Ink; Into this Infusion + shake a convenient quantity of a Cleer, but very strong Solution of + Vitriol, and you shall immediately see the mixture turn Black almost like + Ink, and such a way of producing Blackness is vulgar enough; but if + presently after you doe upon this mixture drop a small quantity of good + oyl of Vitriol, and, by shaking the Vial disperse it nimbly through the + two other liquors, you shall (if you perform your part well, and have + employ'd oyl of Vitriol Cleer and Strong enough) see the Darkness of the + liquor presently begin + <!-- Page 136 --> <span class="pagenum"><a name="Page_136" id="Page_136"></a>[pg + 136]</span> to be discuss'd, and grow pretty Cleer and Transparent, losing + its Inky Blackness, which you may again restore to it by the affusion of a + small quantity of a very strong Solution of Salt of Tartar. And though + neither of these Atramentous liquors will seem other than very Pale Ink, + if you write with a clean Pen dipt in them, yet that is common to them + with some sorts of Ink that prove very good when Dry, as I have also + found, that when I made these carefully, what I wrote with either of them, + especially with the Former, would when throughly Dry grow Black enough not + to appear bad Ink. This Experiment of taking away and restoring Blackness + from and to the liquors, we have likewise tryed in Common Ink; but there + it succeeds not so well, and but very slowly, by reason that the Gum wont + to be employed in the making it, does by its Tenacity oppose the + operations of the above mention'd Saline liquors. But to consider Gum no + more, what some kind of Præcipitation may have to do in the producing and + destroying of Inks without it, I have elsewhere given you some occasion + and assistance to enquire; But I must not now stay to do so my self, only + I shall take notice to you, that though it be taken for granted that + bodies will not be Præcipitated by Alcalizat Salts, + <!-- Page 137 --> <span class="pagenum"><a name="Page_137" id="Page_137"></a>[pg + 137]</span> that have not first been dissolved in some Acid <i>Menstruums</i>, + yet I have found upon tryals, which my conjectures lead me to make on + purpose, That divers Vegetables <i>barely infus'd</i>, or, <i>but slightly + decocted in common water</i>, would, upon the affusion of a Strong and + Cleer <i>Lixivium</i> of Potashes, and much more of some other + Præcipitating liquors that I sometimes employ, afford good store of a + Crudled matter, such as I have had in the Præcipitations of Vegetable + substances, by the intervention of Acid things, and that this matter was + easily separable from the rest of the liquor, being left behind by it in + the Filtre; and in making the first Ink mention'd in this Experiment, I + found that I could by Filtration separate pretty store of a very Black + pulverable substance, that remain'd in the Filtre, and when the Ink was + made Cleer again by the Oyl of Vitriol, the affusion of dissolv'd <i>Sal + Tartari</i> seem'd but to Præcipitate, and thereby to Unite and render + Conspicuous the particles of the Black mixture that had before been + dispers'd into very Minute and singly Invisible particles by the Incisive + and resolving power of the highly Corrosive Oyl of Vitriol. + </p> + <p> + <!-- Erratum: insert: --> + And to manifest, <i>Pyrophilus</i>, that Galls are not so requisite as + many suppose to the making Atramentous Liquors, we have sometimes made the + following Experiment, We took dryed Rose leaves and Decocted them for a + while in Fair Water, into two or three spoonfulls of this Decoction we + shook a few drops of a strong and well filtrated Solution of Vitriol + (which perhaps had it been Green would have done as well) and immediately + the mixture did turn Black, and when into this mixture presently after it + was made, we shook a just Proportion of <i>Aqua Fortis</i>, we turn'd it + from a Black Ink to a deep Red one, which by the affusion of a little + Spirit of Urine may be reduc'd immediately to an Opacous and Blackish + Colour. And in regard, <i>Pyrophilus</i>, that in the former Experiments, + both the Infusion of Galls, and the Decoction of Roses, and the Solution + of Copperis employ'd about them, are endow'd each of them with its own + Colour, there may be a more noble Experiment of the sudden production of + Blackness made by the way mention'd in the Second Section of the Second + Part of our Essays, for though upon the Confusion of the two Liquors there + mention'd, there do immediately emerge a very Black mixture, yet both the + Infusion of <i>Orpiment</i> and the Solution of <i>Minium</i> were before + their being joyn'd together, Limpid and Colourless. + <!-- end insert --> + </p> + <!-- Page 138 --> + <p> + <span class="pagenum"><a name="Page_138" id="Page_138"></a>[pg 138]</span> + </p> + <h3> + <i>EXPERIMENT III.</i> + </h3> + <p> + If pieces of White Harts-horn be with a competent degree of Fire distill'd + in a Glass-retort, they will, after the avolation of the Flegm, Spirit, + Volatile Salt, and the looser and lighter parts of the Oleagenous + substance, remain behind of a Cole-black colour. And even Ivory it self + being skilfully Burnt (how I am wont to do it, I have elsewhere set down) + affords Painters one of the best and deepest Blacks they have, and yet in + the Instance of distill'd Harts-horn, the operation being made in + Glass-vessels carefully clos'd, it appears there is no Extraneous Black + substance that Insinuates it self into White Harts-horn, and thereby makes + it turn Black; but that the Whiteness is destroy'd, and the Blackness + generated, only by a Change of Texture, made in the burnt Body, by the + Recess of some parts and the Transposition of others. And though I + remember not that in many Distillations of Harts-horn I ever sound the <i>Cap. + Mort</i>. to pass from Black to a true Whiteness, whilst it continu'd in + Clos'd vessels, yet having taken out the Cole-black fragments, and + Calcin'd them in Open vessels, I could in few hours quite destroy that + Blackness, & without + <!-- Page 139 --> <span class="pagenum"><a name="Page_139" id="Page_139"></a>[pg + 139]</span> sensibly changing their Bulk or Figure, reduce them to great + Whiteness. So much do these two Colours depend upon the Disposition of the + little parts, that the Bodies wherein they are to be met with do consist + of. And we find, that if Whitewine Tartar, or even the white Crystalls of + such Tartar be burnt without being truly Calcin'd, the <i>Cap. Mortuum</i> + (as the Chymists call the more Fixt part) will be Black. But if you + further continue the Calcination till you have perfectly Incinerated the + Tartar, & kept it long enough in a Strong fire, the remaining <i>Calx</i> + will be White. And so we see that not only other Vegetable substances, but + even White woods, as the Hazel, will yield a Black Charcoal, and + afterwards Whitish ashes; And so Animal substances naturally White, as + Bones and Eggshels, will grow Black upon the being Burnt, and White again + when they are perfectly Calcin'd. + </p> + <h3> + <i>EXPERIMENT IV.</i> + </h3> + <p> + But yet I much Question whether that Rule delivered by divers, as well + Philosophers as Chymists, <i>adusta nigra, sed perusta alba</i>, will hold + as Universally as is presum'd, since I have several Examples to allege + against + <!-- Page 140 --> <span class="pagenum"><a name="Page_140" id="Page_140"></a>[pg + 140]</span> it: For I have found that by burning Alablaster, so as both to + make it appear to boyl almost like Milk, and to reduce it to a very fine + Powder, it would not at all grow Black, but retain its Pure and Native + Whiteness, and though by keeping it longer than is usual in the fire, I + produced but a faint Yellow, even in that part of the Powder that lay + nearest the top of the Crucible, yet having purposely enquired of an + Experienced Stone-cutter, who is Curious enough in tryng Conclusions in + his own Trade, he told me he had found that if Alabaster or Plaster of + Paris be very long kept in a Strong fire, the whole heap of burnt Powder + would exchange its Whiteness for a much deeper Colour than the Yellow I + observ'd. Lead being Calcin'd with a Strong fire turns (after having + purhaps run thorough divers other Colour) into <i>Minium</i>, whose Colour + we know is a deep red; and if you urge this <i>Minium</i>, as I have + purposely done with a Strong fire, you may much easier find a Glassie and + Brittle Body darker than <i>Minium</i>, than any white <i>Calx</i> or + Glass. 'Tis known among Chymists, that the white <i>Calx</i> of Antimony, + by the further and more vehement operation of the fire, may be melted into + Glass, which we have obtain'd of a Red Colour, which is + <!-- Page 141 --> <span class="pagenum"><a name="Page_141" id="Page_141"></a>[pg + 141]</span> far deeper than that of the <i>Calx</i> of Burnt Antimony, and + though common Glafs of Antimony being usually Adulterated with <i>Borax</i>, + have its Colour thereby diluted, oftentimes to a very pale Yellow; yet not + onely ours made more sincerily, was, as we said, of a Colour less remote + from Black, than was the <i>Calx</i>; but we observ'd, that by Melting it + once or twice more, and so exposing it to the further operation of the + Fire, we had, as we expected, the Colour heightned. To which we shall add + but this one Instance, (which is worth the taking notice of in Reference + to Colours:) That, if you take Blew, but Unsophisticated, Vitriol, and + burn it very slowly, and with a Gentle degree of Heat, you may observe, + that when it has Burnt but a Little, and yet so far as that you may rub it + to Powder betwixt your fingers, it will be of a White or Whitish Colour; + But if you Prosecute the Calcination, this Body which by a light Adustion + was made White, will pass through other Colours, as Gray, Yellowish, and + Red; and if you further burn it with a Long and Vehement fire, by that + time it comes to be <i>Perustum</i>, it will be of a dark purple, nearer + to Black, not only than the first <i>Calx</i>, but than the Vitriol before + it at all felt the fire. I might add that <i>Crocus</i> + <!-- Page 142 --> <span class="pagenum"><a name="Page_142" id="Page_142"></a>[pg + 142]</span> <i>Martis</i> (<i>per se</i> as they call it) made by the + Lasting violence of the Reverberated flames is not so near a Kin to White, + as the Iron or Steel that afforded it was before its Calcinations; but + that I suppose, these Instances may Suffice to satisfie you, that Minerals + are to be excepted out of the forementioned Rule, which perhaps, though it + seldome fail in substances belonging to the Vegetable or Animal Kingdome, + may yet be Question'd even in some of these, if that be true, which the + Judicious Traveller <i>Bellonius</i> affirms, that Charcoales made out of + the Wood of <i>Oxycæder</i> are White; And I could not find that though in + Retorts Hartshorn and other White Bodies will be Denigrated by Heat, yet + Camphire would not at all lose its Whiteness, though I have purposely kept + it in such a heat, as made it melt and boyl. + </p> + <!-- Erratum: delete: And to manifest, <i>Pyrophilus</i>, that Galls are not + so requisite as many suppose to the making Atramentous Liquors, we have + sometimes made the following Experiment, We took dryed Rose leaves and + Decocted them for a while in Fair Water, into two or three spoonfulls of + this Decoction we shook a few drops of a strong and well filtrated + Solution of Vitriol (which perhaps had it been Green would have done as + well) and immediately the mixture did turn Black, and when into this + mixture presently after it was made, we shook a just Proportion of <i>Aqua + Fortis</i>, we turn'd it from a Black Ink to a deep Red one, which by the + affusion of a little Spirit of Urine may be reduc'd immediately to an + Opacous and Blackish Colour. And in regard, <i>Pyrophilus</i>, that in the + former Experiments, both the Infusion of Galls, and the Decoction of + Roses, and the Solution of Copperis employ'd about them, are endow'd each + of them with its own Colour, there may be a more noble Experiment of the + sudden production of Blackness made by the way mention'd in the Second + Section of the Second Part of our Essays, for though upon the Confusion of + the two Liquors there mention'd, there do immediately emerge a very Black + mixture, yet both the Infusion of <i>Orpiment</i> and the Solution of + <i>Minium</i> were before their being joyn'd together, Limpid and + Colourless. --> + <!-- Page 143 --> + <p> + <span class="pagenum"><a name="Page_143" id="Page_143"></a>[pg 143]</span> + </p> + <h3> + <i>EXPERIMENT V.</i> + </h3> + <p> + And now I speak of Camphire, it puts me in mind of adding this Experiment, + That, though as I said in Clos'd Glasses, I could not Denigrate it by + Heat, but it would Sublime to the sides and top of the Glass, + <!-- Page 144 --> <span class="pagenum"><a name="Page_144" id="Page_144"></a>[pg + 144]</span> as it was before, yet not only it will, being set on fire in + the Free Air, send forth a Copious smoak, but having purposely upon some + of it that was Flaming, clapt a Large Glass, almost in the form of a Hive, + (but more Slender only) with a Hole at the top, (which I caus'd to be made + to trye Experiments of Fire and Flame in) it continued so long burning + that it Lin'd all the Inside of the Glass with a Soot as Black as Ink, and + so Copious, that the Closeness of the Vessel consider'd, almost all that + part of the White Camphire that did take Fire, seem'd to have been chang'd + into that deep Black Substance. + </p> + <h3> + <i>EXPERIMENT VI</i> + </h3> + <p> + And this also brings into my mind another Experiment that I made about the + production of Blackness, whereof, for Reasons too long to be here deduced, + I expected and found a good Success, an it was this: I took Rectifi'd Oyl + of Vitriol (that I might have the Liquor Clean as well as Strong) and by + degrees mixt with it a convenient proportion of the Essential Oyl, as + Chymists call it, of Wormwood, drawn over with store of Water in a Limbec, + and warily Distilling the mixture in a Retort, there remain'd + <!-- Page 145 --> <span class="pagenum"><a name="Page_145" id="Page_145"></a>[pg + 145]</span> a scarce credible quantity of dry Matter + <!-- Erratum: delete: s -->, Black as a Coal. And because the Oyl of + Wormwood, though a Chymical Oyl drawn by a <i>Virtuoso</i>, seem'd to have + somewhat in it of the Colour of the Plant, I Substituted in its Room, the + Pure and Subtile Essential Oyl of Winter-Savory, and mixing little by + little this Liquor, with (if I mis-remember not) an Equal weight of the + formerly mention'd Rectifi'd Oyl of Vitriol, and Distilling them as before + in a Retort, besides what there pass'd over into the Receiver, even these + two clear Liquors left me a Considerable Proportion, (though not so great + as the two former) of a Substance Black as Pitch, which I yet Keep by me + as a Rarity. + </p> + <h3> + <i>EXPERIMENT VII.</i> + </h3> + <p> + A way of Whiting Wax Cheaply and in Great Quantity may be a thing of good + Oeconomical Use, and we have elsewhere set down the Practice of Trades-men + that Blanch it; But here Treating of Whiteness only in Order to the + Philosophy of Colours, I shall not Examine which of the Slow wayes may be + best Employ'd, to free Wax from the Yellow Melleous parts, but shall + rather set down a Quick + <!-- Page 146 --> <span class="pagenum"><a name="Page_146" id="Page_146"></a>[pg + 146]</span> way of making it White, though but in very Small Quantities. + Take then a little Yellow Wax, scraped or thinly sliced, and putting it + into a + <!-- Erratum: was C... -->Bolts-head or some other Convenient Glass, pour + to it a pretty deal of Spirit of Wine, and placing the Vessel in Warm + Sand, Encrease the Heat by degrees, till the Spirit of Wine begin to + Simper or to Boyl a little; and continuing that degree of Fire, if you + have put Liquor enough, you will quickly have the Wax dissolv'd, then + taking it off the fire, you may either suffer it to Cool as hastily as + with Safety to the Glass you can, or Pour it whilst 'tis yet Hot into a + Filtre of Paper, and either in the Glass where it Cools, or in the Filtre, + you will soon find the Wax and <i>Menstruum</i> together reduc'd into a + White Substance, almost like Butter, which by letting the Spirit Exhale + will shrink into a much Lesser Bulk, but still retaining its Whiteness. + And that which is pretty in the working of this Magistery of Wax, is, that + the Yellowness vanishes, neither appearing in the Spirit of Wine that + passes Limpid through the Filtre, nor in the Butter of Wax, if I may so + call it, that, as I said, is White. + <!-- Page 147 --> <span class="pagenum"><a name="Page_147" id="Page_147"></a>[pg + 147]</span> + </p> + <h3> + <i>EXPERIMENT VIII.</i> + </h3> + <p> + There is an Experiment, <i>Pyrophilus</i>, which though I do not so + exactly remember, and though it be somewhat Nice to make, yet I am willing + to Acquaint You with, because the thing Produc'd, though it be but a + Curiosity, is wont not a little to please the Beholders, and it is a way + of turning by the help of a Dry Substance, an almost Golden-Colour'd + Concrete, into a White one, the Several Tryals are not at present so fresh + in my Memory to enable me to tell you Certainly, whether an Equal onely or + a Double weight of Common Sublimate must be taken in reference to the + Tinglass, but if I mistake not, there was in the Experiment that succeeded + best, Two parts of the Former taken to One of the Latter. These + Ingredients being finely Powdred and Exactly mix'd, we Sublim'd together + by degrees of fire (the due Gradation of which is in this Experiment a + thing of main Importance) there ascended a matter of a very peculiar + Texture, for it was for the most part made up of very Thin, Smooth, Soft + and Slippery Plates, almost like the finest sort of the Scales of Fishes, + but of so Lovely a White Inclining to + <!-- Page 148 --> <span class="pagenum"><a name="Page_148" id="Page_148"></a>[pg + 148]</span> Pearl-Colour, and of so Curious and Shining a Gloss, that they + appear'd in some respect little Inferiour to Orient Pearls, and in other + Regards, they seem'd to Surpass them, and were Applauded for a sort of the + Prettiest Trifles that we had ever prepar'd to Amuse the Eye. I will not + undertake that though you'l hardly miss changing the Colour of your + shining Tinglass, yet you will the first or perhaps the second time hit + Right upon the way of making the Glistring Sublimate I have been + mentioning. + </p> + <h3> + <i>EXPERIMENT IX.</i> + </h3> + <p> + When we Dissolve in <i>Aqua Fortis</i> a mixture of Gold and Silver melted + into one Lump, it usually happens that the Powder of Gold that falls to + the bottom, as not being Dissoluble by that <i>Menstruum</i>, will not + have its own Yellow, but appear of a Black Colour, though neither the + Gold, nor the Silver, nor the <i>Aqua Fortis</i> did before manifest any + Blackness. And divers Alchymists, when they make Solutions of Minerals + they would Examine, are very Glad, if they see a Black Powder Præcipitated + to the Bottom, taking it for a Hopefull Sign, that those Particles are of + a Golden Nature, + <!-- Page 149 --> <span class="pagenum"><a name="Page_149" id="Page_149"></a>[pg + 149]</span> which appear in a Colour so ordinary to Gold parted from other + Metalls by <i>Aqua Fortis</i>, that it is a trouble to the Refiner to + Reduce the Præcipitated <i>Calx</i> to its Native Colour. For though, (as + we have try'd,) that may be Quickly enough done by Fire, which will make + this Gold look very Gloriously (as indeed 'tis at least one of the Best + wayes that is Practis'd for the Refining of Gold,) yet it requires both + Watchfulness and Skill, to give it such a Degree of Fire as will serve to + Restore it to its Lustre, without giving it such a One, as may bring it to + Fusion, to which the Minuteness of the <i>Corpuseles</i> it consists of + makes the Powder very apt. And this brings into my Mind, that having taken + a Flat and Bright piece of Gold, that was Refin'd by a Curious and + Skilfull Person on purpose to Trye to what height of Purity Gold could be + brought by Art, I found that this very piece, as Glorious as it look'd, + being rubb'd a little upon a piece of fine clean Linnen, did sully it with + a kind of Black; and the like I have observ'd in Refin'd Silver, which I + therefore mention, because I formerly suspected that the Impurity of the + Metall might have been the only Cause of what I have divers times obferv'd + in wearing Silver-hilted Swords, Namely, that + <!-- Page 150 --> <span class="pagenum"><a name="Page_150" id="Page_150"></a>[pg + 150]</span> where they rubb'd upon my Clothes, if they were of a + Light-Colour'd Cloath, the Affriction would quickly Black them; and + Congruously hereunto I have found Pens Blackt almost all over, when I had + a while carri'd them about me in a Silver Ink-case. To which I shall only + add, that whereas in these several Instances of Denigration, the Metalls + are worn off, or otherwise Reduc'd into very Minute Parts, that + Circumstance may prove not Unworthy your Notice. + </p> + <h3> + <i>EXPERIMENT X.</i> + </h3> + <p> + That a Solution of Silver does Dye Hair of a Black Colour, is a Known + Experiment, which some persons more Curious than Dextrous, have so + Unluckily made upon themselves as to make their Friends very Merry. And I + remember that the other day, I made my self some Sport by an Improvement + of this Observation, for having dissolv'd some Pure Silver in <i>Aqua + Fortis</i>, and Evaporated the <i>Menstruum ad siccitatem</i>, as they + speak, I caus'd a Quantity of fair Water to be pour'd upon the <i>Calx</i> + two or three several times, and to be at each Evaporated, till the <i>Calx</i> + was very Drye, and all the Greenish Blewness that is wont to appear in + Common Crystals of Silver, + <!-- Page 151 --> <span class="pagenum"><a name="Page_151" id="Page_151"></a>[pg + 151]</span> was quite carry'd away. Then I made those I meant to Deceive, + Moisten some part of their Skin with their own Spittle, and slightly Rub + the moistned parts with a little of this Prepar'd Silver, Whereupon they + Admir'd to see, that a Snow-white Body laid upon the White Skin should + presently produce a deep Blackness, as if the stains had been made with + Ink, especially considering that this Blackness could not, like that + produc'd by ordinary Ink, be readily Wash'd off, but requir'd many Hours, + and part of it some dayes to its Obliteration. And with the same White <i>Calx</i> + and a little Fair Water we likewise Stain'd the White Hafts of Knives, + with a lasting Black in those parts where the <i>Calx</i> was Plentifully + enough laid on, for where it was laid on but very Thinly, the Stain was + not quite of so Deep a Colour. + </p> + <h3> + <i>EXPERIMENT XI</i> + </h3> + <p> + The Cause of the Blackness of those many Nations, which by one common Name + we are wont to call <i>Negroes</i>, has been long since Disputed of by + Learned Men, who possibly had not done amiss, if they had also taken into + Consideration, why some whole races of other Animals besides Men, as + <!-- Page 152 --> <span class="pagenum"><a name="Page_152" id="Page_152"></a>[pg + 152]</span> Foxes and Hares, are Distinguish'd by a Blackness not familiar + to the Generality of Animals of the same Species; The General Opinion (to + be mention'd a little lower) has been rejected even by some of the Antient + Geographers, and among our Moderns <i>Ortelius</i> and divers other + Learned Men have Question'd it. But this is no place to mention what + thoughts I have had to and fro about these Matters: Only as I shall freely + Acknowledge, that to me the inquiry seems more Abstruse than it does to + many others, and that because consulting with Authors, and with Books of + Voyages, and with Travellers, to satisfie my self in matters of Fact, I + have met with some things among them, which seem not to agree very well + with the Notions of the most Classick Authors concerning these things; for + it being my Present Work to deliver rather matters Historical than + Theorys, I shall Annex Some few of my Collections, instead of a Solemn + Disputation. It is commonly presum'd that the Heat of the Climate wherein + they live, is the reason, why so many Inhabitants of the Scorching Regions + of <i>Africa</i> are Black; and there is this familiar Observation to + Countenance this Conjecture, That we plainly see that Mowers, Reapers, and + other Countrey-people, + <!-- Page 153 --> <span class="pagenum"><a name="Page_153" id="Page_153"></a>[pg + 153]</span> who spend the most part of the Hot Summer dayes expos'd to the + Sun, have the skin of their Hands and Faces, which are the parts + immediately Expos'd to the Sun and Air, made of a Darker Colour than + before, and consequently tending to Blackness; And Contrarywise we observe + that the <i>Danes</i> and some other people that Inhabit Cold Climates, + and even the <i>English</i> who feel not so Rigorous a Cold, have usually + Whiter faces than the <i>Spaniards</i>, <i>Portugalls</i> and other + European Inhabitants of Hotter Climates. But this Argument I take to be + far more Specious than Convincing; for though the Heat of the Sun may + Darken the Colour of the Skin, by that Operation, which we in <i>English</i> + call Sun-burning, yet Experience doth not Evince, that I remember, That + that Heat alone can produce a Discolouring that shall amount to a true + Blackness, like that of <i>Negroes</i>, and we shall see by and by that + even the Children of some <i>Negroes</i> not yet 10. dayes Old (perhaps + not so much by three quarters of that time) will notwithstanding their + Infancy be of the same Hue with their Parents. Besides, there is this + strong Argument to be alleg'd against the Vulgar Opinion, that in divers + places in <i>Asia</i> under the same Parallel, or even of the same + <!-- Page 154 --> <span class="pagenum"><a name="Page_154" id="Page_154"></a>[pg + 154]</span> Degree of Latitude with the <i>African</i> Regions Inhabited + by Blacks, the People are at most but Tawny;<a name="NtA_10" id="NtA_10"></a><a + href="#Nt_10"><sup>10</sup></a> And in <i>Africa</i> it self divers + Nations in the Empire of <i>Ethiopia</i> are not <i>Negroes</i>, though + Situated in the Torrid Zone, and as neer the Æquinoctial, as other Nations + that are so (as the Black Inhabitants of <i>Zeylan</i> and <i>Malabar</i> + are not in our Globes plac'd so near the Line as <i>Amara</i> the + Famousest place in <i>Ethiopia</i>.) Moreover, (that which is of no small + Moment in our present Disquisition) I find not by the best Navigators and + Travellers to the <i>West-Indies</i>, whose Books or themselves I have + consulted on this Subject, that excepting perhaps one place or two of + small extent, there are any Blacks Originally Natives of any part of <i>America</i> + (for the Blacks now there have been by the <i>Europeans</i> long + Transplanted thither) though the New World contain in it so great a + Variety of Climates, and particularly reach quite Cross the Torri'd Zone + from one Tropick to another. And enough it be true that the <i>Danes</i> + be a Whiter People than the <i>Spaniards</i>, yet that may proceed rather + from other causes (not here to be enquired into) than from the Coldness of + the Climate, since not onely the + <!-- Page 155 --> <span class="pagenum"><a name="Page_155" id="Page_155"></a>[pg + 155]</span> <i>Swedes</i> and other Inhabitants of those Cold Countreys, + are not usually so White as the <i>Danes</i>, nor Whiter than other + Nations in proportion to their Vicinity to the Pole. [And since the + Writing of the former part of this Essay, having an opportunity on a + Solemn occasion to take Notice of the Numerous Train of Some Extraordinary + Embassadours sent from the <i>Russian</i> Emperour to a great Monarch, + observ'd, that (though it were then Winter) the Colour of their Hair and + Skin was far less Whitish than the <i>Danes</i> who Inhabit a milder + Region is wont to be, but rather for the most part of a Darkish Brown; And + the Physician to the Embassadour with whom those <i>Russes</i> came, being + ask'd by me whether in <i>Muscovy</i> it self the Generality of the People + were more inclin'd to have Dark-colour'd Hair than Flaxen, he answer'd + Affirmatively; but seem'd to suspect that the True and Antient <i>Russians</i>, + a Sept of whom he told me he had met with in one of the Provinces of that + vast Empire, were rather White like the <i>Danes</i>, than any thing near + so Brown as the present <i>Muscovites</i> whom he guesses to be descended + of the <i>Tartars</i>, and to have inherited their Colour from them.] But + to Prosecute our former Discourse, I shall add for further Proof of the + Conjecture I was + <!-- Page 156 --> <span class="pagenum"><a name="Page_156" id="Page_156"></a>[pg + 156]</span> countenancing that good Authors inform us that there are <i>Negroes</i> + in <i>Africa</i> not far from the <i>Cape of good Hope</i>, and + consequently beyond the Southern Tropick, and without the Torrid Zone, + much about the same Northern Latitude (or very little more) wherein there + are divers <i>American</i> Nations that are not <i>Negroes</i>, and + wherein the Inhabitants of <i>Candia</i>, some parts of <i>Sicily</i>, and + even of <i>Spain</i> are not so much as Tawny-Mores. But (which is a fresh + and strong Argument against the common Opinion,) I find by our recent + Relations of <i>Greenland</i> (our Accounts whereof we owe to the + Curiosity of that Royal <i>Virtuoso</i> the present King of <i>Denmark</i>,) + that the Inhabitants are Olive-colour'd, or rather of a Darker Hiew. But + if the Case were the same with Men, and those other kinds of Animals I + formerly nam'd, I should offer something as a considerable proof, That, + Cold may do much towards the making Men White or Black, and however I + shall let down the Observation as I have met with it, as worthy to come + into the History of Whiteness and Blackness, and it is, that in some parts + of <i>Russia</i> and of <i>Livonia</i> it is affirm'd by <i>Olaus Magnus</i> + and others, that Hares and Foxes (some add Partridges) which before were + Black, or Red, or + <!-- Page 157 --> <span class="pagenum"><a name="Page_157" id="Page_157"></a>[pg + 157]</span> Gray, do in the depth of Winter become White by reason of the + great Cold; (for that it should be, as some conceive, by Looking upon the + Snow, seems improbable upon divers accounts) And I remember that having + purposely enquir'd of a <i>Virtuoso</i> who lately Travell'd through <i>Livonia</i> + to <i>Mosco</i> concerning the Truth of this Tradition, he both told me, + he believ'd it, and added, that he saw divers of those lately nam'd + Animals either in <i>Russia</i> or <i>Livonia</i>, (for I do not very well + remember whether of the two) which, though White when he saw them in + Winter, they assur'd him had been Black, or of other Colours before the + Winter began, and would be so again when it was over. But for further + satisfaction, I also consulted one that had for some years been an Eminent + Physician in <i>Russia</i>, who though he rejected some other Traditions + that are generally enough believ'd concerning that Countrey, told me + nevertheless, that he saw no cause to doubt of this Tradition of <i>Olaus + Magnus</i> as to Foxes and Hares, not onely because 'tis the common and + uncontroul'd Assertion of the Natives, but also because he himself in the + Winter could never that he remember'd see Foxes and Hares of any other + Colour than White; And I my self having seen a small White + <!-- Page 158 --> <span class="pagenum"><a name="Page_158" id="Page_158"></a>[pg + 158]</span> Fox brought out of <i>Russia</i> into <i>England</i> towards + the latter end of Winter, foretold those that shew'd him me, that he would + change Colour in Summer, and accordingly coming to look upon him again in + <i>July</i>, I found that the Back and Sides, together with the upper part + of the Head and Tayl were already grown of a Dark Colour, the lower part + of the Head and Belly containing as yet a Whiteness. Let me add, that were + it not for some scruple I have, I should think more than what <i>Olaus</i> + relates, confirm'd by the judicious <i>Olearius</i>, who was twice + employ'd into those parts as a Publick Minister, who in his Account of <i>Moscovy</i> + has this Passage: <i>The Hares there are Gray; but in some Provinces they + grow white in the Winter</i>. And within some few Lines after: <i>It is + not very Difficult to find the Cause of this Change, which certainly + proceeds only from the Outward Cold, since I know that even in Summer, + Hares will change Colour, if they be kept a competent time in a Cellar</i>; + I say, were it not for Some Scruple, because I take notice, that in the + same Page the Author Affirms, that the like change of Colour that happens + to Hares in some Provinces of <i>Muscovy</i>, happens to them also in <i>Livonia</i>, + and yet immediately subjoyns, that in <i>Curland</i> the Hares vary not + their Colour in Winter, + <!-- Page 159 --> <span class="pagenum"><a name="Page_159" id="Page_159"></a>[pg + 159]</span> though these two last named Countries be contiguous, (that is) + sever'd only by the River of <i>Dugna</i>; For it is scarce conceivable + how Cold alone should have, in Countries so near, so strangely differing + an operation, though no less strange a thing is confess'd by many, that + ascribe the Complexion of <i>Negroes</i> to the Heat of the Sun, when they + would have the River of <i>Cenega</i> so to bound the <i>Moors</i>, that + though on the North-side they are but Tawny, on the other side they are + Black. + </p> + <p> + There is another Opinion concerning the Complexion of <i>Negroes</i>, that + is not only embrac'd by many of the more Vulgar Writers, but likewise by + that ingenious Traveller Mr. <i>Sandys</i>, and by a late most learned + Critick, besides other men of Note, and these would have the Blackness of + <i>Negroes</i> an effect of <i>Noah's</i> Curse ratify'd by God's, upon <i>Cham</i>; + But though I think that even a Naturalist may without disparagement + believe all the Miracles attested by the Holy Scriptures, yet in this case + to flye to a Supernatural Cause, will, I fear, look like Shifting off the + Difficulty, instead of Resolving it; for we enquire not the First and + Universal, but the Proper, Immediate, and Physical Cause of the Jetty + Colour of <i>Negroes</i>; And not only we do not find expressed in the + <!-- Page 160 --> <span class="pagenum"><a name="Page_160" id="Page_160"></a>[pg + 160]</span> Scripture, that the Curse meant by <i>Noah</i> to <i>Cham</i>, + was the Blackness of his Posterity, but we do find plainly enough there + that the Curse was quite another thing, namely that he should be a Servant + of Servants, that is by an Ebraism, a very Abject Servant to his Brethren, + which accordingly did in part come to pass, when the <i>Israelites</i> of + the posterity of <i>Sem</i>, subdued the <i>Canaanites</i>, that descended + from <i>Cham</i>, and kept them in great Subjection. Nor is it evident + that Blackness is a Curse, for Navigators tell us of Black Nations, who + think so much otherwise of their own condition, that they paint the Devil + White. Nor is Blackness inconsistent with Beauty, which even to our + European Eyes consists not so much in Colour, as an Advantageous Stature, + a Comely Symmetry of the parts of the Body, and Good Features in the Face. + So that I see not why Blackness should be thought such a Curse to the <i>Negroes</i>, + unless perhaps it be, that being wont to go Naked in those Hot Climates, + the Colour of their Skin does probably, according to the Doctrine above + deliver'd, make the Sun-beams more Scorching to them, than they would + prove to a people of a White Complexion. + </p> + <p> + Greater probability there is, That the Principal Cause (for I would not + exclude + <!-- Page 161 --> <span class="pagenum"><a name="Page_161" id="Page_161"></a>[pg + 161]</span> all concurrent ones) of the Blackness of <i>Negroes</i> is + some Peculiar and Seminal Impression, for not onely we see that <i>Blackmore</i> + boyes brought over into these Colder Climates lose not their Colour; But + good Authors inform us, That the Off-spring of <i>Negroes</i> Transplanted + out of <i>Africa</i>, above a hundred years ago, retain still the + Complexion of their Progenitors, though possibly in Tract of time it will + decay; As on the other side, the White people removing into very Hot + Climates, have their Skins by the Heat of the Sun scorch'd into Dark + Colours; yet neither they, nor their Children have been observ'd, even in + the Countreys of <i>Negroes</i>, to descend to a Colour amounting to that + of the Natives; whereas I remember I have Read in <i>Pisos</i><a + name="NtA_11" id="NtA_11"></a><a href="#Nt_11"><sup>11</sup></a> excellent + account of <i>Brasile</i>, that betwixt the <i>Americans</i> and <i>Negroes</i> + are generated a distinct sort of Men, which they call <i>Cabocles</i>, and + betwixt <i>Portugalls</i> and <i>Æthiopian</i> women, He tells us, he has + sometimes seen Twins, whereof one had a White skin, the other a Black; not + to mention here some other instances, he gives, that the productions of + the mixtures of differing people, that is (indeed,) the effects of Seminal + Impressions which they + <!-- Page 162 --> <span class="pagenum"><a name="Page_162" id="Page_162"></a>[pg + 162]</span> consequently argue to have been their Causes; and we shall not + much scruple at this, if we consider, that even Organical parts may + receive great Differences from such peculiar Impressions, upon what + account soever they came to be setled in the first Individual persons, + from whom they are Propogated to Posterity, as we see in the Blobber-Lips + and Flat-Noses of most Nations of <i>Negroes</i>. And if we may Credit + what Learned men deliver concerning the Little Feet of the <i>Chinesses</i>, + the <i>Macrocephali</i> taken notice of by <i>Hippocrates</i>, will not be + the only Instance we might apply to our present purpose. And on this + occasion it will not perchance be Impertinent to add something of what I + have observ'd in other Animals, as that there is a sort of Hens that want + Rumps; And that (not to mention that in several places there is a sort of + Crows or Daws that are not Cole-black as ours, but partly of a Whitish + Colour) in spight of <i>Porphyries</i> examples of Inseparable Accidents, + I have seen a perfectly White Raven, as to Bill as well as Feathers, which + I attentively considered, for fear of being impos'd upon. And this recalls + into my Memory, what a very Ingenious Physician has divers times related + to me of a young Lady, to whom being call'd, he found that though + <!-- Page 163 --> <span class="pagenum"><a name="Page_163" id="Page_163"></a>[pg + 163]</span> she much complain'd of want of Health, yet there appear'd so + little cause either in her Body, or her Condition to Guess that She did + any more than fancy her self Sick, that scrupling to give her Physick, he + perswaded her Friends rather to divert her Mind by little Journeys of + Pleasure, in one of which going to Visit St. <i>Winifrids</i> Well, this + Lady, who was a <i>Catholick</i>, and devout in her Religion, and a pretty + while in the Water to perform some Devotions, and had occasion to fix her + Eyes very attentively upon the Red pipple-stones, which in a scatter'd + order made up a good part of those that appear'd through the water, and a + while after growing Bigg, she was deliver'd of a Child, whose White Skin + was Copiously speckl'd with spots of the Colour and Bignesss of those + Stones, and though now this Child have already liv'd several years, yet + she still retains them. I have but two things to add concerning the + Blackness of <i>Negroes</i>, the one is, that the Seat of that Colour + seems to be but the thin <i>Epidermes</i>, or outward Skin, for I knew a + young <i>Negroe</i>, who having been lightly Sick of the Small Pox or + Measles, (for it was doubted which of the two was his Disease) I found by + enquiry of a person that was concern'd for him, that in those places + <!-- Erratum: insert --> where the little Tumors + <!-- Page 164 --> <span class="pagenum"><a name="Page_164" id="Page_164"></a>[pg + 164]</span> + <!-- Erratum: dele. that --> had broke their passage through the Skin, + when they were gone, they left Within specks behind them; And the lately + commended <i>Piso</i> assures us, that having the opportunity in <i>Brasil</i> + to Dissect many <i>Negroes</i>, he cleerly found that their Blackness went + no deeper than the very outward Skin, which <i>Cuticula</i> or <i>Epidermis</i> + <!-- Erratum: for Epiderms --> being remov'd, the undermost Skin or <i>Cutis</i> + appear'd just as White as that of <i>Europæan</i> Bodyes. And the like has + been affirmed to me by a Physician of our own, whom, hearing he had + Dissectcd a <i>Negroe</i> here in <i>England</i>, I consulted about this + particular. The other thing to be here taken notice of concerning <i>Negroes</i> + is, That having enquir'd of an Intelligent acquaintance of mine (who keeps + in the <i>Indies</i> about 300. + <!-- Erratum: for 200. --> of them as well Women as Men to work in his + Plantations,) whether their Children come Black into the world; he + answer'd, That they did not, but were brought forth of almost the like + Reddish Colour with our <i>European</i> Children; and having further + enquir'd, how long it was before these Infants appear'd Black, be reply'd, + that 'twas not wont to be many daies. And agreeable to this account I find + that, given us in a freshly publish'd French Book written by a <i>Jesuit</i>, + that had good opportunity + <!-- Page 165 --> <span class="pagenum"><a name="Page_165" id="Page_165"></a>[pg + 165]</span> of Knowing the Truth of what he Delivers, for being one of the + Missionaries of his Order into the Southern <i>America</i> upon the + Laudable Design of Converting Infidels to Christianity, he Baptiz'd + several Infants, which when newly Born, were much of the same Colour with + <i>European</i> Babes, but within about a Week began to appear of the Hue + of their Parents. But more Pregnant is the Testimony of our Countrey-man + <i>Andrew Battel</i>, who being sent Prisoner by the <i>Portugalls</i> to + <i>Angola</i>, liv'd there, and in the adjoyning Regions, partly as a + Prisoner, partly as a Pilot, and partly as a Souldier, near 18. years, and + he mentioning the <i>African</i> Kingdom of <i>Longo</i>, peopl'd with + Blacks, has this passage:<a name="NtA_12" id="NtA_12"></a><a href="#Nt_12"><sup>12</sup></a> + <i>The Children in this Countrey are Born White, and change their Colour + in two dayes to a Perfect Black</i>. As for Example, <i>The</i> Portugalls + <i>which dwell in the Kingdome of</i> Longo <i>have sometimes Children by + the</i> Negroe<i>-women, and many times the Fathers are deceived, + thinking, when the Child is Born, that it is theirs, and within two dayes + it proves the Son or Daughter of a</i> Negroe,<i> which the</i> Portugalls + <i>greatly grieve at</i>; And the same person has elsewhere a Relation, + which, if he have made no use at all of the + <!-- Page 166 --> <span class="pagenum"><a name="Page_166" id="Page_166"></a>[pg + 166]</span> liberty of a Traveller, is very well worth our Notice, since + this, together with that we have formerly mention'd of Seminal + Impressions, shews a possibility, that a Race of <i>Negroes</i> might be + begun, though none of the Sons of <i>Adam</i>, for many Precedent + Generations were of that Complexion. For I see not why it should not be at + least as possible, that White Parents may sometimes have Black Children, + as that <i>African Negroes</i> should sometimes have lastingly White ones, + especially since concurrent causes may easily more befriend the + Productions of the Former kind, than under the scorching Heat of <i>Africa</i> + those of the Latter. And I remember on the occasion of what he delivers, + that of the White Raven formerly mention'd, the Possessor affirm'd to me, + that in the Nest out of which he was taken White, they found with him but + one other Young one, and that he was of as Jetty a Black as any common + Raven. But let us hear our Author himself<a name="NtA_13" id="NtA_13"></a><a + href="#Nt_13"><sup>13</sup></a>; <i>Here are</i> (sayes he, speaking of + the formerly mention'd Regions) <i>Born in this Countrey White Children, + which is very rare among them, for their Parents are</i> Negroes; <i>And + when any of them are Born, they are presented to the King, and are call'd</i> + Dondos; <i>these are as White as any + <!-- Page 167 --> <span class="pagenum"><a name="Page_167" id="Page_167"></a>[pg + 167]</span> White Men. These are the Kings Witches, and are brought up in + Witchcraft, and alwayes wait on the King: There is no man that dare meddle + with these</i> Dondos, <i>if they go to the Market they may take what they + lift, for all Men stand in awe of them. The King of</i> Longo <i>hath four + of them</i>. And yet this Countrey in our Globes is plac'd almost in the + midst of the Torrid Zone (four or five Degrees Southward of the Line.) And + our Author elsewhere tells us of the Inhabitants, that they are so fond of + their Blackness, that they will not suffer any that is not of that Colour + (as the <i>Portugalls</i> that come to Trade thither) to be so much as + Buri'd in their Land, of which he annexes a particular example,<a + name="NtA_14" id="NtA_14"></a><a href="#Nt_14"><sup>14</sup></a> that may + be seen in his Voyage preserv'd by our Industrious Countreyman Mr. <i>Purchas</i>. + But it is high time for me to dismiss Observations, and go on with + Experiments. + </p> + <h3> + <i>EXPERIMENT XII.</i> + </h3> + <p> + The way, <i>Pyrophilus,</i> of producing Whiteness by Chymical + Præcipitations is very well worth our observing, for thereby Bodyes of + very Differing Colours as well as Natures, though dissolv'd in Several + Liquors, + <!-- Page 168 --> <span class="pagenum"><a name="Page_168" id="Page_168"></a>[pg + 168]</span> are all brought into <i>Calces</i> or Powders that are White. + Thus we find that not only Crabs-eyes, that are of themselves White, and + Pearls that are almost so, but <i>Coral</i> and <i>Minium</i> that are + Red, being dissolv'd in Spirit of Vinegar, may be uniformly Præcipitated + by Oyl of <i>Tartar</i> into White Powders. Thus Silver and Tin separately + dissolv'd in <i>Aqua Fortis</i>, will the one Præcipitate it self, and the + other be Præcipitated by common Salt-water into a White <i>Calx</i>, and + so will Crude Lead and Quicksilver first dissolv'd likewise in <i>Aqua + Fortis</i>. The like <i>Calx</i> will be afforded as I have try'd by a + Solution of that shining Mineral Tinglass dissolv'd in <i>Aqua Fortis</i>, + and Præcipitated out of it; and divers of these <i>Calces</i> may be made + at least as Fair and White, if not better Colour'd, if instead of Oyl of + <i>Tartar</i> they were Præcipitated with Oyl of <i>Vitriol</i>, or with + another Liquor I could Name. Nay, that Black Mineral <i>Antimony</i> it + self, being reduc'd by and with the Salts that concurr to the Composition + of common Sublimate, into that Cleer though Unctuous Liquor that Chymists + commonly call Rectifi'd Butter of <i>Antimony</i>, will by the bare + affusion of store of Fair Water be struck down into that Snow-white + Powder, which when the adhering Saltness is well wash'd + <!-- Page 169 --> <span class="pagenum"><a name="Page_169" id="Page_169"></a>[pg + 169]</span> off, Chymists are pleas'd to call <i>Mercurius Vitæ</i>, + though the like Powder may be made of <i>Antimony</i>, without the + addition of any <i>Mercury</i> at all. And this Lactescence if I may so + call it, does also commonly ensue when Spirit of Wine, being Impregnated + with those parts of Gums or other Vegetable Concretions, that are suppos'd + to abound with Sulphureous Corpuscles, fair Water is suddenly pour'd upon + the Tincture or Solution. And I remember that very lately I did, for Tryal + sake, on a Tincture of <i>Benjamin</i> drawn with Spirit of Wine, and + brought to be as Red as Blood, pour some fair Water, which presently + mingling with the Liquor, immediately turn'd the whole Mixture White. But + if such Seeming Milks be suffer'd to stand unstirr'd for a convenient + while, they are wont to let fall to the bottome a Resinous Substance, + which the Spirit of Wine Diluted and Weakned by the Water pour'd into it + <!-- Erratum: for into it -->, was unable to support any longer. And + something of Kin to this change of Colour in Vegetables is that, which + Chymists are wont to observe upon the pouring of Acid Spirits upon the Red + Solution of <i>Sulphur</i>, dissolv'd in an Infusion of Pot-ashes, or in + some other sharp <i>Lixivium</i>, the Præcipitated <i>Sulphur</i> before + it subsides, immediately turning the Red Liquor + <!-- Page 170 --> <span class="pagenum"><a name="Page_170" id="Page_170"></a>[pg + 170]</span> into a White one. And other Examples might be added of this + way of producing Whiteness in Bodyes by Præcipitating them out of the + Liquors wherein they have been Dissolv'd; but I think it may be more + usefull to admonish you, <i>Pyrophilus</i>, that this observation admits + of Restrictions, and is not so Universal, as by this time perhaps you have + begun to think it; For though most Præcipitated Bodyes are White, yet I + know some that are not; For Gold Dissolv'd in <i>Aqua Regis</i>, whether + you Præcipitate it with Oyl of <i>Tartar</i>, or with Spirit of <i>Sal + Armoniack</i>, will not afford a White but a Yellow <i>Calx</i>. <i>Mercury</i> + also though reduc'd into Sublimate, and Præcipitated with Liquors + abounding with Volatile Salts, as the Spirits drawn from Urine, + Harts-horn, and other Animal substances, yet will afford, as we Noted in + our first Experiment about Whiteness and Blackness, a White Præcipitate, + yet with + <!-- Erratum for: the Solution of Pot-ashes and other Lixiviate Salts + read: --> some Solutions hereafter to be mentioned, it will let fall an + Orange-Tawny Powder. And so will Crude <i>Antimony</i>, if, being + dissolv'd in a strong Lye, you pour (as farr as I remember) any Acid + Liquor upon the Solution newly Filtrated, whilst it is yet Warm. And if + upon the Filtrated Solution of <i>Vitriol</i>, you pour a Solution of + <!-- Page 171 --> <span class="pagenum"><a name="Page_171" id="Page_171"></a>[pg + 171]</span> one of these fix'd Salts, there will subside a Copious + substance, very farr from having any Whiteness, which the Chymists are + pleas'd to call, how properly I have elsewhere examin'd, the <i>Sulphur of + Vitriol</i>. So that most + <!-- Erratum: insert --> part of Dissolv'd Bodyes being by Præcipitation + brought to White Powders, and yet some affording Præcipitates of other + Colours, the reason of both the Phænomena may deserve to be enquir'd into. + </p> + <h3> + <i>EXPERIMENT XIII.</i> + </h3> + <p> + Some Learned Modern Writers<a name="NtA_15" id="NtA_15"></a><a + href="#Nt_15"><sup>15</sup></a> are of Opinion, that the Account upon + which Whiteness and Blackness ought to be call'd, as they commonly are, + the two Extreme Colours, is, That Blackness (by which I presume is meant + the Bodyes endow'd with it) receives no other Colours; but Whiteness very + easily receives them all; whence some of them compare Whiteness to the <i>Aristotelian + Materia prima</i>, that being capable of any sort of Forms, as they + suppose White Bodyes to be of every kind of Colour. But not to Dispute + about Names or Expressions, the thing it self that is affirm'd as Matter + of Fact, seems to be True enough in most Cases, not in all, or so, + <!-- Page 172 --> <span class="pagenum"><a name="Page_172" id="Page_172"></a>[pg + 172]</span> as to hold Universally. For though it be a common observation + among Dyers, That Clothes, which have once been throughly imbu'd with + Black, cannot so well afterwards be Dy'd into Lighter Colours, the + præexistent Dark Colour infecting the Ingredients, that carry the Lighter + Colour to be introduc'd, and making it degenerate into Some more Sad one; + Yet the Experiments lately mention'd may shew us, that where the change of + Colour in Black Bodies is attempted, not by mingling Bodyes of Lighter + Colours with them, but by Addition of such things as are proper to alter + the Texture of those Corpuscles that contain the Black Colour, 'tis no + such difficult matter, as the lately mention'd Learned Men imagine, to + alter the Colour of Black Bodyes. For we saw that Inks of several Kinds + might in a trice be depriv'd of all their Blackness; and those made with + Logwood and Red-Roses might also be chang'd, the one into a Red, the other + into a Reddish Liquor; and with Oyl of <i>Vitriol</i> I have sometimes + turn'd Black pieces of Silk into a kind of Yellow, and though the Taffaty + were thereby made Rotten, yet the spoyling of that does no way prejudice + the Experiment, the change of Black Silk into Yellow, being never the less + True, because + <!-- Page 173 --> <span class="pagenum"><a name="Page_173" id="Page_173"></a>[pg + 173]</span> the Yellow Silk is the less good. And as for Whiteness, I + think the general affirmation of its being so easily Destroy'd or + Transmuted by any other Colour, ought not to be receiv'd without some + Cautions and Restrictions. For whereas, according to what I formerly + Noted, Lead is by Calcination turned into that Red Powder we call <i>Minium</i>; + And Tin by Calcination reduc'd to a White <i>Calx</i>, the common Putty + that is sold and us'd so much in Shops, instead of being, as it is + pretended and ought to be, only the <i>Calx</i> of Tin, is, by the + Artificers that make it, to save the charge of Tin, made, (as some, of + themselves have confess'd, and as I long suspected by the Cheap rate it + may be bought for) but of half Tin and half Lead, if not far more Lead + than Tin, and yet the Putty in spight of so much Lead is a very White + Powder, without disclosing any mixture of <i>Minium</i>. And so if you + take two parts of Copper, which is a High-colour'd Metall, to but one of + Tin, you may by Fusion bring them into one Mass, wherein the Whiteness of + the Tin is much more Conspicuous and Predominant than the Reddishness of + the Copper. And on this occasion it may not be Impertinent to mention an + Experiment, which I relate upon the Credit of a very Honest man, + <!-- Page 174 --> <span class="pagenum"><a name="Page_174" id="Page_174"></a>[pg + 174]</span> whom I purposely enquir'd of about it, being my self not very + fond of making Tryals with <i>Arsenick</i>, the Experiment is this, That + if you Colliquate <i>Arsenick</i> and Copper in a due proportion, the <i>Arsenick</i> + will Blanch the Copper both within and without, which is an Experiment + well enough Known; but when I enquir'd, whether or no this White mixture + being skilfully kept a while upon the Cupel would not let go its <i>Arsenick</i>, + which made Whiteness its prædominant Colour, and return to the Reddishness + of Copper, I was assur'd of the Affirmative; so that among Mineral Bodyes, + some of those that are White, may be far more capable, than those I am + reasoning with seem to have known, of Eclipsing others, and of making + their Colour Prædominant in Mixtures. In further Confirmation of which may + be added, that I remember that I also took a lump of Silver and Gold + melted together, wherein by the Æstimate of a very Experienced Refiner, + there might be about a fourth or third part of Gold, and yet the Yellow + Colour of the Gold was so hid by the White of the Silver, that the whole + Mass appear'd to be but Silver, and when it was rubb'd upon the + Touchstone, an ordinary beholder could scarce have distinguish'd it from + the Touch of common + <!-- Page 175 --> <span class="pagenum"><a name="Page_175" id="Page_175"></a>[pg + 175]</span> Silver; though if I put a little <i>Aqua Fortis</i> upon any + part of the White Surface it had given the Touchstone, the Silver in the + moistned part being immediately taken up and conceal'd by the Liquor, the + Golden Particles would presently disclose that native Yellow, and look + rather as if Gold, than if the above mention'd mixture, had been rubb'd + upon the Stone. + </p> + <h3> + <i>EXPERIMENT XIV.</i> + </h3> + <p> + I took a piece of Black-horn, (polish'd as being part of a Comb) this with + a piece of broken glass I scrap'd into many thin and curdled flakes, some + shorter and some longer, and having laid a pretty Quantity of these + scrapings together, I found, as I look'd for, that the heap they compos'd + was White, and though, if I laid it upon a clean piece of White Paper, its + Colour seem'd somewhat Eclips'd by the greater Whiteness of the Body it + was compar'd with, looking somewhat like Linnen that had been sulli'd by a + little wearing, yet if I laid it upon a very Black Body, as upon a Beaver + Hatt, it then appear'd to be of a good White, which Experiment, that you + may in a trice make when you please, seems very much to Disfavour both + their Doctrine + <!-- Page 176 --> <span class="pagenum"><a name="Page_176" id="Page_176"></a>[pg + 176]</span> that would have Colours to flow from the Substantial Forms of + Bodyes, and that of the Chymists also, who ascribe them to one or other of + their three Hypostatical Principles; for though in our Case there was so + great a Change made, that the same Body without being substantially either + Increas'd or Lessened, passes immediately from one extreme Colour to + another (and that too from Black to White) yet this so great and sudden + change is effected by a slight Mechanical Transposition of parts, there + being no Salt or <i>Sulphur</i> or <i>Mercury</i> that can be pretended to + be Added or Taken away, nor yet any substantial Form that can reasonably + be suppos'd to be Generated and Destroy'd, the Effect proceeding only from + a Local Motion of the parts which so vary'd their Position as to multiply + their distinct Surfaces, and to Qualifie them to Reflect far more Light to + the Eye, than they could before they were scrap'd off from the entire + piece of Black horn. + </p> + <h3> + <i>EXPERIMENT XV.</i> + </h3> + <p> + And now, <i>Pyrophilus</i>, it will not be improper for us to take some + notice of an Opinion touching the cause of Blackness, which I judged + <!-- Erratum: insert --> it not so seasonable to Question, till I + <!-- Page 177 --> <span class="pagenum"><a name="Page_177" id="Page_177"></a>[pg + 177]</span> I had set down some of the Experiments, that might justifie my + dissent from it. You know that of late divers Learned Men, having adopted + the three Hypostatical Principles, besides other Notions of the Chymists, + are very inclinable to reduce all Qualities of Bodies to one or other of + those three Principles, and Particularly assign for the cause of Blackness + the Sootie steam of <i>adust</i> or <i>torrifi'd Sulphur</i>. But I hope + that what we have deliver'd above to countenance the Opinion we have + propos'd about the Cause of Blackness, will so easily supply you with + several Particulars that may be made use of against this Opinion, that I + shall now represent to You but two things concerning it. + </p> + <p> + And First it seems that the favourers of the Chymicall Theories might have + pitcht upon some more proper term, to express the Efficient of Blackness + than <i>Sulphur adust</i>; for we know that <i>common Sulphur</i>, not + only when Melted, but even when Sublim'd, does not grow Black by suffering + the Action of the fire, but continues and ascends Yellow, and rather more + than less White, than it was before its being expos'd to the fire. And if + it be set on fire, as when we make that acid Liquor, that Chymists call <i>Oleum + Sulphuris per campanam</i>, it affords + <!-- Page 178 --> <span class="pagenum"><a name="Page_178" id="Page_178"></a>[pg + 178]</span> very little Soot, and indeed the flame yeelds so little, that + it will scarce in any degree Black a sheet of White Paper, held a pretty + while over the flame and smoak of it, which is observed rather to Whiten + than Infect linnen, and which does plainly make Red Roses grow very Pale, + but not at all Black, as far as the Smoak is permitted to reach the + leaves. And I can shew you of a sort of fixt Sulphur made by an + Industrious Laborant of your acquaintance, who assur'd me that he was wont + to keep it for divers weeks together night and day in a naked and Violent + fire, almost like that of the Glass-house, and when, to satisfie my + Curiosity, I made him take out a lump of it, though it were glowing hot + (and yet not melted,) it did not, when I had suffered it to cool, appear + Black, the true Colour of it being a true Red. I know it may be said, that + <i>Chymists</i> in the Opinion above recited mean the <i>Principle of + Sulphur</i>, and not <i>common Sulphur</i> which receives its name, not + from its being <i>all</i> perfectly of a Sulphureous Nature, but for that + <i>plenty</i> and <i>Predominancy</i> of the Sulphureous Principle in it. + But allowing this, 'tis easie to reply, that still according to this very + Reason, torrifi'd Sulphur should afford more Blackness, than most other + concretes, + <!-- Page 179 --> <span class="pagenum"><a name="Page_179" id="Page_179"></a>[pg + 179]</span> wherein that Principle is confess'd to be far less copious. + Also when I have expos'd Camphire to the fire in Close Vessels, as + Inflamable, and consequenly (according to the Chymists) as Sulphureous a + Body as it is, I could not by such a degree of Heat, as brought it to + Fusion, and made it Boyl in the glass, impress any thing of Blackness, or + of any other Colour, than its own pure White, upon this Vegetable + concrete. But what shall we say to Spirit of Wine, which being made by a + Chymical Analysis of the Liquor that affords it, and being totally + Inflamable, seems to have a full right to the title they give it of <i>Sulphur + Vegetabile</i>, & yet this fluid Sulphur not only contracts not any + degree of Blackness by being often so heated, as to be made to Boyl, but + when it burns away with an Actual flame, I have not found that it would + discolour a piece of White Paper held over it, with any discernable soot. + Tin also, that wants not, according to the Chymists, a <i>Sulphur Joviale</i>, + when throughly burned by the fire into a <i>Calx</i>, is not Black, but + eminently White. And I lately noted to you out of <i>Bellonius</i>, that + the Charcoals of Oxy-cedar are not of the former of these two Colours, but + of the latter. And the Smoak of our Tinby coals here in <i>England</i>, + has been + <!-- Page 180 --> <span class="pagenum"><a name="Page_180" id="Page_180"></a>[pg + 180]</span> usually observ'd, rather to Blanch linnen then to Black it. To + all which, other Particulars of the like nature might be added, but I + rather choose to put you in mind of the third Experiment, about making + Black Liquors, or Inks, of Bodies that were non of them Black before. For + how can it be said, that when those Liquors are put together actually + Cold, and continue so after their mixture, there intervenes any new <i>Adustion + of Sulphur</i> to produce the emergent Blackness? (and the same question + will be appliable to the Blackness produc'd upon the blade of a Knife, + that has cut Lemmons and some kind of Sowr apples, if the juyce (though + both Actually and Potentially Cold) be not quickly wip'd of) And when by + the instilling either of a few drops of Oyl of Vitriol as in the second + Experiment, or of a little of the Liquor mention'd in the Passage pointed + at in the fourth Experiment, (where I teach at once to Destroy one black + Ink, and make another) the Blackness produc'd by those Experiments is + presently destroy'd; if the Colour proceeded only from the Plenty of + Sulphurous parts, torrify'd in the Black Bodies, I demand, what becomes of + them, when the Colour so suddenly dissappears? For it cannot Reasonably be + said, that all those that + <!-- Page 181 --> <span class="pagenum"><a name="Page_181" id="Page_181"></a>[pg + 181]</span> suffic'd to make so great a quantity of Black Matter, should + resort to so very small a proportion of the Clarifying Liquor, (if I may + so call it) as to be deluted by it, with out at all Denigrating it. And if + it be said that the Instill'd Liquor dispers'd those Black Corpuscles, I + demand, how that Dispersion comes to destroy their Blackness, but by + making such a Local Motion of their parts, as destroys their former + Texture? which may be a Matter of such moment in cases like ours, that I + remember that I have in few houres, without addition, from Soot it self, + attain'd pretty store of Crystalline Salt, and good store of Transparent + Liquor, and (which I have on another occasion noted as remarkable) this so + Black Substance had its Colour so alter'd, by the change of Texture it + receiv'd from the fire, wherewith it was distill'd, that it did for a + great while afford such plenty of very white Exhalations, that the + Receiver, though large, seem'd to be almost fill'd with Milk. + </p> + <p> + Secondly, But were it granted, as it is in some cases not Improbable, that + divers Bodies may receive a Blackness from a Sootie Exhalation, occasion'd + by the Adustion of their Sulphur, which (for the Reasons lately mention'd + I should rather call their Oyly parts;) yet still this account + <!-- Page 182 --> <span class="pagenum"><a name="Page_182" id="Page_182"></a>[pg + 182]</span> is applicable but to some Particular Bodies, and will afford + us no General Theory of Blackness. For if, for example, White Harts-horn, + being, in Vessels well luted to each other, expos'd to the fire, be said + to turn Black by the Infection of its own Smoak, I think I may justly + demand, what it is that makes the Smoak or Soot it self Black, since no + Such Colour, but its contrary, appear'd before in the Harts-horn? And with + the same Reason, when we are told, that torrify'd Sulphur makes bodies + Black, I desire to be told also, why Torrefaction makes Sulphur it self + Black? nor will there be any Satisfactory Reason assign'd of these + Quæries, without taking in those Fertile as well as intelligible + Mechanical Principles of the Position and Texture of the Minute parts of + the body in reference to the Light and the Eye; and these applicable + Principles may Serve the turn in many cases, where the Adustion of Sulphur + cannot be pretended; as in the appearing Blackness of an Open window, + lookt upon at a somewhat remote distance from the house, as also in the + Blackness Men think they see in the Holes that happen to be in White + linnen, or Paper of the like Colour; and in the Increasing Blackness + immediatly Produc'd barely by so rubbing Velvet, + <!-- Page 183 --> <span class="pagenum"><a name="Page_183" id="Page_183"></a>[pg + 183]</span> whose Piles were Inclin'd before, as to reduce them to a more + Erected posture, in which and in many other cases formerly alleg'd, there + appears nothing requisite to the Production of <i>the</i> Blackness, but + the hindering of the incident Beams of Light from rebounding plentifully + enough to the Eye. To be short, those I reason with, do concerning + Blackness, what the Chymists are wont also to do concerning other + Qualities, namely to content themselves to tell us, in what Ingredient of + a Mixt Body, the Quality enquir'd after, does reside, instead of + explicating the Nature of it, which (to borrow a comparison from their own + Laboratories) is much as if in an enquiry after the cause of Salivation, + they should think it enough to tell us, that the several Kinds of + Præcipitates of Gold and <i>Mercury</i>) as likewise of Quick-silver and + Silver (for I know that make and use of such Precipitates also) do + Salivate upon the account of the <i>Mercury</i>, which though Disguis'd + abounds in them, whereas the Difficulty is as much to know upon what + account <i>Mercury</i> it self, rather than other Bodies, has that power + of working by Salivation. Which I say not, as though it were not <i>something</i> + (and too often the most we can arrive at) to discover in which of the + <!-- Page 184 --> <span class="pagenum"><a name="Page_184" id="Page_184"></a>[pg + 184]</span> Ingredients of a Compounded Body, the Quality, whose Nature is + sought, resides, but because, though this Discovery it self may pass for + <i>something</i>, and is oftentimes more than what is taught us about the + same subjects in the Schools, yet we ought not to think it <i>enough</i>, + when more Clear and Particular accounts are to be had. + </p> + <!-- Page 185 --> + <p> + <span class="pagenum"><a name="Page_185" id="Page_185"></a>[pg 185]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/224a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:50%;">THE</span><br /> <span style="font-size:75%;">Experimental + History</span><br /> <span style="font-size:50%;">OF</span><br /> <span + style="font-size:150%; letter-spacing:6px">COLOURS.</span><br /> <span + style="font-size:75%;">Begun.</span> + </h2> + <hr /> + <h2> + The Third PART. + </h2> + <hr /> + <h2> + <span style="font-size:50%;">Containing</span><br /> <span + style="font-size:75%;">Promiscuous Experiments</span><br /> <span + style="font-size:50%;">About</span><br /> <span + style="font-size:100%; letter-spacing:6px">COLOURS.</span> + </h2> + <hr /> + <h3> + EXPERIMENT I. + </h3> + <p> + <img width="80" height="80" src="images/224b.png" + alt="Illuminated B in Because" /> Ecause that, according to the Conjectures + I have above propos'd, one of the most General Causes of the Diversity of + Colours in Opacous Bodyes, is, that some reflect the Light mingl'd with + more, others with less of Shade (either + <!-- Page 186 --> <span class="pagenum"><a name="Page_186" id="Page_186"></a>[pg + 186]</span> as to Quantity, or as to Interruption) I hold it not unfit to + mention in the first place, the Experiments that I thought upon to examine + this Conjecture. And though coming to transcribe them out of some + Physiological <i>Adversaria</i> I had written in loose Papers, I cannot + find one of the chief Records I had of my Tryals of this Nature, yet the + Papers that scap'd miscarrying, will, I presume, suffice to manifest the + main thing for which I now allege them; I find then Among my <i>Adversaria</i>, + the following Narrative. + </p> + <p> + <i>October</i> the 11. About ten in the Morning in Sun-shiny Weather, (but + not without fleeting Clouds) we took several sorts of Paper Stain'd, some + of one Colour, and some of another; and in a Darken'd Room whose Window + look'd Southward, we cast the Beams that came in at a hole about three + Inches and a half in Diameter, upon a White wall that was plac'd on one + side, about five foot distance from them. + </p> + <p> + The White gave much the Brightest Reflection. + </p> + <p> + The Green, Red, and Blew being Compar'd together, the Red gave much the + strongest Reflection, and manifestly enough also threw its <i>Colour</i> + upon the Wall; The Green and Blew were scarce Discernable + <!-- Page 187 --> <span class="pagenum"><a name="Page_187" id="Page_187"></a>[pg + 187]</span> by their Colours, and seem'd to reflect an almost Equal Light. + </p> + <p> + The Yellow Compar'd with the two last nam'd, Reflected somewhat more + Light. + </p> + <p> + The Red and Purple being Compar'd together, the former manifestly + Reflected a good deal more Light. + </p> + <p> + The Blew and Purple Compar'd together, the former seem'd to Reflect a + little more Light, though the Purple Colour were more manifestly seen. + </p> + <p> + A Sheet of very well fleck'd Marbl'd Paper being Apply'd as the others, + did not cast any or its Distinct Colours upon the Wall; nor throw its + Light upon it with an Equal Diffusion, but threw the Beams Unstain'd and + Bright to this and that part of the Wall, as if it's Polish had given it + the Nature of a specular Body. But comparing it with a sheet of White + Paper, we found the Reflection of the latter to be much Stronger, it + diffusing almost as much Light to a <i>good Extent</i> as the Marble Paper + did to <i>one part</i> of the Wall. + </p> + <p> + The Green and Purple left us somewhat in suspence which Reflected the most + Light; only the Purple seem'd to have some little Advantage over the + Green, which was Dark in its kind. + </p> + <p> + Thus much I find in our above mention'd + <!-- Page 188 --> <span class="pagenum"><a name="Page_188" id="Page_188"></a>[pg + 188]</span> <i>Collections</i>, among which there are also some Notes + concerning the Production of <i>Compounded Colours</i>, <i>by Reflection</i> + from Bodyes differingly Colour'd. And these Notes we intended should + supply us with what we should mention as our second Experiment: but having + lost the Paper that contain'd the Particulars, and remembring onely in + General, that if the Objects which Reflected the Light were not Strongly + Colour'd and somewhat Glossy, the Reflected Beams would not manifestly + make a Compounded Colour upon the Wall, and even then but very Faintly, we + shall now say no more of that Matter, only reserving our selves to mention + hereafter the Composition of a Green, which we still retain in Memory. + </p> + <h3> + <i>EXPERIMENT II.</i> + </h3> + <p> + We may add, <i>Pyrophilus</i>, on this Occasion, that though a Darken'd + Room be Generally thought requisite to make the Colour of a Body appear by + Reflection from another Body, that is not one of those that are commonly + agreed upon to be Specular (as Polish'd Metall, Quick silver, Glass, + Water, &c.) Yet I have often observ'd that when I wore Doublets Lin'd + with some silken + <!-- Page 189 --> <span class="pagenum"><a name="Page_189" id="Page_189"></a>[pg + 189]</span> Stuff that was very Glossy and Vividly Colour'd, especially + Red, I could in an Inlightned Room plainly enough Discern the Colour, upon + the Pure White Linnen that came out at my Sleeve and reach'd to my Cufs; + as if that Fine White Body were more Specular, than Colour'd and + Unpolish'd Bodyes are thought Capable of being. + </p> + <h3> + <i>EXPERIMENT III.</i> + </h3> + <p> + Whilst we were making the newly mention'd Experiments, we thought fit to + try also what Composition of Colours might be made by Altering the Light + in its Passage to the Eye by the Interposition not of Perfectly Diaphanous + Bodies, (that having been already try'd by others as well as by us (as we + shall soon have occasion to take notice) but of Semi-opacous Bodyes, and + those such as look'd upon in an ordinary Light, and not held betwixt it + and the Eye, are not wont to be Discriminated from the rest of Opacous + Bodyes; of this Tryal, our mention'd <i>Adversaria</i> present us the + following Account. + </p> + <p> + Holding these Sheets, sometimes one sometimes the other of them, before + the Hole betwixt the Sun and the Eye, with + <!-- Page 190 --> <span class="pagenum"><a name="Page_190" id="Page_190"></a>[pg + 190]</span> the Colour'd sides obverted to the Sun; we found them <i>single</i> + to be somewhat Transparent, and appear of the same Colour as before, onely + a little alter'd by the great Light they were plac'd in; but laying <i>two</i> + of them one over another and applying them so to the Hole, the Colours + were compounded as follows. + </p> + <p> + The Blew and Yellow scarce exhibited any thing but a Darker Yellow, which + we ascrib'd to the Coarseness of the Blew Papers, and its Darkness in its + Kind. For applying the Blew parts of the Marbl'd Paper with the Yellow + Paper after the same manner, they exhibited a good Green. + </p> + <p> + The Yellow and Red look'd upon together gave us but a Dark Red, somewhat + (and but a little,) inclining to an Orange Colour. + </p> + <p> + The Purple and Red look'd on together appear'd more Scarlet. + </p> + <p> + The Purple and Yellow made an Orange. + </p> + <p> + The Green and Red made a Dark Orange Tawny. + </p> + <p> + The Green and Purple made the Purple appear more Dirty. + </p> + <p> + The Blew and Purple made the Purple more Lovely, and far more Deep. + </p> + <p> + The Red parts of the Marbl'd Paper look'd upon with the Yellow appear'd of + a + <!-- Page 191 --> <span class="pagenum"><a name="Page_191" id="Page_191"></a>[pg + 191]</span> Red far more like Scarlet than without it. + </p> + <p> + But the Fineness or Coarseness of the Papers, their being carefully or + slightly Colour'd, and divers other Circumstances, may so vary the Events + of such Experiments as these, that if, <i>Pyrophilus</i>, you would Build + much on them, you must carefully Repeat them. + </p> + <h3> + <i>EXPERIMENT IV.</i> + </h3> + <p> + The Triangular Prismatical Glass being the Instrument upon whose Effects + we may the most Commodiously speculate the Nature of Emphatical Colours, + (and perhaps that of Others too;) we thought it might be usefull to + observe the several Reflections and Refractions which the Incident Beams + of Light suffer in Rebounding from it, and Passing through it. And this we + thought might be Best done, not (as is usual,) in an ordinary Inlightn'd + Room, where (by reason of the Difficulty of doing otherwise) ev'n the + Curious have left Particulars Unheeded, which may in a convenient place be + easily taken notice of; but in a Darken'd Room, where by placing the Glass + in a convenient Posture, the Various Reflections and Refractions may be + Distinctly observ'd; and where it may appear <i>what</i> Beams are + Unting'd; + <!-- Page 192 --> <span class="pagenum"><a name="Page_192" id="Page_192"></a>[pg + 192]</span> and <i>which</i> they are, that upon the Bodyes that terminate + them, do Paint either the Primary or Secondary Iris. In pursuance of this + we did in the above mention'd Darken'd Room, make observation of no less + than four Reflections, and three Refractions that were afforded us by the + same Prism, and thought that notwithstanding what was taught us by the + Rules of Catoptricks and Dioptricks, it would not be amiss to find also, + by hiding sometimes one part of the Prism, and sometimes another, and + observing where the Light or Colour Vanish'd thereupon, by which + Reflection and by which Refraction each of the several places whereon the + Light rebounding from, or passing through, the Prism appear'd either + Sincere or Tincted, was produc'd. But because it would be Tedious and not + so Intelligible to deliver this in Words, I have thought fit to Referr You + to the Annexed Scheme where the Newly mention'd particulars may be at one + View taken Notice of. + </p> + <h3> + <i>EXPERIMENT V.</i> + </h3> + <table width="100%" cellpadding="5"> + <tr> + <td> + <a href="images/232.png"><img width="400" height="418" + src="images/232.png" alt="The Explication of the Scheme." /></a><br /> + <h3> + The Explication of the Scheme. + </h3> + </td> + <td valign="top"> + <p> + <i>PPP</i>. An Aequilaterotriangular Crystalline Prism, one of whose + edges <i>P</i>. is placed directly towards the Sun. + </p> + <p> + <i>A B</i> & α β Two rays from the Sun falling on the + Prism at <i>B</i> β. and thence partly reflected towards <i>C</i> + & γ. and partly refracted towards <i>D</i> & δ. + </p> + <p> + <i>B C</i> & β γ. Those reflected Rays. + </p> + <p> + <i>B D</i> & β δ. Those refracted Rays which are + partly refracted towards <i>E</i> & ε. and there paint + an Iris 1 2 3 4 5. denoting the five consecutions of colours Red, + Yellow, Green, Blew, and Purple; and are partly reflected towards <i>F</i> + & ζ. + </p> + <p> + <i>D F</i> & δ ζ. Those Reflected Rays which are + partly refracted towards <i>G</i> & η. colourless, and + partly reflected, towards <i>H</i> & θ. + </p> + <p> + <i>F H</i> & ζ θ. Those reflected Rays which are + refracted towards <i>I</i> & ι. and there paint an other + fainter Iris, the colours of which are contrary to the former 5 4 3 + 2 1. signifying Purple, Blew, Green, Yellow, Red, so that the Prism + in this posture exhibits four Rainbows. + </p> + </td> + </tr> + </table> + <!-- Page 193 --> + <p> + <span class="pagenum"><a name="Page_193" id="Page_193"></a>[pg 193]</span> + </p> + <p> + I know not whether you will think it Inconsiderable to annex to this + Experiment, That we observ'd in a Room not Darken'd, that the Prismatical + Iris (if I may so call it) might be Reflected without losing any of its + several <i>Colours</i> (for we now consider not their <i>Order</i>) not + onely from a plain Looking-glass and from the calm Surface of Fair Water, + but also from a Concave Looking-glass; and that Refraction did as little + Destroy those Colours as Reflection. For by the help of a large (double + Convex) Burning-glass through which we Refracted the Suns Beams, we found + that one part of the Iris might be made to appear either beyond, or on + this side of the other Parts of the same Iris; but yet the same Vivid + Colours would appear in the Displac'd part (if I may so term it) as in the + other. To which I shall add, that having, by hiding the side of the Prism, + obverted to the Sun with an Opacous Body, wherein only one small hole was + left for the Light to pass through, reduc'd the Prismatical Iris (cast + upon White Paper) into a very narrow compass, and look'd upon it througn a + Microscope; the Colours appear'd the same as to kind that they did to the + naked Eye. + </p> + <!-- Page 194 --> + <p> + <span class="pagenum"><a name="Page_194" id="Page_194"></a>[pg 194]</span> + </p> + <h3> + <i>EXPERIMENT VI.</i> + </h3> + <p> + It may afford matter of Speculation to the Inquisitive, such as you, <i>Prophilus</i>, + that as the Colours of outward Objects brought into a Darken'd Room, do so + much depend for their Visibility upon the Dimness of the Light they are + there beheld by; that the ordinary Light of the day being freely let in + upon them, they immediately disappear: so our Tryals have inform'd us, + that as to the Prismatical Iris painted on the Floor by the beams of the + Sun Trajected through a Triangular-glass; though the Colours of it appear + very Vivid ev'n at Noon-day, and in Sun shiny Weather, yet by a more + Powerfull Light they may be made to disappear. For having sometimes, (in + prosecution of some Conjectures of mine not now to be Insisted on,) taken + a large Metalline Concave <i>Speculum</i>, and with it cast the converging + Beams of the Sun upon a Prismatical Iris which I had caus'd to be + projected upon the Floor, I found that the over-powerfull Light made the + Colours of the Iris disappear. And if I so Reflected the Light as that it + cross'd but the middle of the Iris, in that part only the Colours vanish'd + or were made Invisible; those + <!-- Page 195 --> <span class="pagenum"><a name="Page_195" id="Page_195"></a>[pg + 195]</span> parts of the Iris that were on the right and left hand of the + Reflected Light (which seem'd to divide them, and cut the Iris asunder) + continuing to exhibit the same Colours as before. But upon this we must + not now stay to Speculate. + </p> + <h3> + <i>EXPERIMENT VII.</i> + </h3> + <p> + I have sometimes thought it worth while to take notice, whether or no the + Colours of Opacous Bodies might not appear to the Eye somewhat + Diversify'd, not only by the Disposition of the Superficial parts of the + Bodyes themselves and by the Position of the Eye in Reference to the + Object and the Light, (for these things are Notorious enough;) but + according also to the Nature of the Lucid Body that shines upon them. And + I remember that in Prosecution of this Curiosity, I observ'd a manifest + Difference in some Kinds of Colour'd Bodyes look'd on by Day-light, and + afterwards by the light of the Moon; either directly falling on them or + Reflected upon them from a Concave Looking-glass. But not finding at + present in my Collections about Colours any thing set down of this Kind, I + shall, till I have opportunity to repeat them, content my self to add what + I find Register'd concerning + <!-- Page 196 --> <span class="pagenum"><a name="Page_196" id="Page_196"></a>[pg + 196]</span> Colours look'd on by Candle-light, in regard that not only the + Experiment is more easie to be repeated, but the Objects being the Same + Sorts of Colour'd Paper lastly mention'd, the Collation of the two + Experiments may help to make the Conjectures they will suggest somewhat + the less uncertain. + </p> + <p> + Within a few dayes of the time above mention'd, divers Sheets of Colour'd + Paper that had been look'd upon before in the Sunshine were look'd upon at + night by the light of a pretty big Candle, (snuff'd) and the Changes that + were observ'd were these. + </p> + <p> + The Yellow seem'd much fainter than in the Day, and inclinable to a pale + Straw Colour. + </p> + <p> + The Red seem'd little Chang'd; but seem'd to Reflect Light more strongly + than any other Colour (for White was none of them.) + </p> + <p> + A fair Deep Green look'd upon by it self seem'd to be a Dark Blew: But + being look'd upon together with a Dark Blew, appear'd Greenish; and beheld + together with a Yellow appear'd more Blew than at first. + </p> + <p> + The Blew look'd more like a Deep Purple or Murray than it had done in the + Daylight. + </p> + <!-- Page 197 --> + <p> + <span class="pagenum"><a name="Page_197" id="Page_197"></a>[pg 197]</span> + The Purple seem'd very little alter'd. + </p> + <p> + The Red look'd upon with the Yellow made the Yellow look almost like Brown + Cap-paper. + </p> + <p> + <i>N</i>. The Caution Subjoyned to the third Experiments is also + Applicable to this. + </p> + <h3> + <i>EXPERIMENT VIII.</i> + </h3> + <p> + But here I must not omit to subjoyn, that to satisfie our Selves, whether + or no the Light of a Candle were not made unsincere, and as it were Ting'd + with a Yellow Colour by the Admixtion of the Corpuscles it assumes from + its Fuel; we did not content our selves with what appears to the Naked + Eye, but taking a pretty thick Rod or Cylinder (for thin Peeces would not + serve the turn) of deep Blew Glass, and looking upon the Candles flame at + a Convenient distance througn it, we perceiv'd as we expected, the Flame + to look Green; which as we often note, is the Colour wont to emerge from + the Composition of Opacous Bodies, which were apart one of them Blew, and + the other Yellow. And this perchance may be the main Reason of that which + some observe, that a sheet of very White Paper being look'd upon by Candle + light, 'tis not easie at first to discern it from + <!-- Page 198 --> <span class="pagenum"><a name="Page_198" id="Page_198"></a>[pg + 198]</span> a light Yellow or Lemon Colour; White Bodyes (as we have + elsewhere observ'd) having more than those that are otherwise Colour'd, of + a Specular Nature; in regard that though they exhibit not, (unless they be + Polish'd,) the shape of the Luminary that shines on them, yet they Reflect + its Light more Sincere and Untroubl'd, by either Shades or Refractions, + than Bodyes of other Colours (as Blew, or Green, or Yellow or the like.) + </p> + <h3> + <i>EXPERIMENT IX.</i> + </h3> + <p> + We took a Leaf of Such Foliated Gold as Apothecaries are wont to Gild + their Pills with; and with the Edge of a Knife, (lightly moysten'd by + drawing it over the Surface of the Tongue, and afterwards) laid upon the + edge of the Gold Leaf; we so fasten'd it to the Knife, that being held + against the light, it conctinu'd extended like a little Flagg. This Leaf + being held very near the Eye, and obverted to the Light, appear'd so full + of Pores, that it seem'd to have such a kind of Transparency as that of a + Sive, or a piece of Cyprus, or a Love-Hood; but the Light that pass'd by + these Pores was in its Passages So Temper'd with Shadow, and Modify'd, + that the Eye discern'd + <!-- Page 199 --> <span class="pagenum"><a name="Page_199" id="Page_199"></a>[pg + 199]</span> no more a Golden Colour, but a Greenish Blew. And for other's + satisfaction, we did in the Night look upon a Candle through such a Leaf + of Gold; and by trying the Effect of Several Proportions of Distance + betwixt the Leaf, the Eye and the Light, we quickly hit upon such a + Position for the Leaf of Gold, as that the flame, look'd on through it, + appear'd of a Greenish Blew, as we have seen in the Day time. The like + Experiment try'd with a Leaf of Silver succeeded not well. + </p> + <hr /> + <h3> + <i>EXPERIMENT X.</i> + </h3> + <p> + We have sometimes found in the Shops of our Druggists, a certain Wood, + which is there called <i>Lignum Nephriticum</i>, because the Inhabitants + of the Country where it grows, are wont to use the Infusion of it made in + fair Water against the Stone of the Kidneys, and indeed an Eminent + Physician of our Acquaintance, who has very Particularly enquir'd into + that Disease, assures me, that he has found such an Infusion one of the + most effectual Remedyes, which he has ever tried against that formidable + Disease. The ancientest Account I have met with of this Simple, is given + us by the Experienc'd <i>Monardes</i> in these Words. + <!-- Page 200 --> <span class="pagenum"><a name="Page_200" id="Page_200"></a>[pg + 200]</span> <i>Nobis,</i> says he,<a name="NtA_16" id="NtA_16"></a><a + href="#Nt_16"><sup>16</sup></a> <i>Nova Hispania mittit quoddam ligni + genus crassum & enode, cujus usus jam diu receptus fuit in his + Regionibus ad Renum vitia & urinæ difficultates ac arenulas pellendas. + Fit autem hac ratione, Lignum assulatim & minutim concisum in + limpidissima aqua fontana maceratur, inque ea relinquitur, donec aqua à + bibentibus absumpta sit, dimidia hora post injectum lignum aqua cæruleum + colorem contrabit, qui sensim intenditur pro temporis diuturnitate, + tametsi lignum candidum fit</i>. This Wood, <i>Pyrophilus</i>, may afford + us an Experiment, which besides the singularity of it, may give no small + assistance to an attentive Considerer towards the detection of the Nature + of Colours. The Experiment as we made it is this. Take <i>Lignum + Nephriticum</i>, and with a Knife cut it into thin Slices, put about a + handfull of these Slices into two three or four pound of the purest + Spring-water, let them infuse there a night, but if you be in hast, a much + shorter time may suffice; <i>decant</i> this Impregnated Water into a + clear Glass Vial, and if you hold it directly between the Light and your + Eye, you shall see it wholly Tincted (excepting the very top of the + Liquor, wherein you will some times discern a Sky-colour'd Circle) with + <!-- Page 201 --> <span class="pagenum"><a name="Page_201" id="Page_201"></a>[pg + 201]</span> an almost Golden Colour, unless your Infusion have been made + too Strong of the Wood, for in that case it will against the Light appear + somewhat Dark and Reddish, and requires to be diluted by the addition of a + convenient quantity of fair Water. But if you hold this Vial from the + Light, so that your Eye be plac'd betwixt the Window and the Vial, the + Liquor will appear of a deep and lovely Cæruleous Colour, of which also + the drops, if any be lying on the outside of the Glass, will seem to be + very perfectly; And thus far we have try'd the Experiment, and found it to + Succeed even by the Light of Candles of the larger size. If you so hold + the Vial over against your Eyes, that it may have a Window on one side of + it, and a Dark part of the Room both before it and on the other side, you + shall see the Liquor partly of a Blewish and partly of a Golden Colour. If + turning your back to the Window, you powr out some of the Liquor towards + the Light and towards your Eyes, it will seem at the comming out of the + Glass to be perfectly Cæruleous, but when it is fallen down a little way, + the drops may seem Particolour'd, according as the Beams of Light do more + or less fully Penetrate and Illustrate them. If you take a Bason about + <!-- Page 202 --> <span class="pagenum"><a name="Page_202" id="Page_202"></a>[pg + 202]</span> half full of Water, and having plac'd it so in the Sun-beams + Shining into a Room, that one part of the Water may be freely illustrated + by the Beams of Light, and the other part of it Darkned by the shadow of + the Brim of the Bason, if then I say you drop of our Tincture, made + somewhat strong, both into the Shaded and Illuminated parts of the Water, + you may by looking upon it from several places, and by a little Agitation + of the water, observe divers pleasing Phænomena which were tedious to + particularize. If you powr a little of this Tincture upon a sheet of White + Paper, so as the Liquor may remain of some depth upon it, you may perceive + the Neighbouring drops to be partly of one Colour, and partly of the + other, according to the position of your Eye in reference to the Light + when it looks upon them, but if you powr off all the Liquor, the Paper + will seem Dy'd of an almost Yellow Colour. And if a sheet of Paper with + some of this Liquor in it be plac'd in a window where the Sunbeams may + shine freely on it, then if you turn your back to the Sun and take a Pen + or some such slender Body, and hold it over-thwart betwixt the Sun and the + Liquor, you may perceive that the Shadow projected by the Pen upon the + Liquor, will not all of it be a vulgar + <!-- Page 203 --> <span class="pagenum"><a name="Page_203" id="Page_203"></a>[pg + 203]</span> and Dark, but in part a curiously Colour'd shadow, that edge + of it, which is next the Body that makes it, being almost of a lively + Golden Colour, and the remoter verge of a Cæruleous one. + </p> + <p> + These and other Phænomena, which I have observ'd in this delightfull + Experiment, divers of my friends have look'd upon not without some wonder, + and I remember an excellent Oculist finding by accident in a friends + Chamber a fine Vial full of this Liquor, which I had given that friend, + and having never heard any thing of the Experiment, nor having any Body + near him that could tell him what this strange Liquor might be, was a + great while apprehensive, as he presently after told me, that some strange + new distemper was invading his Eyes. And I confess that the unusualness of + the Phænomena made me very sollicitous to find out the Cause of this + Experiment, and though I am far from pretending to have found it, yet my + enquiries have, I suppose, enabled me to give such hints, as may lead your + greater sagacity to the discovery of the Cause of this wonder. And first + finding that this Tincture, if it were too copious in the water, Kept the + Colours from being so lively, and their Change from being so discernable, + and + <!-- Page 204 --> <span class="pagenum"><a name="Page_204" id="Page_204"></a>[pg + 204]</span> finding also that the Impregnating Virtue of this Wood did by + its being frequently Infus'd in New Water by degrees Decay, I Conjectur'd + that the Tincture afforded by the Wood must proceed from some Subtiler + parts of it drawn forth by the Water, which swimming too and fro in it did + so Modifie the Light, as to exhibit such and such Colours; and because + these Subtile parts were so easily Soluble even in Cold water, I concluded + that they must abound with Salts, and perhaps contain much of the + Essential Salt, as the <i>Chymists</i> call it, of the Wood. And to try + whether these Subtile parts were Volatile enough to be Distill'd, without + the Dissolution of their Texture, I carefully Distill'd some of the + Tincted Liquor in very low Vessels, and the gentle heat of a Lamp Furnace; + but found all that came over to be as Limpid and Colourless as Rock-water, + and the Liquor remaining in the Vessel to be so deeply Cæruleous, that it + requir'd to be oppos'd to a very strong Light to appear of any other + Colour. I took likewise a Vial with Spirit of Wine, and a little Salt of + Harts-horn, and found that there was a certain proportion to be met with + betwixt the Liquor and the Salt, which made the Mixture fit to exhibit + some little Variety + <!-- Page 205 --> <span class="pagenum"><a name="Page_205" id="Page_205"></a>[pg + 205]</span> of Colours not Observable in ordinary Liquors, as it was + variously directed in reference to the Light and the Eye, but this Change + of Colour was very far short from that which we had admir'd in our + Tincture. But however, I suspected that the Tinging Particles did abound + with such Salts, whose Texture, and the Colour springing from it, would + probably be alter'd by peircing Acid Salts, which would in likelihood + either make some Dissipation of their Parts, or Associate themselves to + the like Bodies, and either way alter the Colour exhibited by them; + whereupon Pouring into a small Vial full of Impregnated Water, a very + little Spirit of Vinegar, I found that according to my Expectation, the + Cæruleous Colour immediately vanish'd, but was deceiv'd in the Expectation + I had, that the Golden Colour would do so too; for, which way soever I + turned the Vial, either to or from the Light, I found the Liquor to appear + always of a Yellowish Colour and no other: Upon this I imagin'd that the + Acid Salts of the Vinegar having been able to deprive the Liquor of its + Cæruleous Colour, a Sulphureous Salt being of a contrary Nature, would be + able to Mortifie the Saline Particles of Vinegar, and Destroy their + <!-- Page 206 --> <span class="pagenum"><a name="Page_206" id="Page_206"></a>[pg + 206]</span> Effects; And accordingly having plac'd my Self betwixt the + Window, and the Vial, and into the Same Liquor dropt a few drops of Oyl of + Tartar <i>per Deliquium</i>, (as <i>Chymists</i> call it) I observ'd with + pleasure, that immediately upon the Diffusion of this Liquor, the + Impregnated Water was restor'd to its former Cæruleous Colour; And this + Liquor of <i>Tartar</i> being very Ponderous, and falling at first to the + Bottom of the Vial, it was easie to observe that for a little while the + Lower part of the Liquor appear'd deeply Cæruleous; whilst all the Upper + part retain'd its former Yellowness, which it immediately lost as soon as + either Agitation or Time had made a competent Diffusion of the Liquor of + <i>Tartar</i> through the Body of the former Tincture; and this restored + Liquor did, as it was Look'd upon against or from the Light, exhibit the + Same <i>Phænomena</i> as the Tincted Water did, before either of the + Adventitious Liquors was pour'd into it. + </p> + <p> + Having made, <i>Pyrophilus</i>, divers Tryals upon this Nephritick Wood, + we found mention made of it by the Industrious Jesuit <i>Kircherus</i>, + who having received a Cup Turned of it from the <i>Mexican</i> Procurator + of his Society, has probably receiv'd also from him the Information he + gives us concerning + <!-- Page 207 --> <span class="pagenum"><a name="Page_207" id="Page_207"></a>[pg + 207]</span> that <i>Exotick</i> Plant, and therefore partly for that + Reason, and partly because what he Writes concerning it, does not + perfectly agree with what we have deliver'd, we shall not Scruple to + acquaint you in his own Words, with as much of what he writes concerning + our Wood, as is requisite to our present purpose. <i>Hoc loco</i> (says + he)<a name="NtA_17" id="NtA_17"></a><a href="#Nt_17"><sup>17</sup></a> <i>neutiquam + omittendum duximus quoddam ligni candidi Mexicani genus, quod Indigenæ + Coalle & Tlapazatli vocant, quod etsi experientia hucusque non nisi + Cæruleo aquam colore tingere docuerit, nos tamen continua experientia + invenimus id aquam in omne Colorum genus transformare, quod merito cuipiam + Paradoxum videri posset; Ligni frutex grandis, ut aiunt, non rarò in molem + arboris excrescit, truncus illius eft crassus, enodis, instar piri + arboris, folia ciceris foliis, aut rutæ haud absimilia, flores exigui, + oblongi, lutei & spicatim digesti; est frigida & humida planta, + licet parum recedat à medio temperamento. Hujus itaque descriptæ arboris + lignum in poculum efformatum, aquam eidem infusam primo in aquam intense + Cæruleam, colore floris Buglossæ; tingit, & quo diutius in eo + steterit, tanto intensiorem colorem acquirit. Hanc igitur aquam si Vitreæ + Sphæræ infuderis, lucique exposueris, ne ullum quidem Cærulei coloris + <!-- Page 208 --> <span class="pagenum"><a name="Page_208" id="Page_208"></a>[pg + 208]</span> vestigium apparebit, sed instar aquæ puræ putæ fontanæ + limpidam claramque aspicientibus se præbebit. Porro si hanc phialam + vitream versus locum magis umbrosum direxeris, totus humor gratissimum + virorem referet; si adhuc umbrosioribus locis, subrubrum, & sic pro + rerum objectarum conditione, mirum dictu, colorem mutabit; in tenebris + verò vel in vase opaco posita, Cæruleum colorem suum resumet.</i> + </p> + <p> + In this passage we may take notice of the following Particulars. And + first, he calls it a White <i>Mexican</i> Wood, whereas (not to mention + that <i>Mornardes</i> informs us that it is brought out of <i>Nova + Hispania</i>) the Wood that we have met with in several places, and + employ'd as <i>Lignum Nephriticum</i>, was not White, but for the most + part of a much Darker Colour, not unlike that of the Sadder Colour'd Wood + of Juniper. 'Tis true, that <i>Monardes</i> himself also says, that the + Wood is White; and it is affirm'd, that the Wood which is of a Sadder + Colour is Adulterated by being Imbu'd with the Tincture of a Vegetable, in + whose Decoction it is steep'd. But having purposely enquir'd of the + Eminentest of our <i>English</i> Druggists, he peremptorily deny'd it. And + indeed, having consider'd some of the fairest Round pieces of this + <!-- Page 209 --> <span class="pagenum"><a name="Page_209" id="Page_209"></a>[pg + 209]</span> Wood that I could meet with in these Parts, I had Opportunity + to take notice that in one or two of them it was the External part of the + Wood that was White, and the more Inward part that was of the other + Colour, the contrary of which would probably have appear'd, if the Wood + had been Adulterated after the afore-mention'd manner. And I have at + present by me a piece of such Wood, which for about an Inch next the Bark + is White, and then as it were abruptly passes to the above-mention'd + Colour, and yet this Wood by the Tincture, it afforded us in Water, + appears to have its Colour'd part Genuine enough; for as for the White + part, it appears upon tryal of both at once, much less enrich'd with the + tingent Property. + </p> + <p> + Next, whereas our Author tells us, that the Infusion of this Wood expos'd + in a Vial to the Light, looks like Spring-water, in which he afterwards + adds, that there is no Tincture to be seen in it, our Observation and his + agree not, for the Liquor, which opposed to the Darker part of a Room + exhibits a Sky-colour, did constantly, when held against the Light, appear + Yellowish or Reddish, according as its Tincture was more Dilute or Deep; + and + <!-- Page 210 --> <span class="pagenum"><a name="Page_210" id="Page_210"></a>[pg + 210]</span> then, whereas it has been already said, that the Cæruleous + Colour was by Acid Salts abolished, this Yellowish one surviv'd without + any considerable Alteration, so that unless our Author's Words be taken in + a very Limited Sense, we must conclude, that either his Memory + mis-inform'd him, or that his White <i>Nephritick</i> Wood, and the Sadder + Colour'd one which we employ'd, were not altogether of the same Nature: + What he mentions of the Cup made of <i>Lignum Nephriticum</i>, we have not + had Opportunity to try, not having been able to procure pieces of that + Wood great enough, and otherwise fit to be turned into Cups; but as for + what he says in the Title of his Experiment, that this Wood tinges the + Water with all Sorts of Colours, that is much more than any of those + pieces of Nephritick Wood that we have hitherto employ'd, was able to make + good; The change of Colours discernable in a Vial full of Water, + Impregnated by any of them, as it is directed towards a place more + Lightsome or Obscure, being far from affording a Variety answerable to so + promising a Title. And as for what he tells us, that in the Dark the + Infusion of our Wood will resume a Cæruleous Colour, I wish he had + Inform'd us how he Try'd it. + </p> + <!-- Page 211 --> + <p> + <span class="pagenum"><a name="Page_211" id="Page_211"></a>[pg 211]</span> + </p> + <p> + But this brings into my mind, that having sometimes for Curiosity sake, + brought a round Vial with a long Neck fill'd with the Tincture of <i>Lignum + Nephriticum</i> into the Darken'd Room already often mention'd, and + holding it sometimes in, sometimes near the Sun-beams that enter'd at the + hole, and sometimes partly in them, and partly out of them, the Glass + being held in several postures, and look'd upon from several Neighbouring + parts of the Room, disclos'd a much greater Variety of Colours than in + ordinary inlightn'd Rooms it is wont to do; exhibiting, besides the usual + Colours, a Red in some parts, and a Green in others, besides Intermediate + Colours produc'd by the differing Degrees, and odd mixtures of Light and + Shade. + </p> + <p> + By all this You may see, <i>Pyrophilus</i>, the reasonableness of what we + elsewhere had occasion to mention, when we have divers times told you, + that it is usefull to have New Experiments try'd over again, though they + were, at first, made by Knowing and Candid Men, such Reiterations of + Experiments commonly exhibiting some New Phænomena, detecting some Mistake + or hinting some Truth, in reference to them, that was not formerly taken + notice of. And some of our friends have been pleas'd to + <!-- Page 212 --> <span class="pagenum"><a name="Page_212" id="Page_212"></a>[pg + 212]</span> think, that we have made no unusefull addition to this + Experiment, by shewing a way, how in a moment our Liquor may be depriv'd + of its Blewness, and restor'd to it again by the affusion of a very few + drops of Liquors, which have neither of them any Colour at all of their + own. And that which deserves some particular wonder, is, that the + Cæruleous Tincture of our Wood is subject by the former Method to be + Destroy'd or Restor'd, the Yellowish or Reddish Tincture continuing what + it was. And that you may see, that Salts are of a considerable use in the + striking of Colours, let me add to the many Experiments which may be + afforded us to this purpose by the Dyers Trade, this Observation; That as + far as we have hitherto try'd, those Liquors in general that are strong of + Acid Salts have the Power of Destroying the Blewness of the Infusion of + our Wood, and those Liquors indiscriminatly that abound with Sulphureous + Salts, (under which I comprehend the Urinous and Volatile Salts of Animal + Substances, and the Alcalisate or fixed Salts that are made by + Incineration) have the vertue of Restoring it. + </p> + <!-- Page 213 --> + <p> + <span class="pagenum"><a name="Page_213" id="Page_213"></a>[pg 213]</span> + </p> + <p> + <i>A Corollary of the Tenth Experiment.</i> + </p> + <p> + That this Experiment, <i>Pyrophilus</i>, may be as well Usefull as + Delightfull to You, I must mind You, <i>Pyrophilus</i>, that in the newly + mention'd Observation, I have hinted to You a New and Easie way of + Discovering in many Liquors (for I dare not say in all) whether it be an + Acid or Sulphureous Salt, that is Predominant; and that such a Discovery + is oftentimes of great Difficulty, and may frequently be of great Use, he + that is not a Stranger to the various Properties and Effects of Salts, and + of how great moment it is to be able to distinguish their Tribes, may + readily conceive. But to proceed to the way of trying other Liquors by an + Infusion of our Wood, take it briefly thus. Suppose I have a mind to try + whether I conjecture aright, when I imagine that Allom, though it be + plainly a Mixt Body, does abound rather with Acid than Sulphureous Salt. + To satisfie my self herein, I turn my back to the Light, and holding a + small Vial full of the Tincture of <i>Lignum Nephriticum</i>, which look'd + upon in that Position, appears Cæruleous, I drop into it a little of a + strong Solution of Allom made in Fair Water, and finding upon the + <!-- Page 214 --> <span class="pagenum"><a name="Page_214" id="Page_214"></a>[pg + 214]</span> Affusion and shaking of this New liquor, that the Blewness + formerly conspicuous in our Tincture does presently vanish, I am thereby + incited to suppose, that the Salt Prædominant in Allom belongs to the + Family of Sour Salts; but if on the other side I have a mind to examine + whether or no I rightly conceive that Salt of Urine, or of Harts-horn is + rather of a Saline Sulphureous (if I may so speak) than of an Acid Nature, + I drop a little of the Saline Spirit of either into the Nephritick + Tincture, and finding that the Cæruleous Colour is rather thereby Deepned + than Destroy'd, I collect that the Salts, which constitute these Spirits, + are rather Sulphureous than Acid. And to satisfie my self yet farther in + this particular, I take a small Vial of fresh Tincture, and placing both + it and my self in reference to the Light as formerly, I drop into the + Infusion just as much Distill'd Vinegar, or other Acid liquor as will + serve to Deprive it of its Blewness (which a few drops, if the Sour Liquor + be strong, and the Vial small will suffice to do) then without changing my + Posture, I drop and shake into the same Vial a small proportion of Spirit + of Hartshorn or Urine, and finding that upon this affusion, the Tincture + immediately recovers its Cæruleous Colour, I am thereby confirm'd + <!-- Page 215 --> <span class="pagenum"><a name="Page_215" id="Page_215"></a>[pg + 215]</span> firm'd in my former Opinion, of the Sulphureous Nature of + these Salts. And so, whereas it is much doubted by Some Modern Chymists to + what sort of Salt, that which is Prædominant in Quick-lime belongs, we + have been perswaded to referr it rather to Lixiviate than Acid Salts, by + having observ'd, that though an Evaporated Infusion of it will scarce + yield such a Salt, as Ashes and other Alcalizate Bodyes are wont to do, + yet if we deprive our Nephritick Tincture of its Blewness by just so much + Distill'd Vinegar as is requisite to make that Colour Vanish, the <i>Lixivium</i> + of Quick-lime will immediately upon its Affusion recall the Banished + Colour; but not so Powerfully as either of the Sulphureous Liquors + formerly mention'd. And therefore I allow my self to guess at the <i>Strength</i> + of the Liquors examin'd by this Experiment, by the <i>Quantity</i> of them + which is sufficient to Destroy or Restore the Cæruleous Colour of our + Tincture. But whether concerning Liquors, wherein neither Acid nor + Alcalisate Salts are Eminently Prædominant, our Tincture will enable us to + conjecture any thing more than that such Salts are not Prædominant in + them, I take not upon me to determine here, but leave to further Tryal; + For I find not that Spirit of + <!-- Page 216 --> <span class="pagenum"><a name="Page_216" id="Page_216"></a>[pg + 216]</span> Wine, Spirit of Tartar freed from Acidity, or Chymical Oyl of + Turpentine, (although Liquors which must be conceiv'd very Saline, if + Chymists have, which is here no place to Dispute, rightly ascrib'd tasts + to the Saline Principle of Bodyes,) have any Remarkable Power either to + deprive our Tincture of its Cæruleous Colour, or restore it, when upon the + Affusion of Spirit of Vinegar it has disappear'd. + </p> + <h3> + <i>EXPERIMENT XI.</i> + </h3> + <p> + And here I must not omit, <i>Pyrophilus</i>, to inform You, that we can + shew You even in a Mineral Body something that may seem very near of Kin + to the Changeable Quality of the Tincture of <i>Lignum Nephriticum</i>, + for we have several flat pieces of Glass, of the thickness of ordinary + Panes for Windows one of which being interposed betwixt the Eye and a + clear Light, appears of a Golden Colour, not much unlike that of the + moderate Tincture of our Wood, but being so look'd upon as that the Beams + of light are not so much Trajected thorough it as Reflected from it to the + Eye, that Yellow seems to degenerate into a pale Blew, somewhat like that + of a Turquoise. And what which may also appear strange, is this, + <!-- Page 217 --> <span class="pagenum"><a name="Page_217" id="Page_217"></a>[pg + 217]</span> that if in a certain posture you hold one of these Plates + Perpendicular to the Horizon, so that the Sun-beams shine upon half of it, + the other half being Shaded, You may see that the part Shin'd upon will be + of a much Diluter Yellow than the Shaded part which will appear much more + Richly Colour'd; and if You alter the Posture of the Glass, so that it be + not held Perpendicular, but Parallel in reference to the Horizon, You may + see, (which perhaps you will admire) the Shaded part look of a Golden + Colour, but the other that the Sun shines freely on, will appear + considerably Blew, and as you remove any part of the Glass thus held + Horizontally into the Sun-beams or Shade, it will in the twinkling of an + Eye seem to pass from one of the above mention'd Colours to the other, the + Sun-beams Trajected through it upon a sheet of White Paper held near it, + do colour it with a Yellow, somewhat bordering upon a Red, but yet the + Glass may be so oppos'd to the Sun, that it may upon Paper project a mix'd + Colour here and there more inclin'd to Yellow, and here and there more to + Blew. The other Phænomena of this odd Glass, I fear it would be scarce + worth while to Record, and therefore I shall rather advertise You, <i>First</i> + that in the trying of these Experiments + <!-- Page 218 --> <span class="pagenum"><a name="Page_218" id="Page_218"></a>[pg + 218]</span> with it, you must take notice that one of the sides has either + alone, or at least principally its Superficial parts dispos'd to the + Reflection of the Blew Colour above nam'd, and that therefore you must + have a care to keep that side nearest to the Eye. And next, that we have + our selves made Glasses not unfit to exhibit an Experiment not unlike that + I have been speaking of, by laying upon pieces of Glass some very finely + foliated Silver, and giving it by degrees a much stronger Fire than is + requisite or usual for the Tinging of Glasses of other Colours. And this + Experiment, not to mention that it was made without a Furnace in which + Artificers that Paint Glass are wont to be very Curious, is the more + considerable, because, that though a Skilfull Painter could not deny to me + that 'twas with Silver he Colour'd his Glasses Yellow; yet he told me, + that when to Burn them (as they speak) he layes on the plates of Glass + nothing but a <i>Calx</i> of Silver Calcin'd without Corrosive Liquors, + and Temper'd with Fair Water, the Plates are Ting'd of a fine Yellow that + looks of a Golden Colour, which part soever of it you turn to or from the + Light; whereas (whether it be what an Artificer would call Over-doing, or + Burning, or else the imploying the Silver + <!-- Page 219 --> <span class="pagenum"><a name="Page_219" id="Page_219"></a>[pg + 219]</span> Crude that makes the Difference,) we have found more than + once, that some Pieces of Glass prepar'd as we have related, though held + against the Light they appear'd of a Transparent Yellow, yet look'd on + with ones back turn'd to the Light they exhibited an Untransparent Blew. + </p> + <h3> + <i>EXPERIMENT XII.</i> + </h3> + <p> + If you will allow me, <i>Pyrophilus</i>, for the avoiding of Ambiguity, to + imploy the Word Pigments, to signifie such prepared materials (as + Cochinele, Vermilion, Orpiment,) as Painters, Dyers and other Artificers + make use of to impart or imitate particular Colours, I shall be the better + understood in divers passages of the following papers, and particularly + when I tell you, That the mixing of Pigments being no inconsiderable part + of the Painters Art, it may seem an Incroachment in me to meddle with it. + But I think I may easily be excus'd (though I do not altogether pass it + by) if I restrain my self to the making of a Transient mention of some few + of their Practices about this matter; and that only so far forth, as may + warrant me to observe to you, that there are but few Simple and Primary + Colours (if I may so call them) + <!-- Page 220 --> <span class="pagenum"><a name="Page_220" id="Page_220"></a>[pg + 220]</span> from whose Various Compositions all the rest do as it were + Result. For though Painters can imitate the Hues (though not always the + Splendor) of those almost Numberless differing Colours that are to be met + with in the Works of Nature, and of Art, I have not yet found, that to + exhibit this strange Variety they need imploy any more than <i>White</i>, + and <i>Black</i>, and <i>Red</i>, and <i>Blew</i>, and <i>Yellow</i>; + these <i>five</i>, Variously <i>Compounded</i>, and (if I may so speak) <i>Decompounded</i>, + being sufficient to exhibit a Variety and Number of Colours, such, as + those that are altogether Strangers to the Painters Pallets, can hardly + imagine. + </p> + <p> + Thus (for Instance) Black and White differingly mix'd, make a Vast company + of Lighter and Darker Grays. + </p> + <p> + Blew and Yellow make a huge Variety of Greens. + </p> + <p> + Red and Yellow make Orange Tawny. + </p> + <p> + Red with a little White makes a Carnation. + </p> + <p> + Red with an Eye of Blew, makes a Purple; and by these simple Compositions + again Compounded among themselves, the Skilfull Painter can produce what + kind of Colour he pleases, and a great many more than we have yet Names + for. But, as I intimated above, 'tis not my Design + <!-- Page 221 --> <span class="pagenum"><a name="Page_221" id="Page_221"></a>[pg + 221]</span> to prosecute this Subject, though I thought it not unfit to + take some Notice of it, because we may hereafter have occasion to make use + of what has been now deliver'd, to illustrate the Generation of + Intermediate Colours; concerning which we must yet subjoyn this Caution, + that to make the Rules about the Emergency of Colours, fit to be Relied + upon, the Corpuscles whereof the Pigments consist must be such as do not + Destroy one anothers Texture, for in case they do, the produced Colour may + be very Different from that which would Result from the Mixture of other + harmless Pigments of the same Colours, as I shall have Occasion to shew + ere long. + </p> + <h3> + <i>EXPERIMENT XIII.</i> + </h3> + <p> + It may also give much light to an Enquirer into the Nature of Colours, to + know that not only in Green, but in many (if not all) other Colours, the + Light of the Sun passing through Diaphanous Bodies of differing Hues may + be tinged of the same Compound Colour, as if it came from some Painters + Colours of the same Denomination, though this later be exhibited by + Reflection, and be (as the + <!-- Page 222 --> <span class="pagenum"><a name="Page_222" id="Page_222"></a>[pg + 222]</span> former Experiment declares) manifestly Compounded of material + Pigments. Wherefore to try the Composition of Colours by Trajection, we + provided several Plates of Tinged Glass, which being laid two at a time + one on the top of another, the Object look'd upon through them both, + appear'd of a Compounded Colour, which agrees well with what we have + observ'd in the second Experiment, of Looking against the Light through + differingly Colour'd Papers. But we thought the Experiment would be more + Satisfactory, if we procur'd the Sun-beams to be so Ting'd in their + passage through Plates of Glass, as to exhibit the Compounded Colour upon + a Sheet of White Paper. And though by reason of the Thickness of the + Glasses, the Effect was but Faint, even when the Sun was High and Shin'd + forth clear, yet, we easily remedied that by Contracting the Beams we cast + on them by means of a Convex Burning-glass, which where it made the Beams + much converge Increas'd the Light enough to make the Compounded Colour + very manifest upon the Paper. By this means we observ'd, that the Beams + trajected through Blew and Yellow compos'd a Green, that an intense and + moderate Red did with Yellow make differing + <!-- Page 223 --> <span class="pagenum"><a name="Page_223" id="Page_223"></a>[pg + 223]</span> degrees of Saffron, and Orange Tawny Colours, that Green and + Blew made a Colour partaking of both, such as that which some Latin + Writers call <i>Pavonaceus</i>, that Red and Blew made a Purple, to which + we might add other Colours, that we produc'd by the Combinations of + Glasses differingly Ting'd, but that I want proper Words to express them + in our Language, and had not when we made the Tryals, the Opportunity of + consulting with a Painter, who perchance might have Suppli'd me with some + of the terms I wanted. + </p> + <p> + I know not whether it will be requisite to subjoyn on this Occasion, what + I tried concerning Reflections from Colour'd Glasses, and other + Transparent Bodies, namely, that having expos'd four or five sorts of them + to the Sun, and cast the Reflected Beams upon White Paper held near at + hand, the Light appear'd not manifestly Ting'd, but as if it had been + Reflected from the Impervious parts of a Colourless Glass, only that + Reflected from the Yellow was here and there stain'd with the same Colour, + as if those Beams were not all Reflected from the Superficial, but some + from the Internal parts of the Glass; upon which Occasion you may take + notice, that a Skilfull Tradesman, who makes such Colour'd + <!-- Page 224 --> <span class="pagenum"><a name="Page_224" id="Page_224"></a>[pg + 224]</span> Glass told me, that where as the Red Pigment was but + Superficial, the Yellow penetrated to the very midst of the Plate. But for + further Satisfaction, not having the Opportunity to Foliate those Plates, + and so turn them into Looking-glasses, we Foliated a Plate of <i>Muscovy</i> + Glass, and then laying on it a little Transparent Varnish of a Gold + Colour, we expos'd it to the Sun-beams, so as to cast them upon a Body fit + to receive them, on which the Reflected Light, appearing, as we expected, + Yellow, manifested that Rebounding from the Specular part of the <i>Selenitis</i>, + it was Ting'd in its return with the Colour of the Transparent Varnish + through which it pass'd. + </p> + <h3> + <i>EXPERIMENT XIV.</i> + </h3> + <p> + After what we have said of the Composition of Colours, it will now be + seasonable to annex some Experiments that we made in favour of those + Colours, that are taught in the Schools not to be Real, but only Apparent + and Phantastical; For we found by Tryals, that these Colours might be + Compounded, both with True and Stable Colours, and with one another, as + well as unquestionably Genuine and Lasting Colours, and that the Colours + <!-- Page 225 --> <span class="pagenum"><a name="Page_225" id="Page_225"></a>[pg + 225]</span> resulting from such Compositions, would respectively deserve + the same Denominations. + </p> + <p> + For first, having by the Trajection of the Sun-beams through a Glass-prism + thrown an Iris on the Floor, I found that by placing a Blew Glass at a + convenient distance betwixt the Prism and the Iris, that part of the Iris + that was before Yellow, might be made to appear Green, though not of a + Grass Green, but of one more Dilute and Yellowish. And it seems not + improbable, that the narrow Greenish List (if I may so call it) that is + wont to be seen between the Yellow and Blew parts of the Iris, is made by + the Confusion of those two Bordering Colours. + </p> + <p> + Next, I found, that though the want of a sufficient Liveliness in either + of the Compounding Colours, or a light Error in the manner of making the + following Tryals, was enough to render some of them Unsuccessfull, yet + when all necessary Circumstances were duely observ'd, the Event was + answerable to our Expectation and Desire. + </p> + <p> + And (as I formerly Noted) that Red and Blew compound a Purple, so I could + produce this last nam'd Colour, by casting at some Distance from the Glass + the Blew + <!-- Page 226 --> <span class="pagenum"><a name="Page_226" id="Page_226"></a>[pg + 226]</span> part of the Prismatical Iris (as I think it may be call'd for + Distinction sake) upon a Lively Red, (for else the Experiment succeeds not + so well.) And I remember, that sometimes when I try'd this upon a piece of + Red Cloath, <i>that</i> part of the Iris which would have been Blew, (as I + try'd by covering that part of the Cloath with a piece of White Paper) and + Compounded with the Red, wherewith the Cloath was Imbued before, appear'd + of a fair Purple, did, when I came to View it near at hand, look very + Odly, as if there were some strange Reflection or Refraction or both made + in the Hairs of which that Cloath was composed. + </p> + <p> + Calling likewise the Prismatical Iris upon a very Vivid Blew, I found that + part of it, which would else have been the Yellow, appear Green. (Another + somewhat differing Tryal, and yet fit to confirm this, you will find in + the fifteenth Experiment.) + </p> + <p> + But it may seem somewhat more strange, that though the Prismatical Iris + being made by the Refraction of Light through a Body that has no Colour at + all, must according to the Doctrine of the Schools consist of as purely + Emphatical Colours, as may be, yet even these may be Compounded with one + another, as well as Real Colours in + <!-- Page 227 --> <span class="pagenum"><a name="Page_227" id="Page_227"></a>[pg + 227]</span> the Grossest Pigments. For I took at once two Triangular + Glasses, and one of them being kept fixt in the same Posture, that the + Iris it projected on the Floor might not Waver, I cast on the same Floor + another Iris with the other Prism, and Moving it too and fro to bring what + part of the second Iris I pleas'd, to fall upon what part of the first I + thought fit, we did sometimes (for a small Errour suffices to hinder the + Success) obtain by this means a Green Colour in that part of the more + Stable Iris, that before was Yellow, or Blew, and frequently by casting + those Beams that in one of the Iris's made the Blew upon the Red parts of + the other Iris, we were able to produce a lovely Purple, which we can + Destroy or Recompose at pleasure, by Severing and Reapproaching the Edges + of the two Iris's. + </p> + <h3> + <i>EXPERIMENT XV.</i> + </h3> + <p> + On this occasion, <i>Pyrophilus</i>, I shall add, that finding the + Glass-prism to be the usefullest Instrument Men have yet imploy'd about + the Contemplation of Colours, and considering that Prisms hitherto in use + are made of Glass, Transparent and Colourless, I thought it would not be + amiss to try, + <!-- Page 228 --> <span class="pagenum"><a name="Page_228" id="Page_228"></a>[pg + 228]</span> what change the Superinduction of a Colour, without the + Destruction of the Diaphaneity, would produce in the Colours exhibited by + the Prism. But being unable to procure one to be made of Colour'd Glass, + and fearing also that if it were not carefully made, the Thickness of it + would render it too Opacous, I endeavoured to substitute one made of + Clarify'd Rosin, or of Turpentine brought (as I elsewhere teach) to the + consistence of a Transparent Gum. But though these Endeavours were not + wholly lost, yet we found it so difficult to give these Materials their + true Shape, that we chose rather to Varnish over an ordinary Prism with + some of these few Pigments that are to be had Transparent; as accordingly + we did first with Yellow, and then with Red, or rather Crimson, made with + Lake temper'd with a convenient Oyl, and the Event was, That for want of + good Transparent Colours, (of which you know there are but very few) both + the Yellow and the Red made the Glass so Opacous, (though the Pigment were + laid on but upon two Sides of the Glass, no more being absolutely + necessary) that unless I look'd upon an Inlightned Window, or the Flame of + a Candle, or some other Luminous or very Vivid object, + <!-- Page 229 --> <span class="pagenum"><a name="Page_229" id="Page_229"></a>[pg + 229]</span> I could scarce discern any Colours at all, especially when the + Glass was cover'd with Red. But when I did look on such Objects, it + appear'd (as I expected) that the Colour of the Pigment had Vitiated or + Drown'd some of those which the Prism would according to its wont have + exhibited, and mingling with others, Alter'd them: as I remember, that + both to my Eyes, and others to whom I show'd it, when the Prism was + cover'd with Yellow, it made those Parts of bright Objects, where the Blew + would else have been Conspicuous, appear of a light Green. But, <i>Pyrophilus</i>, + both the Nature of the Colours, and the Degree of Transparency, or of + Darkness in the Pigment, besides divers other Circumstances, did so vary + the <i>Phænomena</i> of these Tryals, that till I can procure small + Colour'd Prisms, or Hollow ones that may be filled with Tincted Liquor, or + obtain Some better Pigments than those I was reduc'd to imploy, I shall + forbear to Build any thing upon what has been delivered, and shall make no + other use of it, than to invite you to prosecute the Inquiry further. + </p> + <!-- Page 230 --> + <p> + <span class="pagenum"><a name="Page_230" id="Page_230"></a>[pg 230]</span> + </p> + <h3> + <i>EXPERIMENT XVI.</i> + </h3> + <p> + And here, <i>Pyrophilus</i>, since we are treating of Emphatical Colours, + we shall add what we think not unworthy your Observation, and not unfit to + afford some Exercise to the Speculative. For there are some Liquors, which + though Colourless themselves, when they come to be Elevated, and Dispers'd + into Exhalations, exhibit a conspicuous Colour, which they lose again, + when they come to be Reconjoyn'd into a Liquor, as good Spirit of <i>Nitre</i>; + or upon its account strong <i>Aqua-fortis</i>, though devoid of all + appearance of Redness whilst they continue in the form of a Liquor, if a + little Heat chance to turn the Minute parts of them into Vapour, the Steam + will appear of a Reddish or deep Yellow Colour, which will Vanish when + those Exhalations come to resume the form of Liquor. + </p> + <p> + And not only if you look upon a Glass half full of <i>Aqua-fortis</i>, or + Spirit of <i>Nitre</i>, and half full of <i>Nitrous</i> steams proceeding + from it, you will see the Upper part of the Glass of the Colour freshly + mention'd, if through it you look upon the Light. But which is much more + considerable, I + <!-- Page 231 --> <span class="pagenum"><a name="Page_231" id="Page_231"></a>[pg + 231]</span> have tried, that putting <i>Aqua-fortis</i> in a long clear + Glass, and adding a little Copper or some such open Metall to it, to + excite Heat and Fumes, the Light trajected through those Fumes, and cast + upon a sheet of White Paper, did upon that appear of the Colour that the + Fumes did, when directly Look'd upon, as if the Light were as well Ting'd + in its passage through these Fumes, as it would have been by passing + through some Glass or Liquor in which the same Colour was Inherent. + </p> + <p> + To which I shall further add, that having sometimes had the Curiosity to + observe whether the Beams of the Sun near the Horizon trajected through a + very Red Sky, would not (though such rednesses are taken to be but + Emphatical Colours) exhibit the like Colour, I found that the Beams + falling within a Room upon a very White Object, plac'd directly opposite + to the Sun, disclos'd a manifest Redness, as if they had pass'd through a + Colour'd <i>Medium</i>. + </p> + <h3> + <i>EXPERIMENT XVII.</i> + </h3> + <p> + The emergency, <i>Pyrophilus</i>, of Colours upon the Coalition of the + Particles of such Bodies as were neither of them of the Colour of that + Mixture whereof they are the + <!-- Page 232 --> <span class="pagenum"><a name="Page_232" id="Page_232"></a>[pg + 232]</span> Ingredients, is very well worth our attentive Observation, as + being of good use both Speculative and Practical; For much of the + Mechanical use of Colours among Painters and Dyers, doth depend upon the + Knowledge of what Colours may be produc'd by the Mixtures of Pigments so + and so Colour'd. And (as we lately intimated) 'tis of advantage to the + contemplative Naturalist, to know how many and which Colours are Primitive + (if I may so call them) and Simple, because it both eases his Labour by + confining his most sollicitous Enquiry to a small Number of Colours upon + which the rest depend, and assists him to judge of the nature of + particular compounded Colours, by shewing him from the Mixture of what + more Simple ones, and of what Proportions of them to one another, the + particular Colour to be consider'd does result. But because to insist on + the Proportions, the Manner and the Effects of such Mixtures would oblige + me to consider a greater part of the Painters Art and Dyers Trade, than I + am well acquainted with, I confin'd my self to make Trial of <i>several + ways to produce Green</i>, by the composition of Blew and Yellow. And + shall in this place both Recapitulate most of the things I have + Dispersedly deliver'd + <!-- Page 233 --> <span class="pagenum"><a name="Page_233" id="Page_233"></a>[pg + 233]</span> already concerning that Subject, and Recruit them. + </p> + <p> + And first, whereas Painters (as I noted above) are wont to make Green by + tempering Blew and Yellow, both of them made into a soft Consistence, with + either Water or Oyl, or some Liquor of Kin to one of those two, according + as the Picture is to be Drawn with those they call <i>water Colours</i>, + or those they term <i>Oyl Colours</i>, I found that by choosing fit + Ingredients, and mixing them in the form of Dry Powders, I could do, what + I could not if the Ingredients were temper'd up with a Liquor; But the + Blew and Yellow Powders must not only be finely Ground, but such as that + the Corpuscles of the one may not be too unequal to those of the other, + lest by their Disproportionate Minuteness the Smaller cover and hide the + Greater. We us'd with good success a slight Mixture of the fine Powder of + Bise, with that of Orpiment, or that of good Yellow Oker, I say a <i>slight</i> + Mixture, because we found that an <i>exquisite</i> Mixture did not do so + well, but by lightly mingling the two Pigments in several little Parcels, + those of them in which the Proportion and Manner of Mixture was more + Lucky, afforded us a good Green. + </p> + <!-- Page 234 --> + <p> + <span class="pagenum"><a name="Page_234" id="Page_234"></a>[pg 234]</span> + </p> + <p> + 2. We also learn'd in the Dye-houses, that Cloth being Dy'd Blew with + Woad, is afterwards by the Yellow Decoction of <i>Luteola</i> or + <!-- Erratum: insert --> Woud-wax or Wood-wax Dy'd into a Green Colour. + </p> + <p> + 3. You may also remember what we above Related, where we intimated, that + having in a Darkn'd Room taken two Bodies, a Blew and a Yellow, and cast + the Light Reflected from the one upon the other, we likewise obtain'd a + Green. + </p> + <p> + 4. And you may remember, that we observ'd a Green to be produc'd, when in + the same Darkn'd Room we look'd at the Hole at which alone the Light + enter'd, through the Green and Yellow parts of a sheet of Marbl'd Paper + laid over one another. + </p> + <p> + 5. We found too, that the Beams of the Sun being trajected through two + pieces of Glass, the one Blew and the other Yellow, laid over one another, + did upon a sheet of White paper on which they were made to fall, exhibit a + lovely Green. + </p> + <p> + 6. I hope also, that you have not already forgot, what was so lately + deliver'd, concerning the composition of a Green, with a Blew and Yellow; + of which most Authors would call the one a <i>Real</i>, and the other an + <i>Emphatical</i>. + </p> + <!-- Page 235 --> + <p> + <span class="pagenum"><a name="Page_235" id="Page_235"></a>[pg 235]</span> + </p> + <p> + 7. And I presume, you may have yet fresh in your memory, what the + fourteenth Experiment informs you, concerning the exhibiting of a Green, + by the help of a Blew and Yellow, that were both of them Emphatical. + </p> + <p> + 8. Wherefore we will proceed to take notice, that we also devis'd a way of + trying whether or no Metalline Solutions though one of them at least had + its Colour Adventitious, by the mixture of the <i>Menstruum</i> employ'd + to dissolve it, might not be made to compound a Green after the manner of + other Bodies. And though this seem'd not easie to be perform'd by reason + of the Difficulty of finding Metalline Solutions of the Colour requisite, + that would mix without Præcipitating each other; yet after a while having + consider'd the matter, the first Tryal afforded me the following + Experiment. I took a High Yellow Solution of good Gold in <i>Aqua-Regis</i>, + (made of <i>Aqua-fortis</i>, and as I remember half its weight of Spirit + of Salt) To this I put a due Proportion of a deep and lovely Blew Solution + of Crude Copper, (which I have elsewhere taught to be readily Dissoluble + in strong Spirit of Urine) and these two Liquors though at first they + seem'd a little to Curdle one another, yet being throughly mingl'd by + Shaking, + <!-- Page 236 --> <span class="pagenum"><a name="Page_236" id="Page_236"></a>[pg + 236]</span> they presently, as had been Conjectur'd, united into a + Transparent Green Liquor, which continu'd so for divers days that I kept + it in a small Glass wherein 'twas made, only letting fall a little + Blackish Powder to the Bottom. The other <i>Phænomena</i> of this + Experiment belong not to this place, where it may suffice to take notice + of the Production of a Green, and that the Experiment was more than once + repeated with Success. + </p> + <p> + 9. And lastly, to try whether this way of compounding Colours would hold + ev'n in Ingredients actually melted by the Violence of the Fire, provided + their Texture were capable of safely induring Fusion, we caus'd some Blew + and Yellow Ammel to be long and well wrought together in the Flame of a + Lamp, which being Strongly and Incessantly blown on them kept them in some + degree of Fusion, and at length (for the Experiment requires some Patience + as well as Skil) we obtain'd the expected Ammel of a Green Colour. + </p> + <p> + I know not, <i>Pyrophilus</i>, whether it be worth while to acquaint you + with the ways that came into my Thoughts, whereby in some measure to + explicate the first of the mention'd ways of making a Green; for I have + sometimes Conjectur'd, that the mixture + <!-- Page 237 --> <span class="pagenum"><a name="Page_237" id="Page_237"></a>[pg + 237]</span> of the Bise and the Orpiment produc'd a Green by so altering + the Superficial Asperity, which each of those Ingredients had apart, that + the Light Incident on the mixture was Reflected with differing Shades, as + to Quantity, or Order, or both, from those of either of the Ingredients, + and such as the Light is wont to be Modify'd with, when it Reflects from + Grass, or Leaves, or some of those other Bodies that we are wont to call + Green. And sometimes too I have doubted, whether the produced Green might + not be partly at least deriv'd from this, That the Beams that Rebound from + the Corpuscles of the Orpiment, giving one kind of stroak upon the <i>Retina</i>, + whose Perception we call Yellow, and the Beams Reflected from the + Corpuscles of the Bise, giving another stroak upon the same <i>Retina</i>, + like to Objects that are Blew, the Contiguity and Minuteness of these + Corpuscles may make the Appulse of the Reflected Light fall upon the <i>Retina</i> + within so narrow a Compass, that the part they Beat upon being but as it + were a Physical point, they may give a Compounded stroak, which may + consequently exhibit a Compounded and new Kind of Sensation, as we see + that two Strings of a Musical Instrument being struck together, making two + <!-- Page 238 --> <span class="pagenum"><a name="Page_238" id="Page_238"></a>[pg + 238]</span> Noises that arrive at the Ear at the same time as to Sense, + yield a Sound differing from either of them, and as it were Compounded of + both; Insomuch that if they be Discordantly ton'd, though each of them + struck apart would yield a Pleasing Sound, yet being struck together they + make but a Harsh and troublesome Noise. But this not being so fit a place + to prosecute Speculations, I shall not insist, neither upon these + Conjectures nor any others, which the Experiment we have been mentioning + may have suggested to me. And I shall leave it to you, <i>Pyrophilus</i>, + to derive what Instruction you can from comparing together the Various + ways whereby a Yellow and a Blew can be made to Compound a Green. That + which I now pretend to, being only to shew that the first of those + mention'd ways, (not to take at present notice of the rest) does far + better agree with our Conjectures about Colours, than either with the + Doctrine of the Schools, or with that of the <i>Chymists</i>, both which + seem to be very much Disfavour'd by it. + </p> + <p> + For first, since in the Mixture of the two mention'd Powders I could by + the help of a very excellent <i>Microscope</i> (for ordinary ones will + scarce serve the turn) discover that which seem'd to the naked Eye a Green + <!-- Page 239 --> <span class="pagenum"><a name="Page_239" id="Page_239"></a>[pg + 239]</span> Body, to be but a heap of Distinct, though very small Grains + of Yellow Orpiment and Blew Bise confusedly enough Blended together, it + appears that the Colour'd Corpuscles of either kind did each retain its + own Nature and Colour; By which it may be guess'd, what meer Transposition + and Juxtaposition of Minute and Singly unchang'd Particles of Matter can + do to produce a new Colour; For that this Local Motion and new Disposition + of the small parts of the Orpiment did Intervene is much more manifest + than it is easie to Explicate how they should produce this new Green + otherwise than by the new Manner of their being put together, and + consequently by their new Disposition to Modifie the Incident Light by + Reflecting it otherwise than they did before they were Mingl'd together. + </p> + <p> + Secondly, The Green thus made being (if I may so speak) Mechanically + produc'd, there is no pretence to derive it from I know not what + incomprehensible Substantial Form, from which yet many would have us + believe that Colours must flow; Nor does this Green, though a Real and + Permanent, not a Phantastical and Vanid Colour, seem to be such an + Inherent Quality as they would have it, since not only each part of + <!-- Page 240 --> <span class="pagenum"><a name="Page_240" id="Page_240"></a>[pg + 240]</span> the Mixture remains unalter'd in Colour, and consequently of a + differing Colour from the Heap they Compose, but if the Eye be assisted by + a <i>Microscope</i> to discern things better and more distinctly than + before it could, it sees not a Green Body, but a Heap of Blew and Yellow + Corpuscles. + </p> + <p> + And in the third place, I demand what either Sulphur, or Salt, or Mercury + has to do in the Production of this Green; For neither the Bise nor the + Orpiment were indu'd with that Colour before, and the bare Juxtaposition + of the Corpuscles of the two Powders that work not upon each other, but + might if we had convenient Instruments be separated, unalter'd, cannot + with any probability be imagin'd either to Increase or Diminish any of the + three Hypostatical Principles, (to which of them soever the <i>Chymists</i> + are pleas'd to ascribe Colours) nor does there here Intervene so much as + Heat to afford them any colour to pretend, that at least there is made an + Extraversion (as the <i>Helmontians</i> speak) of the Sulphur or of any of + the two other supposed Principles; But upon this Experiment we have + already Reflected enough, if not more than enough for once. + </p> + <!-- Page 241 --> + <p> + <span class="pagenum"><a name="Page_241" id="Page_241"></a>[pg 241]</span> + </p> + <h3> + <i>EXPERIMENT XVIII.</i> + </h3> + <p> + But here, <i>Pyrophilus</i>, I must advertise you, that 'tis not every + Yellow and every Blew that being mingl'd will afford a Green; For in case + one of the Ingredients do not Act only as endow'd with such a Colour, but + as having a power to alter the Texture of the Corpuscles of the other, so + as to Indispose them to Reflect the Light, as Corpuscles that exhibit a + Blew or a Yellow are wont to Reflect it, the emergent Colour may be not + Green, but such as the change of Texture in the Corpuscles of one or both + of the Ingredients qualifies them to shew forth; as for instance, if you + let fall a few Drops of Syrrup of Violets upon a piece of White Paper, + though the Syrrup being spread will appear Blew, yet mingling with it two + or three Drops of the lately mention'd Solution of Gold, I obtain'd not a + Green but a Reddish mixture, which I expected from the remaining Power of + the Acid Salts abounding in the Solution, such Salts or Saline Spirits + being wont, as we shall see anon, though weakn'd, so to work upon that + Syrrup as to change it into a Red or Reddish Colour. And to confirm that + for which I allege the former + <!-- Page 242 --> <span class="pagenum"><a name="Page_242" id="Page_242"></a>[pg + 242]</span> Experiment, I shall add this other, that having made a very + strong and high-colour'd Solution of Filings of Copper with Spirit of + Urine, though the <i>Menstruum</i> seem'd Glutted with the Metall, because + I put in so much Filings that many of them remain'd for divers days + Undissolv'd at the Bottom, yet having put three or four Drops of Syrrup of + Violets upon White Paper, I found that the deep Blew Solution + proportionably mingl'd with this other Blew Liquor did not make a Blew + mixture, but, as I expected, a fair Green, upon the account of the Urinous + Salt that was in the <i>Menstruum</i>. + </p> + <h3> + <i>EXPERIMENT XIX.</i> + </h3> + <p> + To shew the <i>Chymists</i>, that Colours may be made to Appear or Vanish, + where there intervenes no Accession or Change either of the Sulphureous, + or the Saline, or the Mercurial principle (as they speak) of Bodies: I + shall not make use of the Iris afforded by the Glass-prism, nor of the + Colours to be seen in a fair Morning in those drops of Dew that do in a + convenient manner Reflect and Refract the Beams of Light to the Eye; But I + will rather mind them of what they may observe in their + <!-- Page 243 --> <span class="pagenum"><a name="Page_243" id="Page_243"></a>[pg + 243]</span> own Laboratories, namely, that divers, if not all, Chymical + Essential Oyls, as also good Spirit of Wine, being shaken till they have + good store of Bubbles, those Bubbles will (if attentively consider'd) + appear adorn'd with various and lovely Colours, which all immediately + Vanish, upon the relapsing of the Liquor that affords those Bubbles their + Skins, into the rest of the Oyl, or Spirit of Wine, so that a Colourless + Liquor may be made in a trice to exhibit variety of Colours, and may lose + them in a moment without the Accession or Diminution of any of its + Hypostatical Principles. And, by the way, 'tis not unworthy our notice, + that some Bodies, as well Colourless, as Colour'd, by being brought to a + great Thinness of parts, acquire Colours though they had none before, or + Colours differing from them they were before endued with: For, not to + insist on the Variety of Colours, that Water, made somewhat Glutinous by + Sope, acquires, when 'tis blown into such Sphærical Bubbles as Boys are + wont to make and play with; Turpentine (though it have a Colour deep + enough of its own) may (by being blown into after a certain manner) be + brought to afford Bubbles adorn'd with variety of Orient Colours, which + though + <!-- Page 244 --> <span class="pagenum"><a name="Page_244" id="Page_244"></a>[pg + 244]</span> they Vanish after some while upon the breaking of the Bubbles, + yet they would in likelihood always exhibit Colours upon their <i>Superfices</i>, + (though not always the same in the same Parts of them, but Vary'd + according to the Incidence of the Sight, and the Position of the Eye) if + their Texture were durable enough: For I have seen one that was Skill'd at + fashioning Glasses by the help of a Lamp, blowing some of them so strongly + as to burst them, whereupon it was found, that the Tenacity of the Metall + was such, that before it broke it suffer'd it self to be reduc'd into + Films so extremely thin, that being kept clean they constantly shew'd on + their Surfaces (but after the manner newly mention'd) the varying Colours + of the Rain-bow, which were exceedingly Vivid, as I had often opportunity + to observe in some, that I caus'd purposely to be made, to keep by me. + </p> + <p> + But lest it should be objected, that the above mentioned Instances are + drawn from Transparent Liquors, it may possibly appear, not impertinent to + add, what I have sometimes thought upon, and several times tried, when I + was considering the Opinions of the <i>Chymists</i> about Colours, I took + then a Feather of a convenient Bigness + <!-- Page 245 --> <span class="pagenum"><a name="Page_245" id="Page_245"></a>[pg + 245]</span> and Shape, and holding it at a fit distance betwixt my Eye and + the Sun when he was near the Horizon, me thought there appear'd to me a + Variety of little Rain-bows, with differing and very vivid Colours, of + which none was constantly to be seen in the Feather; the like <i>Phænomenon</i> + I have at other times (though not with altogether so good success) + produc'd, by interposing at a due distance a piece of Black Ribband + betwixt the almost setting Sun and my Eye, not to mention the Trials I + have made to the same purpose, with other Bodies. + </p> + <h3> + <i>EXPERIMENT XX.</i> + </h3> + <p> + Take good Syrrup of Violets, Imprægnated with the Tincture of the flowers, + drop a little of it upon a White Paper (for by that means the Change of + Colour will be more conspicuous, and the Experiment may be practis'd in + smaller Quantities) and on this Liquor let fall two or three drops of + Spirit either of Salt or Vinegar, or almost any other eminently Acid + Liquor, and upon the Mixture of these you shall find the Syrrup immediatly + turn'd Red, and the way of Effecting such a Change has not been unknown to + divers Persons + <!-- Page 246 --> <span class="pagenum"><a name="Page_246" id="Page_246"></a>[pg + 246]</span> who have produc'd the like, by Spirit of Vitriol, or juice of + Limmons, but have Groundlessly ascrib'd the Effect to some Peculiar + Quality of those two Liquors, whereas, (as we have already intimated) + almost any Acid Salt will turn Syrrup of Violets Red. But to improve the + Experiment, let me add what has not (that I know of) been hitherto + observ'd, and has, when we first shew'd it them, appear'd something + strange, even to those that have been inquisitive into the Nature of + Colours; namely, that if instead of Spirit of Salt, or that of Vinegar, + you drop upon the Syrrup of Violets a little Oyl of Tartar <i>per + Deliquium</i>, or the like quantity of Solution of Potashes, and rubb them + together with your finger, you shall find the Blew Colour of the Syrrup + turn'd in a moment into a perfect Green, and the like may be perform'd by + divers other Liquors, as we may have occasion elsewhere to Inform you. + </p> + <p class="center"> + <i>Annotation upon the twentieth Experiment</i>. + </p> + <p> + The use of what we lately deliver'd concerning the way of turning Syrrup + of Violets, Red or Green, may be this; That, though it be a far more + common and procurable + <!-- Page 247 --> <span class="pagenum"><a name="Page_247" id="Page_247"></a>[pg + 247]</span> Liquor than the Infusion of <i>Lignum Nephriticum</i>, it may + yet be easily substituted in its Room, when we have a mind to examine, + whether or no the Salt predominant in a Liquor or other Body, wherein 'tis + Loose and Abundant, belong to the Tribe of <i>Acid</i> Salts or not. For + if such a Body turn the Syrrup of a Red or Reddish Purple Colour, it does + for the most part argue the Body (especially if it be a distill'd Liquor) + to abound with Acid Salt. But if the Syrrup be made Green, that argues the + Predominant Salt to be of a Nature repugnant to that of the Tribe of + Acids. For, as I find that either Spirit of Salt, or Oyl of Vitriol, or <i>Aqua-fortis</i>, + or Spirit of Vinegar, or Juice of Lemmons, or any of the Acid Liquors I + have yet had occasion to try, will turn Syrrup of Violets, of a <i>Red</i>, + (or at least, of a <i>Reddish</i> Colour, so I have found, that not only + the Volatile Salts of all Animal Substances I have us'd, as Spirit of + Harts-horn, of Urine, of Sal-Armoniack, of Blood, &c. but also all the + Alcalizate Salts I have imploy'd, as the Solution of Salt of Tartar, of + Pot-ashes, of common Wood-ashes, Lime-water, &c. will immediately + change the Blew Syrrup, into a perfect Green. And by the same way (to hint + that upon + <!-- Page 248 --> <span class="pagenum"><a name="Page_248" id="Page_248"></a>[pg + 248]</span> the by) I elsewhere show you, both the changes that Nature and + Time produce, in the more Saline parts of some Bodies, may be discover'd, + and also how ev'n such Chymically prepar'd Bodies, as belong not either to + the Animal Kingdome, or to the Tribe of <i>Alcali's</i>, may have their + new and superinduc'd Nature successfully Examin'd. In this place I shall + only add, that not alone the Changing the Colour of the Syrrup, requires, + that the Changing Body be more strong, of the Acid, or other sort of Salt + that is Predominant in it, than is requisite for the working upon the + Tincture of <i>Lignum Nephriticum</i>; but that in this is also, the + Operation of the formerly mention'd Salts upon our Syrrup, differs from + their Operation upon our Tinctures, that in this Liquor, if the Cæruleous + Colour be <i>Destroy'd</i> by an Acid Salt, it may be <i>Restor'd</i> by + one that is either Volatile, or Lixiviate; whereas in Syrrup of Violets, + though one of these contrary Salts will <i>destroy</i> the Action of the + other, yet neither of them will <i>restore</i> the Syrrup to its native + Blew; but each of them will Change it into the Colour which it self doth + (if I may so speak) affect, as we shall have Occasion to show in the Notes + on the twenty fifth Experiment. + </p> + <!-- Page 249 --> + <p> + <span class="pagenum"><a name="Page_249" id="Page_249"></a>[pg 249]</span> + </p> + <h3> + <i>EXPERIMENT XXI.</i> + </h3> + <p> + There is a Weed, more known to Plowmen than belov'd by them, whose Flowers + from their Colour are commonly call'd <i>Blew-bottles</i>, and <i>Corn-weed</i> + from their Growing among Corn<a name="NtA_18" id="NtA_18"></a><a + href="#Nt_18"><sup>18</sup></a>. These Flowers some Ladies do, upon the + account of their Lovely Colour, think worth the being Candied, which when + they are, they will long retain so fair a Colour, as makes them a very + fine Sallad in the Winter. But I have try'd, that when they are freshly + gather'd, they will afford a Juice, which when newly express'd, (for in + some cases 'twill soon enough degenerate) affords a very deep and pleasant + Blew. Now, (to draw this to our present Scope) by dropping on this fresh + Juice, a little Spirit of Salt, (that being the Acid Spirit I had then at + hand) it immediately turn'd (as I predicted) into a Red. And if instead of + the Sowr Spirit I mingled with it a little strong Solution of an + Alcalizate Salt, it did presently disclose a lovely Green; the same + Changes being by those differing sorts of Saline Liquors, producible in + this <i>Natural juice</i>, that we lately mention'd to + <!-- Page 250 --> <span class="pagenum"><a name="Page_250" id="Page_250"></a>[pg + 250]</span> have happen'd to that <i>factitious Mixture</i>, the Syrrup of + Violets. And I remember, that finding this Blew Liquor, when freshly made, + to be capable of serving in a Pen for an Ink of that Colour, I attempted + by moistning one part of a piece of White Paper with the Spirit of Salt I + have been mentioning, and another with some Alcalizate or Volatile Liquor, + to draw a Line on the leisurely dry'd Paper, that should, e'vn before the + Ink was dry, appear partly Blew, partly Red, and partly Green: But though + the latter part of the Experiment succeeded not well, (whether because + Volatile Salts are too Fugitive to be retain'd in the Paper, and + Alcalizate ones are too Unctuous, or so apt to draw Moisture from the Air, + that they keep the Paper from drying well) yet the former Part succeeded + well enough; the Blew and Red being Conspicuous enough to afford a + surprizing Spectacle to those, I acquaint not with (what I willingly allow + you to call) the <i>Trick</i>. + </p> + <p class="center"> + <i>Annotation upon the one and twentieth Experiment.</i> + </p> + <p> + But lest you should be tempted to think (<i>Pyrophilus</i>) that Volatile + or Alcalizate + <!-- Page 251 --> <span class="pagenum"><a name="Page_251" id="Page_251"></a>[pg + 251]</span> Salts change Blews into Green, rather upon the score of the + easie Transition of the former Colour into the latter, than upon the + account of the Texture, wherein most Vegetables, that afford a Blew, seem, + though otherwise differing, to be Allied, I will add, that when I + purposely dissolv'd Blew Vitriol in fair Water, and thereby imbu'd + sufficiently that Liquor with that Colour, a Lixiviate Liquor, and a + Urinous Salt being Copiously pour'd upon distinct Parcels of it, did each + of them, though perhaps with some Difference, turn the Liquor not Green, + but of a deep Yellowish Colour, almost like that of Yellow Oker, which + Colour the Precipitated Corpuscles retain'd, when they had Leisurely + subsided to the Bottom. What this Precipitated Substance is, it is not + needfull now to Enquire in this place, and in another, I have shown you, + that notwithstanding its Colour, and its being Obtainable from an Acid <i>Menstruum</i> + by the help of Salt of Tartar, it is yet far enough from being the true + Sulphur of Vitriol. + </p> + <h3> + <i>EXPERIMENT XXII.</i> + </h3> + <p> + Our next Experiment (<i>Pyrophilus</i>) will perhaps seem to be of a + contrary Nature + <!-- Page 252 --> <span class="pagenum"><a name="Page_252" id="Page_252"></a>[pg + 252]</span> to the two former, made upon Syrrup of Violets, and Juice of + Blew-bottles. For as in them by the Affusion of Oyl of Tartar, a Blewish + Liquor is made Green, so in this, by the sole Mixture of the same Oyl, a + Greenish Liquor becomes Blew. The hint of this Experiment was given us by + the practice of some <i>Italian</i> Painters, who being wont to + Counterfeit <i>Ultra-marine Azure</i> (as they call it) by Grinding + Verdigrease with Sal-Armoniack, and some other Saline Ingredients, and + letting them Rot (as they imagine) for a good while together in a + Dunghill, we suppos'd, that the change of Colour wrought in the + Verdigrease by this way of Preparation, must proceed from the Action of + certain Volatile and Alcalizate Salts, abounding in some of the mingled + Concretes, and brought to make a further Dissolution of the Copper + abounding in the Verdigrease, and therefore we Conjectur'd, that if both + the Verdigrease, and such Salts were dissolv'd in fair Water, the small + Parts of both being therein more subdivided, and set at liberty, would + have better access to each other, and thereby Incorporate much the more + suddenly; And accordingly we found, that if upon a strong Solution of good + French Verdigrease (for 'tis that we + <!-- Page 253 --> <span class="pagenum"><a name="Page_253" id="Page_253"></a>[pg + 253]</span> are wont to imploy, as the best) you pour a just quantity of + Oyl of Tartar, and shake them well together, you shall immediately see a + notable Change of Colour, and the Mixture will grow thick, and not + transparent, but if you stay a while, till the Grosser part be + Precipitated to, and setled in the Bottom, you may obtain a clear Liquor + of a very lovely Colour, and exceeding delightfull to the Eye. But, you + must have a care to drop in a competent Quantity of Oyl of Tartar, for + else the Colour will not be so Deep, and Rich; and if instead of this Oyl + you imploy a clear <i>Lixivium</i> of Pot-ashes, you may have an Azure + somewhat Lighter or Paler than, and therefore differing from, the former. + And if instead of either of these Liquors, you make use of Spirit of + Urine, or of Harts-horn, you may according to the Quantity and Quality of + the Spirit you pour in, obtain some further Variety (though scarce + considerable) of Cæruleous Liquors. And yet lately by the help of this + Urinous Spirit we made a Blew Liquor, which not a few Ingenious Persons, + and among them, some, whose Profession makes them very Conversant with + Colours, have looked upon with some wonder. But these Azure Colour'd + Liquors + <!-- Page 254 --> <span class="pagenum"><a name="Page_254" id="Page_254"></a>[pg + 254]</span> should be freed from the Subsiding matter, which the Salts of + Tartar or Urine precipitate out of them, rather by being Decanted, than by + Filtration. For by the latter of these ways we have sometimes found, the + Colour of them very much Impair'd, and little Superiour to that of the + grosser Substance, that it left in the Filtre. + </p> + <h3> + <i>EXPERIMENT XXIII.</i> + </h3> + <p> + That Roses held over the Fume of Sulphur, may quickly by it be depriv'd of + their Colour, and have as much of their Leaves, as the Fume works upon, + burn'd pale, is an Experiment, that divers others have tried, as well as + I. But (<i>Pyrophilus</i>) it may seem somewhat strange to one that has + never consider'd the Compounded nature of Brimstone, That, whereas the + Fume of Sulphur will, as we have said, Whiten the Leaves of Roses; That + Liquor, which is commonly call'd Oyl of Sulphur <i>per Campanam</i>, + because it is suppos'd to be made by the Condensation of these Fumes in + Glasses shap't like Bells, into a Liquor, does powerfully heighten the + Tincture of Red Roses, and make it more Red and Vivid, as we have easily + tried by putting some Red-Rose Leaves, + <!-- Page 255 --> <span class="pagenum"><a name="Page_255" id="Page_255"></a>[pg + 255]</span> that had been long dried, (and so had lost much of their + Colour) into a Vial of fair Water. For a while after the Affusion of a + convenient Quantity of the Liquor we are speaking of, both the Leaves + themselves, and the Water they were Steep'd in, discover'd a very fresh + and lovely Colour. + </p> + <h3> + <i>EXPERIMENT XXIV.</i> + </h3> + <p> + It may (<i>Pyrophilus</i>) somewhat serve to Illustrate, not only the + Doctrine of <i>Pigments</i>, and of <i>Colours</i>, but divers other Parts + of the <i>Corpuscular Philosophy</i>; as that explicates Odours, and many + other things, not as the Schools by Aery Qualities, but by Real, though + extremely Minute Bodies; to examine, how much of a Colourless Liquor, a + very small Parcel of a Pigment may Imbue with a <i>discernable</i> Colour. + And though there be scarce any thing of Preciseness to be expected from + such Trials, yet I presum'd, that (at least) I should be able to show a + much further Subdivision of the Parts of Matter into <i>Visible</i> + Particles, than I have hitherto found taken notice of, and than most men + would imagine; no Body, that I know of, having yet attempted to reduce + this Matter to any Measure. + </p> + <!-- Page 256 --> + <p> + <span class="pagenum"><a name="Page_256" id="Page_256"></a>[pg 256]</span> + </p> + <p> + The Bodies, the most promising for such a purpose, might seem to be the + Metalls, especially Gold, because of the Multitude, and Minuteness of its + Parts, which might be argu'd from the incomparable Closeness of its + Texture: But though we tried a Solution of Gold made in <i>Aqua Regia</i> + first, and then in fair Water; yet in regard we were to determine the + Pigment we imploy'd, not by <i>Bulk</i> but <i>Weight</i>, and because + also, that the Yellow Colour of Gold is but a faint one in Comparison of + the deep Colour of <i>Cochineel</i>, we rather chose this to make our + Trials with. But among divers of these it will suffice to set down one, + which was carefully made in Vessels conveniently Shap'd; (and that in the + presence of a Witness, and an Assistant) the Sum whereof I find among my + <i>Adversaria</i>, Registred in the following Words. To which I shall only + premise, (to lessen the wonder of so strange a diffusion of the Pigment) + That <i>Cochineel</i> will be better Dissolv'd, and have its Colour far + more heightn'd by Spirit of Urine, than (I say not by common Water, but) + by Rectify'd Spirit of Wine it self. + </p> + <p> + The Note I spoke off is this. [One Grain of <i>Cochineel</i> dissolv'd in + a pretty Quantity of Spirit of Urine, and then dissolv'd + <!-- Page 257 --> <span class="pagenum"><a name="Page_257" id="Page_257"></a>[pg + 257]</span> further by degrees in fair Water, imparted a discernable, + though but a very faint Colour, to about six Glass-fulls of Water, each of + them containing about forty three Ounces and an half, which amounts to + above a hundred twenty five thousand times its own Weight.] + </p> + <h3> + <i>EXPERIMENT XXV.</i> + </h3> + <p> + It may afford a considerable Hint (<i>Pyrophilus</i>) to him, that would + improve the Art of Dying, to know what change of Colours may be produc'd + by the three several sorts of Salts already often mention'd, (some or + other of which may be procur'd in Quantity at reasonable Rates) in the + Juices, Decoctions, Infusions, and (in a word) the more soluble parts of + Vegetables. And, though the design of this Discourse be the Improvement of + Knowledge, not of Trades: yet thus much I shall not scruple to intimate + here, That the Blew Liquors, mention'd in the twentieth and one and + twentieth Experiments, are far from being the only Vegetable Substances, + upon which Acid, Urinous, and Alcalizate Salts have the like Operations to + those recited in those two Experiments. For Ripe <i>Privet Berries</i> + (for instance) being crush'd + <!-- Page 258 --> <span class="pagenum"><a name="Page_258" id="Page_258"></a>[pg + 258]</span> upon White Paper, though they stain it with a Purplish Colour, + yet if we let fall on some part of it two or three drops of Spirit of + Salt, and on the other part a little more of the Strong Solution of + Pot-ashes, the former Liquor immediately turn'd that part of the Thick + juice or Pulp, on which it fell, into a lovely Red, and the latter turn'd + the other part of it into a delightfull Green. Though I will not + undertake, that those Colours in that Substance shall not be much more + Orient, than Lasting; and though (<i>Pyrophilus</i>) this Experiment may + seem to be almost the same with those already deliver'd concerning Syrrup + of Violets, and the Juice of Blew-bottles, yet I think it not amiss to + take this Occasion to inform you, that this Experiment reaches much + farther, than perhaps you yet imagine, and may be of good Use to those, + whom it concerns to know, how Dying Stuffs may be wrought upon by Saline + Liquors. For, I have found this Experiment to succeed in so many Various + Berries, Flowers, Blossoms, and other finer Parts of Vegetables, that + neither my Memory, nor my Leisure serves me to enumerate them. And it is + somewhat surprizing to see, by how Differingly-colour'd Flowers, or + Blossoms, (for example) the Paper being + <!-- Page 259 --> <span class="pagenum"><a name="Page_259" id="Page_259"></a>[pg + 259]</span> stain'd, will by an Acid Spirit be immediately turn'd Red, and + by any <i>Alcaly</i> or any Urinous Spirit turn'd Green; insomuch that + ev'n the crush'd Blossoms of <i>Meserion</i>, (which I gather'd in Winter + and frosty Weather) and those of Pease, crush'd upon White Paper, how + remote soever their Colours be from Green, would in a moment pass into a + deep Degree of that Colour, upon the Touch of an Alcalizate Liquor. To + which let us add, That either of those new Pigments (if I may so call + them) may by the Affusion of enough of a contrary Liquor, be presently + chang'd from Red into Green, and from Green into Red, which Observation + will hold also in Syrrup of Violets, Juices of Blew-bottles, &c. + </p> + <p class="center"> + <i>Annotation.</i> + </p> + <p> + After what I have formerly deliver'd to evince, That there are many + Instances, wherein new Colours are produc'd or acquir'd by Bodies, which + <i>Chymists</i> are wont to think destitute of Salt, or to whose change of + Colours no new Accession of Saline Particles does appear to contribute, I + think we may safely enough acknowledge, + <!-- Page 260 --> <span class="pagenum"><a name="Page_260" id="Page_260"></a>[pg + 260]</span> that we have taken notice of so many Changes made by the + Intervention of Salts in the Colours of Mix'd Bodies, that it has lessen'd + our Wonder, That though <i>many Chymists</i> are wont to ascribe the + Colours of Such Bodies to their Sulphureous, and <i>the rest</i> to their + Mercurial Principle; yet <i>Paracelsus</i> himself directs us in the + Indagation of Colours, to have an Eye principally upon Salts, as we find + in that passage of his, wherein he takes upon him to Oblige his Readers + much by Instructing them, of what things they are to expect the Knowledge + from each of the three distinct Principles of Bodies. <i>Alias</i> (says + he) <i>Colorum similis ratio est: De quibus brevem institutionem hanc + attendite, quod scilicet colores omnes ex Sale prodeant. Sal enim dat + colorem, dat Balsamum.</i><a name="NtA_19" id="NtA_19"></a><a href="#Nt_19"><sup>19</sup></a> + And a little beneath. <i> Iam natura Ipsa colores protrathit ex sale, + cuique speciei dans illum, qui ipsi competit</i>, &c. After which he + concludes; <i>Itaque qui rerum omnium corpora cognoscere vult, huic opus + est, ut ante omnia cognoscat Sulphur, Ab hoc, qui desiderat novisse + Colores is scientiam istorum petat à Sale, Qui scire vult Virtutes, is + scrutetur arcana Mercurii. Sic nimirum fundamentum hauserit Mysteriorum, + in quolibet crescenti indagandorum, + <!-- Page 261 --> <span class="pagenum"><a name="Page_261" id="Page_261"></a>[pg + 261]</span> prout natura cuilibet speciei ea ingessit</i>. But though <i>Paracelsus</i> + ascribes to each of his belov'd Hypostatical Principles, much more than I + fear will be found to belong to it; yet if we please to consider Colours, + not as <i>Philosophers</i>, but as <i>Dyers</i>, the concurrence of Salts + to the striking and change of Colours, and their Efficacy, will, I + suppose, appear so considerable, that we shall not need to quarrel much + with <i>Paracelsus</i>, for ascribing in this place (for I dare not affirm + that he uses to be still of one Mind) the Colours of Bodies to their + Salts, if by Salts he here understood, not only Elementary Salts, but such + also as are commonly taken for Salts, as Allom, Crystals of Tartar, + Vitriol, &c. because the Saline principle does chiefly abound in them, + though indeed they be, as we elsewhere declare, mix'd Bodies, and have + most of them, besides what is Saline, both Sulphureous, Aqueous, and Gross + or Earthy parts. + </p> + <p> + But though (<i>Pyrophilus</i>) I have observ'd a Red and Green to be + produc'd, the former, by Acid Salts, the later by Salts not Acid, in the + express Juices of so many differing Vegetable Substances, that the + Observation, if persued, may prove (as I said) of good Use: yet to show + you how much e'vn these Effects depend upon the + <!-- Page 262 --> <span class="pagenum"><a name="Page_262" id="Page_262"></a>[pg + 262]</span> particular Texture of Bodies, I must subjoyn some cases + wherein I (who am somewhat backwards to admit Observations for Universal) + had the Curiosity to discover, that the Experiments would not Uniformly + succeed, and of these Exceptions, the chief that I now remember, are + reducible to the following three. + </p> + <h3> + <i>EXPERIMENT XXVI.</i> + </h3> + <p> + And, (first) I thought fit to try the Operation of Acid Salts upon + Vegetable Substances, that are already and by their own Nature Red. And + accordingly I made Trial upon Syrrup of Clove-july-flowers, the clear + express'd Juice of the succulent Berries of <i>Spina Cervina</i>, or + Buckthorn (which I had long kept by me for the sake of its deep Colour) + upon Red Roses, Infusion of Brazil, and divers other Vegetable Substances, + on some of which crush'd (as is often mention'd) upon White Paper, (which + is also to be understood in most of these Experiments, if no Circumstance + of them argue otherwise) Spirit of Salt either made no considerable + Change, or alter'd the Colour but from a Darker to a Lighter Red. How it + will succeed in many other Vegetable Juices, + <!-- Page 263 --> <span class="pagenum"><a name="Page_263" id="Page_263"></a>[pg + 263]</span> and Infusions of the same Colour, I have at present so few at + hand, that I must leave you to find it out your self. But as for the + Operation of the other sorts of Salts upon these Red Substances, I found + it not very Uniform, some Red, or Reddish Infusions, as of Roses, being + turn'd thereby into a dirty Colour, but yet inclining to Green. Nor was + the Syrrup of Clove-july-flowers turn'd by the solution of Pot-ashes to a + much better, though somewhat a Greener, Colour. Another sort of Red + Infusions was by an <i>Alcaly</i> not turn'd into a Green, but advanc'd + into a Crimson, as I shall have occasion to note ere long. But there were + other sorts, as particularly the lovely Colour'd juice of Buckthorn + Berries, that readily pass'd into a lovely Green. + </p> + <h3> + <i>EXPERIMENT XXVII.</i> + </h3> + <p> + Among other Vegetables, which we thought likely to afford Exceptions to + the General Observation about the differing Changes of Colours produc'd by + Acid and Sulphureous Salts, we thought fit to make Trial upon the Flowers + of <i>Jasmin</i>, they being both White as to Colour, and esteem'd to be + of a more Oyly nature than other Flowers. Whereupon having taken + <!-- Page 264 --> <span class="pagenum"><a name="Page_264" id="Page_264"></a>[pg + 264]</span> the White parts only of the Flowers, and rubb'd them somewhat + hard with my Finger upon a piece of clean Paper, it appear'd very little + Discolour'd. Nor had Spirit of Salt, wherewith I moisten'd one part of it, + any considerable Operation upon it. But Spirit of Urine, and somewhat more + effectually a strong Alcalizate Solution, did immediately turn the almost + Colourless Paper moisten'd by the Juice of the <i>Jasmin</i>, not as those + Liquors are wont to do, when put upon the Juices of other Flowers, of a + good Green, but of a Deep, though somewhat Greenish Yellow, which + Experiment I did afterwards at several times repeat with the like success. + But it seems not that a great degree of Unctuousness is necessary to the + Production of the like Effects, for when we try'd the Experiment with the + Leaves of those purely White Flowers that appear about the end of Winter, + and are commonly call'd <i>Snow drops</i>, the event, was not much unlike + that, which, we have been newly mentioning. + </p> + <h3> + <i>EXPERIMENT XXVIII.</i> + </h3> + <p> + Another sort of Instances to show, how much changes of Colour effected by + Salts, depend upon the particular Texture of the + <!-- Page 265 --> <span class="pagenum"><a name="Page_265" id="Page_265"></a>[pg + 265]</span> Colour'd Bodies, has been afforded me by several <i>Yellow</i> + Flowers, and other Vegetables, as Mary-gold Leaves, early Prim-roses, + fresh Madder, &c. For being rubb'd upon White Paper, till they imbued + it with their Colour, I found not, that by the addition of Alcalizate + Liquors, nor yet by that of an Urinous Spirit, they would be turn'd either + Green or Red: nor did so Acid a Spirit, as that of Salt, considerably + alter their Colour, save that it seem'd a little to Dilute it. Only in + some early Prim-roses it destroy'd the greatest part of the Colour, and + made the Paper almost White agen. And Madder also afforded some thing + peculiar, and very differing from what we have newly mention'd: For having + gather'd Some Roots of it, and, (whilst they were recent) express'd upon + White Paper the Yellow Juice, an Alcalizate Solution drop'd upon it did + not turn it either Green or White, but Red. And the bruis'd Madder it self + being drench'd with the like Alcalizate Solution, exchang'd also its + Yellowishness for a Redness. + </p> + <!-- Page 266 --> + <p> + <span class="pagenum"><a name="Page_266" id="Page_266"></a>[pg 266]</span> + </p> + <p class="center"> + <i>An admonition touching the four preceding Experiments.</i> + </p> + <p> + Having thus (<i>Pyrophilus</i>) given you divers Instances, to countenance + the General observation deliver'd in the twenty fifth Experiment, and + divers Exceptions whereby it ought to be Limited; I must leave the further + Inquiry into these Matters to your own Industry. For not remembring at + present many of those other Trials, long since made to satisfie my self + about Particulars, and not having now the Opportunity to repeat them, I + must content my Self to have given you the Hint, and the ways of + prosecuting the search your Self; and only declare to you in general, + that, As I have made many Trials, unmention'd in this Treatise, whose + Events were agreeable to those mention'd in the twenty fifth Experiment, + so (to name now no other Instances) what I have try'd with Acid and + Sulphureous Salts upon the Pulp of Juniper Berries, rubb'd upon White + Paper, inclines me to think, That among that vast Multitude, and strange + Variety of Plants that adorn the face of the Earth, perhaps many other + Vegetables may be found, on which such <i>Menstruums</i> may not + <!-- Page 267 --> <span class="pagenum"><a name="Page_267" id="Page_267"></a>[pg + 267]</span> have such Operations, as upon the Juice of Violets, + Pease-blossoms, &c. no nor upon any of those three other sorts of + Vegetables, that I have taken notice of in the three fore-going + Experiments. It sufficiently appearing ev'n by these, that the effects of + a Salt upon the Juices of particular Vegetables do very much depend upon + their particular Textures. + </p> + <h3> + <i>EXPERIMENT XXIX.</i> + </h3> + <p> + It may be of some Use towards the discovery of the nature of these + Changes, which the Alimental Juice receives in some Vegetables, according + to the differing degrees of their Maturity, and according to the differing + kinds of Plants of the same Denomination, to observe what Operation Acid, + Urinous, and Alcalizate Salts will have upon the Juices of the several + sorts of the Vegetable substances I have been mentioning. + </p> + <p> + To declare my meaning by an Example, I took from the same Cluster, one + Blackberry full Ripe, and another that had not yet gone beyond a Redness, + and rubbing apiece of white Paper, with the former, I observ'd, that the + Juice adhering to it was of adark Reddish Colour, full of little + <!-- Page 268 --> <span class="pagenum"><a name="Page_268" id="Page_268"></a>[pg + 268]</span> Black Specks; and that this Juice by a drop of a strong <i>Lixivium</i>, + was immediately turn'd into a Greenish Colour deep enough, by as much + Urinous Spirit into a Colour much of Kin to the former, though somewhat + differing, and fainter; and by a drop of Spirit of Salt into a fine and + lightsome Red: where as the Red Berry being in like manner rubb'd upon + Paper, left on it a Red Colour, which was very little alter'd by the Acid + Spirit newly nam'd, and by the Urinous and Lixiviate Salts receiv'd + changes of Colour differing from those that had been just before produc'd + in the dark Juice of the Ripe Blackberry. + </p> + <p> + I remember also, that though the Infusion of Damask-Roses would as well, + though not so much, as that of Red, be heightned by Acid Spirits to an + intense degree of Redness, and by Lixiviate Salts be brought to a Darkish + Green; yet having for Trials sake taken a Rose, whose Leaves, which were + large and numerous, like those of a Province Rose, were perfectly Yellow, + though in a Solution of Salt of Tartar, they afforded a Green Blewish + Tincture, yet I did not by an Acid Liquor obtain a Red one; all that the + Saline Spirit I imploy'd, perform'd, being (if I much misremember + <!-- Page 269 --> <span class="pagenum"><a name="Page_269" id="Page_269"></a>[pg + 269]</span> not) to Dilute Somewhat the Yellowness of the Leaves. I would + also have tried the Tincture of Yellow Violets, but could procure none. + And if I were in those Islands of <i>Banda</i>, which are made Famous as + well as Rich, by being the almost only places, where Cloves will prosper, + I should think it worth my Curiosity to try, what Operation the three + differing Kinds of Salts, I have so often mention'd, would have upon the + Juice of this Spice, (express'd at the several Seasons of it) as it grows + upon the Tree. Since good Authors inform us, (of what is remarkable) that + these whether Fruits, or Rudiments of Fruits, are at first <i>White</i>, + afterward <i>Green</i>, and then <i>Reddish</i>, before they be beaten off + the Tree, after which being Dry'd before they are put up, they grow <i>Blackish</i> + as we see them. And one of the recentest <i>Herbarists</i> informs us, + that the Flower grows upon the top of the Clove it self, consisting of + four small Leaves, like a Cherry Blossom, but of an excellent <i>Blew</i>. + But (<i>Pyrophilus</i>) to return to our own Observations, I shall add, + that I the rather choose, to mention to you an Example drawn from Roses, + because that though I am apt to think, as I elsewhere advertise, that + something may be guess'd at about + <!-- Page 270 --> <span class="pagenum"><a name="Page_270" id="Page_270"></a>[pg + 270]</span> some of the Qualities of the Juices of Vegetables, by the + Resemblance or Disparity that we meet with in the Changes made of their + Colours, by the Operation of the same kinds of Salts; yet that those + Conjectures should be very warily made, may appear among other things, by + the Instance I have chosen to give in Roses. For though, (as I formerly + told you) the Dry'd Leaves, both of the Damask, and of Red ones, give a + Red Tincture to Water sharpen'd with Acid Salts, yet the one sort of + Leaves is known to have a Purgative faculty,<a name="NtA_20" id="NtA_20"></a><a + href="#Nt_20"><sup>20</sup></a> and the other are often, and divers ways, + imploy'd for Binding. + </p> + <p> + And I also choose (<i>Pyrophilus</i>) to subjoyn this twenty ninth + Experiment to those that precede it, about the change of the Colours of + Vegetables by Salts, for these two reasons: The first, that you may not + easily entertain Suspitions, if in the Trials of an Experiment of some of + the Kinds formerly mention'd, you should meet with an Event somewhat + differing from what my Relations may have made you expect. And the second, + That you may hereby be invited to discern, that it may not be amiss to + take notice of the particular Seasons wherein you gather the Vegetables + which + <!-- Page 271 --> <span class="pagenum"><a name="Page_271" id="Page_271"></a>[pg + 271]</span> in Nicer Experiments you make use of. For, it I were not + hindred both by haste and some justifiable Considerations, I could perhaps + add considerable Instances, to those lately deliver'd, for the making out + of this Observation; but for certain reasons I shall at present substitute + a remarkable passage to be met with in that Laborious Herbarist Mr. <i>Parkinson</i>, + where treating of the Virtues of the (already divers times mention'd) + Buckthorn Berries, he subjoyns the following account of several Pigments + that are made of them, not only according to the several ways of Handling + them, but according to the differing Seasons of Maturity, at which they + are Gather'd; <i>Of these Berries</i>, (says he) <i>are made three several + sorts of Colours as they shall be gather'd, that is, being gather'd while + they are Green, and kept Dry, are call'd Sapberries, which being steep'd + into some Allom-water, or fresh bruis'd into Allom-water, they give a + reasonable fair Yellow Colour which Painters use for their Work, and + Book-binders to Colour the edges of Books, and Leather-dressers to Colour + Leather, as they use also to make a Green Colour, call'd Sap-green, taken + from the Berries when they are Black, being bruis'd and put into a Brass + or Copper Kettle or Pan, and there suffer'd to abide three or four</i> + <!-- Page 272 --> <span class="pagenum"><a name="Page_272" id="Page_272"></a>[pg + 272]</span> <i>Days, or a little heated upon the Fire, and some beaten + Allom put unto them, and afterwards press'd forth, the Juice or Liquor is + usually put in great Bladders tied with strong thred at the Head and hung + up untill it be Dry, which is dissolv'd in Water or Wine, but Sack</i> (he + affirms) <i>is the best to preserve the Colour from Starving, (as they + call it) that is, from Decaying, and make it hold fresh the longer. The + third Colour (where of none</i> (says he) <i>that I can find have made + mention but only</i> Tragus<i>) is a Purplish Colour, which is made of the + Berries suffer'd to grow upon the Bushes untill the middle or end of</i> + November, <i>that they are ready to drop from the Trees.</i> + </p> + <p> + And, I remember (<i>Pyrophilus</i>) that I try'd, with a success that + pleas'd me well enough, to make such a kind of Pigment, as Painters call + Sap-green, by a way not unlike that, deliver'd here by our Author, but I + cannot now find any thing relating to that matter among my loose Papers. + And my Trials were made so many years ago, that I dare not trust my Memory + for Circumstances, but will rather tell you, that in a noted Colour-shop, + I brought them by Questions to confess to me, that they made their + Sap-green much after the ways by our <i>Botanist</i> here mention'd. And + on this occasion + <!-- Page 273 --> <span class="pagenum"><a name="Page_273" id="Page_273"></a>[pg + 273]</span> I shall add an Observation, which though it does not strictly + belong to this place, may well enough be mention'd here, namely, that I + find by an account given us by the Learned <i>Clusius</i>, of <i>Alaternus</i>, + that ev'n the Grosser Parts of the same Plant, are some of them one + Colour, and some another; For speaking of that Plant, he tells us, that + the <i>Portugalls</i> use the Bark to Dye their Nets into a Red Colour, + and with the Chips of the Wood, which are Whitish, they Dye a Blackish + Blew. + </p> + <h3> + <i>EXPERIMENT XXX.</i> + </h3> + <p> + Among the Experiments that tend to shew that the change of Colours in + Bodies may proceed from the Vary'd Texture of their Parts, and the + consequent change of their Disposition to Reflect or Refract the Light, + that sort of Experiments must not be left unmention'd, which is afforded + us by Chymical Digestions. For, if <i>Chymists</i> will believe several + famous Writers about what they call the Philosophers Stone, they must + acknowledge that the same Matter, seald up Hermetically in a Philosophical + Egg, will by the continuance of Digestion, or if they will have it so (for + it is not Material in our case which of the two it be) + <!-- Page 274 --> <span class="pagenum"><a name="Page_274" id="Page_274"></a>[pg + 274]</span> of Decoction, run through a great Variety of differing + Colours, before it come to that of the Noblest <i>Elixir</i>; whether that + be Scarlet, or Purple, or what ever other Kind of Red. But without + building any thing on so Obtruse and Questionable an Operation, (which yet + may be pertinently represented to those that believe the thing) we may + observe, that divers Bodies digested in carefully-clos'd Vessels, will in + tract of time, change their Colour: As I have elsewhere mention'd my + having observ'd ev'n in Rectify'd Spirit of Harts-horn, and as is evident + in the Precipitations of Amalgams of Gold, and Mercury, without Addition, + where by the continuance of a due Heat the Silver-Colour'd Amalgam is + reduc'd into a shining Red Powder. Further Instances of this Kind you may + find here and there in divers places of my other Essays. And indeed it has + been a thing, that has much contributed to deceive many <i>Chymists</i>, + that there are more Bodies than one, which by Digestion will be brought to + exhibit that Variety and Succession of Colours, which they imagine to be + Peculiar to what they call the <i>True matter of the Philosophers</i>. But + concerning this, I shall referr you to what you may elsewhere find in the + Discourse written touching the + <!-- Page 275 --> <span class="pagenum"><a name="Page_275" id="Page_275"></a>[pg + 275]</span> passive Deceptions of <i>Chymists</i>, and more about the + Production of Colours by Digestion you will meet with presently. Wherefore + I shall now make only this Observation from what has been deliver'd, That + in these Operations there appears not any cause to attribute the new + Colours emergent to the Action of a new Substantial form, nor to any + Increase or Decrement of either the Salt, Sulphur, or Mercury of the + Matter that acquires new Colours: For the Vessels are clos'd, and these + Principles according to the <i>Chymists</i> are Ingenerable and + Incorruptible; so that the Effect seems to proceed from hence, that the + Heat agitating and shuffling the Corpuscles of the Body expos'd to it, + does in process of time so change its Texture, as that the Transposed + parts do Modifie the incident Light otherwise, than they did when the + Matter appear'd of another Colour. + </p> + <h3> + <i>EXPERIMENT XXXI.</i> + </h3> + <p> + Among the several changes of Colour, which Bodies acquire or disclose by + Digestion, it it very remarkable, that <i>Chymists</i> find a Redness + rather than any other Colour in most of the Tinctures they Draw, and ev'n + in the more Gross Solutions they + <!-- Page 276 --> <span class="pagenum"><a name="Page_276" id="Page_276"></a>[pg + 276]</span> make of almost all Concretes, that abound either with Mineral + or Vegetable Sulphur, though the <i>Menstruum</i> imploy'd about these + Solutions or Tinctures be never so Limpid or Colourless. + </p> + <p> + This we have observ'd in I know not how many Tinctures drawn with Spirit + of Wine from <i>Jalap</i>, <i>Guaicum</i>, and several other Vegetables; + and not only in the Solutions of <i>Amber</i>, <i>Benzoin</i>, and divers + other Concretes made with the same <i>Menstruum</i>, but also in divers + Mineral Tinctures. And, not to urge that familiar Instance of the Ruby of + Sulphur, as <i>Chymists</i> upon the score of its Colour, call the + Solution of Flowers of Brimstone, made with the Spirit of Turpentine, nor + to take notice of other more known Examples of the aptness of Chymical + Oyls, to produce a Red Colour with the Sulphur they extract, or dissolve; + not to insist (I say) upon Instances of this nature, I shall further + represent to you, as a thing remarkable, that, both Acid and Alcalizate + Salts, though in most other cases of such contrary Operations, in + reference to Colours, will with many Bodies that abound with Sulphureous, + or with Oyly parts, produce a Red; as is manifest partly in the more + Vulgar Instances of the Tinctures, or Solutions of + <!-- Page 277 --> <span class="pagenum"><a name="Page_277" id="Page_277"></a>[pg + 277]</span> Sulphur made with <i>Lixiviums</i>, either of Calcin'd Tartar + or Pot-ashes, and other Obvious examples, partly by this, that the true + Glass of Antimony extracted with some Acid Spirits, with or without Wine, + will yield a Red Tincture, and that I know an Acid Liquor, which in a + moment will turn Oyl of Turpentine into a deep Red. But among the many + Instances I could give you of the easie Production of Redness by the + Operation of Saline Spirit, as well as of Spirit of Wine; I remember two + or three of those I have tried, which seem remarkable enough to deserve to + be mention'd to you apart. + </p> + <h3> + <i>EXPERIMENT XXXII.</i> + </h3> + <p> + But before we set them down, it will not perhaps appear impertinent to + premise; + </p> + <p> + That there seems to be a manifest Disparity betwixt Red Liquors, so that + some of them may be said to have a Genuine Redness in comparison of + others, that have a Yellowish Redness: For if you take (for example) a + good Tincture of <i>Chochineel</i>, dilute it never so much with fair + Water, you will not (as far as I can judge by what I have tried) be able + to make it a Yellow Liquor. Insomuch that a Single + <!-- Page 278 --> <span class="pagenum"><a name="Page_278" id="Page_278"></a>[pg + 278]</span> drop of a rich Solution of <i>Cochineel</i> in Spirit of + Urine, being Diluted with above an Ounce of fair Water, exhibited no + Yellowishness at all, but a fair (though somewhat faint) Pinck or + Carnation; and even when <i>Cochineel</i> was by degrees Diluted much + beyond the newly mention'd Colour, by the way formerly related to you in + the twenty fourth Experiment, I remember not, that there appear'd in the + whole Trial any Yellow. But if you take Balsom of Sulphur (for Instance) + though it may appear in a Glass, where it has a good Thickness, to be of a + deep Red, yet if you shake the Glass, or pour a few drops on a sheet of + White Paper, spreading them on it with your Finger, the Balsom that falls + back along the sides of the Glass, and that which stains the Paper, will + appear Yellow, not Red. And there are divers Tinctures, such as that of + Amber made with Spirit of Wine, (to name now no more) that will appear + either Yellow or Red, according as the Vessels that they fill, are Slender + or Broad. + </p> + <h3> + <i>EXPERIMENT XXXIII.</i> + </h3> + <p> + But to proceed to the Experiments I was about to deliver; <i>First</i>; + Oyl or Spirit + <!-- Page 279 --> <span class="pagenum"><a name="Page_279" id="Page_279"></a>[pg + 279]</span> of Turpentine, though clear as fair Water, being Digested upon + the purely White Sugar of Lead, has, in a short time, afforded us a high + Red Tincture, that some Artists are pleas'd to call the Balsom of <i>Saturn</i>, + which they very much (and probably not altogether without cause) extoll as + an excellent Medicine in divers Outward affections. + </p> + <h3> + <i>EXPERIMENT XXXIV.</i> + </h3> + <p> + <i>Next</i>, take of common Brimstone finely powdred five Ounces, of + Sal-Armoniack likewise pulveriz'd an equal weight, of beaten Quick-lime + six Ounces, mix these Powders exquisitely, and Distill them through a + Retort plac'd in Sand by degrees of Fire, giving at length as intense a + Heat as you well can in Sand, there will come over (if you have wrought + well) a Volatile Tincture of Sulphur, which may probably prove an + excellent Medicine, and should have been mention'd among the other + Preparations of Sulphur, which we have elsewhere imparted to you, but that + it is very pertinent to our present Subject, The change of Colours. For + though none of the Ingredients be Red, the Distill'd Liquor will be so: + and this Liquor if it + <!-- Page 280 --> <span class="pagenum"><a name="Page_280" id="Page_280"></a>[pg + 280]</span> be well Drawn, will upon a little Agitation of the Vial first + unstop'd (especially if it be held in a Warmer hand) lend forth a copious + Fume, not Red, like that of Nitre, but White; And sometimes this Liquor + may be so Drawn, that I remember, not long since, I took pleasure to + observe in a parcel of it, that Ingredients not Red, did not only yield by + Distillation a Volatile Spirit that was Red, but though that Liquor did + upon the bare opening of the Bottle it was kept in, drive us away with the + plenty and sulphureous sent of a White steam which it sent forth, yet the + Liquor it self being touch'd by our Fingers, did immediately Dye them + Black. + </p> + <h3> + <i>EXPERIMENT XXXV.</i> + </h3> + <p> + The third and <i>last</i> Experiment I shall now mention to shew, how + prone Bodies abounding in Sulphureous parts are to afford a Red Colour, is + one, wherein by the Operation of a Saline Spirit upon a White or Whitish + Body, which according to the <i>Chymists</i> should be altogether + Sulphureous, a Redness may be produc'd, not (as in the former Experiments) + slowly, but in the twinkling of an Eye. We took then of the Essential Oyl + of Anniseeds, + <!-- Page 281 --> <span class="pagenum"><a name="Page_281" id="Page_281"></a>[pg + 281]</span> which has this Peculiarity, that in Cold weather it loses its + Fluidity and the greatest part of its Transparency, and looks like a White + or Whitish Oyntment, and near at hand seems to consist of a Multitude of + little soft Scales: Of this Coagulated Stuff we spread a little with a + Knife upon a piece of White Paper, and letting fall on it, and mixing with + it a drop or two of Oyl of Vitriol, immediately (as we fore-saw) there + emerg'd together with some Heat and Smoak, a Blood-Red Colour, which + therefore was in a trice produc'd by two Bodies, whereof the one had but a + Whitish Colour, and the other (if carefully rectify'd) had no Colour at + all. + </p> + <h3> + <i>EXPERIMENT XXXVI.</i> + </h3> + <p> + But on this Occasion (<i>Pyrophilus</i>) we must add once for all, that in + many of the above-recited Experiments, though the changes of Colour + happen'd as we have mention'd them: yet the emergent or produc'd Colour is + oft times very subject to Degenerate, both quickly and much. + Notwithstanding which, since the Changes, we have set down, do happen + presently upon the Operation of the Bodies upon each other, or at the + times by us specify'd; + <!-- Page 282 --> <span class="pagenum"><a name="Page_282" id="Page_282"></a>[pg + 282]</span> <i>that</i> is sufficient both to justifie our Veracity, and + to shew what we Intend; it not being Essential to the Genuineness of a + Colour to be Durable. For a fading Leaf, that is ready to Rot, and moulder + into Dust, may have as true a Yellow, as a Wedge of Gold, which so + obstinately resists both Time and Fire. And the reason, why I take + occasion from the former Experiment to subjoyn this general Advertisement, + is, that I have several times observ'd, that the Mixture resulting from + the Oyls of Vitriol, and of Anniseeds, though it acquire a thicker + consistence than either of the Ingredients had, has quickly lost its + Colour, turning in a very short time into a dirty Gray, at least in the + Superficial parts, where 'tis expos'd to the Air; which last Circumstance + I therefore mention, because that, though it seem probable, that this + Degeneration of Colours may oft times and in divers cases proceed from the + further Action of the Saline Corpuscles, and the other Ingredients upon + one another, yet in many cases much of the Quick change of Colours seems + ascribeable to the Air, as may be made probable by several reasons: The + first whereof may be fetcht from the newly recited Example of the two + Oyls; The next may be, that we have sometimes observ'd + <!-- Page 283 --> <span class="pagenum"><a name="Page_283" id="Page_283"></a>[pg + 283]</span> long Window-Curtains of light Colours, to have that part of + them, which was expos'd to the Air, when the Window was open, of one + Colour, and the lower part, that was sheltred from the Air by the Wall, of + another Colour: And the third Argument may be fetch'd from divers + Observations, both of others, and our own; For of that Pigment so well + known in Painters Shops, by the name of <i>Turnsol</i>, our Industrious <i>Parkinson</i>, + in the particular account he gives of the Plant that bears it, tells us + also, That <i>the Berries when they are at their full Maturity, have + within them between the outer Skin and the inward Kirnel or Seed, a + certain Juice or Moisture, which being rubb'd upon Paper or Cloath, at the + first appears of a fresh and lovely Green Colour, but presently changeth + into a kind of Blewish Purple, upon the Cloath or Paper, and the same + Cloath afterwards wet in Water, and wrung forth, will Colour the Water + into a Claret Wine Colour, and these</i> (concludes he) <i>are those Raggs + of Cloath, which are usually call'd</i> Turnsol <i>in the Druggists or + Grocers Shops</i><a name="NtA_21" id="NtA_21"></a><a href="#Nt_21"><sup>21</sup></a>. + And to this Observation of our <i>Botanist</i> we will add an Experiment + of our own, (made before we met with That) which, though in many + Circumstances, very + <!-- Page 284 --> <span class="pagenum"><a name="Page_284" id="Page_284"></a>[pg + 284]</span> differing, serves to prove the same thing; for having taken of + the deeply Red Juice of <i>Buckthorn</i> Berries, which I bought of the + Man that uses to sell it to the Apothecaries, to make their Syrrup <i>de + Spina Cervina</i>, I let some of it drop upon a piece of White Paper, and + having left it there for many hours, till the Paper was grown dry again, I + found what I was inclin'd to suspect, namely, That this Juice was + degenerated from a deep Red to a dirty kind of Greyish Colour, which, in a + great part of the stain'd Paper seem'd not to have so much as an Eye of + Red: Though a little Spirit of Salt or dissolv'd <i>Alcaly</i> would turn + this unpleasant Colour (as formerly I told you it would change the not yet + alter'd Juice) into a Red or Green. And to satisfie my self, that this + Degeneration of Colour did not proceed from the Paper, I drop'd some of + the deep Red or Crimson Juice upon a White glaz'd Tile, and suffering it + to dry on there, I found that ev'n in that Body, on which it could not + Soak, and by which it could not be Wrought, it nevertheless lost its + Colour. And these Instances (<i>Pyrophilus</i>) I am the more carefull to + mention to you, that you may not be much Surpris'd or Discourag'd, if you + should sometimes miss of performing + <!-- Page 285 --> <span class="pagenum"><a name="Page_285" id="Page_285"></a>[pg + 285]</span> punctually what I affirm my self to have done in point of + changing Colours; since in these Experiments the over-sight or neglect of + such little Circumstances, as in many others would not be perhaps + considerable, may occasion the mis-carrying of a Trial. And I was willing + also to take this occasion of Advertising you in the repeating of the + Experiments mention'd in this Treatise, to make use of the Juices of + Vegetables, and other things prepar'd for your Trials, as soon as ever + they are ready, lest one or other of them grow less fit, if not quite + unfit by delay; and to estimate the Event of the Trials by the Change, + that is produc'd presently upon the due and sufficient Application of + Actives to Passives, (as they speak) because in many cases the effects of + such Mixtures may not be lasting, and the newly produc'd Colour may in a + little time degenerate. But, (<i>Pyrophilus</i>) I forgot to add to the + two former Observations lately made about Vegetables, a third of the same + Import, made in Mineral substances, by telling you, That the better to + satisfie a Friend or two in this particular, I sometimes made, according + to some Conjectures of mine, this Experiment; That having dissolv'd good + Silver in <i>Aqua-fortis</i>, and Precipitated it with Spirit of Salt, + upon + <!-- Page 286 --> <span class="pagenum"><a name="Page_286" id="Page_286"></a>[pg + 286]</span> the first Decanting of the Liquor, the remaining Matter would + be purely White; but after it had lain a while uncover'd, that part of it, + that was Contiguous to the Air, would not only lose its Whiteness, but + appear of a very Dark and almost Blackish Colour, I say that part that was + Contiguous to the Air, because if that were gently taken off, the + Subjacent part of the same Mass would appear very White, till that also, + having continu'd a while expos'd to the Air, would likewise Degenerate. + Now whether the Air perform these things by the means of a Subtile Salt, + which we elsewhere show it not to be destitute of, or by a peircing + Moisture, that is apt easily to insinuate it self into the Pores of some + Bodies, and thereby change their Texture, and so their Colour; Or by + solliciting the Avolation of certain parts of the Bodies, to which 'tis + Contiguous; or by some other way, (which possibly I may elsewhere propose + and consider) I have not now the leisure to discourse. And for the same + reason, though I could add many other Instances, of what I formerly noted + touching the emergency of Redness upon the Digestion of many Bodies, + insomuch that I have often seen upon the Borders of <i>France</i> (and + probably we may have the like in + <!-- Page 287 --> <span class="pagenum"><a name="Page_287" id="Page_287"></a>[pg + 287]</span> <i>England</i>) a sort of Pears, which digested for some time + with a little Wine, in a Vessel exactly clos'd, will in not many hours + appear throughout of a deep Red Colour, (as also that of the Juice, + wherein they are Stew'd, becomes) but ev'n on pure and white Salt of + Tartar, pure Spirit of Wine, as clear as Rock-water, will (as we elsewhere + declare) by long Digestion acquire a Redness; Though I say such Instances + might be Multiply'd, and though there be some other Obvious changes of + Colours, which happen so frequently, that they cannot but be as well + Considerable as Notorious; such as is the Blackness of almost all Bodies + burn'd in the open Air: yet our haste invites us to resign you the + Exercise of enquiring into the Causes of these Changes. And certainly, the + reason both <i>why</i> the Soots of such differing Bodies are almost all + of them all Black, <i>why</i> so much the greater part of Vegetables + should be rather Green than of any other Colour, and particularly (which + more directly concerns this place) <i>why</i> gentle Heats do so + frequently in Chymical Operations produce rather a Redness than another + Colour in digested <i>Menstruums</i>, not only Sulphureous, as Spirit of + Wine, but Saline, as Spirit of Vinegar, may be very well worth + <!-- Page 288 --> <span class="pagenum"><a name="Page_288" id="Page_288"></a>[pg + 288]</span> a serious Inquiry; which I shall therefore recommend to <i>Pyrophilus</i> + and his Ingenious Friends. + </p> + <h3> + <i>EXPERIMENT XXXVII.</i> + </h3> + <p> + It may seem somewhat strange, that if you take the Crimson Solution of <i>Cochineel</i>, + or the Juice of Black Cherries, and of some other Vegetables that afford + the like Colour, (which because many take but for a deep Red, we do with + them sometimes call it so) and let some of it fall upon a piece of Paper, + a drop or two of an Acid Spirit, such as Spirit of Salt, or <i>Aqua-fortis</i>, + will immediately turn it into a fair Red. Whereas if you make an Infusion + of Brazil in fair Water, and drop a little Spirit of Salt or <i>Aqua-fortis</i> + into it, that will destroy its Redness, and leave the Liquor of a Yellow, + (sometimes Pale) I might perhaps plausibly enough say on this occasion, + that if we consider the case a little more attentively, we may take + notice, that the action of the Acid Spirit seems in both cases, but to + weaken the Colour of the Liquor on which it falls. And so though it + destroy Redness in the Tincture of Brazil, as well as produce Red in the + Tincture of <i>Chochineel</i>, its Operations may be Uniform + <!-- Page 289 --> <span class="pagenum"><a name="Page_289" id="Page_289"></a>[pg + 289]</span> enough, since as Crimson seems to be little else than a very + deep Red, with (perhaps) an Eye of Blew, so some kinds of Red seem (as I + have lately noted) to be little else than heightned Yellow. And + consequently in such Bodies, the Yellow seems to be but a diluted Red. And + accordingly Alcalizate Solutions and Urinous Spirits, which seem dispos'd + to Deepen the Colours of the Juices and Liquors of most Vegetables, will + not only restore the Solution of <i>Cochineel</i> and the Infusion of + Brazil to the Crimson, whence the Spirit of Salt had chang'd them into a + truer Red; but will also (as I lately told you) not only heighthen the + Yellow Juice of Madder into Red, but advance the Red Infusion of Brazil to + a Crimson. But I know not whether it will not be much safer to derive + these Changes from vary'd Textures, than certain kinds of Bodies; and you + will perhaps think it worth while, that I should add on this occasion, + That it may deserve some Speculation, why, notwithstanding what we have + been observing, though Blew and Purple seem to be deeper Colours than Red, + and therefore the Juices of Plants of either of the two former Colours may + (congruously enough to what has been just now noted) be turn'd Red by + <!-- Page 290 --> <span class="pagenum"><a name="Page_290" id="Page_290"></a>[pg + 290]</span> Spirit of Salt or <i>Aqua-fortis</i>, yet Blew Syrrup of + Violets and some Purples should both by Oyl of Tartar and Spirit of Urine + be chang'd into Green, which seems to be not a deeper but a more diluted + Colour than Blew, if not also than Purple. + </p> + <h3> + <i>EXPERIMENT XXXVIII.</i> + </h3> + <p> + It would much contribute to the History of Colours, if <i>Chymists</i> + would in their Laboratories take a heedfull notice, and give us a + faithfull account of the Colours observ'd in the Steams of Bodies either + Sublim'd or Distill'd, and of the Colours of those Productions of the + Fire, that are made up by the Coalition of those Steams. As (for Instance) + we observe in the Distilling of pure Salt peter, that at a certain season + of the Operation, the Body, though it seem either Crystalline, or White, + affords very Red Fumes: whereas though Vitriol be Green or Blew, the + Spirit of it is observ'd to come over in Whitish Fumes. The like Colour I + have taken notice of in the Fumes of several other Concretes of differing + Colours, and Natures, especially when Distill'd with strong Fires. And we + elsewhere note, that ev'n Soot, as Black as it is, has fill'd our + Receivers + <!-- Page 291 --> <span class="pagenum"><a name="Page_291" id="Page_291"></a>[pg + 291]</span> with such copious White Fumes, that they seem'd to have had + their In-sides wash'd with Milk. And no less observable may be, the + Distill'd Liqours, into which such Fumes convene, (for though we will not + deny, that by skill and care a Reddish Liqour may be obtain'd from Nitre) + yet the common Spirit of it, in the making ev'n of which store of these + Red Fumes are wont to pass over into the Receiver, appears not to be at + all Red. And besides, that neither the Spirit of Vitriol, nor that of Soot + is any thing White; And, besides also, that as far as I have observ'd, + most (for I say not all) of the Empyreumatical Oyls of Woods, and other + Concretes, are either of a deep Red, or of a Colour between Red and Black; + besides this, I say, 'tis very remarkable that notwithstanding that great + Variety of Colours to be met with in the Herbs, Flowers, and other Bodies + wont to be Distill'd in <i>Balneo</i>: yet (as far at least as our common + Distillers Experience reacheth) all the Waters and Spirits that first come + over by that way of Distillation, leave the Colours of their Concretes + behind them, though indeed there be one or two Vegetables not commonly + taken notice of, whose Distill'd Liqours I elsewhere observe to carry over + <!-- Page 292 --> <span class="pagenum"><a name="Page_292" id="Page_292"></a>[pg + 292]</span> the Tincture of the Concrete with them. And as in + Distillations, so in Sublimations, it were worth while to take notice of + what comes up, in reference to our present scope, by purposely performing + them (as I have in some cafes done) in conveniently shap'd Glasses, that + the Colour of the ascending Fumes may be discern'd; For it may afford a + Naturalist good Information to observe the Congruities or the Differences + betwixt the Colours of the ascending Fumes, and those of the <i>Flowers</i>, + they compose by their Convention. For it is evident, that these <i>Flowers</i>, + do many of them in point of Colour, much differ, not only from one + another, but oft times from the Concretes that afforded them. Thus, (not + here to repeat what I formerly noted of the Black Soots of very + differingly Colour'd Bodies) though Camphire and Brimstone afford <i>Flowers</i> + much of their own Colour, save that those of Brimstone are wont to be a + little Paler, than the Lumps that yielded them; yet ev'n of Red <i>Benzoin</i>, + that sublim'd Substance, which <i>Chymists</i> call its <i>Flowers</i>, is + wont to be White or Whitish. And to omit other Instances, ev'n one and the + same Black Mineral, Antimony, may be made to afford <i>Flowers</i>, some + of them Red, and some Grey, and, which is more strange, + <!-- Page 293 --> <span class="pagenum"><a name="Page_293" id="Page_293"></a>[pg + 293]</span> some of them purely White. And 'tis the Prescription of some + Glass-men by exquisitely mingling a convenient proportion of Brimstone, + Sal-Armoniack, and Quicksilver, and Subliming them, together, to make a + Sublimate of an excellent Blew; and though having caus'd the Experiment to + be made, we found the produc'd Sublimate to be far from being of a lovely + Colour, (as was promis'd) that there and there, it seem'd Blewish, and at + least was of a Colour differing enough from either of the Ingredients, + which is sufficient for our present purpose. But a much finer Colour is + promis'd by some of the Empiricks, that pretend to Secrets, who tell us, + that Orpiment, being Sublim'd, will afford among the Parts of it that fly + Upward, some little Masses, which, though the Mineral it self be of a good + Yellow, will be Red enough to emulate Rubies, both in Colour and + Translucency. And this Experiment may, for ought I know, sometimes + succeed; for I remember, that having in a small Bolt-head purposely + sublim'd some powder'd Orpiment, we could in the Lower part of the + Sublimate discern here and there some Reddish Lines, though much of the + Upper part of the Sublimate consisted of a matter, which was not alone + purely + <!-- Page 294 --> <span class="pagenum"><a name="Page_294" id="Page_294"></a>[pg + 294]</span> Yellow, but transparent almost like a Powder. And we have also + this way obtain'd a Sublimate, the Lower part whereof though it consisted + not of Rubies, yet the small pieces of it, which were Numerous enough, + were of a pleasant Reddish Colour, and Glitter'd very prettily. But to + insist on such kind of Trials and Observations (where the ascending Fumes + of Bodies differ in Colour from the Bodies themselves) though it might + indeed Inrich the History of Colours, would Robb me of too much of the + little time I have to dispatch what I have further to tell you concerning + them. + </p> + <h3> + <i>EXPERIMENT XXXIX</i> + </h3> + <p> + Take the dry'd Buds (or Blossoms) of the Pomegranate Tree, (which are + commonly call'd in the Shops <i>Balaustiums</i>) pull off the Reddish + Leaves, and by a gentle Ebullition of them in fair Water, or by a + competent Infusion of them in like Water well heated, extract a faint + Reddish Tincture, which if the Liquor be turbid, you may Clarifie it by + Filtrating it Into this, if you pour a little good Spirit of Urine, or + some other Spirit abounding in the like sort of Volatile Salts, the + Mixture will + <!-- Page 295 --> <span class="pagenum"><a name="Page_295" id="Page_295"></a>[pg + 295]</span> presently turn of a dark Greenish Colour, but if instead of + the fore-mention'd Liquor, you drop into the simple Infusion a little + rectify'd Spirit of Sea-Salt, the Pale and almost Colourless Liquor will + immediately not only grow more Transparent, but acquire a high Redness, + like that of Rich Claret Wine, which so suddenly acquir'd Colour, may as + quickly be Destroy'd and turn'd into a dirty Blewish Green, by the + affusion of a competent quantity of the above-mention'd Spirit of Urine. + </p> + <p class="center"> + <i>Annotation.</i> + </p> + <p> + This Experiment may bring some Light to, and receive some from a couple of + other Experiments, that I remember I have met with in the ingenious <i>Gassendus</i>'s + Animadversions upon <i>Epicurus</i>'s Philosophy, whilst I was turning + over the Leaves of those Learned Commentaries; (my Eyes being too weak to + let me read such Voluminous Books quite thorough) And I the less scruple + (notwithstanding my contrary Custom in this Treatise) to set down these + Experiments of another, because I shall a little improve the latter of + them, and because by comparing there with that which I have last recited, + we may be assisted to Conjecture + <!-- Page 296 --> <span class="pagenum"><a name="Page_296" id="Page_296"></a>[pg + 296]</span> upon what account it is, that Oyl of Vitriol heightens the + Tincture of Red-rose Leaves, since Spirit of Salt, which is a highly Acid + <i>Menstruum</i>, but otherwise differing enough from Oyl of Vitriol, does + the same thing. Our Authors Experiments then, as we made them, are these; + We took about a Glass-full of luke-warm Water, and in it immerg'd a + quantity of the Leaves of <i>Senna</i>, and presently upon the Immersion + there did not appear any Redness in the Water, but dropping into it a + little Oyl of Tartar, the Liquor soon discover'd a Redness to the + watchfull Eye, whereas by a little of that Acid Liquor of Vitriol, which + is like the former, undeservedly called Oyl, such a Colour would not be + extracted from the infused <i>Senna</i>. On the other side we took some + Red-rose Leaves dry'd, and having shaken them into a Glass of fair Water, + they imparted to it no Redness, but upon the affusion of a little Oyl of + Vitriol the Water was immediately turn'd Red, which it would not have + been, if instead of Oyl of Vitriol, we had imployed Oyl of Tartar to + produce that Colour: That these were <i>Gassendus</i> his Experiments, I + partly remember, and was assur'd by a Friend, who lately Transcribed them + out of <i>Gassendus</i> his Book, which I + <!-- Page 297 --> <span class="pagenum"><a name="Page_297" id="Page_297"></a>[pg + 297]</span> therefore add, because I have not now that Book at hand. And + the design of <i>Gassendus</i> in these Experiments our Friend affirms to + be, to prove, that of things not Red a Redness may be made only by + Mixture, and the Varied position of parts, wherein the Doctrine of that + Subtil Philosopher doth not a little Authorize, what we have formerly + delivered concerning the Emergency and Change of Colours. But the + instances, that we have out of him set down, seem not to be the most + Eminent, that may be produced of this truth: For our next Experiment will + shew the production of several Colours out of Liquors, which have not any + of them any such Colour, nor indeed any discernable one at all; and + whereas though our Author tells us, that there was no Redness either in + the Water, or the Leaves of <i>Senna</i>, or the Oyl of Tartar; And though + it be true, that the Predominant Colour of the Leaves of <i>Senna</i> be + another than Red, yet we have try'd, that by steeping that Plant a Night + even in Cold water, it would afford a very deep Yellow or Reddish Tincture + without the help of the Oyl of Tartar, which seems to do little more than + assist the Water to extract more nimbly a plenty of that Red Tincture, + wherewith the Leaves of <i>Senna</i> + <!-- Page 298 --> <span class="pagenum"><a name="Page_298" id="Page_298"></a>[pg + 298]</span> do of themselves abound, and having taken off the Tincture of + <i>Senna</i>, made only with fair Water, before it grew to be Reddish, and + Decanted it from the Leaves, we could not perceive, that by dropping some + Oyl of Tartar into it, that Colour was considerable, though it were a + little heightned into a Redness; which might have been expected, if the + particles of the Oyl did eminently Co-operate, otherwise than we have + expressed, to the production of this Redness. + </p> + <p> + And as for the Experiment with Red-rose Leaves, the same thing may be + alleged, for we found that such Leaves by bare Infusion for a Night and + Day in fair Water, did afford us a Tincture bordering at least upon + Redness, and that Colour being conspicuous in the Leaves themselves, would + not by some seem so much to be produc'd as to be extracted by the affusion + of Oyl of Vitriol. And the Experiment try'd with the dry'd Leaves of + Damask-roses succeeded but imperfectly, but that is indeed observable to + our Authors purpose, that Oyl of Tartar will not perform in this + Experiment what Oyl of Vitriol doth; but because this last named Liquor is + not so easily to be had, give me leave to Advertise you, that the + Experiment will succeed, + <!-- Page 299 --> <span class="pagenum"><a name="Page_299" id="Page_299"></a>[pg + 299]</span> if instead of it you imploy <i>Aqua-fortis</i>. And though + some Trials of our own formerly made, and others easily deducible from + what we have already deliver'd, about the different Families and + Operations of Salt, might enable us to present you an Experiment upon + Red-rose Leaves, more accommodated to our Authors purpose, than that which + he hath given us; yet our Reverence to so Candid a Philosopher, invites us + rather to improve his Experiment, than substitute another in its place. + Take therefore of the Tincture of Red-rose Leaves, (for with Damask-rose + Leaves the Experiment succeedeth not well) made as before hath been taught + with a little Oyl of Vitriol, and a good quantity of fair Water, pour off + this Liquor into a clear Vial, half fill'd with Limpid water; till the + Water held against the Light have acquir'd a competent Redness, without + losing its Transparency, into this Tincture drop leisurely a little good + Spirit of Urine, and shaking the Vial, which you must still hold against + the Light, you shall see the Red Liquor immediately turn'd into a fine + Greenish Blew, which Colour was not to be found in any of the Bodies, upon + whose Mixture it emerg'd, and this Change is the more observable, because + in many Bodies + <!-- Page 300 --> <span class="pagenum"><a name="Page_300" id="Page_300"></a>[pg + 300]</span> the Degenerating of Blew into Red is usual enough, but the + turning of Red into Blew is very unfrequent. If at every drop of Spirit of + Urine you shake the Vial containing the Red Tincture, you may delightfully + observe a pretty variety of Colours in the passage of that Tincture from a + Red to a Blew, and sometimes we have this way hit upon such a Liquor, as + being look't upon against and from the Light, did seem faintly to emulate + the above-mention'd Tincture of <i>Lignum Nephriticum</i>. And if you make + the Tincture of Red-roses very high, and without Diluting it with fair + Water, pour on the Spirit of Urine, you may have a Blew so deep, as to + make the Liquor Opacous, but being dropt upon White Paper the Colour will + soon disclose it self. Also having made the Red, and consequently the Blew + Tincture very Transparent, and suffer'd it to rest in a small open Vial + for a Day or two, we found according to our Conjecture, that not only the + Blew but the Red Colour also was Vanish'd; the clear Liquor being of a + bright Amber Colour, at the bottom of which subsided a Light, but Copious + feculency of almost the same Colour, which seems to be nothing but the + Tincted parts of the Rose Leaves drawn out by the Acid + <!-- Page 301 --> <span class="pagenum"><a name="Page_301" id="Page_301"></a>[pg + 301]</span> Spirits of the Oyl of Vitriol, and Precipitated by the + Volatile Salt of the Spirit of Urine, which makes it the more probable, + that the Redness drawn by the Oyl of Vitriol, was at least as well an + extraction of the Tinging parts of the Roses, as a production of Redness; + and lastly, if you be destitute of Spirit of Urine, you may change the + Colour of the Tincture of Roses with many other Sulphureous Salts, as a + strong Solution of Pot-ashes, Oyl of Tartar, &c. which yet are seldome + so free from Feculency, as the Spirituous parts of Urine becomes by + repeated Distillation. + </p> + <p class="center"> + <i>Annotation</i>. + </p> + <p> + On this, occasion, I call to mind, that I found, a way of producing, + though not the same kind of Blew, as I have been mentioning, yet a Colour + near of Kin to it, namely, a fair Purple, by imploying a Liquor not made + Red by Art, instead of the Tincture of Red-roses, made with an Acid + Spirit; And my way was only to take Log-wood, (a Wood very well known to + Dyers) having by Infusion the Powder of it a while in fair Water made that + Liquor Red, I dropt into it a <i>Tantillum</i> of an Urinous Spirit, as + that of Sal-Armoniack, + <!-- Page 302 --> <span class="pagenum"><a name="Page_302" id="Page_302"></a>[pg + 302]</span> (and I have done the same thing with an <i>Alcali</i>) by + which the Colour was in a moment turn'd into a Rich, and lovely Purple. + But care must be had, that you let not fall into a Spoonfull above two or + three Drops, lest the Colour become so deep, as to make the Liquor too + Opacous. And (to answer the other part of <i>Gassendus</i> his Experiment) + if instead of fair Water, I infus'd the Log-wood in Water made somewhat + sowr by the Acid Spirit of Salt, I should obtain neither a Purple Liquor, + nor a Red, but only a Yellow one. + </p> + <h3> + <i>EXPERIMENT XL.</i> + </h3> + <p> + The Experiment I am now to mention to you, <i>Pyrophilus</i>, is that + which both you, and all the other <i>Virtuosi</i> that have seen it, have + been pleas'd to think very strange; and indeed of all the Experiments of + Colours, I have yet met with, it seems to be the fittest to recommend the + Doctrine propos'd in this Treatise, and to shew that we need not suppose, + that all Colours must necessarily be Inherent Qualities, flowing from the + Substantial Forms of the Bodies they are said to belong to, since by a + bare Mechanical change of Texture in the Minute parts of Bodies; two + Colours may in + <!-- Page 303 --> <span class="pagenum"><a name="Page_303" id="Page_303"></a>[pg + 303]</span> a moment be Generated quite <i>De novo,</i> and utterly + Destroy'd. For there is this difference betwixt the following Experiment, + and most of the others deliver'd in these Papers, that in this, the Colour + that a Body already had, is not chang'd into another, but betwixt two + Bodies, each of them apart devoid of Colour, there is in a moment + generated a very deep Colour, and which if it were let alone, would be + permanent; and yet by a very small Parcel of a third Body, that has no + Colour of its own, (lest some may pretend I know not what Antipathy + betwixt Colours) this otherwise permanent Colour will be in another trice + so quite Destroy'd, that there will remain no foot-stepts either of it or + of any other Colour in the whole Mixture. + </p> + <p> + The Experiment is very easie, and it is thus perform'd: Take good common + Sublimate, and fully satiate with it what quantity of Water you please, + Filtre the Solution carefully through clean and close Paper, that it may + drop down as Clear and Colourless as Fountain water. Then when you'l shew + the Experiment, put of it about a Spoonfull into a small Wine-glass, or + any other convenient Vessel made of clear Glass, and droping in three or + four + <!-- Page 304 --> <span class="pagenum"><a name="Page_304" id="Page_304"></a>[pg + 304]</span> drops of good Oyl of Tartar, <i>per Deliquium</i>; well + Filtred that it may likewise be without Colour, these two Limpid Liquors + will in the twinkling of an Eye turn into an Opacous mixture of a deep + Orange Colour, which by keeping the Glass continually shaking in your + hand, you must preserve from setling too soon to the Bottom; And when the + Spectators have a little beheld this first Change, then you must presently + drop in about four or five drops of Oyl of Vitriol, and continuing to + shake the Glass pretty strongly, that it may the Nimbler diffuse it self, + the whole Colour, if you have gone Skilfully to work, will immediately + disappear, and all the Liquor in the Glass will be Clear and Colourless as + before, without so much as a Sediment at the Bottom. But for the more + gracefull Trial of this Experiment, 'twill not be amiss to observe, First, + That there should not be taken too much of the Solution of Sublimate, nor + too much of the Oyl of Tartar drop'd in, to avoid the necessity of putting + in so much Oyl of Vitriol as may make an Ebullition, and perhaps run over + the Glass. Secondly, That 'tis convenient to keep the Glass always a + little shaking, both for the better mixing of the Liquors, and to keep the + Yellow Substance from Subsiding, which + <!-- Page 305 --> <span class="pagenum"><a name="Page_305" id="Page_305"></a>[pg + 305]</span> else it would in a short time do, though when 'tis subsided it + will retain its Colour, and also be capable of being depriv'd of it by the + Oyl newly mention'd. Thirdly, That if any Yellow matter stick at the sides + of the Glass, 'tis but inclining the Glass, till the clarify'd Liquor can + wash alongst it, and the Liquor will presently imbibe it, and deprive it + of its Colour. + </p> + <p> + Many have somewhat wondred, how I came to light upon this Experiment, but + the Notions or Conjectures I have about the differing Natures of the + Several Tribes of Salts, having led me to devise the Experiment, it will + not be difficult for me to give you the Chymical Reason, if I may so + speak, of the <i>Phænomenon</i>. Having then observ'd, that <i>Mercury</i> + being dissolv'd in Some <i>Menstruums</i>, would yield a dark Yellow + Precipitate, and supposing that, as to this, common Water, and the Salts + that stick to the <i>Mercury</i> would be equivalent to those Acid <i>Menstruums</i>, + which work upon the <i>Quick-silver</i>, upon the account of their Saline + particles, I substituted a Solution of Sublimate in fair Water, instead of + a Solution of <i>Mercury</i> in <i>Aqua-fortis</i>, or Spirit of <i>Nitre</i>, + that simple Solution being both clearer and free from that very offensive + Smell, which accompanies the Solutions + <!-- Page 306 --> <span class="pagenum"><a name="Page_306" id="Page_306"></a>[pg + 306]</span> of <i>Mercury</i> made with those other corrosive Liquors; + then I consider'd, that That, which makes the Yellow Colour, is indeed but + a Precipitate made by the means of the Oyl of Tartar, which we drop in, + and which, as <i>Chymists</i> know, does generally precipitate Metalline + Bodies corroded by Acid Salts; so that the Colour in our case results from + the Coalition of the Mercurial particles with the Saline ones, wherewith + they were formerly associated, and with the Alcalizate particles of the + Salt of Tartar that swim up and down in the Oyl. Wherefore considering + also, that very many of the effects of Lixiviate Liquors, upon the + Solutions of other Bodies, may be destroy'd by Acid <i>Menstruums</i>, as + I elsewhere more particularly declare, I concluded, that if I chose a very + potently Acid Liquor, which by its Incisive power might undo the work of + the Oyl of Tartar, and disperse again those Particles, which the other had + by Precipitation associated, into such minute Corpuscles as were before + singly Inconspicuous, they would become Inconspicuous again, and + consequently leave the Liquor as Colourless as before the Precipitation + was made. + </p> + <p> + This, as I said, <i>Pyrophilus</i>, seems to be the Chymical reason of + this Experiment, that + <!-- Page 307 --> <span class="pagenum"><a name="Page_307" id="Page_307"></a>[pg + 307]</span> is such a reason, as, supposing the truth of those Chymical + Notions I have elsewhere I hope evinc'd, may give such an account of the + <i>Phænomena</i> as Chymical Notions can supply us with; but I both here + and elsewhere make use of this way of speaking, to intimate that I am + sufficiently aware of the difference betwixt a Chymical Explication of a + <i>Phænomenon</i>, and one that is truly Philosophical or Mechanical; as + in our present case, I tell you something, when I tell you that the + Yellowness of the Mercurial Solution and the Oyl of Tartar is produc'd by + the Precipitation occasion'd by the affusion of the latter of those + Liquors, and that the destruction of the Colour proceeds from the + Dissipation of that Curdl'd matter, whose Texture is destroy'd, and which + is dissolv'd into Minute and Invisible particles by the potently Acid <i>Menstruum</i>, + which is the reason, why there remains no Sediment in the Bottom, because + the infused Oyl takes it up, and resolves it into hidden or invisible + Parts, as Water does Salt or Sugar. But when I have told you all this, I + am far from thinking I have told all that such an Inquisitive Person as + your self would know, for I presume you would desire as well as I to learn + (at least) why the Particles of the + <!-- Page 308 --> <span class="pagenum"><a name="Page_308" id="Page_308"></a>[pg + 308]</span> <i>Mercury</i>, of the Tartar, and of the Acid Salts convening + together, should make rather an Orange Colour than a Red, or a Blew, or a + Green, for 'tis not enough to say what I related a little before, that + divers Mercurial Solutions, though otherwise made, would yield a Yellow + precipitate, because the Question will recurr concerning them; and to give + it a satisfactory answer, is, I freely acknowledge, more than I dare as + yet pretend to. + </p> + <p> + But to confirm my conjecture about the Chymical reason of our Experiment, + I may add, that as I have (<i>viz.</i> pag. 34<sup>th</sup>. of this + Treatise) elsewhere (on another occasion) told you, with Saline Liquors of + another kind and nature than Salt of Tartar, (namely, with Spirit of + Urine, and Liquors of kin to that) I can make the <i>Mercury</i> + precipitate out of the first simple Solution quite of another Colour than + that hitherto mention'd; Nay, if instead of altering the Precipitating + liquor, I alter'd the Texture of the Sublimate in such a way as my Notions + about Salt requir'd, I could produce the same <i>Phænomenon</i>. For + having purposely Sublim'd together Equal parts (or thereabout) of + Sal-Armoniack and Sublimate, first diligently Mix'd, the ascending Flowers + being diffolv'd in fair Water, + <!-- Page 309 --> <span class="pagenum"><a name="Page_309" id="Page_309"></a>[pg + 309]</span> and Filtred, gave a Solution Limpid and Colourless, like that + of the other Sublimates, and yet an <i>Akaly</i> drop'd into this Liquor + did not turn it Yellow but White. And upon the same Grounds we may with <i>Quick-silver</i>, + without the help of common Sublimate, prepare another sort of Flowers + dissoluble in Water without Discolouring it, with which I could likewise + do what I newly mention'd; to which I shall add, (what possibly you'l + somewhat wonder at) That so much does the Colour depend upon the Texture + resulting from the Convention of the several sorts of Corpuscles, that + though in out Experiment, Oyl of Vitriol destroys the Yellow Colour, yet + with <i>Quick-silver</i> and fair Water, by the help of Oyl of Vitriol + alone, we may easily make a kind of Precipitate of a fair and permanent + Yellow, as you will e're long (in the forty second Expement of this third + Part) be taught. And I may further add, that I chose Oyl of Vitriol, not + so much for any other or peculiar Quality, as for its being, when 'tis + well rectify'd, (which 'tis somewhat hazardous to bring it to be) not only + devoid of Colour and in Smells, but extremely Strong and Incisive; For + though common and undephlegmated <i>Aqua-fortis</i> will not perform + <!-- Page 310 --> <span class="pagenum"><a name="Page_310" id="Page_310"></a>[pg + 310]</span> the same thing well, yet that which is made exceeding Strong + by being carefully Dephlegm'd, will do it pretty well, though not so well + as Oyl of Vitriol which is so Strong, that even without Rectification it + may for a need be made use of. I will not here tell you what I have try'd, + that I may be able to deprive at pleasure the Precipitate that one of the + Sulphureous Liquors had made, by the copious Affusion of the other: + Because I found, though this Experiment is too ticklish to let me give a + full account of it in few words, I shall therefore tell you, that it is + not only for once, that the other above-mention'd Experiment may be made, + the same Numerical parcels of Liquor being still imploy'd in it; for after + I have Clarify'd the Orange Colour'd Liquor, by the addition of as little + of the Oyl of Viriol as will suffice to perform the effect, I can again at + pleasure re-produce the Opacous Colour, by the dropping in of fresh Oyl of + Tartar, and destroy it again by the Re-affusion of more of the Acid <i>Menstruum</i>; + and yet oftner if I please, can I with these two contrariant Liquors + recall and disperse the Colour, though by reason of the addition of so + much new Liquor, in reference to the Mercurial particles, the Colour will + at length appear more dilute and faint. + <!-- Page 311 --> <span class="pagenum"><a name="Page_311" id="Page_311"></a>[pg + 311]</span> + </p> + <p class="center"> + <i>An improvement of the fortieth Experiment</i>. + </p> + <p> + And, <i>Pyrophilus</i>, to confirm yet further the Notions that led me to + think on the propos'd Experiment, I shall acquaint you with another, which + when I had conveniency I have sometimes added to it, and which has to the + Spectators appear'd little less Odd than the first; And though because the + Liquor, requisite to make the Trial succeed well, must be on purpose + prepar'd anew a while before, because it will not long retain its fitness + for this work, I do but seldome annex this Experiment to the other, yet I + shall tell you how I devis'd it, and how I make it. If you boyl Crude + Antimony in a strong and clear <i>Lixivium</i>, you shall separate a + Substance from it, which some Modern <i>Chymists</i> are pleas'd to call + its Sulphur, but how deservedly I shall not here examine, having elsewhere + done it in an Opportune place; wherefore I shall now but need to take + notice, that when this suppos'd Sulphur (not now to call it rather a kind + of <i>Crocus</i>) is let fall by the Liquor upon its Refrigeration, it + often settles in Flakes, or such like parcels of a Yellow Substance, + (which being by the precedent + <!-- Page 312 --> <span class="pagenum"><a name="Page_312" id="Page_312"></a>[pg + 312]</span> dissolution reduc'd into Minute parts, may peradventure be + made to take Fire much more easily than the Grosser Powder of unprepar'd + Antimony would have done.) Considering therefore, that common Sulphur + boyl'd in a <i>Lixivium</i> may be Precipitated out of it by Rhenish-wine + or White-wine, which are Sowrish Liquors, and have in them, as I elsewhere + shew, an Acid Salt; and having found also by Trial, that with other Acid + Liquors I could Precipitate out of Lixiviate Solvents some other Mineral + concretions abounding with Sulphureous parts, of which sort is crude + Antimony, I concluded it to be easie to Precipitate the Antimony + dissolv'd, as was lately mention'd, with the Acid Oyl of Vitriol; and + though common Sulphur yields a White Precipitate, which the <i>Chymists</i> + call <i>Lac Sulphuris</i>, yet I suppos'd the Precipitated Antimony would + be of a deep Yellow Colour, as well, if made with Oyl of Vitriol, as if + made only by Refrigeration and length of Time. From this 'twas easie to + deduce this Experiment, that if you put into one Glass some of the freshly + Impregnated and Filtrated Solution of Antimony, and into another some of + the Orange-Colour'd Mixture, (which I formerly shew'd you how to make with + a + <!-- Page 313 --> <span class="pagenum"><a name="Page_313" id="Page_313"></a>[pg + 313]</span> Mercurial Solution and Oyl of Tartar) a few drops of Oyl of + Vitriol dropp'd into the last mention'd Glass, would, as I told you + before, turn the Deep Yellow mixture into a Cleer Liquor; whereas a little + of the same Oyl dropp'd out of the same Viol into the other Glass would + presently (but not without some ill sent) turn the moderately cleer + Solution into a Deep Yellow Substance, But this, as I Said, succeeds not + well, unless you employ a <i>Lixivium</i> that has but newly dissolv'd + Antimony, and has not yet let it fall. But yet in Summer time, if your <i>Lixivium</i> + have been duly Impregnated and well Filtred after it is quite cold, it + will for some dayes (perhaps much longer than I had occasion to try) + retain Antimony enough to exhibit, upon the Affusion of the Corrosive Oyl, + as much of a good Yellow Substance as is necessary to satisfie the + Beholders of the Possibility of the Experiment. + </p> + <p class="center"> + <i>Reflections upon the XL. Experiment Compared with the X. and XX.</i> + </p> + <p> + The Knowledge of the Distinction of Salts which we have propos'd, whereby + they are discriminated into <i>Acid, Volatile,</i> + <!-- Page 314 --> <span class="pagenum"><a name="Page_314" id="Page_314"></a>[pg + 314]</span> or <i>Salfuginous</i> (if I may for Distinction sake so call + the Fugitive Salts of Animal Substances) and <i>fix'd</i> or <i>Alcalizate</i>, + may possibly (by that little part which we have already deliver'd, of what + we could say of its Applicableness) appear of so much Use in Natural + Philosophy (especially in the Practick part of it) that I doubt not but it + will be no Unwelcome Corollary of the Preceding Experiment, if by the help + of it I teach you to distinguish, which of those Salts is Predominant in + Chymical Liquors, as well as whether any of them be so or not. For though + in our Notes upon the X. and XX. Experiments I have shown you a way by + means of the Tincture of <i>Lignum Nephriticum</i>, or of Syrrup of + Violets, to discover whether a propounded Salt be Acid or not, yet you can + thereby only find in general that such and such Salts belong not to the + Tribe of Acids, but cannot determine whether they belong to the Tribe of + Urinous Salts (under which for distinction sake I comprehend all those + Volatile Salts of Animal or other Substances that are contrary to Acids) + or to that of Alcalies. For as well the one as the other of these + Salino-Sulphurous Salts will restore the Cæruleous Colour to the Tincture + of <i>Lignum Nephriticum</i>, and turn that of Syrrup of Violets + <!-- Page 315 --> <span class="pagenum"><a name="Page_315" id="Page_315"></a>[pg + 315]</span> into Green. Wherefore this XL. Experiment does opportunely + supply the deficiency of those. For being sollicitous to find out some + ready wayes of discriminating the Tribes of Chymical Salts, I found that + all those I thought fit to make Tryal of, would, if they were of a + Lixiviate Nature, make with Sublimate dissolv'd in Fair Water an <i>Orange + Tawny</i> Precipitate; whereas if they were of an Urinous Nature the + Precipitate would be <i>White</i> and Milky. So that having alwayes by me + some Syrrup of Violets and some Solution of Sublimate, I can by the help + of the first of those Liquors discover in a trice, whether the propounded + Salt or Saline Body be of an Acid Nature or no, if it be I need (you know) + inquire no further; but if it be not, I can very easily, and as readily + distinguish between the other two kinds of Salts, by the White or + Orange-Colour that is immediately produc'd, by letting fall a few Drops or + Grains of the Salt to be examin'd, into a spoonfull of the cleer Solution + of Sublimate. For Example, it has been suppos'd by some eminently Learned, + That when Sal Armoniack being mingled with an Alcaly is forc'd from it by + the Fire in close Vessels, the Volatile Salt that will thereby be obtain'd + (if the Operation be skilfully perform'd,) + <!-- Page 316 --> <span class="pagenum"><a name="Page_316" id="Page_316"></a>[pg + 316]</span> is but a more fine and subtile sort of Sal Armoniack, which, + 'tis presum'd, this Operation do's but more exquisitely purifie, than + common Solutions, Filtrations, and Coagulations. But this Opinion may be + easily shown to be Erroneous, as by other Arguments, so particularly by + the lately deliver'd Method of distinguishing the Tribes of Salts. For the + Saline Spirit of Sal Armoniack, as it is in many other manifest Qualities + very like the Spirit of Urine, so like, that it will in a trice make + Syrrup of Violets of a Lovely Green, turn a Solution of good Verdigrease + into an Excellent Azure, and make the Solution of a Sublimate yield a + White Precipitate, insomuch that in most (for I say not all of the + Experiments) where I Aim onely at producing a sudden change of Colour, I + scruple not to use Spirit of Sal Armoniack when it is at hand, instead of + Spirit of Urine, as indeed it seems chiefly to consist (besides the flegm + that helps to make it fluid) of the Volatile Urinous Salt (yet not + excluding that of Soot) that abounds in the Sal Armoniack and is set at + liberty from the Sea Salt wherewith it was formerly associated, and + clogg'd, by the Operation of the Alcaly, that divides the Ingredients of + Sal Armoniack, and retains that Sea Salt with it self. What use may be + <!-- Page 317 --> <span class="pagenum"><a name="Page_317" id="Page_317"></a>[pg + 317]</span> made of the like way of exploration in that inquiry which + puzzles so many Modern Naturalists, whether the Rich Pigment (which we + have often had occasion to mention) belongs to the Vegetable or Animal + Kingdome, you may find in another place where I give you some account of + what I try'd about Cocheneel. But I think it needless to exemplifie here + our Method by any other Instances, many such being to be met with in + divers parts of this Treatise; but I will rather advertise you, that, by + this way of examining Chymical Liquors, you may not onely in most Cases + conclude <i>Affirmatively</i>, but in some Cases <i>Negatively</i>. As + since Spirit of Wine, and as far as I have try'd, those Chymical Oyles + which Artists call Essential, did not (when I us'd them as I had us'd the + several Families of Salts upon that Syrrup) turn Syrrup of Violets Red or + Green, nor the Solution of Sublimate White or Yellow, I inferr'd it may + thence be probably argued, that either they are destitute of Salt, or have + such as belongs not to either of the three Grand families already often + mention'd. When I went to examine the Spirit of Oak or of such like + Concretes forced over through a Retort, I found by this means amongst + others, that (as I elsewhere show) these Chymists are + <!-- Page 318 --> <span class="pagenum"><a name="Page_318" id="Page_318"></a>[pg + 318]</span> much mistaken in it, that account it a simple Liquor, and one + of their Hypostatical Principles: for not to mention what flegm it may + have, I found that with a few drops of one of this sort of Spirits mix'd + with a good proportion of Syrrup of Violets, I could change the Colour and + make it Purplish, by the affinity of which Colour to Redness, I + conjectur'd that this Spirit had some Acid Corpuscles in it, and + accordingly I found that as it would destroy the Blewness of a Tincture of + <i>Lignum Nephriticum</i>, so being put upon Corals it would Corrode them, + as common Spirit of Vinegar, and other Acid Liquors are wont to do. And + farther to examine whether there were not a great part of the Liquor that + was not of an Acid nature, having separated the Sour or Vinegar-like part + from the rest, which (if I mistake not) is far the more Copious, we + concluded as we had conjectured, the other or remaining part, though it + had a strong taste as well as smell, to be of a nature differing from that + of either of the three sorts of Salts above mention'd, since it did as + little as Spirit of Wine, and Chymical Oyls, alter the Colour either of + Syrrup of Violets or Solution of Sublimate, whence we also inferr'd that + the change that had been made of that Syrrup into a Purple Colour, was + <!-- Page 319 --> <span class="pagenum"><a name="Page_319" id="Page_319"></a>[pg + 319]</span> effected by the Vinegar, that was one of the two Ingredients + of the Liquor, which was wont to pass for a Simple or Uncompounded Spirit. + And, upon this account, 'twas of the Spirit of Oak (and the like + Concretes) freed from it's Vinegar that I elsewhere told you, that I had + not then observ'd it, (and I have repeated the Tryal but very lately) to + destroy the Cæruleous Tincture of <i>Lignum Nephriticum</i>. But this + onely, <i>en passant</i>; for the Chief thing I had to add was this, That + by the same way may be examin'd and discover'd, divers changes that are + produc'd in Bodies either by Nature only, or by Art; either of them being + able by changing the Texture of some Concretes I could name, to qualifie + them to Operate after a New manner upon the above mention'd Syrrup, or + Solution, or both. And by this means, to tell you that upon the by, I have + been able to discover, that there may be made Bodies, which though they + run <i>per Deliquium</i>, as readily as Salt of Tartar, belong in other + respects, not to the family of Alcaliz, much less to that of Salfuginous, + or that of Acid Salts. Perhaps too, I may know a way of making a highly + operative Saline Body that shall neither change the Colour of Syrrup of + Violets, nor Precipitate the Solution of Sublimate; And, I can + <!-- Page 320 --> <span class="pagenum"><a name="Page_320" id="Page_320"></a>[pg + 320]</span> likewise if I please conceal by what Liquors I perform such + changes of Colour, as I have been mentioning to you, by quite altering the + Texture of some ordinary Chymical productions, the Exploration of which is + the main use of the fortieth Experiment, which I think teaches not a + little, if it teach us to discover the nature of those things (in + reference to Salt) that are obtain'd by the ordinary Chymical Analysis of + mix'd Bodyes, though perhaps there may be other Bodyes prepar'd by + Chymistry which may have the same Effects in the change of Colours; and + yet be produc'd not from what Chymists call the Resolution of Bodies, but + from their Composition. But the discoursing of things of this nature is + more proper for another place. I shall now onely add, what might perhaps + have been more seasonably told you before; That the Reason why the way of + Exploration of Salts hitherto deliver'd, succeeds in the Solution of + Sublimate, depends upon the particular Texture of that Solution, as well + as upon the differing Natures of the Saline Liquors imploy'd to + Precipitate it. For Gold dissolv'd in <i>Aqua Regia</i>, whether you + Precipitate it with Oyl of Tartar which is an Alcaly, or with Spirit of + Urine + <!-- Erratum: for Urne --> , or Sal Armoniack which belongs to the + family of + <!-- Page 321 --> <span class="pagenum"><a name="Page_321" id="Page_321"></a>[pg + 321]</span> Volatile Salts, will either way afford a Yellow substance: + though with such an Acid Liquor, as, I say not Spirit of Salt, the Body + that yields it, being upon the matter an Ingredient of <i>Aqua Regis</i>, + but Oyl of Vitriol it self, I did not find that I could Precipitate the + Metall out of the Solution, or destroy the Colour of it, though the same + Oyl of Vitriol would readily Precipitate Silver dissolv'd in <i>Aqua-fortis</i>. + And if you dissolve pure Silver in <i>Aqua-fortis</i>, and suffer it to + shoot into Crystals, the cleer Solution of these made in fair Water, will + afford a very White Precipitate, whether it be made with an Alcaly, or an + Acid Spirit, as that of Salt, whereas, which may seem somewhat strange, + with Spirit of Sal Armoniack (that I us'd was made of Quicklime) I could + obtain no such White Precipitate; that Volatile Spirit, nor (as I + remember) that of Urine, scarce doing any more than striking down a very + small quantity of Matter, which was neither White nor Whitish, so that the + remaining Liquor being suffer'd to evaporate till the superfluous Moisture + was gone, the greatest part of the Metalline Corpuscles with the Saline + ones that had imbib'd them, concoagulated into Salt, as is usual in such + Solutions, wherein the Metall has not been Precipitated. + </p> + <!-- Page 322 --> + <p> + <span class="pagenum"><a name="Page_322" id="Page_322"></a>[pg 322]</span> + </p> + <h3> + <i>EXPERIMENT XLI.</i> + </h3> + <p> + Of Kin to the last or fortieth Experiment is another which I remember I + have sometimes shewn to <i>Virtuosi</i> that were pleas'd not to dislike + it. I took Spirit of Urine made by Fermentation, and with a due proportion + of Copper brought into small parts, I obtain'd a very lovely Azure + Solution, and when I saw the Colour was such as was requisite, pouring + into a clean Glass, about a spoonfull of this tincted Liquor, (of which I + us'd to keep a Quantity by me,) I could by shaking into it some drops of + Strong Oyl of Vitriol, deprive it in a trice of its Deep Colour, and make + it look like Common-water. + </p> + <p class="center"> + <i>Annotation</i>. + </p> + <p> + This Experiment brings into my mind this other, which oftentimes succceds + well enough, though not quite so well as the former; Namely, that if into + about a small spoonfull of a Solution of good French Verdigrease made in + fair Water, I drop't and shak'd some strong Spirit of Salt, or rather + deflegm'd <i>Aqua Fortis</i>, the Greenness of the Solution would be made + in a trice almost + <!-- Page 323 --> <span class="pagenum"><a name="Page_323" id="Page_323"></a>[pg + 323]</span> totally to disappear, & the Liquor held against the Light + would scarce seeme other than Cleer or Limpid, to any but an Attentive + Eye, which is therefore remarkable; because we know that <i>Aqua-fortis</i> + corroding Copper, which is it that gives the Colour to Verdigrease, is + wont to reduce it to a Green Blew Solution. But if into the other + altogether or almost Colourless Liquor I was speaking of, you drop a just + quantity either of Oyl of Tartar or Spirit of Urine, you shall find that + after the Ebullition is ceas'd, the mixture will disclose a lively Colour, + though somewhat differing from that which the Solution of Verdigrease had + at first. + </p> + <h3> + <i>EXPERIMENT XLII.</i> + </h3> + <p> + That the Colour (<i>Pyrophilus</i>) of a Body may be chang'd by a Liquor + which of it self is of no Colour, provided it be Saline, we have already + manifested by a multitude of instances. Nor doth it seem so strange, + because Saline Particles swimming up and down in Liquors, have been by + many observ'd to be very operative in the Production and change of + Colours. But divers of our Friends that are not acquainted with Chymical + Operations have thought it very strange that a White Body, and a Dry one + <!-- Page 324 --> <span class="pagenum"><a name="Page_324" id="Page_324"></a>[pg + 324]</span> too, should immediately acquire a rich new Colour upon the + bare affusion of Spring-Water destitute as well of adventitious Salt as of + Tincture. And yet (<i>Pyrophilus</i>) the way of producing such a change + of Colours may be easily enough lighted on by those that are conversant in + the Solutions of Mercury. For we have try'd, that though by Evaporating a + Solution of Quick-Silver in <i>Aqua-fortis</i>, and abstracting the Liquor + till the remaining matter began to be well, but not too strongly dryed, + fair Water pour'd on the remaining <i>Calx</i> made it but somewhat + Yellowish; yet when we took good Quick-Silver, and three or four times its + weight of Oyl of Vitriol, in case we in a Glass Retort plac'd in Sand drew + off the Saline <i>Menstruum</i> from the Metalline Liquor, till there + remain'd a dry <i>Calx</i> at the bottome, though this Precipitate were a + Snow White Body, yet upon pouring on it a large quantity of fair Water, we + did almost in a moment perceive it to pass from a Milky Colour to one of + the loveliest Light Yellows that ever we had beheld. Nor is the Turbith + Mineral, that Chymists extol for its power to Salivate, and for other + vertues, of a Colour much inferiour to this, though it be often made with + a differing proportion of the Ingredients, + <!-- Page 325 --> <span class="pagenum"><a name="Page_325" id="Page_325"></a>[pg + 325]</span> a more troublesome way. For <i>Beguinus</i>,<a name="NtA_22" + id="NtA_22"></a><a href="#Nt_22"><sup>22</sup></a> who calls it <i>Mercurius + præcipitatus optimus</i>, takes to one part of Quick-Silver, but two of + Liquor, and that is Rectifi'd Oyl of Sulphur, which is (in <i>England</i> + at least) far more scarce and dear than Oyl of Vitriol; he also requires a + previous Digestion, two or three Cohobations, and frequent Ablutions with + hot Distill'd Water, with other prescriptions, which though they may + conduce to the Goodness of the Medicine, which is that he aims at, are + troublesome, and, our Tryals have inform'd you unneccessary to the <i>obtaining + the Lemmon Colour</i> which he regards not. But though we have very rarely + seen either in Painters Shops, or elsewhere a finer Yellow than that which + we have divers times this way produc'd (which is the more considerable, + because durable and pleasant Yellows are very hard to be met with, as may + appear by the great use which Painters are for its Colours sake fain to + make of that pernicious and heavy Mineral, Orpiment) yet I fear our Yellow + is too costly, to be like to be imploy'd by Painters, unless about Choice + pieces of Work, nor do I know how well it will agree with every Pigment, + especially, wich Oyl'd Colours. And whether this + <!-- Page 326 --> <span class="pagenum"><a name="Page_326" id="Page_326"></a>[pg + 326]</span> Experiment, though it have seem'd somewhat strange to most we + have shown it to, be really of another Nature than those wherein Saline + Liquors are imploy'd, may, as we formerly also hinted, be so plausibly + doubted, that whether the Water pour'd on the <i>Calx</i>, do barely by + imbibing some of its Saline parts alter its Colour by altering its + Texture, or whether by dissolving the Concoagulated Salts, it does become + a Saline <i>Menstruum</i>, and, as such, work upon the Mercury, I freely + leave to you (<i>Pyrophilus</i>) to consider. And that I may give you some + Assistance in your Enquiry, I will not only tell you, that I have several + times with fair Water wash'd from this <i>Calx</i>, good store of strongly + tasted Corpuscles, which by the abstraction of the <i>Menstruum</i>, I + could reduce into Salt; but I will also subjoyn an Experiment, which I + devis'd, to shew among other things, how much a real and permanent Colour + may be as it were drawn forth by a Liquor that has neither Colour, nor so + much as Saline or other Active parts, provided it can but bring the parts + of the Body it imbibes to convene into clusters dispos'd after the manner + requisite to the exhibiting of the emergent Colour. The Experiment was + this. + </p> + <!-- Page 327 --> + <p> + <span class="pagenum"><a name="Page_327" id="Page_327"></a>[pg 327]</span> + </p> + <h3> + <i>EXPERIMENT XLIII.</i> + </h3> + <p> + We took good common Vitriol, and having beaten it to Powder, and put it + into a Crucible, we kept it melted in a gentle heat, till by the + Evaporation of some parts, and the shuffling of the rest, it had quite + lost its former Colour, what remain'd we took out, and found it to be a + friable <i>Calx</i>, of a dirty Gray. On this we pour'd fair Water, which + it did not Colour Green or Blew, but only seem'd to make a muddy mixture + with it, then stopping the Vial wherein the Ingredients were put, we let + it stand in a quiet place for some dayes, and after many hours the water + having dissolv'd a good part of the imperfectly calcin'd Body, the + Vitriolate Corpuscles swiming to and fro in the Liquor, had time by their + opportune Occursions to constitute many little Masses of Vitriol, which + gave the water they impregnated a fair Vitriolate Colour; and this Liquor + being pour'd off, the remaining dirty Powder did in process of time + communicate the like Colour, but not so deep, to a second parcel of cleer + Water that we pour'd on it. But this Experiment <i>Pyrophilus</i> is, (to + give you that hint by the way) of too Luciferous a Nature to be fit to be + <!-- Page 328 --> <span class="pagenum"><a name="Page_328" id="Page_328"></a>[pg + 328]</span> fully prosecuted, now that I am in haste, and willing to + dispatch what remains. And we have already said of it, as much as is + requisite to our present purpose. + </p> + <h3> + <i>EXPERIMENT XLIV.</i> + </h3> + <p> + It may (<i>Pyrophilus</i>) somewhat contribute towards the shewing how + much some Colours depend upon the less or greater mixture, and (as it + were,) Contemperation of the Light with shades, to observe, how that + sometimes the number of Particles, of the same Colour, receiv'd into the + Pores of a Liquor, or swiming up and down in it, do seem much to vary the + Colour of it. I could here present you with particular instances to show, + how in many (if not most) consistent Bodyes, if the Colour be not a Light + one, as White, Yellow, or the like, the closeness of parts in the Pigments + makes it look Blackish, though when it is display'd and laid on thinly, it + will perhaps appear to be either Blew, or Green, or Red. But the Colours + of consistent Pigments, not being those which the Preamble of this + Experiment has lead you to expect Examples in, I shall take the instances + I am now to give you, rather from Liquors than Dry Bodyes. If then you put + a little fair Water into a + <!-- Page 329 --> <span class="pagenum"><a name="Page_329" id="Page_329"></a>[pg + 329]</span> cleer and slender Vial, (or rather into one of those pipes of + Glass, which we shall by and by mention;) and let fall into it a few drops + of a strong Decoction or Infusion of <i>Cochineel</i>, or (for want of + that) of <i>Brazil</i>; you may see the tincted drops descend like little + Clouds into the Liquor; through which, if, by shaking the Vial, you + diffuse them, they will turn the water either of a Pinck Colour, or like + that which is wont to be made by the washing of raw flesh in fair Water; + by dropping a little more of the Decoction, you may heighten the Colour + into a fine Red, almost like that which ennobles Rubies; by continuing the + affusion, you may bring the Liquor to a kind of a Crimson, and afterwards + to a Dark and Opacous Redness, somewhat like that of Clotted Blood. And in + the passage of the Liquor from one of these Colours to the other, you may + observe, if you consider it attentively, divers other less noted Colours + belonging to Red, to which it is not easie to give Names; especially + considering how much the proportion of the Decoction to the fair Water, + and the strength of that Decoction, together with that of the trajected + Light and other Circumstances, may vary the Phænomena of this Experiment. + For the convenienter making whereof, we use + <!-- Page 330 --> <span class="pagenum"><a name="Page_330" id="Page_330"></a>[pg + 330]</span> instead of a Vial, any slender Pipe of Glass of about a foot + or more in length, and about the thickness of a mans little finger; For, + if leaving one end of this Pipe open, you Seal up the other Hermetically, + (or at least stop it exquisitely with a Cork well fitted to it, and + over-laid with hard Sealing Wax melted, and rubb'd upon it;) you shall + have a Glass, wherein may be observ'd the Variations of the Colours of + Liquors much better than in large Vials, and wherein Experiments of this + Nature may be well made with very small quantities of Liquor. And if you + please, you may in this Pipe produce variety of Colours in the various + parts of the Liquor, and keep them swimming upon one another unmix'd for a + good while. And some have marveil'd to see, what variety of Colours we + have sometimes (but I confess rather by chance than skill) produc'd in + those Glasses, by the bare infusion of Brazil, variously diluted with fair + Water, and alter'd by the Infusion of several Chymical Spirits and other + Saline Liquors devoid themselves of Colour, and when the whole Liquor is + reduc'd to an Uniform degree of Colour, I have taken pleasure to make that + very Liquor seem to be of Colours gradually differing, by filling with it + Glasses of a Conical figure, (whether the Glass have + <!-- Page 331 --> <span class="pagenum"><a name="Page_331" id="Page_331"></a>[pg + 331]</span> its basis in the ordinary position, or turn'd upwards.) And + yet you need not Glasses of an extraordinary shape to see an instance of + what the vari'd mixture of Light and Shadow can do in the diversifying of + the Colour. For if you take but a large round Vial, with a somewhat long + and slender Neck, and filling it with our Red Infusion of Brazil, hold it + against the Light, you will discern a notable Disparity betwixt the Colour + of that part of the Liquor which is in the Body of the Vial, and that + which is more pervious to the Light in the Neck. Nay, I remember, that I + once had a Glass and a Blew Liquor (consisting chiefly (or only, if my + memory deceive me not,) of a certain Solution of Verdigrease) so fitted + for my purpose, that though in other Glasses the Experiment would not + succeed, yet when that particular Glass was fill'd with that Solution, in + the Body of the Vial it appear'd of a Lovely Blew, and in the neck, (where + the Light did more dilute the Colour,) of a manifest Green; and though I + suspected there might be some latent Yellowness in the substance of the + neck of the Glass, which might with the Blew compose that Green, yet was I + not satisfi'd my self with my Conjecture, but the thing seem'd odd to me, + as well as to divers curious + <!-- Page 332 --> <span class="pagenum"><a name="Page_332" id="Page_332"></a>[pg + 332]</span> persons to whom it was shown. And I lately had a Broad piece + of Glass, which being look'd on against the Light seem'd clear enough, and + held from the Light appear'd very lightly discolour'd, and yet it was a + piece knock'd off from a great lump of Glass, to which if we rejoyn'd it, + where it had been broken off, the whole Mass was as green as Grass. And I + have several times us'd Bottles and stopples that were both made (as + those, I had them from assur'd me) of the very same Metall, and yet whilst + the bottle appear'd but inclining towards a Green, the Stopple (by reason + of its great thickness) was of so deep a Colour that you would hardly + believe they could possibly be made of the same materials. But to satisfie + some Ingenious Men, on another occasion, I provided my self of a flat + Glass (which I yet have by me,) with which if I look against the Light + with the Broad side obverted to the Eye, it appeares like a good ordinary + window Glass; but if I turn the Edge of it to my Eye, and place my Eye in + a convenient posture in reference to the Light, it may contend for + deepness of Colour with an Emerald. And this Greeness puts me in mind of a + certain thickish, but not consistent Pigment I have sometimes made, and + can show you when you please, + <!-- Page 333 --> <span class="pagenum"><a name="Page_333" id="Page_333"></a>[pg + 333]</span> which being dropp'd on a piece of White Paper appears, where + any quantity of it is fallen, of a somewhat Crimson Colour, but being with + ones finger spread thinly on the Paper does presently exhibit a fair + Green, which seems to proceed only from its disclosing its Colour upon the + Extenuation of its Depth into Superficies, if the change be not somewhat + help'd by the Colours degenerating upon one or other of the Accounts + formerly mention'd. Let me add, that having made divers Tryals with that + Blew substance, which in Painters shops is call'd <i>Litmase</i>, we have + sometimes taken Pleasure to observe, that being dissolv'd in a due + proportion of fair Water, the Solution either oppos'd to the Light, or + dropp'd upon White paper, did appear of a deep Colour betwixt Crimson and + Purple; and yet that being spread very thin on the Paper and suffer'd to + dry on there, the Paper was wont to appear Stain'd of a Fine Blew. And to + satisfie my selfe, that the diversity came not from the Paper, which one + might suspect capable of inbibing the Liquor, and altering the Colour, I + made the Tryal upon a flat piece of purely White Glass'd Earth, (which I + sometimes make use of about Experiments of Colours) with an Event not + unlike the former. + </p> + <!-- Page 334 --> + <p> + <span class="pagenum"><a name="Page_334" id="Page_334"></a>[pg 334]</span> + </p> + <p> + And now I speak of <i>Litmass</i>, I will add, that having this very day + taken a piece of it, that I had kept by me these several years, to make + Tryals about Colours, and having let fall a few drops of the strong + Infusion of it in fair water, into a fine Crystal Glass, shap'd like an + inverted Cone, and almost full of fair Water, I had now (as formerly) the + pleasure to see, and to show others, how these few tincted drops variously + dispersing themselves through the Limpid Water, exhibited divers Colours, + or varieties of Purple and Crimson. And when the Corpuscles of the Pigment + seem'd to have equally diffus'd themselves through the whole Liquor, I + then by putting two or three drops of Spirit of Salt, first made an odd + change in the Colour of the Liquor, as well as a visible commotion among + its small parts, and in a short time chang'd it wholly into a very + Glorious Yellow, like that of a Topaz. After which if I let fall a few + drops of the strong and heavy Solution of Pot-ashes, whose weight would + quickly carry it to the sharp bottome of the Glass, there would soon + appear four very pleasant and distinct Colours; Namely, a Bright, but + Dilute Colour at the picked bottome of the Glass; a Purple, a little + higher; a deep and glorious Crimson, (which Crimson + <!-- Page 335 --> <span class="pagenum"><a name="Page_335" id="Page_335"></a>[pg + 335]</span> seem'd to terminate the operation of the Salt upward) in the + confines betwixt the Purple and the Yellow; and an Excellent Yellow, the + same that before enobled the whole Liquor, reaching from thence to the top + of the Glass. And if I pleas'd to pour very gently a little Spirit of Sal + Armoniack, upon the upper part of this Yellow, there would also be a + Purple or a Crimson, or both, generated there, so that the unalter'd part + of the Yellow Liquor appear'd intercepted betwixt the two Neighbouring + Colours. + </p> + <p> + My scope in this 3<sup>d</sup>. Experiment (<i>Pyrophilus</i>) is + manifold, as first to invite you to be wary in judging of the Colour of + Liquors in such Glasses as are therein recommended to you, and + consequently as much, if not more, when you imploy other Glasses. + Secondly, That you may not think it strange, that I often content my self + to rub upon a piece of White paper, the Juice of Bodies I would examine, + since not onely I could not easily procure a sufficient Quantity of the + juices of divers of them; but in several Cases the Tryals of the + quantities of such Juices in Glasses would make us more lyable to + mistakes, than the way that in those cases I have made use of. Thirdly, I + hope you will by these and divers other + <!-- Page 336 --> <span class="pagenum"><a name="Page_336" id="Page_336"></a>[pg + 336]</span> particulars deliver'd in this Treatise, be easily induc'd to + think that I may have set down many Phænomena very faithfully, and just as + they appear'd to me, and yet by reason of some unheeded circumstance in + the conditions of the matter, and in the degree of Light, or the manner of + trying the Experiment, you may find some things to vary from the Relations + I make of them. Lastly, I design'd to give you an opportunity to free your + self from the amazement which possesses most Men, at the Tricks of those + Mountebancks that are commonly call'd Water-drinkers. For though not only + the vulgar, but ev'n many persons that are far above that Rank, have so + much admir'd to see, a man after having drunk a great deal of fair water, + to spurt it out again in the form of Claret Wine, Sack, and Milk, that + they have suspected the intervening of Magick, or some forbidden means to + effect what they conceived above the power of Art; yet having once by + chance had occasion to oblige a Wanderer that made profession of that and + other Jugling Tricks, I was easily confirm'd by his Ingenious confession + to me, That this so much Admir'd Art, indeed consisted rather in a few + Tricks, than in any great Skill, in altering the Nature and Colours of + things. And I am easy + <!-- Page 337 --> <span class="pagenum"><a name="Page_337" id="Page_337"></a>[pg + 337]</span> to be perswaded; that there may be a great deal of Truth in a + little Pamphlet Printed divers years ago in English, wherein the Author + undertakes to discover, and that (if I mistake not) by the confession of + some of the Complices themselves, That a famous Water-drinker then much + Admir'd in <i>England</i>, perform'd his pretended Transmutations of + Liquors by the help of two or three inconsiderable preparations and + mixtures of not unobvious Liquors, and chiefly of an Infusion of Brazil + variously diluted and made Pale or Yellowish, (and otherwise alter'd) with + Vinegar, the rest of their work being perform'd by the shape of the + Glasses, by Craft and Legerdemane. And for my part, that which I marvel at + in this business, is, the Drinkers being able to take down so much Water, + and spout it out with that violence; though Custome and a Vomit seasonably + taken before hand, may in some of them much facilitate the work. But as + for the changes made in the Liquors, they were but few and slight in + comparison of those, that the being conversant in Chymical Experiments, + and dextrous in applying them to the Transmuting of Colours, may easily + enough enable a man to make, as ev'n what has been newly deliver'd in + this, and the foregoing Experiment; especially if we add + <!-- Page 338 --> <span class="pagenum"><a name="Page_338" id="Page_338"></a>[pg + 338]</span> to it the things contained in the XX, the XXXIX and the XL. + Experiments, may perhaps have already perswaded You. + </p> + <h3> + <i>EXPERIMENT XLV.</i> + </h3> + <p> + You may I presume (<i>Pyrophilus</i>) have taken notice, that in this + whole Treatise, I purposely decline (as far as I well can) the mentioning + of Elaborate Chymical Experiments, for fear of frighting you by their + tediousness and difficulty; but yet in confirmation of what I have been + newly telling you about the possibility of Varying the Colours of Liquors, + better than the Water-drinkers are wont to do, I shall add, that <i>Helmont</i> + used to make a preparation of Steel, which a very Ingenious Chymist, his + Sons Friend, whom you know, sometimes employes for a succedaneum to the + Spaw-waters, by Diluting this <i>Essentia Martis Liquida</i> (as he calls + it) with a due proportion of Water. Now that for which I mention to you + this preparation, (which as he communicated to me, I know he will not + refuse to <i>Pyrophilus</i>) is this, that though the Liquor (as I can + shew you when you please) be almost of the Colour of a German (not an + Oriental) Amethyst, and consequently remote enough from Green, + <!-- Page 339 --> <span class="pagenum"><a name="Page_339" id="Page_339"></a>[pg + 339]</span> yet a very few drops being let fall into a Large proportion of + good Rhenish, or (in want of that) White Wine (which yet do's not quite so + well) immediately turn'd the Liquor into a lovely Green, as I have not + without delight shown several curious Persons. By which <i>Phænomenon</i> + you may learn, among other things, how requisite it is in Experiments + about the changes of Colours heedfully to mind the Circumstances of them; + for Water will not, as I have purposely try'd, concurr to the production + of any such Green, nor did it give that Colour to moderate Spirit of Wine, + wherein I purposely dissolv'd it, and Wine it self is a Liquor that few + would suspect of being able to work suddenly any such change in a + Metalline preparation of this Nature; and to satisfie my self that this + new Colour proceeds rather from the peculiar Texture of the Wine, than + from any greater Acidity, that Rhenish or White-wine (for that may not + absurdly be suspected) has in comparison of Water; I purposely sharpen'd + the Solution of this Essence in fair Water, with a good quantity of Spirit + of Salt, notwithstanding which, the mixture acquir'd no Greenness. And to + vary the Experiment a little, I try'd, that if into a Glass of Rhenish + Wine made Green by this Essence, + <!-- Page 340 --> <span class="pagenum"><a name="Page_340" id="Page_340"></a>[pg + 340]</span> I dropp'd an Alcalizate Solution, or Urinous Spirit, the Wine + would presently grow Turbid, and of an odd Dirty Colour; But if instead of + dissolving the Essence in Wine, I dissolv'd it in fair Water sharpen'd + perhaps with a little Spirit of Salt, then either the Urinous Spirit of + Sal Armoniack, or the solution of the fix'd Salt of Pot-ashes would + immediately turn it of a Yellowish Colour, the fix'd or Urinous Salt + Precipitating the Vitriolate substance contain'd in the Essence. But here + I must not forget to take notice of a circumstance that deserves to be + compar'd with some part of the foregoing Experiment, for whereas our + Essence imparts a Greenness to Wine, but not to Water, the Industrious <i>Olaus + Wormius</i><a name="NtA_23" id="NtA_23"></a><a href="#Nt_23"><sup>23</sup></a> + in his late <i>Musæum</i> tells us of a rare kind of Turn-Sole which he + calls <i>Bezetta Rubra</i> given him by an Apothecary that knew not how it + was made, whose lovely Redness would be easily communicated to Water, if + it were immers'd in it; but scarce to Wine, and not at all to Spirit of + Wine, in which last circumstance it agrees with what I lately told you of + our Essence, notwithstanding their disagreement in other particulars. + </p> + <!-- Page 341 --> + <p> + <span class="pagenum"><a name="Page_341" id="Page_341"></a>[pg 341]</span> + </p> + <h3> + <i>EXPERIMENT XLVI.</i> + </h3> + <p> + We have often taken notice, as of a remarkable thing, that Metalls as they + appear to the Eye, before they come to be farther alter'd by other Bodyes, + do exhibit Colours very different from those which the Fire and the <i>Menstruum</i>, + either apart, or both together, do produce in them; especially considering + that these Metalline Bodyes are after all these disguises reducible not + only to their former Metalline Consistence and other more radical + properties, but to their Colour too, as if Nature had given divers Metalls + to each of them a double Colour, an <i>External</i>, and an <i>Internal</i>; + But though upon a more attentive Consideration of this difference of + Colours, it seem'd probable to me, that divers (for I say not all) of + those Colours which we have just now call'd <i>Internal</i>, are rather + produc'd by the Coalition of Metalline Particles with those of the Salts, + or other Bodyes employ'd to work on them, than by the bare alteration of + the parts of the Metalls themselves: and though therefore we may call the + obvious Colours, Natural or Common, & the others Adventitious, yet + because such changes of Colours, from whatsoever cause they be resolv'd to + <!-- Page 342 --> <span class="pagenum"><a name="Page_342" id="Page_342"></a>[pg + 342]</span> proceed may be properly enough taken in to illustrate our + present Subject, we shall not scruple to take notice of some of them, + especially because there are among them such as are produc'd without the + intervention of Saline <i>Menstruums</i>. Of the Adventitious Colours of + Metalline Bodies the Chief sorts seem to be these three. The first, such + Colours as are produc'd without other Additaments by the Action of the + fire upon Metalls. The next such as emerge from the Coalition of Metalline + Particles with those of some <i>Menstruum</i> imploy'd to Corrode a Metall + or Precipitate it; And the last, The Colours afforded by Metalline Bodyes + either Colliquated with, or otherwise Penetrating into, other Bodies, + especially fusible ones. But these (<i>Pyrophilus,</i>) are only as I told + you, the <i>Chief</i> sorts of the adventitious Colours of Metalls, for + there may others belong to them, of which I shall hereafter have occasion + to take notice of some, and of which also there possibly may be others + that I never took notice of. + </p> + <p> + And to begin with the first sort of Colours, 'tis well enough known to + Chymists, that Tin being Calcin'd by fire alone is wont to afford a White + <i>Calx</i>, and Lead Calcin'd by fire alone affords that most Common + Red-Powder we call <i>Minium:</i> Copper also + <!-- Page 343 --> <span class="pagenum"><a name="Page_343" id="Page_343"></a>[pg + 343]</span> Calcin'd <i>per se</i>, by a long or violent fire, is wont to + yield (as far as I have had occasion to take notice of it) a very Dark or + Blackish Powder; That Iron likewise may by the Action of Reverberated + flames be turn'd into a Colour almost like that of Saffron, may be easily + deduc'd from the Preparation of that Powder, which by reason of its Colour + and of the Metall 'tis made of is by Chymists call'd, <i>Crocus Martis per + se</i>. And that <i>Mercury</i> made by the stress of Fire, may be turn'd + into a Red Powder, which Chymists call Precipitate <i>per se</i>, I + elsewhere more particularly declare. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + It is not unworthy the Admonishing you, (<i>Pyrophilus</i>,) and it agrees + very well with our Conjectures about the dependence of the change of a + Body's Colour upon that of its Texture, that the same Metall may by the + successive operation of the fire receive divers Adventitious Colours, as + is evident in Lead, which before it come to so deep a Colour as that of <i>Minium</i>, + may pass through divers others. + </p> + <!-- Page 344 --> + <p> + <span class="pagenum"><a name="Page_344" id="Page_344"></a>[pg 344]</span> + </p> + <p class="center"> + <i>Annotation II</i>. + </p> + <p> + Not only the <i>Calces</i>, but the Glasses of Metalls, Vitrify'd <i>per + se</i>, may be of Colours differing from the Natural or Obvious Colour of + the Metall; as I have observ'd in the Glass of Lead, made by long exposing + Crude Lead to a violent fire, and what I have observ'd about the Glass or + Slagg of Copper, (of which I can show you some of an odd kind of Texture,) + may be elsewhere more conveniently related. I have likewise seen a piece + of very Dark Glass, which an Ingenious Artificer that show'd it me + profess'd himself to have made of Silver alone by an extreme <i>Violence</i> + (which seems to be no more than is needfull) of the fire. + </p> + <p class="center"> + <i>Annotation III</i>. + </p> + <p> + Minerals also by the Action of the Fire may be brought to afford Colours + very differing from their own, as I not long since noted to you about the + variously Colour'd Flowers of Antimony, to which we may add the Whitish + Grey-Colour of its <i>Calx</i>, and the Yellow or Reddish Colour of the + Glass, where into that <i>Calx</i> may be flux'd. + </p> + <p> + And I remember, that I elsewhere told + <!-- Page 345 --> <span class="pagenum"><a name="Page_345" id="Page_345"></a>[pg + 345]</span> you, that Vitriol Calcin'd with a very gentle heat, and + afterwards with higher and higher degrees of it, may be made to pass + through several Colours before it descends to a Dark Purplish Colour, + whereto a strong fire is wont at length to reduce it. But to insist on the + Colours produc'd by the Operation of fire upon several Minerals would take + up farr more time than I have now to spare. + </p> + <h3> + <i>EXPERIMENT XLVII.</i> + </h3> + <p> + The Adventitious Colours produc'd upon Metalls, or rather with them, by + Saline Liquors, are many of them so well known to Chymists, that I would + not here mention them, but that besides a not un-needed Testimony, I can + add something of my own, to what I shall repeat about them, and divers + Experiments which are familiar to Chymists, are as yet unknown to the + greatest part of Ingenious Men. + </p> + <p> + That Gold dissolv'd in <i>Aqua Regia</i> ennobles the <i>Menstruum</i> + with its own Colour, is a thing that you cannot (<i>Pyrophilus</i>,) but + have often seen. The Solutions of Mercury in <i>Aqua-fortis</i> are not + generally taken notice of, to give any notable Tincture to the <i>Menstruum</i>; + but sometimes when the + <!-- Page 346 --> <span class="pagenum"><a name="Page_346" id="Page_346"></a>[pg + 346]</span> Liquor first falls upon the Quick Silver, I have observ'd a + very remarkable, though not durable, Greenness, or Blewness to be + produc'd, which is a <i>Phænomenon</i> not unfit for you to consider, + though I have not now the leisure to discourse upon it. Tin Corroded by <i>Aqua-fortis</i> + till the <i>Menstruum</i> will work no farther on it, becomes exceeding + White, but as we elsewhere note, does very easily of it self acquire the + consistence, not of a Metalline <i>Calx</i>, but of a Coagulated matter, + which we have observ'd with pleasure to look so like, either to curdled + Milk, or curdled Whites of Eggs, that a person unacquainted with such + Solutions may easily be mistaken in it. But when I purposely prepar'd a <i>Menstruum</i> + that would dissolve it as <i>Aqua-fortis</i> dissolves Silver, and not + barely Corrode it, and quickly let it fall again, I remember not that I + took notice of any particular Colour in the Solution, as if the more + Whitish Metalls did not much Tinge their <i>Menstruums</i>, though the + conspicuously Colour'd Metalls as Gold, and Copper, do. For Lead dissolv'd + in Spirit of Vinegar or <i>Aqua-fortis</i> gives a Solution cleer enough, + and if the <i>Menstruum</i> be abstracted appears either Diaphanous or + White. Of the Colour of Iron we have elsewhere said something: And 'tis + worth + <!-- Page 347 --> <span class="pagenum"><a name="Page_347" id="Page_347"></a>[pg + 347]</span> noting, that though if that Metall be dissolv'd in oyl of + Vitriol diluted with water, it affords a Salt or Magistery so like in + colour, as well as some other Qualities, to other green Vitriol, that + Chymists do not improperly call it <i>Vitriolum Martis</i>; yet I have + purposely try'd, that, by changing the <i>Menstruum</i>, and pouring upon + the filings of Steel, instead of oyl of Vitriol, <i>Aqua Fortis</i>, + (whereof as I remember, I us'd 4 parts to one of the Metall) I obtain'd + not a Green, but a Saffron Colour Solution; or rather a thick Liquor of a + deep but yellowish Red. Common Silver, such as is to be met with in + Coines, being dissolv'd in <i>Aqua fortis</i>, yields a Solution tincted + like that of Copper, which is not to be wondred at, because in the coining + of Silver, they are wont (as we elsewhere particularly inform you) to give + it an Allay of Copper, and that which is sold in shops for refined silver, + is not (so far as we have tryed) so perfectly free from that ignobler + Metall, but that a Solution of It in <i>Aqua fortis</i>, will give a + Venereal Tincture to the <i>Menstruum</i>. But we could not observe upon + the solution of some Silver, which was perfectly refin'd, (such as some + that we have, from which 8 or 10 times its weight of Lead has been blown + off) that the <i>Menstruum</i> + <!-- Page 348 --> <span class="pagenum"><a name="Page_348" id="Page_348"></a>[pg + 348]</span> though held against the Light in a Crystal Vial did manifestly + disclose any Tincture, only it seem'd sometimes not to be quite destitute + of a little, but very faint Blewishness. + </p> + <p> + But here I must take notice, that of all the Metalls, there is not any + which doth so easily and constantly disclose its unobvious colour as + Copper doth. For not only in acid <i>Menstruums</i> as <i>Aqua Fortis</i> + and Spirit of Vinegar, it gives a Blewish green solution, but if it be + almost any way corroded, it <i>appears of one of those</i> two colours, as + may be observ'd in Verdigreese made several wayes, in that odd preparation + of <i>Venus</i>, which we elsewhere teach you to make with Sublimate, and + in the common Vitriols of <i>Venus</i> deliver'd by Chymists; and so + constant is the disposition of Copper, notwithstanding the disguise + Artists put upon it, to disclose the colour we have been mentioning, that + we have by forcing it up with <i>Sal Armoniack</i> obtain'd a Sublimate of + a Blewish Colour. Nay a famous Spagyrist affirms, that the very Mercury of + it is green, but till he teach us an intelligible way of making such a + Mercury, we must content ourselves to inform you, that we have had a + Cupreous Body, that was Præcipitated out of a distill'd Liquor, that + seem'd to be the + <!-- Page 349 --> <span class="pagenum"><a name="Page_349" id="Page_349"></a>[pg + 349]</span> the Sulphur of <i>Venus</i>, and seem'd even when flaming, of + a Greenish Colour. And indeed Copper is a Metall so easily wrought upon by + Liquors of several kinds, that I should tell you, I know not any Mineral, + that will concurr to the production of such a variety of Colours as Copper + dissol'd in several <i>Menstruums</i>, as Spirit of Vinegar, <i>Aqua + fortis</i>, <i>Aqua Regis</i>, Spirit of Nitre, of Urine, of Soot, Oyls of + several kinds, and I know not how many other Liquors, if the variety of + somewhat differing colours (that Copper will be made to assume, as it is + wrought upon by several Liquors) were not comprehended within the Limits + of Greenish Blew, or Blewish Green. + </p> + <p> + And yet I must advertise you (<i>Pyrophilus</i>) that being desirous to + try if I could not make with crude Copper a Green Solution without the + Blewishness that is wont to accompany its Vulgar Solutions, I bethought my + self of using two <i>Menstruums</i>, which I had not known imploy'd to + work on this Metall, and which I had certain Reasons to make Tryal of, as + I successfully did. The one of these Liquors (if I much misremember not) + was Spirit of Sugar distill'd in a Retort, which must be warily done, (if + you will avoid breaking your + <!-- Page 350 --> <span class="pagenum"><a name="Page_350" id="Page_350"></a>[pg + 350]</span> glasses) and the other, Oyl or Spirit of Turpentine, which + affords a fine Green Solution that is useful to me on several occasions. + And yet to shew that the adventitious colour may result, as well from the + true and permanent Copper it self, as the Salts wherewith 'tis corroded, I + shall add, that if you take a piece of good <i>Dantzick</i> Copperis, or + any other Vitriol wherein <i>Venus</i> is prædominant, and having + moistened it in your Mouth, or with fair water, rubb it upon a whetted + knife, or any other bright piece of Steel or Iron, it will (as we have + formerly told you) present'y stain the Steel with a Reddish colour, like + that of Copper, the reason of which, we must not now stay to inquire. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + I presume you may have taken notice (<i>Pyrophilus</i>) that I have + borrowed some of the Instances mention'd in this 47<sup>th</sup> + Experiment, from the Laboratories of Chymists, and because in some (though + very few) other passages of this Essay, I have likewise made use of + Experiments mention'd also by some Spagyrical Writers, I think it not + amiss to represent to you on this Occasion once for all, some things + besides + <!-- Page 351 --> <span class="pagenum"><a name="Page_351" id="Page_351"></a>[pg + 351]</span> those which I intimated in the præamble of this present + Experiment; For besides, that 'tis very allowable for a Writer to repeat + an Experiment which he invented not, in case he improve it; And besides + that many Experiments familiar to Chymists are unknown to the generality + of Learned Men, who either never read Chymical processes, or never + understood their meaning, or never durst believe them; besides these + things, I say, I shall represent, That, as to the few Experiments I have + borrowed from the Chymists, if they be very Vulgar, 'twould perhaps be + difficult to ascribe each of them its own Author, and 'tis more than the + generality of Chymists themselves can do: and if they be not of very known + and familiar practise among them, unless the Authors wherein I found them + had given me cause to believe, themselves had try'd them, I know not why I + might not set them down, as a part of the <i>Phænomena</i> of Colours + which I present you; Many things unanimously enough deliver'd as matters + of fact by (I know not how many Chymical Writers) being not to be rely'd + on, upon the single Authority of such Authors: For Instance, as some + Spagyrists deliver (perhaps amongst several deceitful processes) that <i>Saccarum + Saturni</i> + <!-- Page 352 --> <span class="pagenum"><a name="Page_352" id="Page_352"></a>[pg + 352]</span> with Spirit of Turpentine will afford a Balsom, so <i>Beguinus</i> + and many more tell us, that the same Concrete (<i>Saccarum Saturni</i>) + will yield an incomparably fragrant Spirit, and a pretty Quantity of two + several Oyles, and yet since many have complain'd, as well as I have done, + that they could find no such odoriferous, but rather an ill-sented Liquor, + and scarce any oyl in their Distillation of that sweet Vitriol, a wary + person would as little build any thing on what they say of the former + Experiment, as upon what they averr of the later, and therefore I scrupled + not to mention this Red Balsom of which I have not seen any, (but what I + made) among my other experiments about redness. + </p> + <p class="center"> + <i>Annot. II.</i> + </p> + <p> + We have sometimes had the Curiosity to try what Colours Minerals, as + Tinglass, Antimony, Spelter, &c. would yield in several <i>Menstruums</i>, + nor have we forborn to try the Colours of stones, of which that famous + one, (which <i>Helmont</i> calls <i>Paracelsus's Ludus</i>) though it be + digg'd out of the Earth and seem a true stone, has afforded in <i>Menstruums</i> + capable to dissolve so solid a stone, sometimes a Yellowish, + <!-- Page 353 --> <span class="pagenum"><a name="Page_353" id="Page_353"></a>[pg + 353]</span> sometimes a Red solution of both which I can show you. But + though I have from Minerals obtain'd with several <i>Menstruums</i> very + differing Colours, and some such as perhaps you would be surpriz'd to see + drawn from such Bodies: yet I must now pass by the particulars, being + desirous to put an End to this Treatise, before I put an end to your + Patience and my own. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + And yet before I pass to the next Experiment, I must put you in mind, that + the Colours of Metals may in many cases be further alter'd by imploying, + either præcipitating Salts, or other convenient Substances to act upon + their Solutions. Of this you may remember, that I have given you several + Instances already, to which may be added such as these, That if + Quicksilver be dissolv'd in <i>Aqua fortis</i>, and Præcipitated out of + the Solution, either with water impregnated with Sea salt, or with the + spirit of that Concrete, it falls to the Bottom in the form of a white + powder, whereas if it be Præcipitated with an Alcaly, it will afford a + Yellowish or tawny powder, and if there be no Præcipitation made, and the + <i>Menstruum</i> be drawn off with a convenient + <!-- Page 354 --> <span class="pagenum"><a name="Page_354" id="Page_354"></a>[pg + 354]</span> fire, the corroded Mercury will remain in the bottom, in the + form of a substance that may be made to appear of differing Colours by + differing degrees of Heat; As I remember that lately having purposely + abstracted <i>Aqua fortis</i> from some Quicksilver that we had dissolv'd + in it, so that there remain'd a white <i>Calx</i>, exposing that to + several degrees of Fire, and afterwards to a naked one, we obtain'd some + new Colours, and at length the greatest part of the <i>Calx</i> lying at + the Bottome of the Vial, and being brought partly to a Deep Yellow, and + partly to a Red Colour, the rest appear'd elevated to the upper part and + neck of the Vial, some in the form of a Reddish, and some of an Ash-Colour + Sublimate. But of the differing Colours which by differing wayes and + working of Quick Silver with Fire, and Saline Bodies, may be produc'd in + Precipitates, I may elsewhere have occasion to take further notice. I also + told you not long since, that if you corrode Quick-silver with Oyl of + Vitriol instead of <i>Aqua-fortis</i>, and abstract the <i>Menstruum</i>, + there will remain a White <i>Calx</i> which by the Affusion of Fair Water + presently turns into a Lemmon Colour. And ev'n the <i>Succedaneum</i> to a + <i>Menstruum</i> may sometimes serve the turn to change the Colours of a + Metal. The lovely + <!-- Page 355 --> <span class="pagenum"><a name="Page_355" id="Page_355"></a>[pg + 355]</span> Red which Painters call Vermillion, is made of Mercury, which + is of the Colour of Silver, and of Brimstone which is of Kin to that of + Gold, Sublim'd up together in a certain proportion, as is vulgarly known + to Spagyrists. + </p> + <h3> + <i>EXPERIMENT XLVIII.</i> + </h3> + <p> + The third chief sort of the Adventitious Colours of Metals, is, that which + is produc'd by associating them (especially when Calcin'd) with other + fusible Bodies, and Principally Venice, and other fine Glass devoid of + Colour. + </p> + <p> + I have formerly given you an Example, whereby it may appear, that a Metal + may impart to Glass a Colour much differing from its own, when I told you, + how with Silver, I had given Glass a lovely Golden Colour. And I shall now + add, that I have Learn'd from one of the Chief Artificers that sells + Painted Glass, that those of his Trade Colour it Yellow with a preparation + of the <i>Calx</i> of Silver. Though having lately had occasion among + other Tryals to mingle a few grains of Shell-silver (such as is imploy'd + with the Pensil and Pen) with a convenient proportion of powder'd Crystal + Glass, having kept them two or three + <!-- Page 356 --> <span class="pagenum"><a name="Page_356" id="Page_356"></a>[pg + 356]</span> hours in fusion, I was surpriz'd to find the Colliquated Mass + to appear upon breaking the Crucible of a lovely Saphirine Blew, which + made me suspect my Servant might have brought me a wrong Crucible, but he + constantly affirm'd it to be the same wherein the Silver was put, and + considerable Circumstances countenanc'd his Assertion, so that till I have + opportunity to make farther Tryal, I cannot but suspect, either that + Silver which is not (which is not very probable) brought to a perfect + Fusion and Colliquation with Glass, may impart to it other Colours than + when Neal'd upon it, or else (which is less unlikely) that though Silver + Beaters usually chuse the finest Coyn they can get, as that which is most + extensive under the Hammer, yet the Silver-leaves of which this + Shel-silver was made, might retain so much Copper as to enable it to give + the predominant tincture to the Glass. + </p> + <p> + For, I must proceed to tell you (<i>Pyrophilus</i>) as another instance of + the Adventitious Colours of Metals, that which is something strange, + Namely, That though Copper Calcin'd <i>per se</i> affords but a Dark and + basely Colour'd <i>Calx</i>, yet the Glassmen do with it, as themselves + inform me, Tinge their Glass green. And I remember, that when once we took + some crude Copper, + <!-- Page 357 --> <span class="pagenum"><a name="Page_357" id="Page_357"></a>[pg + 357]</span> and by frequent Ignition quenching it in Water had reduc'd it + to a Dark and Ill-colour'd Powder, and afterward kept it in Fusion in + about a 100. times its weight of fine Glass, we had, though not a Green, + yet a Blew colour'd Mass, which would perhaps have been Green, if we had + hit right upon the Proportion of the Materials, and the Degree of Fire, + and the Time wherein it ought to be kept in Fusion, so plentifully does + that Metal abound in a Venerial Tincture, as Artists call it, and in so + many wayes does it disclose that Richness. But though Copper do as we have + said give somewhat near the like Colour to Glass, which it does to <i>Aqua-fortis</i>, + yet it seems worth inquiry, whether those new Colours which Mineral Bodies + disclose in melted Glass, proceed from the Coalition of the Corpuscles of + the Mineral with the Particles of the Glass as such, or from the Action + (excited or actuated by fire) of the Alcalizate Salt (which is a main + Ingredient of Glass,) upon the Mineral Body, or from the concurrence of + both these Causes, or else from any other. But to return to that which we + were saying, we may observe that <i>Putty</i> made by calcining together a + proportion of Tin and Lead, as it is it self a White <i>Calx</i>, so does + it turn the <i>Pitta di Crystallo</i> (as the + <!-- Page 358 --> <span class="pagenum"><a name="Page_358" id="Page_358"></a>[pg + 358]</span> Glassmen call the matter of the Purer sort of Glass, wherewith + it is Colliquated into a White Mass, which if it be opacous enough is + employ'd, as we elsewhere declare, for White Amel. But of the Colours + which the other Metals may be made to produce in Colourless Glass, and + other Vitrifiable Bodies, that have native Colours of their own, I must + leave you to inform your self upon Tryal, or at least must forbear to do + it till another time, considering how many Annotations are to follow, upon + what has in this and the two former Experiments been said already. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + When the Materials of Glass being melted with Calcin'd Tin, have compos'd + a Mass Undiaphanous and White, this White Amel is as it were the Basis of + all those fine Concretes that Goldsmiths and several Artificers imploy in + the curious Art of Enamelling. For this White and Fusible substance will + receive into it self, without spoyling them, the Colours of divers other + Mineral substances, which like it will indure the fire. + </p> + <!-- Page 359 --> + <p> + <span class="pagenum"><a name="Page_359" id="Page_359"></a>[pg 359]</span> + </p> + <p class="center"> + <i>Annotation II.</i> + </p> + <p> + So that as by the present (XLVIII.) Experiment it appears, that divers + Minerals will impart to fusible Masses, Colours differing from their own; + so by the making and compounding of Amels, it may appear, that divers + Bodies will both retain their Colour in the fire, and impart the <i>same</i> + to some others wherewith they were vitrifi'd, and in such Tryals as that + mention'd in the 17. Experiment, where I told you, that ev'n in Amels a + Blew and Yellow will compound a Green. 'Tis pretty to behold, not only + that some Colours are of so fix'd a Nature, as to be capable of mixture + without receiving any detriment by the fire, that do's so easily destroy + or spoyl those of other Bodies; but Mineral Pigments may be mingled by + fire little less regularly and successfully, than in ordinary Dyeing + Fatts, the vulgar Colours are wont to be mingled by the help of Water. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + 'Tis not only Metalline, but other Mineral Bodies, that may be imploy'd, + to give Tinctures unto Glass (and 'tis worth noting + <!-- Page 360 --> <span class="pagenum"><a name="Page_360" id="Page_360"></a>[pg + 360]</span> how small a quantity of some Mineral substances, will Tinge a + Comparatively vast proportion of Glass, and we have sometimes attempted to + Colour Glass, ev'n with Pretious Stones, and had cause to think the + Experiment not cast away. And 'tis known by them that have look'd into the + Art of Glass, that the Artificers use to tinge their Glass Blew, with that + Dark Mineral <i>Zaffora</i>, (some of my Tryals on which I elsewhere + acquaint you) which some would have to be a Mineral Earth, others a Stone, + and others neither the one, nor the other, but which is confessedly of a + Dark, but not a Blew Colour, though it be not agreed of what particular + Colour it is. 'Tis likewise though a familiar yet a remarkable practise + among those that Deal in the making of Glass, to imploy (as some of + themselves have inform'd me) what they call Manganess, and some Authors + call <i>Magnesia</i> (of which I make particular mention in another + Treatise) to exhibit in Glass not only other Colours than its own, (which + is so like in Darkness or blackishness to the Load stone, that 'tis given + by Mineralists, for one of the Reasons of its Latine Name) but Colours + differing from one another. For though they use it, (which is somewhat + strange) to Clarifye their Glass, and free + <!-- Page 361 --> <span class="pagenum"><a name="Page_361" id="Page_361"></a>[pg + 361]</span> it from that Blewish Greenish Colour, which else it would too + often be subject to, yet they also imploy it in certain proportions, to + tinge their Glass both with a Red colour, and with a Purplish or Murry, + and putting in a greater Quantity, they also make with it that deep + obscure Glass which is wont to pass for Black, which agrees very well + with, and may serve to confirm what we noted near the beginning of the 44<sup>th</sup> + Experiment, of the seeming Blackness of those Bodies that are overcharg'd + with the Corpuscles of such Colours, as Red, or Blew, or Green, &c. + And as by several Metals and other Minerals we can give various Colours to + Glass, so on the other side, by the differing Colours that Mineral Oars, + or other Mineral Powders being melted with Glass disclose in it, a good + Conjecture may be oftentimes made of the Metall or known Mineral, that the + Oar propos'd, either holds, or is most of kin to. And this easie way of + examining Oars, may be in some cases of good use, and is not ill deliver'd + by <i>Glauber</i>, to whom I shall at present refer you, for a more + particular account of it: unless your Curiosity command also what I have + observ'd about these matters; only I must here advertise you, that great + circumspection is + <!-- Page 362 --> <span class="pagenum"><a name="Page_362" id="Page_362"></a>[pg + 362]</span> requisite to keep this way from proving fallacious, upon the + account of the variations of Colour that may be produc'd by the differing + proportions that may be us'd betwixt the Oar and the Glass, by the + Richness or Poorness of the Oar it self, by the Degree of Fire, and + (especially) by the Length of Time, during which the matter is kept in + fusion; as you will easily gather from what you will quickly meet with in + the following Annotation upon this present 48<sup>th</sup> Experiment. + </p> + <p class="center"> + <i>Annotation IV.</i> + </p> + <p> + There is another way and differing enough from those already mention'd, by + which Metalls may be brought to exhibit adventitious Colours: For by This, + the Metall do's not so much impart a Colour to another Body, as receive a + Colour from it, or rather both Bodies do by the new Texture resulting from + their mistion produce a new Colour. I will not insist to this purpose upon + the Examples afforded us by yellow Orpiment, and common Sea Salt, from + which, sublim'd together, Chymists unanimously affirm their White or + Crystalline Arsenick to be made: But 'tis not unworthy our noting, That + though Yellow + <!-- Page 363 --> <span class="pagenum"><a name="Page_363" id="Page_363"></a>[pg + 363]</span> Orpiment be acknowledg'd to be the Copiousest by far of the + two Ingredients of Arsenick, yet this last nam'd Body being duely added to + the highest Colour'd Metall Copper, when 'tis in fusion, gives it a + whiteness both within and without. Thus <i>Lapis Calaminaris</i> changes + and improves the Colour of Copper by turning it into Brass. And I have + sometimes by the help of Zinck duely mix'd after a certain manner, given + Copper one of the Richest Golden Colours that ever I have seen the Best + true Gold Ennobled with. But pray have a care that such Hints fall not + into any hands that may mis-imploy them. + </p> + <p class="center"> + <i>Annotation V.</i> + </p> + <p> + Upon the Knowledge of the differing wayes of making Minerals and Metalls + produce their adventitious Colours in Bodies capable of Vitrification, + depends the pretty Art of making what Chymists by a Barbarous Word are + pleas'd to call <i>Amanses</i>, that is counterfeit, or factitious Gemms, + as Emeralds, Rubies, Saphires, Topazes, and the like. For in the making of + these, though pure Sand or Calcin'd Crystal give the Body, yet 'tis for + the most part some Metalline or Mineral <i>Calx</i>, mingled in a + <!-- Page 364 --> <span class="pagenum"><a name="Page_364" id="Page_364"></a>[pg + 364]</span> small proportion that gives the Colour. But though I have many + years since taken delight, to divert my self with this pleasing Art, and + have seen very pretty Productions of it, yet besides that I fear I have + now forgot most of the little Skill I had in it, this is no place to + entertain you with what would rather take up an intire Discourse, than be + comprehended in an Annotation; wherefore the few things which I shall here + take notice of to you, are only what belong to the present Argument, + Namely, + </p> + <p> + First, That I have often observ'd that Calcin'd Lead Colliquated with fine + White Sand or Crystal, reduc'd by ignitions and subsequent extinctions in + Water to a subtile Powder, will of it self be brought by a due Decoction + to give a cleer Mass Colour'd like a <i>German</i> Amethyst. For though + this glass of Lead, is look'd upon by them that know no better way of + making <i>Amanses</i>, as the grand Work of them all, yet which is an + inconvenience that much blemishes this way, the Calcin'd Lead it self does + not only afford matter to the <i>Amanses</i>, but has also as well as + other Metals a Colour of its own, which as I was saying, I have often + found to be like that of <i>German</i> (as many call them) not Eastern + Amethysts. + </p> + <p> + Secondly, That nevertheless this Colour + <!-- Page 365 --> <span class="pagenum"><a name="Page_365" id="Page_365"></a>[pg + 365]</span> may be easily over-powr'd by those of divers other Mineral + Pigments (if I may so call them) so that with a glass of Lead, you may + Emulate (for Instance) the fresh and lovely Greenness of an Emerald, + though in divers cases the Colour which the Lead it self upon + Vitrification tends to, may vitiate that of the Pigment, which you would + introduce into the Mass. + </p> + <p> + Thirdly, That so much ev'n these Colours depend upon Texture, that in the + Glass of Lead it self made of about three parts of <i>Lytharge</i> or <i>Minium</i> + Colliquated with one of very finely Powder'd Crystal or Sand, we have + taken pleasure to make the mixture pass through differing Colours, as we + kept it more or less in the Fusion. For it was not usually till after a + pretty long Decoction that the Mass attain'd to the Amethystin Colour. + </p> + <p> + Fourthly and lastly, That the degrees of Coction and other Circumstances + may so vary the Colour produc'd in the same mass, that in a Crucible that + was not great I have had fragments of the same Mass, in some of which + perhaps not so big as a Hazel-Nut, you may discern four distinct Colours. + </p> + <!-- Page 366 --> + <p> + <span class="pagenum"><a name="Page_366" id="Page_366"></a>[pg 366]</span> + </p> + <p class="center"> + <i>Annotation VI.</i> + </p> + <p> + You may remember (<i>Pyrophilus</i>) that when I mention'd the three sorts + of adventitious Colours of Metals, I mention'd them but as the chief, not + the only. For there may be other wayes, which though they do not in so + strict a sense belong to the adventitious Colours of Metals, may not + inconveniently be reduc'd to them. And of these I shall name now a couple, + without denying that there may be more. + </p> + <p> + The first may be drawn from the practise of those that Dye Scarlet. For + the famousest Master in that Art, either in <i>England</i> or <i>Holland</i>, + has confess'd to me, that neither others, nor he can strike that lovely + Colour which is now wont to be call'd the <i>Bow-Dye</i>, without their + Materials be Boyl'd in Vessels, either made of, or lin'd with a particular + Metall. But of what I have known attempted in this kind, I must not as yet + for fear of prejudicing or displeasing others give you any particular + Account.<a name="NtA_24" id="NtA_24"></a><a href="#Nt_24"><sup>24</sup></a> + </p> + <p> + The other way (<i>Pyrophilus</i>) of making Metals afford unobvious + Colours, is by imbuing divers Bodies with Solutions of them made in their + proper <i>Menstruum's</i>, As (for + <!-- Page 367 --> <span class="pagenum"><a name="Page_367" id="Page_367"></a>[pg + 367]</span> Instance) though Copper plentifully dissolv'd in <i>Aqua + fortis</i>, will imbue several Bodies with the Colour of the Solution; Yet + Some other Metalls will not (as I elsewhere tell you) and have often + try'd. Gold dissolv'd in <i>Aqua Regia</i>, will, (which is not commonly + known) Dye the Nails and Skin, and Hafts of Knives, and other things made + of Ivory, not with a Golden, but a Purple Colour, which though it manifest + it self but slowly, is very durable, and scarce ever to be wash'd out. And + if I misremember not, I have already told you in this Treatise, that the + purer Crystals of fine Silver made with <i>Aqua fortis</i>, though they + appear White, will presently Dye the Skin and Nails, with a Black, or at + least a very Dark Colour, which Water will not wash off, as it will + ordinary Ink from the same parts. And divers other Bodies may the Same way + be Dy'd, some of a Black, and others of a Blackish Colour. + </p> + <p> + And as Metalline, so likewise Mineral Solutions may produce Colours + differing enough from those of the Liquors themselves. I shall not fetch + an Example of this, from what we daily see happen in the powdring of Beef, + which by the Brine imploy'd about it (especially if the flesh be + <!-- Page 368 --> <span class="pagenum"><a name="Page_368" id="Page_368"></a>[pg + 368]</span> over salted) do's oftentimes appear at our Tables of a Green, + and sometimes of a Reddish Colour, (deep enough) nor shall I insist on the + practise of some that deal in Salt Petre, who, (as I suspected, and as + themselves acknowledg'd to me) do, with the mixture of a certain + proportion of that; and common Salt, give a fine Redness, not only to + Neats Tongues, but which is more pretty as well as difficult, to such + flesh, as would otherwise be purely White; These Examples, I say, I shall + decline insisting on, as chusing rather to tell you, that I have several + times try'd, that a Solution of the Sulphur of Vitriol, or ev'n of common + Sulphur, though the Liquor appear'd clear enough, would immediately tinge + a piece of new Coin, or other clean Silver, sometimes with a Golden, + sometimes with a deeper, and more Reddish colour, according to the + strength of the Solution, and the quantity of it, that chanc'd to adhere + to the Metall; which may take off your wonder that the water of the hot + Spring at <i>Bath</i>, abounding with dissolv'd Substances of a very + Sulphureous Nature, should for a while, as it were gild, the new or clean + pieces of Silver coyn, that are for a due time immers'd in it. And to + these may be added those formerly mention'd Examples + <!-- Page 369 --> <span class="pagenum"><a name="Page_369" id="Page_369"></a>[pg + 369]</span> of the adventitious Colours of Mineral Bodies; which brings + into my mind, that, ev'n Vegetable Liquors, whether by degeneration, or by + altering the Texture of the Body that imbibes them, may stain other Bodies + with Colours differing enough, from their own, of which very good + Herbarists have afforded us a notable Example, by affirming that the Juice + of <i>Alcanna</i> being green (in which state I could never here procure + it) do's yet Dye the Skin and Nails of a Lasting Red. But I see this + Treatise is like to prove too bulky without the addition of further + Instances of this Nature. + </p> + <h3> + <i>EXPERIMENT XLIX.</i> + </h3> + <p> + Meeting the other day, <i>Pyrophilus</i>, in an <i>Italian</i> book, that + treats of other matters, with a way of preparing what the Author calls a + <i>Lacca</i> of Vegetables, by which the <i>Italians</i> mean a kind of + Extract fit for Painting, like that rich <i>Lacca</i> in English commonly + call'd <i>Lake</i>, which is imploy'd by Painters as a glorious Red. And + finding the Experiment not to be inconsiderable, and very defectively set + down, it will not be amiss to acquaint you with what some Tryals have + inform'd us, in reference to this + <!-- Page 370 --> <span class="pagenum"><a name="Page_370" id="Page_370"></a>[pg + 370]</span> Experiment, which both by our Italian Author, and by divers of + his Countrymen, is look'd upon as no trifling Secret. + </p> + <p> + Take then the root call'd in Latin <i>Curcuma</i>, and in English + Turmerick, (which I made use of, because it was then at hand, and is among + Vegetables fit for that purpose one of the most easiest to be had) and + when it is beaten, put what Quantity of it you please into fair Water, + adding to every pound of Water about a spoonfull or better of as strong a + <i>Lixivium</i> or Solution of Potashes as you can well make, clarifying + it by Filtration before you put it to the Decocting water. Let these + things boyl, or rather simper over a soft Fire in a clean glaz'd Earthen + Vessel, till you find by the Immersion of a sheet of White Paper (or by + some other way of Tryal) that the Liquor is sufficiently impregnated with + the Golden Tincture of the Turmerick, then take the Decoction off the + Fire, and Filter or Strain it that it may be clean, and leisurely dropping + into it a strong Solution of Roch Allum, you shall find the Decoction as + it were curdl'd, and the tincted part of it either to emerge, to subside, + or to swim up and down, like little Yellow flakes; and if you pour this + mixture into a Tunnel lin'd with Cap Paper, the Liquor that Filtred + formerly + <!-- Page 371 --> <span class="pagenum"><a name="Page_371" id="Page_371"></a>[pg + 371]</span> so Yellow, will now pass clean thorow the Filtre, leaving its + tincted, and as it were curdled parts in the Filtre, upon which fair Water + must be so often pour'd, till you have Dulcifi'd the matter therein + contain'd, the sign of which Dulcification is (you know) when the Water + that has pass'd through it, comes from it as tasteless as it was pour'd on + it. And if without Filtration you would gather together the flakes of this + Vegetable Lake, you must pour a great Quantity of fair Water upon the + Decoction after the affusion of the Alluminous Solution, and you shall + find the Liquor to grow clearer, and the Lake to settle together at the + bottom, or emerge to the top of the Water, though sometimes having not + pour'd out a sufficient Quantity of fair Water, we have observ'd the Lake + partly to subside, and partly to emerge, leaving all the middle of the + Liquor clear. But to make this Lake fit for use, it must by repeated + affusions of fresh Water, be Dulcifi'd from the adhering Salts, as well as + that separated by Filtration, and be spread and suffer'd to dry leisurely + upon pieces of Cloth, with Brown Paper, or Chalk, or Bricks under + <!-- Page 372 --> <span class="pagenum"><a name="Page_372" id="Page_372"></a>[pg + 372]</span> them to imbibe the Moisture<a name="NtA_25" id="NtA_25"></a><a + href="#Nt_25"><sup>25</sup></a>. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + Whereas it is presum'd that the Magistery of Vegetables obtain'd this way + consists but of the more Soluble and Coloured parts of the Plants that + afford it, I must take the liberty to Question the supposition. And for my + so doing, I shall give you this account. + </p> + <p> + According to the Notions (such as they were) that I had concerning Salts; + Allom, though to sense a Homogeneous Body, ought not to be reckon'd among + true Salts, but to be it self look'd upon as a kind of Magistery, in + regard that as Native Vitriol (for such I have had) contains both a Saline + substance and a Metall, whether Copper, or Iron, corroded by it, and + associated with it; so Allom which may be of so near a kin to Vitriol, + that in some places of <i>England</i> (as we are assur'd by good Authority + the same stone will + <!-- Page 373 --> <span class="pagenum"><a name="Page_373" id="Page_373"></a>[pg + 373]</span> sometimes afford both) seems manifestly to contain a peculiar + kind of Acid Spirit, generated in the Bowels of the Earth, and some kind + of stony matter dissolv'd by it. And though in making our ordinary Allom, + the Workmen use the Ashes of a Sea Weed (vulgarly call'd Kelp) and Urine: + yet those that should know, inform us, that, here in <i>England</i>, there + is besides the factitious Allom, Allom made by Nature Without the help of + those Additaments. Now (<i>Pyrophilus</i>) when I consider'd this + composition of Allom, and that Alcalizate Salts are wont to Præcipitate + what acid Salts have dissolv'd, I could not but be prone to suspect that + the Curdled Matter, which is call'd the Magistery of Vegetables, may have + in it no inconsiderable proportion of a stony substance Præcipitated out + of the Allom by the <i>Lixivium</i>, wherein the Vegetable had been + decocted, and to shew you, that there is no necessity, that all the + curdl'd substance must belong to the Vegetable, I shall add, that I took a + strong Solution of Allom, and having Filtred it, by pouring in a + convenient Quantity of a strong Solution of Potashes, I presently, as I + expected, turn'd the mixture into a kind of white Curds, which being put + to Filtre, the Paper retain'd a stony + <!-- Page 374 --> <span class="pagenum"><a name="Page_374" id="Page_374"></a>[pg + 374]</span> <i>Calx</i>, copious enough, very White, and which seem'd to + be of a Mineral Nature, both by some other signes, and this, that little + Bits of it being put upon a live Coal, which was Gently Blown whilst they + were on it, they did neither melt nor fly away, and you may keep a + Quantity of this White substance for a good while, (nay for ought I can + guess for a very long one) in a red hot Crucible without losing or + spoiling it; nor did hot Water wherein I purposely kept another parcel of + such <i>Calx</i>, seem to do any more than wash away the looser adhering + Salts from the stony substance, which therefore seem'd unlikely to be + separable by ablutions (though reiterated) from the Præcipitated parts of + the Vegetable, whose Lake is intended. And to shew you, that there is + likewise in Allom a Body, with which the fix'd Salt of the Alcalizate + Solution will concoagulate into a Saline Substance differing from either + of them, I shall add, that I have taken pleasure to recover out of the + slowly exhal'd Liquor, that pass'd through the filtre, and left the + foremention'd <i>Calx</i> behind, a Body that at least seem'd a Salt very + pretty to look on, as being very White, and consisting of an innumerable + company of exceeding slender, and shining Particles, which + <!-- Page 375 --> <span class="pagenum"><a name="Page_375" id="Page_375"></a>[pg + 375]</span> would in part easily melt at the flame of a Candle, and in + part flye away with some little noise. But of this substance, and its odd + Qualities more perhaps elsewhere; for now I shall only take notice to you, + that I have likewise with Urinous Salts, such as the Spirit of Sal + Armoniack, as well as with the Spirit of Urine it self, Nay, (if I much + mistake not) ev'n with Stale Urine undistil'd, easily Precipitated such a + White <i>Calx</i> as I was formerly speaking of, out of a Limpid Solution + of Allom, so that there is need of Circumspection in judging of the + Natures of Liquors by Precipitations wherein Allom intervenes, else we may + sometimes mistakingly imagine that to be Precipitated out of a Liquor by + Allom, which is rather Precipitated out of Allom by the Liquor: And this + puts me in mind to tell you, that 'tis not unpleasant to behold how + quickly the Solution of Allom (or injected lumps of Allom) do's occasion + the severing of the colour'd parts of the Decoction from the Liquor that + seem'd to have so perfectly imbib'd them. + </p> + <!-- Page 376 --> + <p> + <span class="pagenum"><a name="Page_376" id="Page_376"></a>[pg 376]</span> + </p> + <p class="center"> + <i>Annot. II.</i> + </p> + <p> + The above mention'd way of making Lakes we have tryed not only with + Turmerick, but also with Madder, which yielded us a Red Lake; and with + Rue, which afforded us an extract, of (almost if not altogether) the same + Colour with that of the leaves. + </p> + <p> + But in regard that 'tis Principally the Alcalizate Salt of the Pot-ashes, + which enables the water to Extract so powerfully the Tincture of the + Decocted Vegetables, I fear that our Author may be mistaken by supposing + that the Decoction will alwayes be of the very same Colour with the + Vegetable it is made off. For Lixiviate Salts, to which Pot-ashes + eminently belong, though by peircing and opening the Bodies of Vegetables, + they prepare and dispose them to part readily with their Tincture, yet + some Tinctures they do not only draw out, but likewise alter them, as may + be easily made appear by many of the Experiments already set down in this + Treatise, and though Allom being of an Acid Nature, its Solutions may in + some Cases destroy the Adventitious Colours produc'd by the Alcaly, and + restore the former: yet + <!-- Page 377 --> <span class="pagenum"><a name="Page_377" id="Page_377"></a>[pg + 377]</span> besides that Allom is not, as I have lately shown, a meer Acid + Salt, but a mixt Body, and besides, that its operations are languid in + comparison of the activity of Salts freed by Distillation, or by + Incineration and Dissolution, from the most of their Earthy parts, we have + seen already Examples, that in divers Cases an Acid Salt will not restore + a Vegetable substance to the Colour of which an Alcalizate one had + depriv'd it, but makes it assume a third very differing from both, as we + formerly told you, that if Syrrup of Violets were by an Alcaly turn'd + Green, (which Colour, as I have try'd, may be the same way produc'd in the + Violet-leaves themselves without any Relation to a Syrrup) an Acid Salt + would not make it Blew again, but Red. And though I have by this way of + making Lakes, made Magisteries (for such they seem to be) of Brazil, and + as I remember of Cochinele it self, and of other things, Red, Yellow or + Green which Lakes were enobled with a Rich Colour, and others had no bad + one; yet in some the colour of the Lake seem'd rather inferiour than + otherwise to that of the Plant, and in others it seem'd both very + differing, and much worse; but Writing this in a time and place where I + cannot provide my self of Flowres and other Vegetables to prosecute + <!-- Page 378 --> <span class="pagenum"><a name="Page_378" id="Page_378"></a>[pg + 378]</span> such Tryals in a competent variety of Subjects, I am content + not to be positive in delivering a judgment of this way of Lakes, till + Experience, or You, <i>Pyrophilus</i>, shall have afforded me a fuller and + more particular Information. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + And on this occasion (<i>Pyrophilus</i>) I must here (having forgot to do + it sooner) advertise you once for all, that having written several of the + foregoing Experiments, not only in haste but at seasons of the year, and + in places wherein I could not furnish my self with such Instruments, and + such a variety of Materials, as the design of giving you an Introduction + into the History of Colours requir'd, it can scarce be otherwise but that + divers of the Experiments, that I have set down, may afford you some + matter of new Tryals, if you think fit to supply the deficiencies of some + of them (especially the freshly mention'd about Lakes, and those that + concern Emphatical Colours) which deficiencies for want of being + befriended with accommodations I could better discern than avoid. + </p> + <!-- Page 379 --> + <p> + <span class="pagenum"><a name="Page_379" id="Page_379"></a>[pg 379]</span> + </p> + <p class="center"> + <i>Annotation IV.</i> + </p> + <p> + The use of Allom is very great as well as familiar in the Dyers Trade, and + I have not been ill pleas'd with the use I have been able to make of it in + preparing other pigments than those they imploy with Vegetable Juices. But + the Lucriferous practises of Dyers and other Tradesmen, I do, for Reasons + that you may know when you please, purposely forbear in this Essay, though + not strictly from pointing at, yet from making it a part of my present + work explicitly and circumstantially to deliver, especially since I now + find (though late and not without some Blushes at my prolixity) that what + I intended but for a short Essay, is already swell'd into almost a Volume. + </p> + <h3> + <i>EXPERIMENT L.</i> + </h3> + <p> + Yet here, <i>Pyrophilus</i>, I must take leave to insert an Experiment, + though perhaps you'l think its coming in here an Intrusion, For I confess + its more proper place would have been among those Experiments, that were + brought as proofs and applications of our Notions concerning the + differences of + <!-- Page 380 --> <span class="pagenum"><a name="Page_380" id="Page_380"></a>[pg + 380]</span> Salts; but not having remembred to insert it in its fittest + place, I had rather take notice of it in this, than leave it quite + unmention'd: partly because it doth somewhat differ from the rest of our + Experiments about Colours, in the way whereby 'tis made; and partly + because the grounds upon which I devis'd it, may hint to you somewhat of + the Method I use in Designing and Varying Experiments about Colours, and + upon this account I shall inform you, not only What I did, but Why I did + it. + </p> + <p> + I consider'd then that the work of the former Experiments was either to + change the Colour of a Body into another, or quite to destroy it, without + giving it a successor, but I had a mind to give you also a way, whereby to + turn a Body endued with one Colour into two Bodies, of Colours, as well as + consistencies, very distinct from each other, and that by the help of a + Body that had it self no Colour at all. In order to this, I remembred, + that finding the Acidity of Spirit of Vinegar to be wholly destroy'd by + its working upon <i>Minium</i> (or calcin'd Lead) whereby the Saline + particles of the <i>Menstruum</i> have their Taste and Nature quite + alter'd, I had, among other Conjectures I had built upon that change, + rightly concluded, that the Solution of Lead + <!-- Page 381 --> <span class="pagenum"><a name="Page_381" id="Page_381"></a>[pg + 381]</span> in Spirit of Vinegar would alter the Colour of the Juices and + Infusions of Several Plants, much after the like manner that I had found + Oyl of Tartar to do; and accordingly I was quickly satisfied upon Tryal, + that the Infusion of Rose-leaves would by a small quantity of this + Solution well mingl'd with it, be immediately turn'd into a somewhat sad + Green. + </p> + <p> + And further, I had often found, that Oyl of Vitriol, though a potently + Acid <i>Menstruum</i>, will yet Præcipitate many Bodies, both Mineral and + others, dissolv'd not onely in <i>Aqua fortis</i> (as some Chymists have + observ'd) but particularly in Spirit of Vinegar, and I have further found, + that the <i>Calces</i> or Powders Præcipitated by this Liquor were usually + fair and White. + </p> + <p> + Laying these things together, 'twas not difficult to conclude, that if + upon a good Tincture of Red Rose-leaves made with fair Water, I dropp'd a + pretty quantity of a strong and sweet Solution of <i>Minium</i>, the + Liquor would be turn'd into the like muddy Green Substance, as I have + formerly intimated to You, that Oyl of Tartar would reduce it to, and that + if then I added a convenient quantity of good Oyl of Vitriol, this last + nam'd Liquor would have two distinct operations upon the Mixture, the one, + that + <!-- Page 382 --> <span class="pagenum"><a name="Page_382" id="Page_382"></a>[pg + 382]</span> it would Præcipitate that resolv'd Lead in the form of a White + Powder; the other, that it would Clarifie the muddy Mixture, and both + restore, and exceedingly heighten the Redness of the Infusion of Roses, + which was the most copious Ingredient of the Green composition, and + accordingly trying the Experiment in a Wine glass sharp at the bottom + (like an inverted Cone) that the subsiding Powder might seem to take up + the more room, and be the more conspicuous, I found that when I had shaken + the Green Mixture, that the colour'd Liquor might be the more equally + dispersed, a few drops of the rectifi'd Oyl of Vitriol did presently turn + the opacous Liquor into one that was cleer and Red, almost like a Rubie, + and threw down good store of a Powder, which when 'twas settl'd, would + have appear'd very White, if some interspers'd Particles of the red Liquor + had not a little Allay'd the Purity, though not blemish'd the Beauty of + the Colour. And to shew you, <i>Pyrophilus</i>, that these Effects do not + flow from the Oyl of Vitriol, as it is such, but as it is a strongly Acid + <i>Menstruum</i>, that has the property both to Præcipitate Lead, as well + as some other Concretes out of Spirit of Vinegar, and to heighten the + Colour of Red Rose-leaves, I add, that I + <!-- Page 383 --> <span class="pagenum"><a name="Page_383" id="Page_383"></a>[pg + 383]</span> have done the same thing, though perhaps not quite so well + with Spirit of Salt, and that I could not do it with <i>Aqua-fortis</i>, + because though that potent <i>Menstruum</i> does as well as the others + heighthen the Redness of Roses, yet it would not like them Precipitate + Lead out of Spirit of Vinegar, but would rather have dissolv'd it, if it + had not found it dissolv'd already. + </p> + <p> + And as by this way we have produc'd a Red Liquor, and a White Precipitate + out of a Dirty Green magistery of Rose-leaves, so by the same Method, you + may produce a fair Yellow, and sometimes a Red Liquor, and the like + Precipitate, out of an Infusion of a curious Purple Colour. For you may + call to mind, that in the Annotation upon the 39<sup>th</sup>. Experiment + I intimated to you, that I had with a few drops of an Alcaly turn'd the + Infusion of Logg-wood into a lovely Purple. Now if instead of this Alcaly + I substituted a very Strong and well Filtrated Solution of <i>Minium</i>, + made with Spirit of Vinegar, and put about half as much of this Liquor as + there was of the Infusion of Logg-wood, (that the mixture might afford a + pretty deal of Precipitate,) the affusion of a convenient proportion of + Spirit of Salt, would (if the Liquors were well and nimbly stirr'd + together) presently + <!-- Page 384 --> <span class="pagenum"><a name="Page_384" id="Page_384"></a>[pg + 384]</span> strike down a Precipitate like that formerly mention'd, and + turn the Liquor that swam above it, for the most part into a lovely + Yellow. + </p> + <p> + But for the advancing of this Experiment a little further, I consider'd, + that in case I first turn'd a spoonfull of the infusion of Logg-wood + Purple, by a convenient proportion of the Solution of <i>Minium</i>, the + Affusion of Spirit of Sal Armnoniack, would Precipitate the Corpuscles of + Lead conceal'd in the Solution of <i>Minium</i>, and yet not destroy the + Purple colour of the Liquor; whereupon I thus proceeded; I took about a + spoonfull of the <i>fresh</i> Tincture of Logg-wood, (for I found that if + it were <i>stale</i> the Experiment would not alwayes succeed,) and having + put to it a convenient proportion of the Solution of <i>Minium</i> to turn + it into a deep and almost opacous Purple, I then drop'd in as much Spirit + of Sal Armoniack, as I guess'd would Precipitate about half or more (but + not all) of the Lead, and immediately stirring the mixture well together, + I mingled the Precipitated parts with the others, so that they fell to the + bottom, partly in the form of a Powder, and partly in the form of a + Curdled Substance, that (by reason of the Predominancy of the Ting'd + Corpuscles over + <!-- Page 385 --> <span class="pagenum"><a name="Page_385" id="Page_385"></a>[pg + 385]</span> the White) retain'd as well as the Supernatant Liquor; a + Blewish Purple colour sufficiently Deep, and then instantly (but yet + Warily,) pouring on a pretty Quantity of Spirit of Salt, the matter first + Precipitated, was, by the above specified figure of the bottome of the + Glass preserv'd from being reach'd by the Spirituous Salt; which hastily + Precipitated upon it a new Bed (if I may so call it) of White Powder, + being the remaining Corpuscles of the Lead, that the Urinous Spirit had + not struck down: So that there appear'd in the Glass three distinct and + very differingly colour'd Substances; a Purple or Violet-colour'd + Precipitate at the bottom, a White and Carnation (sometimes a Variously + colour'd) Precipitate over That, and at the Top of all a Transparent + Liquor of a lovely Yellow, or Red. + </p> + <p> + Thus you see, <i>Pyrophilus</i>, that though to some I may have seem'd to + have lighted on this (50<sup>th</sup>.) Experiment by chance, and though + others may imagine, that to have excogitated it, must have proceeded from + some extraordinary insight into the nature of Colours, yet indeed, the + devising of it need not be look'd upon as any great matter, especially to + one that is a little vers'd in the notions, I have in these, and other + Papers + <!-- Page 386 --> <span class="pagenum"><a name="Page_386" id="Page_386"></a>[pg + 386]</span> hinted concerning the differences of Salts. And perhaps I + might add upon more than conjecture, that these very notions and some + particulars scatteringly deliver'd in this Treatise, being skilfully put + together, may suggest divers matters (at least,) about Colours, that will + not be altogether Despicable. But those hinted, <i>Pyrophilus</i>, I must + now leave such as You to prosecute, having already spent farr more time + than I intended to allow my self in acquainting You with particular + Experiments and Observations concerning the changes of Colour, to which I + might have added many more, but that I hope I may have presented You with + a competent number to make out in some measure what I have at the + beginning of this Essay either propos'd as my Design in this Tract, or + deliver'd as my Conjectures concerning these matters. And it not being my + present Designe, as I have more than once Declar'd, to deliver any + Positive Hypothesis or solemn Theory of Colours, but only to furnish You + with some Experiments towards the framing of such a Theory; I shall add + nothing to what I have said already, but a request that you would not be + forward to think I have been mistaken in any thing I have deliver'd as + matter of Fact concerning the changes of Colours, in case you + <!-- Page 387 --> <span class="pagenum"><a name="Page_387" id="Page_387"></a>[pg + 387]</span> should not every time you trye it, find it exactly to succeed. + For besides the Contingencies to which we have elsewhere shewn some other + Experiments to be obnoxious, the omission or variation of a seemingly + unconsiderable circumstance, may hinder the success of an Experiment, + wherein no other fault has been committed. Of which truth I shall only + give you that single and almost obvious, but yet illustrious instance of + the Art of Dying Scarlets, for though you should see every Ingredient that + is us'd about it, though I should particularly inform You of the weight of + each, and though you should be present at the kindling of the fire, and at + the increasing and remitting of it, when ever the degree of Heat is to be + alter'd, and though (in a word) you should see every thing done so + particularly that you would scarce harbour the least doubt of your + comprehending the whole Art: Yet if I should not disclose to You, that the + Vessels, that immediately contain the Tinging Ingredients, are to be made + of or to be lin'd with Tin, You would never be able by all that I could + tell you else (at-least, if the Famousest and Candidest Artificers do not + strangely delude themselves) to bring your Tincture of + <!-- Page 388 --> <span class="pagenum"><a name="Page_388" id="Page_388"></a>[pg + 388]</span> Chochinele to Dye a perfect Scarlet. So much depends upon the + very Vessel, wherein the Tinging matters are boyl'd, and so great an + Influence may an unheeded Circumstance have on the Success of Experiments + concerning Colours. + </p> + <hr /> + <h3> + <i>FINIS.</i> + </h3> + <hr /> + <!-- Page 389 --> + <p> + <span class="pagenum"><a name="Page_389" id="Page_389"></a>[pg 389]</span> + </p> + <h2> + <span style="font-size:50%;">A SHORT</span><br /> <span + style="font-size:125%;">ACCOUNT</span><br /> <span style="font-size:50%;">OF + SOME</span><br /> <span style="font-size:100%;">OBSERVATIONS</span><br /> + <span style="font-size:75%;">Made by Mr. <i>BOYLE</i></span><br /> <span + style="font-size:50%;">About a <i>Diamond</i> that <i>Shines</i> in the + Dark.</span> + </h2> + <p class="center"> + First enclosed in a Letter written to<br /> a Friend, + </p> + <p class="center"> + And now together with it annexed to the Foregoing<br /> Treatise, upon the + score of the<br /> Affinity Betwixt + </p> + <h2> + <span style="font-size:75%;"><i>Light</i> and <i>Colours</i>.</span> + </h2> + <hr /> + <div class="figcenter" style="width:25%;"> + <img width="100%" src="images/429.png" alt="Decorative tiles" /> + </div> + <hr /> + <h3> + <i>LONDON,</i> + </h3> + <h4> + Printed for <i>Henry Herringman</i>. 1664 + </h4> + <!-- Page 390 blank --> + <!-- Page 391 --> + <p> + <span class="pagenum"><a name="Page_391" id="Page_391"></a>[pg 391]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/431a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px">A COPY</span><br /> <span + style="font-size:50%;">OF THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">LETTER</span> + </h2> + <p class="center"> + That Mr. <i>Boyle</i> wrote to Sir <i>Robert Morray</i>,<br /> to accompany + the <i>Observations</i> touching<br /> the <i>Shining Diamond</i>. + </p> + <p> + <i>SIR,</i> + </p> + <p> + <img width="100" height="100" src="images/431b.png" + alt="Illuminated T in Though" /> Hough Sir <i>Robert Morray</i> and + Monsieur <i>Zulichem</i> be Persons that have deserv'd so well of the + Commonwealth of Learning, that I should think my self unworthy to be + look'd upon as a Member of it, if I declin'd to Obey them, or to Serve + them; yet I should not without Reluctancy send you the Notes, you desire + for him, if I did not hope that you will transmit together with them, some + Account why they are not less unworthy of his perusal; which, that you may + do; I must inform you, how + <!-- Page 392 --> <span class="pagenum"><a name="Page_392" id="Page_392"></a>[pg + 392]</span> the writing of them was Occasion'd, which in short was thus. + As I was just going out of Town, hearing that an Ingenious Gentleman of my + Acquaintance, lately return'd from <i>Italy</i>, had a Diamond, that being + rubb'd, would shine in the Dark, and that he was not far off, I snatch'd + time from my Occasions to make him a Visit, but finding him ready to go + abroad, and having in vain try'd to make the Stone yield any Light in the + Day time, I borrow'd it of him for that Night, upon condition to restore + it him within a Day or two at furthest, at <i>Gresham</i> College, where + we appointed to attend the meeting of the Society, that was then to be at + that place. And hereupon I hasted that Evening out of Town, and finding + after Supper that the Stone which in the Day time would afford no + discernable Light, was really Conspicuous in the Dark, I was so taken with + the Novelty, and so desirous to make some use of an opportunity that was + like to last so little a while, that though at that time I had no body to + assist me but a Foot-Boy, yet sitting up late, I made a shift that Night + to try a pretty number of such of the things that then came into my + thoughts, as were not in that place and time unpracticable. And the next + Day being otherwise imploy'd, + <!-- Page 393 --> <span class="pagenum"><a name="Page_393" id="Page_393"></a>[pg + 393]</span> I was fain to make use of a drowsie part of the Night to set + down hastily in Writing what I had observ'd, and without having the time + in the Morning, to stay the transcribing of it, I order'd the Observations + to be brought after me to <i>Gresham</i> College, where you may remember, + that they were together with the Stone it self shown to the Royal Society, + by which they had the good Fortune not to be dislik'd, though several + things were through hast omitted, some of which you will find in the + Margin of the inclosed Paper. The substance of this short Narrative I hope + you will let Monsieur <i>Zulichem</i> know, that he may be kept from + expecting any thing of finish'd in the Observations, and be dispos'd to + excuse the want of it. But such as they are, I hope they will prove + (without a Clinch) Luciferous Experiments, by setting the Speculations of + the Curious on work, in a diligent Inquiry after the Nature of Light, + towards the discovery of which, perhaps they have not yet met with so + considerable an Experiment, since here we see Light produc'd in a dead and + opacous Body, and that not as in rotten Wood, or in Fishes, or as in the + <i>Bolonian</i> Stone, by a Natural Corruption, or by a + <!-- Page 394 --> <span class="pagenum"><a name="Page_394" id="Page_394"></a>[pg + 394]</span> Violent Destruction of the Texture of the Body, but by so + slight a Mechanical operation upon its Texture, as we seem to know what it + is, and as is immediately perform'd, and that several wayes without at all + prejudicing the Body, or making any sensible alterations in its Manifest + Qualities. And I am the more willing to expose my hasty Tryals to Monsieur + <i>Zulichem</i>, and to You, because, he being upon the Consideration of + Dioptricks, so odd a <i>Phœnomemon</i> relateing to the Subject, as + probably he treats of, Light will, I hope, excite a person to consider it, + that is wont to consider things he treats of very well. And for you Sir, I + hope you will both recrute and perfect the Observations you receive, For + you know that I cannot add to them, having a good while since restor'd to + Mr. <i>Clayton</i> the Stone, which though it be now in the hands of a + Prince that so highly deserves, by understanding them, the greatest + Curiosities; yet he vouchsafes you that access to him as keeps me from + doubting, you may easily obtain leave to make further Tryals with it, of + such a Monarch as ours, that is not more inquisitive himself, than a + favourer of them that are so. I doubt not but these Notes will put you in + mind of the Motion you made to the Society, to impose upon + <!-- Page 395 --> <span class="pagenum"><a name="Page_395" id="Page_395"></a>[pg + 395]</span> me the Task of bringing in, what I had on other occasions + observ'd concerning shining Bodies. But though I deny not, that I + sometimes made observations about the <i>Bolonian</i> Stone, and try'd + some Experiments about some other shining Bodies; Yet the same Reasons + that reduc'd me then to be unwilling to receive ev'n their commands, must + now be my Apology for not answering your Expectations, Namely the abstruse + nature of Light, and my being already over-burden'd, and but too much kept + imploy'd by the Urgency of the Press, as well as by more concerning and + distracting Occasions. But yet I will tell you some part of what I have + met with in reference to the Stone, of which I send you an account. + Because I find on the one side, that a great many think it no Rarity upon + a mistaken perswasion, that not only there are store of Carbuncles, of + which this is one; but that all Diamonds and other Glistering Jewels shine + in the Dark. Whereas on the other side there are very Learn'd Men, who + (plausibly enough) deny that there are any Carbuncles or shining Stones at + all. + </p> + <p> + And certainly, those Judicious men have much more to say for themselves, + than the others commonly Plead, and therefore did deservedly look upon Mr. + <i>Clayton</i>'s Diamond + <!-- Page 396 --> <span class="pagenum"><a name="Page_396" id="Page_396"></a>[pg + 396]</span> as a great Rarity. For not only <i>Boetius de Boot</i>, who is + judg'd the best Author on this Subject, ascribes no such Virtue to + Diamonds, but begins what he delivers of Carbuncles, with this passage.<a + name="NtA_26" id="NtA_26"></a><a href="#Nt_26"><sup>26</sup></a> <i>Magna + fama est Carbunculi. Is vulgo putatur in tenebris Carbonis instar lucere; + fortassis quia Pyropus seu Anthrax appellatus a veteribus fuit. Verum + hactenus nemo nunquam verè asserere ausus fuit, se gemmam noctu lucentem + vidisse. Garcias ab Horto proregis Indiæ Medicus, refert se allocutum + fuisse, qui se vidisse affirmarent. Sed iis fidem non habuit.</i> And a + later Author, the Diligent and Judicious <i>Johannes de Laet</i> in his + Chapter of Carbuncles and of Rubies, has this passage. <i>Quia autem + Carbunculi, Pyropi & Anthraces a veteribus nominantur, vulgo creditum + fuit, Carbonis instar in tenebris lucere, quod tamen nullâ gemmâ hastenus + deprehensum, licet à quibusdam temerè jactetur.</i> And the recentest + Writer I have met with on this Subject, <i>Olaus Wormius</i>, in his + Account of his well furnish'd <i>Musæum</i>, do's, where he treats of + Rubies, concurr with the former Writers by these Words.<a name="NtA_27" + id="NtA_27"></a><a href="#Nt_27"><sup>27</sup></a> <i>Sunt qui Rubinum + veterum Carbunculum esse existimant, sed deest una illa nota, quod + <!-- Page 397 --> <span class="pagenum"><a name="Page_397" id="Page_397"></a>[pg + 397]</span> in tenebris instar Anthracis non luceat: Ast talem Carbunculum + in rerum naturâ non inveniri major pars Authoram existimant. Licet unum + aut alterum in India apud Magnates quosdam reperiri scribant, cum tamen ex + aliorum relatione id habeant saltem, sed ipsi non viderint.</i> In + confirmation of which I shall only add, that hearing of a Rubie, so very + Vivid, that the Jewellers themselves have several times begg'd leave of + the fair Lady to whom it belong'd, that they might try their choicest + Rubies by comparing them with That, I had the Opportunity by the Favour of + this Lady and her Husband, (both which I have the Honour to be acquainted + with) to make a Trial of this famous Rubie in the Night, and in a Room + well Darkn'd, but not only could not discern any thing of Light, by + looking on the Stone before any thing had been done to it, but could not + by all my Rubbing bring it to afford the least Glimmering of Light. + </p> + <p> + But, Sir, though I be very backward to admit strange things for truths, + yet I am not very forward to reject them as impossibilities, and therefore + I would not discourage any from making further Inquiry, whether or no + there be Really in <i>Rerum natura</i>, any such thing as a true Carbuncle + or Stone that without Rubbing will shine + <!-- Page 398 --> <span class="pagenum"><a name="Page_398" id="Page_398"></a>[pg + 398]</span> in the Dark. For if such a thing can be found, it may afford + no small Assistance to the Curious in the Investigation of Light, besides + the Nobleness and Rarity of the thing it selfe. And though <i>Vartomannus</i> + was not an Eye witness of what he relates, that the King of <i>Pegu</i>, + one of the Chief Kings of the <i>East-Indies</i>, had a true Carbuncle of + that Bigness and Splendour, that it shin'd very Gloriously in the Dark, + and though <i>Garcias ab Horto</i>, the <i>Indian</i> Vice-Roys Physician, + speaks of another Carbuncle, only upon the Report of one, that he + Discours'd with, who affirmed himself to have seen it; yet as we are not + sure that these Men that gave themselves out to be Eye-witnesses speak + true, yet they may have done so for ought we know to the contrary. And I + could present you with a much considerabler Testimony to the same purpose, + if I had the permission of a Person concern'd, without whose leave I must + not do it. I might tell you that <i>Marcus Paulus Venetus</i><a + name="NtA_28" id="NtA_28"></a><a href="#Nt_28"><sup>28</sup></a> (whose + suppos'd Fables, divers of our later Travellours and Navigatours have + since found to be truths) speaking of the King of <i>Zeilan</i> that then + was, tells us, that he was said to have the best Rubie in the World, a + Palm long and as + <!-- Page 399 --> <span class="pagenum"><a name="Page_399" id="Page_399"></a>[pg + 399]</span> big as a mans Arm, without spot, shining like a Fire, and he + subjoyns, that the Great <i>Cham</i>, under whom <i>Paulus</i> was a + considerable Officer, sent and offer'd the value of a City for it; But the + King answer'd, he would not give it for the treasure of the World, nor + part with it, having been his Ancestours. And I could add, that in the + Relation made by two <i>Russian</i> Cossacks of their Journey into <i>Catay</i><a + name="NtA_29" id="NtA_29"></a><a href="#Nt_29"><sup>29</sup></a>, written + to their Emperour, they mention'd their having been told by the people of + those parts, that their King had a Stone, which Lights as the Sun both Day + and Night, call'd in their Language <i>Sarra</i>, which those Cossacks + interpret a Ruby. But these Relations are too uncertain for me to build + any thing upon, and therefore I shall proceed to tell you, that there came + hither about two years since out of <i>America</i>, the Governour of one + of the Principal Colonies there, an Ancient <i>Virtuoso</i>, and one that + has the Honour to be a member of the Royal Society; this Gentleman finding + some of the chief Affairs of his Country committed to another and me, made + me divers Visits, and in one of them when I enquir'd what Rare Stones they + had in those parts of the <i>Indies</i> he belong'd to, he told me, that + the <i>Indians</i> had a Tradition + <!-- Page 400 --> <span class="pagenum"><a name="Page_400" id="Page_400"></a>[pg + 400]</span> that in a certain hardly accessible Hill, a pretty way up in + the Country, there was a Stone which in the Night time shin'd very + vividly, and to a great distance, and he assur'd me, that though he + thought it not fit to venture himself so far among those Savages, yet he + purposely sent thither a bold <i>Englishman</i>, with some Natives to be + his guides, and that this Messenger brought him back word, that at a + distance from the Hillock he had plainly perceiv'd such a shining + Substance as the <i>Indians</i> Tradition mention'd, and being stimulated + by Curiosity, had slighted those Superstitious Fears of the Inhabitants, + and with much ado by reason of the Difficulty of the way, had made a shift + to clamber up to that part of the Hill, where, by a very heedful + Observation, he suppos'd himself to have seen the Light: but whether + 'twere that he had mistaken the place, or for some other Reason, he could + not find it there, though when he was return'd to his former Station, he + did agen see the Light shining in the same place where it shone before. A + further Account of this Light I expect from the Gentleman that gave me + this, who lately sent me the news of his being landed in that Country. And + though I reserve to my self a full Liberty of Believing no more + <!-- Page 401 --> <span class="pagenum"><a name="Page_401" id="Page_401"></a>[pg + 401]</span> than I see cause; yet I do the less scruple to relate this, + because a good part of it agrees well enough with another Story that I + shall in the next place have occasion to subjoyn, in order whereunto I + shall tell you, that though the Learned Authors I formerly mention'd, tell + us, that no Writer has affirm'd his having himself seen a real Carbuncle, + yet, considering the Light of Mr. <i>Claytons</i> Diamond, it recall'd + into my mind, that some years before, when I was Inquisitive about Stones, + I had met with an old <i>Italian</i> Book highly extoll'd to me by very + competent Judges, and that though the Book were very scarce, I had + purchas'd it at a dear Rate, for the sake of a few considerable passages I + met with in it, and particularly one, which being very remarkable in it + self, and pertinent to our present Argument, I shall put it for you, + though not word for word, which I fear I have forgot to do, yet as to the + Sense, into <i>English</i>. + </p> + <p> + <i>Having promis'd</i> (Says our Author)<a name="NtA_30" id="NtA_30"></a><a + href="#Nt_30"><sup>30</sup></a> <i>to say something of that most precious + sort of Jewels,</i> Carbuncles, <i>because they are very rarely to be met + with, we shall briefly deliver what we know of them. In</i> Clement <i>the + seventh's time, I happen'd to see one of</i> + <!-- Page 402 --> <span class="pagenum"><a name="Page_402" id="Page_402"></a>[pg + 402]</span> <i>them at a certain</i> Ragusian <i>Merchants, nam'd</i> + Beigoio di Bona, <i>This was a Carbuncle white, of that kind of whiteness + which we said was to be found in those Rubies of which we made mention a + little above,</i> (where he had said that those Rubies had a kind of Livid + Whiteness or Paleness like that of a Calcidonian) <i>but it had in it a + Lustre so pleasing and so marveilous, that it shin'd in the Dark, but not + as much as colour'd Carbuncles, though it be true, that in an exceeding + Dark place I saw it shine in the manner of fire almost gone out. But as + for colour'd Carbuncles, it has not been my Fortune to have seen any, + wherefore I will onely set down what I Learn'd about them Discoursing in + my Youth with a</i> Roman <i>Gentleman of antient Experience in matters of + Jewels, who told me, That one</i> Jacopo Cola <i>being by Night in a + Vineyard of his, and espying something in the midst of it, that shin'd + like a little</i> glowing Coal, at the foot of a Vine, went near towards + the place where he thought himself to have seen that fire, but not finding + it, he said, that being return'd to the same place, whence he had first + descry'd it, and perceiving there the same splendor as before, he mark'd + it so heedfully, that he came at length to it, where he took up a very + little Stone, which he carry'd away with Transports and Joy. And the next + <!-- Page 403 --> <span class="pagenum"><a name="Page_403" id="Page_403"></a>[pg + 403]</span> day carrying it about to show it divers of his Friends, whilst + he was relating after what manner he found it, there casually interven'd a + <i>Venetian</i> Embassadour, exceedingly expert in Jewels, who presently + knowing it to be a Carbuncle, did craftily before he and the said <i>Jacopo</i> + parted (so that there was no Body present that understood the Worth of so + Precious a Gemm) purchase it for the Value of 10. Crowns, and the next day + left <i>Rome</i> to shun the being necessitated to restore it, and (as he + affirm'd) it was known within some while after that the said <i>Venetian</i> + Gentleman did in <i>Constantinople</i> sell that Carbuncle to the then + Grand Seignior, newly come to the Empire, for a hundred thousand Crowns. + <i>And this is what I can say</i> concerning <i>Carbuncles</i>, and this + is not a little at least as to the first part of this account, where our + <i>Cellini</i> affirms himself to have seen a Real Carbuncle with his own + Eyes, especially since this Author appears wary in what he delivers, and + is inclin'd rather to lessen, than increase the wonder of it. And his + Testimony is the more considerable, because though he were born a Subject + neither to the Pope nor the then King of <i>France</i> (that Royal <i>Virtuoso</i> + <i>Francis</i> the first) yet both the one and the other of those Princes + imploy'd him much + <!-- Page 404 --> <span class="pagenum"><a name="Page_404" id="Page_404"></a>[pg + 404]</span> about making of their Noblest Jewels. What is now reported + concerning a Shining Substance to be seen in one of the Islands about <i>Scotland</i>, + were very improper for me to mention to Sr. <i>Robert Morray</i>, to whom + the first Information was Originally brought, and from whom I expect a + farther (for I scarce dare expect a convincing) account of it. But I must + not omit that some <i>Virtuoso</i> questioning me the other day at <i>White-Hall</i> + about Mr. <i>Claytons</i> Diamond, and meeting amongst them an Ingenious + <i>Dutch</i> Gentleman, whose Father was long Embassador for the + Netherlands in <i>England</i>, I Learn'd of him, that, he is acquainted + with a person, whose Name he told (but I do not well remember it) who was + Admiral of the <i>Dutch</i> in the <i>East-Indies</i>, and who assur'd + this Gentleman <i>Monsieur Boreel</i>, that at his return from thence he + brought back with him into <i>Holland</i> a Stone, which though it look'd + but like a Pale Dull Diamond, such as he saw Mr. <i>Claytons</i> to be, + yet was it a Real Carbuncle, and did without rubbing shine so much, that + when the Admiral had occasion to open a Chest which he kept under Deck in + a Dark place, where 'twas forbidden to bring Candles for fear of + Mischances, as soon as he open'd the Trunck, the Stone + <!-- Page 405 --> <span class="pagenum"><a name="Page_405" id="Page_405"></a>[pg + 405]</span> would by its Native Light, shine so as to Illustrate a great + part of it, and this Gentleman having very civilly and readily granted me + the request I made him, to Write to the Admiral, who is yet alive in <i>Holland</i>, + (and probably may still have the Jewel by him,) for a particular account + of this Stone, I hope ere long to receive it, which will be the more + welcome to me, not onely because so unlikely a thing needs a cleer + evidence, but because I have had some suspition of that (supposing the + truth of the thing) what may be a shining Stone in a very hot Countrey as + the <i>East-Indies</i>, may perhaps cease to be so (at least in certain + seasons,) in one as cold as <i>Holland</i>. For I observ'd in the Diamond + I send you an account of, that not onely rubbing but a very moderate + degree of warmth, though excited by other wayes, would make it shine a + little. And 'tis not impossible that there may be Stones as much more + susceptible than that, of the Alterations requisite to make a Diamond + shine, as that appeares to be more susceptible of them, than ordinary + Diamonds. And I confess to you, that this is not the only odd suspition + (for they are not so much as conjectures) that what I try'd upon this + Diamond suggested to me. For not here to entertain you with the + <!-- Page 406 --> <span class="pagenum"><a name="Page_406" id="Page_406"></a>[pg + 406]</span> changes I think may be effected ev'n in harder sorts of + Stones, by wayes not vulgar, nor very promising, because I may elsewhere + have occasion to speak of them, and this Letter is but too Prolix already, + that which I shall now acknowledge to you is, That I began to doubt + whether there may not in some Cases be some Truth in what is said of the + right Turquois, that it often changes Colour as the wearer is Sick or + Well, and manifestly loses its splendor at his Death. For when I found + that ev'n the warmth of an Affriction that lasted not above a quarter of a + minute, Nay, that of my Body, (whose Constitution you know is none of the + hottest) would make a manifest change in the solidest of Stones a Diamond, + it seem'd not impossible, that certain warm and Saline steams issuing from + the Body of a living man, may by their plenty or paucity, or by their + peculiar Nature, or by the total absence of them, diversifie the Colour, + and the splendor of so soft a Stone as the Turquois. And though I admir'd + to see, that I know not how many Men otherwise Learn'd, should confidently + ascribe to Jewels such Virtues as seem no way competible to Inanimate + Agents, if to any Corporeal ones at all, yet as to what is affirm'd + concerning the Turquois's + <!-- Page 407 --> <span class="pagenum"><a name="Page_407" id="Page_407"></a>[pg + 407]</span> changing Colour, I know not well how to reject the Affirmation + of so Learned (and which in this case is much more considerable) so + Judicious a Lapidary as <i>Boetius de Boot</i><a name="NtA_31" id="NtA_31"></a><a + href="#Nt_31"><sup>31</sup></a>, who upon his own particular and repeated + Experience delivers so memorable + <!-- Page 408 --> <span class="pagenum"><a name="Page_408" id="Page_408"></a>[pg + 408]</span> a Narrative of the Turquois's changing Colour, that I cannot + but think it worth your Perusal, especially since a much later and very + Experienc'd Author, <i>Olaus Wormius</i>,<a name="NtA_32" id="NtA_32"></a><a + href="#Nt_32"><sup>32</sup></a> where he treats of that Stone, Confirms it + with this Testimony. <i>Imprimis memorandum exemplum quod Anshelmus + Boetius de seipso refert, tam mutati Coloris, quam à casu preservationis. + Cui & ipse haud dissimile adferre possum, nisi ex Anshelmo petitum + quis putaret.</i> I remember that I saw two or three years since a <i>Turcois</i> + (worn in a Ring) wherein there were some small spots, which the <i>Virtuoso</i> + whose it was asur'd me he had observ'd to grow sometimes greater sometimes + less, and to be sometimes in one part of the Stone, sometimes in another. + And I having encourag'd to make Pictures from time to time of the Stone, + and of the Situation of the cloudy parts, thatso their Motion may be more + indisputable, and better observ'd, he came to me about the midle of this + very week, and assur'd me that he had, as I wish'd, made from time to time + Schemes or Pictures of the differing parts of the Stone, whereby the + several Removes and motions of the above mentioned Clouds are very + manifest, though the cause seem'd to him very occult: these Pictures + <!-- Page 409 --> <span class="pagenum"><a name="Page_409" id="Page_409"></a>[pg + 409]</span> he has promis'd to show me, and is very ready to put the Stone + it self into my hands. But the ring having been the other day casually + broken upon his finger, unless it can be taken out, and set again without + any considerable heat, he is loath to have it medled with, for fear its + peculiarity should be thereby destroy'd. And possibly his apprehension + would have been strengthen'd, if I had had opportunity to tell him what is + related by the Learned <i>Wormius</i><a name="NtA_33" id="NtA_33"></a><a + href="#Nt_33"><sup>33</sup></a> of an acquaintance of his, that had a <i>Nephritick</i> + stone, of whose eminent Virtues he had often Experience ev'n in himself, + and for that cause wore it still about his Wrist; and yet going upon a + time into a Bath of fair Water only, wherein certain Herbs had been + boyl'd, the Stone by being wetted with this decoction, was depriv'd of all + his Virtue, whence <i>Wormius</i> takes Occasion to advertise the sick, to + lay by such stones whensoever they make use of a Bath. And we might expect + to find <i>Turcos</i> likewise, easily to be wrought upon in point of + Colour, if that were true, which the curious <i>Antonio Neri</i>, in his + ingenious <i>Arte Vetraria</i><a name="NtA_34" id="NtA_34"></a><a + href="#Nt_34"><sup>34</sup></a> teaches of it, namely, That <i>Turcois's + discolour'd</i> and grown white, will regain and acquire + <!-- Page 410 --> <span class="pagenum"><a name="Page_410" id="Page_410"></a>[pg + 410]</span> an excellent Colour, if you but keep them two or three days at + most cover'd with Oyl of sweet Almonds kept in a temperate heat by warm + ashes, I say if it were true, because I doubt whether it be so, and have + not as yet had opportunity to satisfie my self by Tryals, because I find + by the confession of the most Skilfull Persons among whom I have laid out + for <i>Turcoises</i>, that the true ones are great rarities, though others + be not at all so. And therefore I shall now only mind you of one thing + that you know as well as I, namely, that the rare Stone which is called <i>Oculus + Mundi</i>, if it be good in its Kind, will have so great a change made in + its Texture by being barely left a while in the Languidest of Liquors, + common Waters, that from Opacous it will become Transparent, and acquire a + Lustre of which it will again be depriv'd, without using any other Art or + Violence, by leaving it a while in the Air. And before experience had + satisfy'd us of the truth of this, it seem'd as unlikely that common Water + or Air, should work such great changes in that Gemm, as it now seems that + the Effluviums of a human Body should effect lesser changes in a <i>Turcois</i>, + especially if more susceptible of them, than other Stones of the same + kind. But both my Watch and my Eyes tell me that + <!-- Page 411 --> <span class="pagenum"><a name="Page_411" id="Page_411"></a>[pg + 411]</span> 'tis now high time to think of going to sleep, matters of this + Nature, will be better, as well as more easily, clear'd by Conference, + than Writing. And therefore since I think you know me too well to make it + needfull for me to disclame Credulity, notwithstanding my having + entertain'd you with all these Extravagancies; for you know well, how wide + a difference I am wont to put betwixt things that barely <i>may be</i>, + and things that <i>are</i>, and between those Relations that are but not + unworthy to be inquir'd into, and those that are not worthy to be actually + believ'd; without making Apologies for my Ravings, I shall readily comply + with the drowsiness that calls upon me to release You, and the rather, + because Monsieur <i>Zulichem</i> being concern'd in your desire to know + the few things I have observed about the shining Stone. To entertain those + with Suspicions that are accustomed not to acquiesce but in + Demonstrations, were a thing that cannot be look'd upon as other than very + improper by, + </p> + <p class="i16"> + SIR, + </p> + <p class="center"> + <i>Your most Affectionate</i><br /> and<br /> <i>most Faithfull Servant,</i> + </p> + <p class="center"> + RO. BOYLE. + </p> + <!-- Page 412 blank --> + <!-- Page 413 --> + <p> + <span class="pagenum"><a name="Page_413" id="Page_413"></a>[pg 413]</span> + </p> + <div class="figcenter" style="width:50%;"> + <img width="100%" src="images/453.png" alt="Decorative rule" /> + </div> + <h2> + OBSERVATIONS + </h2> + <p> + Made this 27<sup>th</sup>.<a name="NtA_35" id="NtA_35"></a><a href="#Nt_35"><sup>35</sup></a> + of <i>October</i> 1663. about Mr. <i>Clayton</i>'s Diamond.<a name="NtA_36" + id="NtA_36"></a><a href="#Nt_36"><sup>36</sup></a> + </p> + <p> + Being look'd on in the Day time, though in a Bed, whose Curtains were + carefully drawn, I could not discern it to Shine at all, though well + Rubb'd, but about a little after Sun-set, whilst the Twilight yet lasted, + Nay, this Morning<a name="NtA_37" id="NtA_37"></a><a href="#Nt_37"><sup>37</sup></a> + a pretty while after Sun-rising, (but before I had been abroad in the more + freely inlightned Air of the Chamber) I could upon a light Affriction + easily perceive the Stone to Shine. + </p> + <!-- Page 414 --> + <p> + <span class="pagenum"><a name="Page_414" id="Page_414"></a>[pg 414]</span> + </p> + <p> + Secondly, The Candles being removed, I could not in a Dark place discern + the Stone to have any Light, when I looked on it, without having Rubb'd or + otherwise prepar'd it. + </p> + <p> + Thirdly, By two white Pibbles though hard Rubb'd one against another, nor + by the long and vehement Affriction of Rock Crystal against a piece of Red + cloath, nor yet by Rubbing two Diamonds set in Ring, as I had Rubb'd this + Stone, I could produce any sensible degree of Light. + </p> + <p> + Fourthly, I found this Diamond hard enough, not only to enable me to write + readily with it upon Glass, but to Grave on Rock Crystal it self. + </p> + <p> + Fifthly, I found this to have like other Diamonds, an Electrical faculty.<a + name="NtA_38" id="NtA_38"></a><a href="#Nt_38"><sup>38</sup></a> + </p> + <p> + Sixthly, Being rubb'd upon my Cloaths, as is usual for the exciting of + Amber, Wax, and other Electrical Bodies, it did in the Dark manifestly + shine like Rotten Wood, or the Scales of Whitings, or other putrified + Fish. + </p> + <p> + Seventhly, But this Conspicuousness was Fainter than that of the Scales, + and Slabber (if I may so call it) of Whitings, and much Fainter than the + Light of a Glow-worm, by + <!-- Page 415 --> <span class="pagenum"><a name="Page_415" id="Page_415"></a>[pg + 415]</span> which I have been sometimes able to Read a short Word, whereas + after an ordinary Affriction of this Diamond I was not able to discern + distinctly by the Light of it any of the nearest Bodies: And this + Glimmering also did very manifestly and considerably Decay presently upon + the ceasing of the Affriction, though the Stone continued Visible some + while after. + </p> + <p> + Eighthly, But if it were Rubb'd upon a convenient Body for a pretty while, + and Briskly enough, I found the Light would be for some moments much more + considerable, almost like the Light of a Glow-worm, insomuch after I + ceased Rubbing, I could with the Chaf'd stone exhibit a little Luminous + Circle, like that, but not so bright as that which Children make by moving + a stick Fir'd at the end, and in this case it would continue Visible about + seven or eight times as long as I had been in Rubbing it. + </p> + <p> + Ninthly, I found that holding it a while near<a name="NtA_39" id="NtA_39"></a><a + href="#Nt_39"><sup>39</sup></a> the Flame of a Candle, (from which yet I + was carefull to avert my Eyes) and + <!-- Page 416 --> <span class="pagenum"><a name="Page_416" id="Page_416"></a>[pg + 416]</span> being immediately remov'd into the Dark, it disclosed some + faint Glimmering, but inferiour to that, it was wont to acquire by + Rubbing. And afterward holding it near a Fire that had but little Flame, I + found the Stone to be rather less than more excited, than it had been by + the Candle. + </p> + <p> + Tenthly, I likewise indeavour'd to make it Shine, by holding it a pretty + while in a very Dark place, over a thick piece of Iron, that was well + Heated, but not to that Degree as to be Visibly so. And though at length I + found, that by this way also, the Stone acquired some Glimmering, yet it + was less than by either of the other ways above mention'd. + </p> + <p> + Eleventhly, I also brought it to some kind of Glimmering Light, by taking + it into Bed with me, and holding it a good while upon a warm part of my + Naked Body. + </p> + <p> + Twelfthly, To satisfie my self, whether the Motion introduc'd into the + Stone did generate the Light upon the account of its producing Heat there, + I held it near the Flame of a Candle, till it was qualify'd to shine + pretty well in the Dark, and then immediately I apply'd a slender Hair to + try whether it would attract it, but found not that it did so; though if + it were made to + <!-- Page 417 --> <span class="pagenum"><a name="Page_417" id="Page_417"></a>[pg + 417]</span> shine by Rubbing, it was as I formerly noted Electrical. And + for further Confirmation, though I once purposedly kept it so near the hot + Iron I just now mention'd, as to make it sensibly Warm, yet it shin'd more + Dimly than it had done by Affriction or the Flame of a Candle, though by + both those ways it had not acquir'd any warmth that was sensible. + </p> + <p> + Thirteenthly, Having purposely rubb'd it upon several Bodies differing as + to Colour, and as to Texture, there seem'd to be some little Disparity in + the excitation (if I may so call it) of Light. Upon White and Red Cloths + it seem'd to succeed best, especially in comparison of Black ones. + </p> + <p> + Fourteenthly, But to try what it would do rubb'd upon Bodies more hard, + and less apt to yield Heat upon a light Affriction, than Cloath, I first + rubb'd it upon a white wooden Box, by which it was excited, and afterwards + upon a piece of purely Glazed Earth, which seem'd during the Attrition to + make it Shine better than any of the other Bodies had done, without + excepting the White ones, which I add, lest the Effect should be wholly + ascrib'd to the disposition White Bodies are wont to have to Reflect much + Light. + </p> + <!-- Page 418 --> + <p> + <span class="pagenum"><a name="Page_418" id="Page_418"></a>[pg 418]</span> + </p> + <p> + Fifteenthly, Having well excited the Stone, I nimbly plung'd it under + Water<a name="NtA_40" id="NtA_40"></a><a href="#Nt_40"><sup>40</sup></a>, + that I had provided for that purpose, and perceiv'd it to Shine whilst it + was beneath the Surface of that Liquor, and this I did divers times. But + when I indeavour'd to produce a Light by rubbing it upon the lately + mentioned Cover of the Box, the Stone and it being both held beneath the + Surface of the Water, I did not well satisfie my self in the Event of the + Trial; But this I found, if I took the Stone out, and Rubb'd it upon a + piece of Cloath, it would not as else it was wont to do, presently acquire + a Luminousness, but needed to be rubb'd manifestly much longer before the + desired Effect was found. + </p> + <p> + Sixteenthly, I also try'd several times, that by covering it with my + <!-- Page 419 --> <span class="pagenum"><a name="Page_419" id="Page_419"></a>[pg + 419]</span> warm Spittle (having no warm Water at hand) it did not lose + his Light.<a name="NtA_41" id="NtA_41"></a><a href="#Nt_41"><sup>41</sup></a> + </p> + <p> + Seventeenthly, Finding that by Rubbing the Stone with the Flat side + downwards, I did by reason of the Opacity of the Ring; and the sudden + Decay of Light upon the ceasing of the Attrition, probably lose the sight + of the Stones greatest Vividness; and supposing that the Commotion made in + one part of the stone will be easily propagated all over, I sometimes held + the piece of Cloath upon which I rubb'd it, so, that one side of the Stone + was exposed to my Eye, whilst I was rubbing the other, whereby it appear'd + more Vivid than formerly, and to make Luminous Tracts by its Motions too + and fro. And sometimes holding the Stone upwards, I rubb'd its Broad side + with a fine smooth piece of Transparent Horn, by which means the Light + through that Diaphanous Substance, did whilst I was actually rubbing the + Stone, appear so Brisk that sometimes and in some places it seem'd to have + little Sparks of fire. + </p> + <p> + Eighteenthly, I took also a piece of flat Blew Glass, and having rubb'd + the Diamond well upon a Cloath, and nimbly clapt the Glass upon it, to try + whether in case the Light could peirce it, it would by + <!-- Page 420 --> <span class="pagenum"><a name="Page_420" id="Page_420"></a>[pg + 420]</span> appearing Green, or of some other Colour than Blew, assist me + to guess whether it self were sincere or no. But finding the Glass + impervious to so faint a Light, I then thought it fit to try whether that + hard Bodies would not by Attrition increase the Diamonds Light so as to + become penetrable thereby, and accordingly when I rubb'd the Glass briskly + upon the Stone, I found the Light to be Conspicuous enough, and somewhat + Dy'd in its passage, but found it not easie to give a Name to the Colour + it exhibited. + </p> + <p> + Lastly, To comply with the Suspition I had upon the whole Matter, that the + chief manifest Change wrought in the Stone, was by Compression of its + parts, rather than Incalescence, I took a piece of white Tile well Glaz'd, + and if I press'd the Stone hard against it, it seem'd though I did not rub + it to and fro, to shine at the Sides: And however it did both very + manifestly and vigorously Shine, if whilst I so press'd it, I mov'd it any + way upon the Surface of the Tile, though I did not make it draw a Line of + above a quarter of an Inch long, or thereabouts. And though I made it not + move to and fro, but only from one end of the short Line to the other, + without any return or Lateral motion. Nay, after it had been + <!-- Page 421 --> <span class="pagenum"><a name="Page_421" id="Page_421"></a>[pg + 421]</span> often rubb'd, and suffer'd to lose its Light again, not only + it seem'd more easie to be excited than at the beginning of the Night; but + if I did press hard upon it with my Finger, at the very instant that I + drew it briskly off, it would disclose a very Vivid but exceeding short + Liv'd Splendour, not to call it a little Coruscation.<a name="NtA_42" + id="NtA_42"></a><a href="#Nt_42"><sup>42</sup></a> So that a <i>Cartesian</i> + would scarce scruple to think he had found in this Stone no slight + Confirmation of his Ingenious Masters <i>Hypothesis</i>, touching the + Generation of Light in Sublunary Bodies, not sensibly Hot. + </p> + <!-- Page 422 --> + <p> + <span class="pagenum"><a name="Page_422" id="Page_422"></a>[pg 422]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/462.png" alt="Decorative rule" /> + </div> + <h2> + A Postscript. + </h2> + <h3> + Annexed some Hours after the<br /> Observations were Written. + </h3> + <p> + <i>So many particulars taken notice of in one Night, may make this Stone + appear a kind of Prodigie, and the rather, because having try'd as I + formerly noted, not only a fine Artificial Crystal, and some also that is + Natural, but a Ruby and two Diamonds, I did not find that any of these + disclos'd the like Glimmering of + <!-- Page 423 --> <span class="pagenum"><a name="Page_423" id="Page_423"></a>[pg + 423]</span> Light;<a name="NtA_43" id="NtA_43"></a><a href="#Nt_43"><sup>43</sup></a> + yet after all, perceiving by the Hardness, and the Testimony of a Skilfull + Goldsmith, that this was rather a Natural than Artificial Stone; for fear + lest there might be some difference in the way of Setting, or in the shape + of the Diamonds I made use of, neither of which was like this, a flat + Table-stone, I thought fit to make a farther Trial of my own Diamonds, by + such a brisk and assiduous Affriction as might make amends for the + Disadvantages above-mention'd, in case they were the cause of the + unsuccessfulness of the former Attempts: And accordingly I found, that by + this way I could easily bring a Diamond I wore on my Finger to disclose a + Light, that was sensible enough, and continued so though I cover'd it with + Spittle, and us'd some other trials about it. And this will much lessen + the wonder of all the formerly mention'd Observations, by shewing that the + properties that are so strange are not peculiar to one Diamond, but may be + found in others also, and perhaps in divers other hard and</i> Diaphanous + <i>Stones. Yet I hope that what this Discovery takes away from the Wonder + of these Observations, it will add to the Instructiveness of them, by + affording pregnants Hints, towards the Investigation of the Nature of + Light.</i> + </p> + <h3> + FINIS. + </h3> + <hr /> + <h2> + Notes. + </h2> + <p class="note"> + <a name="Nt_1" id="Nt_1"></a><a href="#NtA_1">1</a> L. Annæ Senecæ Natur. + Quest. l. 6. c. 5. + </p> + <p class="note"> + <a name="Nt_2" id="Nt_2"></a><a href="#NtA_2">2</a> He that desires more + instances of this kind and matter, that according to this doctrine may + much help the Theory of colours, and particularly the force both of + Sulphureous and volatile, is likewise of Alcalizate and Acid Salts, and in + what particulars, Colours likely depend not in the causation from any Salt + at all, may beg his information from M. Boyle who hath some while since + honoured me with the sight of his papers concerning this subject, + containing many excellent experiments, made by him for the Elucidation of + this doctrine, &c Dr. R. Sharrock in his ingenious and usefull History + of the Propagation and Improvement of Vegetables, published in the yeare + 1660. + </p> + <p class="note"> + <a name="Nt_3" id="Nt_3"></a><a href="#NtA_3">3</a> <i>See the Discourse + of the Nature of Whiteness and Blackness.</i> + </p> + <p class="note"> + <a name="Nt_4" id="Nt_4"></a><a href="#NtA_4">4</a> Since for his eminent + Qualities and Loyalty Grac'd, by his Majesty, with the Honour of + Knighthood. + </p> + <p class="note"> + <a name="Nt_5" id="Nt_5"></a><a href="#NtA_5">5</a> Exercitat. 325 Parag. + 4 + </p> + <p class="note"> + <a name="Nt_6" id="Nt_6"></a><a href="#NtA_6">6</a> <i>Album quippe & + agrum, hoc quidem asperum esse dicit, hoc vero læve. de Sensu & + Sensib. 3. 3.</i> + </p> + <p class="note"> + <a name="Nt_7" id="Nt_7"></a><a href="#NtA_7">7</a> Epist. 2. pag. 45. + </p> + <p class="note"> + <a name="Nt_8" id="Nt_8"></a><a href="#NtA_8">8</a> Gent. Septen. Histor. + lib. 4 cap. 13. + </p> + <p class="note"> + <a name="Nt_9" id="Nt_9"></a><a href="#NtA_9">9</a> Hist. Anatom. Cent. 3. + Hist. 44. + </p> + <p class="note"> + <a name="Nt_10" id="Nt_10"></a><a href="#NtA_10">10</a> Olearius Voyage de + Mosco. et de Perse <i>liv</i>. 3. + </p> + <p class="note"> + <a name="Nt_11" id="Nt_11"></a><a href="#NtA_11">11</a> <i>Piso</i> Nat. + & Med. Hist. <i>Brasil. lib</i> 1. in fine. + </p> + <p class="note"> + <a name="Nt_12" id="Nt_12"></a><a href="#NtA_12">12</a> <i>Purchas</i> + Pilgrim. Second part, Seventh Book 3. Chap. Sect 5. + </p> + <p class="note"> + <a name="Nt_13" id="Nt_13"></a><a href="#NtA_13">13</a> <i>Purchas</i>. + Ibid. + </p> + <p class="note"> + <a name="Nt_14" id="Nt_14"></a><a href="#NtA_14">14</a> <i>Purchas</i> + Ibid. in fin + </p> + <p class="note"> + <a name="Nt_15" id="Nt_15"></a><a href="#NtA_15">15</a> See <i>Scaliger</i> + Exercit. 325. Sect. 9. + </p> + <p class="note"> + <a name="Nt_16" id="Nt_16"></a><a href="#NtA_16">16</a> <i>Nicolaus + Monardes</i> lib <i>simplic. ex India allatis</i>, cap. 27. + </p> + <p class="note"> + <a name="Nt_17" id="Nt_17"></a><a href="#NtA_17">17</a> Kircher. Art. Mag. + lucis & umbræ, <i>lib. 1. part. 3.</i> + </p> + <p class="note"> + <a name="Nt_18" id="Nt_18"></a><a href="#NtA_18">18</a> <i>Herbarists</i> + are wont to call this Plant <i>Cyanus vulgaris minor</i>. + </p> + <p class="note"> + <a name="Nt_19" id="Nt_19"></a><a href="#NtA_19">19</a> Paracelsus de + Mineral. tract. 1. pag. m. 243 + </p> + <p class="note"> + <a name="Nt_20" id="Nt_20"></a><a href="#NtA_20">20</a> See <i>Parkinson</i> + Th. Boran. Trib. 9. cap. 26. + </p> + <p class="note"> + <a name="Nt_21" id="Nt_21"></a><a href="#NtA_21">21</a> <i>Parkinson</i>, + Thea. Bot. Trib. 4 cap. 12. + </p> + <p class="note"> + <a name="Nt_22" id="Nt_22"></a><a href="#NtA_22">22</a> <i>Beguinus</i>, + Tyr. Chy. Lib. 2º. Cap. 13º. + </p> + <p class="note"> + <a name="Nt_23" id="Nt_23"></a><a href="#NtA_23">23</a> Libr. 2<sup>do</sup> + Cap. 34. + </p> + <p class="note"> + <a name="Nt_24" id="Nt_24"></a><a href="#NtA_24">24</a> See the latter end + of the fiftieth Experiment. + </p> + <p class="note"> + <a name="Nt_25" id="Nt_25"></a><a href="#NtA_25">25</a> <i>The Curious + Reader that desires further Information concerning Lakes, may Resort to + the 7th Book of</i> Neri's <i>Art of Glass, Englished (6 or 7 years since + the Writing of this 49th Experiment) and Illustrated with Learned + Observations, by the Inquisitive and experienc'd Dr.</i> Charles Merret. + </p> + <p class="note"> + <a name="Nt_26" id="Nt_26"></a><a href="#NtA_26">26</a> Boetius de Boot. + Gem. & Lapid. Histor. Lib. 3. Cap. 8. + </p> + <p class="note"> + <a name="Nt_27" id="Nt_27"></a><a href="#NtA_27">27</a> Musæi Wormiani. + Cap. 17. + </p> + <p class="note"> + <a name="Nt_28" id="Nt_28"></a><a href="#NtA_28">28</a> <i>Purchas</i>'s + Pilgrim. lib. 1. cap. 4. pag. 104. + </p> + <p class="note"> + <a name="Nt_29" id="Nt_29"></a><a href="#NtA_29">29</a> In the year 1619. + </p> + <p class="note"> + <a name="Nt_30" id="Nt_30"></a><a href="#NtA_30">30</a> Benvonuto Cellini + <i>nell Arte del</i> Gioiellare, <i>Lib.</i> 1. <i>pag.</i> 10. + </p> + <p class="note"> + <a name="Nt_31" id="Nt_31"></a><a href="#NtA_31">31</a> The Narrative in + the Authors own words, is this. <i>Ego</i> (sayes he) <i>sanctè affirmare + possum me unam aureo Annulo inclusam perpetuo gestare, cujus facultatem + (si gemmæ est) nunquam satis admirari potui. Gestaverat enim ante Triginta + annos Hispanus quidam non procula puternis ædibus habitans. Is cum vitâ + functus esset, & ipsius suspellex (ut moris apud nos est) venum + exposita esset, inter cætera etiam Turcois exponebatur. Verum nemo (licet + complures eo concurrissent, ut eam propter Coloris Elegantiam, quam vivo + Domino habuerat emerent) sibi emptam voluit, pristinum enim nitorem & + Colorem prorsus amiserat, ut potius Malachites, quam Turcois videretur. + Aderat tum temporis gemmæ habendæ desiderio etiam parens & frater + meus, qui antea sæpius gratiam & elegantiam ipsius viderant, mirabundi + eam nunc tam esse deformem, Emit eam nihilominus pater, satisque vili + pretio, qua omnibus contemptui erat, ac presentes non eam esse quam + Hispanus gestarat, arbitrarentur. Domum reversus Pater, qui tam turpem + Gemmam gestare sibi indecorum putabat, eam mihi dono dat, inquiens; + Quandoquidem, fili mi, vulgi fama est, Turcoidem, ut facultates suas + exercere possit, dono dari debere tibi eam devoveo, ego acceptam Gemmam + sculptori trado, at gentilitia mea insignia illi, quamadmodum fieri solet, + in Jaspide Chalcedono, aliisque Ignobilioribus Gemmis, insculperat. Turpe + enim existimabam, hujusmodi Gemmâ ornatus gratia, dum gratiam nullam + haberet, uti. Paret Sculptor redditque Gemmam, quam gesto pro annulo + Signatorio. Vix per mensem gestaram, redit illi pristinus color, sed non + ita nitens propter Sculpturam, ac inæqualem superficiem. Miramur omnes + gemmam, atque id præcipuè quod color indies pulchrior fieret. Id quià + observabam, nunquam fere eam à manu deposui, ita ut nunc adhuc candem + gestem.</i> + </p> + <p class="note"> + <a name="Nt_32" id="Nt_32"></a><a href="#NtA_32">32</a> <i>Olaus Wormius, + in Musæ. 18º pag. 186.</i> + </p> + <p class="note"> + <a name="Nt_33" id="Nt_33"></a><a href="#NtA_33">33</a> <i>Musæ. Worm.</i> + pag. 99. + </p> + <p class="note"> + <a name="Nt_34" id="Nt_34"></a><a href="#NtA_34">34</a> Arte Vetraria, + lib. 7 cap. 102. + </p> + <p class="note"> + <a name="Nt_35" id="Nt_35"></a><a href="#NtA_35">35</a> These were brought + in and Read before the Royal Society, (the Day following) <i>Oct.</i> 28. + 1663. + </p> + <p class="note"> + <a name="Nt_36" id="Nt_36"></a><a href="#NtA_36">36</a> <i>The Stone it + self being to be shown to the Royal Society, when the Observations were + deliver'd, I was willing (being in haste) to omit the Description of it, + which is in short, That it was a Flat or Table Diamond, of about a third + part of an Inch in length, and somewhat less in breadth, that it was a + Dull Stone, and of a very bad Water, having in the Day time very little of + the Vividness of ev'n ordinary Diamonds, and being Blemished with a + whitish Cloud about the middle of it, which covered near a third part of + the Stone.</i> + </p> + <p class="note"> + <a name="Nt_37" id="Nt_37"></a><a href="#NtA_37">37</a> <i>Hast made me + forget to take notice that I went abroad the same Morning, the Sun shining + forth clear enough, to look upon the Diamond though a</i> Microscope, <i>that + I might try whether by that Magnifying Glass any thing of peculiar could + be discern'd in the Texture of the Stone, and especially of the whitish + Cloud that possest a good part of it. But for all my attention I could not + discover any peculiarity worth mentioning.</i> + </p> + <p class="note"> + <a name="Nt_38" id="Nt_38"></a><a href="#NtA_38">38</a> V. <i>For it drew + light Bodies like Amber, Jet, and other Concretes that are noted to do so; + But its attractive power seem'd inferiour to theirs.</i> + </p> + <p class="note"> + <a name="Nt_39" id="Nt_39"></a><a href="#NtA_39">39</a> IX. <i>We durst + not hold it in the Flame of a Candle, no more than put it into a naked + Fire; For fear too Violent a Heat (which has been observ'd to spoil many + other precious Stones) should vitiate and impair a Jewel, that was but + borrow'd, and was suppos'd to be the only one of its Kind.</i> + </p> + <p class="note"> + <a name="Nt_40" id="Nt_40"></a><a href="#NtA_40">40</a> XV. <i>We likewise + Plung'd it as soon as we had excited it, under Liquors of several sorts, + as Spirit of Wine, Oyl both Chymical and express'd, an Acid Spirit, and as + I remember an Alcalizate Solution, and found not any of those various + Liquors to destroy its Shining property.</i> + </p> + <p class="note"> + <a name="Nt_41" id="Nt_41"></a><a href="#NtA_41">41</a> XVI. <i>Having + found by this Observation, that a warm Liquor would not extinguish Light + in the Diamond, I thought fit to try, whether by reason of its warmth it + would not excite it, and divers times I found, that if it were kept + therein, till the Water had leisure to communicate some of its Heat to it, + it would often shine as soon as it was taken out, and probably we should + have seen it Shine more, whilst it was in the Water, if some degree of + Opacity which heated Water is wont to acquire, upon the score of the + Numerous little Bubbles generated in it, had not kept us from discerning + the Lustre of the Stone.</i> + </p> + <p class="note"> + <a name="Nt_42" id="Nt_42"></a><a href="#NtA_42">42</a> <i>I after + bethought my self of imploying a way, which produc'd the desir'd Effect + both sooner and better. For holding betwixt my Fingers a Steel Bodkin, + near the Lower part of it, I press'd the point hard against the Surface of + the Diamond, and much more if I struck the point against it, the + Coruscation would be extremely suddain, and very Vivid, though very + Vanishing too, and this way which commonly much surpris'd and pleas'd the + Spectators, seem'd far more proper than the other, to show that pressure + alone, if forcible enough, though it were so suddain, and short, that it + could not well be suppos'd to give the Stone any thing near a sensible + degree of Warmth, as may be suspected of Rubbing, yet 'tis sufficient to + generate a very Vivid Light.</i> + </p> + <p class="note"> + <a name="Nt_43" id="Nt_43"></a><a href="#NtA_43">43</a> We afterwards, + try'd precious Stones, as Diamonds, Rubies, Saphires, and Emeralls, &c. + but found not any of them to Shine except some Diamonds, and of these we + were not upon so little practice, able to fore-tell before hand, which + would be brought to Shine, and which would not; For several very good + Diamonds, either would not Shine at all, or much less than others that + were farr inferiour to them. And yet those Ingenious Men are mistaken, + that think a Diamond must be foul and cloudy, as Mr. <i>Claytons</i> was, + to be fit for Shining; for as we could bring some such to afford a + Glimmering Light, so with some clear and excellent Diamonds, we could do + the like. But none of those many that we try'd of all Kinds, were equal to + the Diamond on which the Observations were made, not only considering the + degree of Light it afforded, but the easiness wherewith it was excited, + and the Comparatively great duration of its Shining. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/039a.png" alt="Decorative rule" /> + </div> + <p> + <b>Transcriber's notes.</b> + </p> + <p> + The Errata of the printed book have all been corrected. They were as + follows: + </p> + <p> + Pag. <a href="#Page_142">142</a>. l. 20. These words, <i>And to manifest</i>, + with the rest of what is by a mistake further printed in this fourth + Experiment, belongeth, and is to be referred to the end of the second + Eperiment, p.<a href="#Page_137">137</a>. pag. <a href="#Page_145">145</a>. + l. 1. leg. <i>matter</i>. <a href="#Page_146">146</a>. l. 4. leg. <i>Bolts-head</i>. + pag <a href="#Page_161">161</a>. in the marginal note l. 2. dele <i>de</i> + ib. l. 3. lege lib 1. p <a href="#Page_163">163</a>. l. ult. insert <i>where</i> + between the words <i>places</i> and <i>the</i>. p. <a href="#Page_164">164</a> + l. 1. dele <i>that</i>. ibid, l. 8. leg <i>Epidermis</i>. ibid. l. 19 leg. + 300. for 200. p. <a href="#Page_169">169</a>. l. 22. leg. <i>into it</i>. + p. <a href="#Page_170">170</a>. l. 23. & 24. leg. <i>Some Solutions + hereafter to be mentioned</i>, for <i>the Solutions of Potashes</i>, and + other <i>Lixiviate Salts</i>. p. <a href="#Page_171">171</a>. l. 6. insert + <i>part of</i> between the words <i>most</i> and <i>dissolved</i> p. <a + href="#Page_176">176</a>. l. ult. insert the participle <i>it</i> between + the words <i>Judged</i> and <i>not</i> p. <a href="#Page_234">234</a>. l. + 4. leg. <i>Woud-wax</i> or <i>Wood-wax</i>. p. <a href="#Page_320">320</a> + l. 29. leg. <i>urine</i> for <i>urne</i>. + </p> + <p> + In addition I have corrected the following original typos: + </p> + <p> + The preface: I devis'd tbem -> I devis'd them<br /> The preface: make + Expements -> make Experiments<br /> The Publisher to the reader: made of + Eperiments -> made of Experiments<br /> I. Ch. III.6 divers Expements -> + divers Experiments<br /> I. Ch. III.13 epecially with some sorts -> + especially with some sorts<br /> II. Ch. II.8 Slightet Texture -> Slightest + Texture<br /> II. Exp. I two Colonrs -> two Colours<br /> II. Exp. XIII were + the change of Colour ... is attempted -> where the change (etc.)<br /> III. + Exp. XII avoiding of Ambignity -> avoiding of Ambiguity<br /> III. Exp. + XXIX Juice of this Sipce -> Juice of this Spice<br /> III. Exp. XL forty + second Expement -> forty second Experiment<br /> III. Exp. XLIV keep them + swimning -> keep them swimming<br /> III. Exp. XLVI it seem'd propable to + me -> it seem'd probable to me<br /> III. Exp. XLVII where not comprehended + -> were not comprehended<br /> III. Exp. XLVIII frequent Igintion -> + frequent Ignition<br /> III. Exp. L I could tell yon -> I could tell you<br /> + A Copy of the Letter: nemo unqnam vere asserere -> nemo nunquam vere + asserere<br /> (ib.): what is reladed -> what is related<br /> Observations: + carefulsy drawn -> carefully drawn + </p> + <p> + - and emended<br /> Phœnomenon/a to Phænomenon/a 10 times and<br /> Cœruleous + etc. -> Cæruleous 20 times + </p> + <p> + + <a name="long" id="long"> </a> + </p> + <h2> + <span style="font-size:100%;">EXPERIMENTS</span><br /> <span + style="font-size:50%;">AND</span><br /> <span style="font-size:100%;">CONSIDERATIONS</span><br /> + <span style="font-size:50%;">Touching</span><br /> <span + style="font-size:150%; letter-spacing:6px">COLOURS.</span><br /> + </h2> + <p class="center"> + Firſt occaſionally Written, among ſome other<br /> <i>Eſſays</i>, + to a Friend; and now ſuffer'd to<br /> come abroad as + </p> + <h2> + <span style="font-size:50%;">THE</span><br /> <span style="font-size:50%;">BEGINNING</span><br /> + <span style="font-size:50%;">Of An</span><br /> <span style="font-size:75%;">Experimental + Hiſtory</span><br /> <span style="font-size:50%;">OF</span><br /> <span + style="font-size:100%; letter-spacing:6px">COLOURS.</span><br /> + </h2> + <hr class="short" /> + <p class="center"> + By the Honourable <i>ROBERT BOYLE</i>,<br /> Fellow of the ROYAL SOCIETY. + </p> + <hr class="short" /> + <p class="center"> + <i>Non fingendum, aut excogitandum, ſed inveniendum,<br /> quid Natura + faciat, aut ferat</i>. Bacon. + </p> + <hr class="short" /> + <h3> + <i>LONDON</i>. + </h3> + <p class="center"> + Printed for <i>Henry Herringman</i> at the<br /> <i>Anchor</i> on the Lower + walk of the <i>New<br /> Exchange</i>. MDCLXIV. + </p> + <div class="figcenter" style="width:50%;"> + <img width="100%" src="images/002a.png" alt="Decorative tile" /> + </div> + <h2> + <span style="font-size:50%; letter-spacing:6px">THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">PREFACE.</span><br /> + </h2> + <p> + <img width="100" height="100" src="images/002b.png" + alt="Illuminated H in Having" /> <i>Aving in convenient places of the + following Treatiſe, mention'd the Motives, that induc'd me to write + it, and the Scope I propos'd to my ſelf in it; I think it ſuperfluous + to entertain the Reader now, with what he will meet with hereafter. And I + ſhould judge it needleſs, to trouble others, or my ſelf, + with any thing of Preface: were it not that I can ſcarce doubt, but + this Book will fall into the hands of ſome Readers, who being + unacquainted with the difficulty of attempts of this nature, will think + itn ſtrange that I ſhould publiſh any thing about Colours, + without a particular Theory of them. But I dare expect that Intelligent + and Equitable Readers will conſider on my behalf: That the profeſſed + Deſign of this Treatiſe is to deliver things rather</i> Hiſtorical + <i>than</i> Dogmatical, <i>and conſequently if I have added divers + new</i> ſpeculative <i>Conſiderations and hints, which perhaps + may afford no deſpicable Aſſiſtance, towards the + framing of a ſolid and comprehenſive Hypotheſis, I have + done at least as much as I promis'd, or as the nature of my undertaking + exacted. But another thing there is, which if it ſhould be objected, + I fear I ſhould not be able ſo eaſily to anſwer it, + and that is; That in the following treatiſe (eſpecially in the + Third part of it) the Experiments might have been better Marſhall'd, + and ſome of them deliver'd in fewer words. For I muſt confeſs + that this Eſſay was written to a private Friend, and that too, + by ſnatches, at ſeveral times, and places, and (after my manner) + in looſe ſheets, of which I oftentimes had not all by me that I + had already written, when I was writing more, ſo that it needs be no + wonder if all the Experiments be not rang'd to the beſt Advantage, + and if ſome connections and conſecutions of them might eaſily + have been mended. Eſpecially ſince having careleſſly + laid by the looſe Papers, for ſeveral years after they were + written, when I came to put them together to diſpatch them to the Preſs, + I found ſome of thoſe I reckon'd upon, to be very unſeaſonably + wanting. And to make any great change in the order of the reſt, was + more than the Printers importunity, and that, of my own avocations (and + perhaps alſo conſiderabler ſolicitations) would permit. But + though ſome few preambles of the particular Experiments might have + (perchance) been ſpar'd, or ſhorten'd, if I had had all my + Papers under my View at once; Yet in the moſt of thoſe + Introductory paſſages, the Reader will (I hope) find hints, or + Advertiſements, as well as Tranſitions. If I ſometimes + ſeem to inſiſt long upon the circumſtances of a + Tryall, I hope I ſhall be eaſily excuſed by thoſe that + both know, how nice divers experiments of Colours are, and conſider + that I was not barely to</i> relate <i>them, but ſo as to teach a + young Gentleman to make them. And if I was not ſollicitous, to make a + nicer diviſion of the whole Treatiſe, than into three parts, + whereof the One contains ſome Conſiderations about Colours in + general. The Other exhibits a ſpecimen of an Account of particular + Colours, Exemplifi'd in Whiteneſs and Blackneſs. And the Third + promiſcuous Experiments about the remaining Colours (eſpecially + Red) in order to a Theory of them. If, I ſay, I contented my ſelf + with this eaſie Diviſion of my Diſcourſe, it was + perhaps becauſe I did not think it ſo neceſſary to be + Curious about the Method or Contrivance of a Treatiſe, wherein I do + not pretend to preſent my Reader with a compleat Fabrick, or ſo + much as Modell; but only to bring in Materials proper for the Building; + And if I did not well know how Ingenious the Curioſity and Civility + of Friends makes them, to perſwade Men by ſpecious allegations, + to gratifie their deſires; I ſhould have been made to believe by + perſons very well qualify'd to judge of matters of this nature, that + the following Experiments will not need the addition of accurate Method + and ſpeculative Notions to procure Acceptance for the Treatiſe + that contains them: For it hath been repreſented, That in moſt + of them, as the Novelty will make them ſurprizing, and the Quickneſs + of performance, keep them from being tedious; ſo the ſenſible + changes, that are effected by them, are ſo manifest, ſo great, + and ſo ſudden, that ſcarce any will be diſpleaſed + to ſee them, and thoſe that are any thing Curious will ſcarce + be able to ſee them, without finding themſelves excited, to make + Reflexions upon Them. But though with me, who love to meaſure Phyſical + things by their</i> uſe, <i>not their</i> ſtrangeneſs, <i>or</i> + prettineſs, <i>the partiality of others prevails not to make me over + value theſe, or look upon them in themſelves as other than + Trifles: Yet I confeſs, that ever ſince I did divers years ago + ſhew ſome of them to a Learned Company of</i> Virtuoſi: <i>ſo + many perſons of differing Conditions, and ev'n Sexes, have been + Curious to ſee them, and pleas'd not to Diſlike them, that I + cannot Deſpair, but that by complying with thoſe that urge the + Publication of them, I may both gratifie and excite the Curious, and lay + perhaps a Foundation whereon either others or my ſelf may in time + ſuperſtruct a ſubſtantial theory of Colours. And if</i> + Ariſtotle, <i>after his Maſter</i> Plato, <i>have rightly obſerv'd + Admiration to be the</i> Parent of Philoſophy, <i>the wonder, ſome + of theſe Trifles have been wont to produce in all ſorts of + Beholders, and the acceſs they have ſometimes gain'd ev'n to the + Cloſets of Ladies, ſeem to promiſe, that ſince the + ſubject is ſo pleaſing, that the Speculation appears as + Delightful! as Difficult, ſuch eaſie and recreative Experiments, + which require but little time, or charge, or trouble in the making, and + when made are ſenſible and ſurprizing enough, may + contribute more than others, (far more important but as much more + difficult) to recommend thoſe parts of Learning (Chymistry and Corpuſcular + Philoſophy) by which they have been produc'd, and to which they give + Teſtimony ev'n to ſuch kind of perſons, as value a pretty + Trick more than a true Notion, and would ſcarce admit Philoſophy, + if it approach'd them in another Dreſs: without the ſtrangeneſs + or endearments of pleaſantneſs to recommend it. I know that I do + but ill conſult my own Advantage in the conſenting to the + Publication of the following Treatiſe: For thoſe things, which, + whilſt men knew not how they were perform'd, appear'd ſo ſtrange, + will, when the way of making them, and the Grounds on which I devis'd + them, ſhall be Publick, quickly loſe all that their being</i> + Rarityes, <i>and their</i> being thought Myſteries, <i>contributed to + recommend them. But 'tis fitter for Mountebancks than Naturalis to deſire + to have their diſcoverys rather admir'd than underſtood, and for + my part I had much rather deſerve the thanks of the Ingenious, than + enjoy the Applauſe of the Ignorant. And if I can ſo farr + contribute to the diſcovery of the nature of Colours, as to help the + Curious to it, I ſhall have reach'd my End, and ſav'd my ſelf + ſome Labour which elſe I may chance be tempted to undergo in proſecuting + that ſubect, and Adding to this Treatiſe, which I therefore call + a</i> History, <i>becauſe it chiefly contains matters of fact, and + which Hiſtory the Title declares me to look upon but as</i> Begun: <i>Becauſe + though that above a hundred, not to ſay a hundred and fifty + Experiments, (ſome looſe, and others interwoven amongſt the + diſcourſes themſelves) may ſuffice to give a</i> + Beginning <i>to a Hiſtory not hitherto, that I know, begun, by any; + yet the ſubject is ſo fruitfull, and ſo worthy, that thoſe + that are Curious of theſe Matters will be farr more wanting to themſelves + than I can ſuſpect, if what I now publiſh prove any more + than a</i> Beginning. <i>For, as I hope my Endeavours may afford them + ſome aſſistance towards this work, ſo thoſe + Endeavours are much too Vnfiniſh'd to give them any diſcouragement, + as if there were little left for others to do towards the Hiſtory of + Colours.</i> + </p> + <p> + <i>For (firſt) I have been willing to leave unmention'd the</i> moſt + part <i>of thoſe Phænomena of Colours, that Nature preſents us + of her own accord, (that is, without being guided or over-ruld by man) + ſuch as the different Colours that ſeveral ſorts of Fruites + paſs through before they are perfectly ripe, and thoſe that + appear upon the fading of flowers and leaves, and the putrifaction (and + its ſeveral degrees) of fruits, &c. together with a thouſand + other obvious Instances of the changes of colours. Nor have I</i> much <i>medled + with thoſe familiar Phænomena wherein man is not an Idle ſpectator; + ſuch as the Greenneſs produc'd by ſalt in Beef much + powder'd, and the Redneſs produc'd in the ſhells of Lobſters + upon the boyling of thoſe fiſhes; For I was willing to leave the</i> + gathering <i>of</i> Obſervations <i>to thoſe that have not the + Opportunity to</i> make Experiments. <i>And for the ſame Reaſons, + among others, I did purpoſly omit the Lucriferous practiſe of + Trades-men about colours; as the ways of making Pigments, of Bleanching + wax, of dying Scarlet, &c. though to divers of them I be not a + stranger, and of ſome I have myſelf made Tryall.</i> + </p> + <p> + <i>Next; I did purpoſely paſs by divers Experiments of other + Writers that I had made Tryall of (and that not without regiſtring + ſome of their Events) unleſs I could ſome way or other + improve them, becauſe I wanted leaſure to inſert them, and + had thoughts of proſecuting the work once begun of laying together + thoſe I had examin'd by themſelves in caſe of my not being + prevented by others diligence. So that there remains not a little, among + the things that are already publiſhed, to imploy thoſe that have + a mind to exerciſe themſelves in repeating and examining them. + And I will not undertake, that</i> none <i>of the things deliver'd, ev'n + in this Treatiſe, though never ſo faithfully ſet down, may + not prove to be thus farr of this Sort, as to afford the Curious ſomewhat + to add about them. For I remember that I have ſomewhere in the Book + it ſelf acknowledged, that having written it by ſnatches, partly + in the Counntrey, and partly at unſeaſonable times of the year, + when the want of fit Inſtruments, and of a competent variety of + flowers, ſalts, Pigments, and other materials made me leave ſome + of the following Experiments, (eſpecialy thoſe about Emphatical + Colours) far more unfiniſh'd than they ſhould have been, if it + had been as eaſie for me to</i> ſupply <i>what was wanting to + compleat them, as to</i> diſcern<i>. Thirdly to avoyd diſcouraging + the young Gentleman I call Pyrophilus, whom the leſs Familiar, and + more Laborious operations of Chymistry would probably have frighted, I + purpoſely declin'd in what I writ to him, the ſetting down any + Number of ſuch Chymicall Experiments, as, by being very elaborate or + tedious, would either require much skill, or exerciſe his patience. + And yet that this ſort of Experiments is exceedingly Numerous, and + might more than a little inrich the Hiſtory of Colours, thoſe + that are vers'd in Chymical proceſſes, will, I preſume, eaſily + allow me.</i> + </p> + <p> + <i>And (Laſtly) for as much as I have occaſion more than once in + my ſeveral Writings to treat either porpoſely or incidentally of + matters relating to Colours; I did not, perhaps, conceive my ſelf + oblig'd, to deliver in one Treatiſe</i> all <i>that I would ſay + concerning that ſubject.</i> + </p> + <p> + <i>But to conclude, by ſumming up what I would ſay concerning + what I</i> have <i>and what I</i> have not <i>done, in the following + Papers; I ſhall not</i> (on the one ſide) <i>deny, that conſidering + that I pretended not to write an accurate Treatiſe of Colours, but an + Occaſional Eſſay to acquaint a private friend with what + then occurrd to me of the things I had thought or try'd concerning them; I + might preſume I did enough for once, if I did clearly and faithfully + ſet down, though not</i> all <i>the Experiments I could, yet at leaſt + ſuch a variety of them, that an attentive Reader that ſhall conſider + the Grounds on which they have been made, and the hints that are purpoſely + (though diſperſedly) couched in them, may eaſily</i> + compound <i>them, and otherwiſe</i> vary <i>them, ſo as very + much to increaſe their Number. And yet</i> (on the other ſide) + <i>I am ſo ſenſible both of how much I have, either out of + neceſſity or choice, left undone, and of the fruitfullneſs + of the ſubject I have begun to handle; that though I had performed + far more then 'tis like many Readers will judge I have, I ſhould yet + be very free to let them apply to my Attempts that of</i> Seneca, <i>where + having ſpoken of the Study of Natures Myſteries, and + Particularly of the Cauſe of Earth-Quakes, he ſubjoins.<a + name="LNtA_1" id="LNtA_1_"></a><a href="#LNt_1"><sup>1</sup></a></i> Nulla + res conſummata eſt dum incipit. Nec in hac tantum re omnium + maxima ac involutiſſimá, in quâ etiam cum multum actum erit, + omnis ætas, quod agat inveniet; ſed in omni alio Negotio, longè + ſemper à perfecto fuere Principia. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/012a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:100%;"><i>The Publiſher to the</i></span><br /> + <span style="font-size:100%; letter-spacing:10px">READER.</span><br /> + </h2> + <p> + <i>Friendly Reader,</i> + </p> + <p> + <img width="80" height="80" src="images/012b.png" + alt="Illuminated H in Here" />Ere is preſented to thy view one of the + Abſtruſeſt as well as the Gentileſt Subjects of + Natural Philoſophy, the <i>Experimentall Hiſtory of Colours</i>; + which though the Noble Author be pleaſed to think but <i>Begun</i>, + yet I muſt take leave to ſay, that I think it ſo well + begun, that the work is more than half diſpatcht. Concerning which I + cannot but give this advertiſement to the Reader, that I have heard + the Author expreſs himſelf, that it would not ſurpriſe + him, if it ſhould happen to be objected, that ſome of theſe + Experiments have been already publiſhed, partly by Chymiſts, and + partly by two or three very freſh Writers upon other Subjects. And + though the number of theſe Experiments be but very ſmall, and + though they be none of the conſiderableſt, yet it may on this + occaſion be further repreſented, that it is eaſie for our + Author to name ſeveral men, (of whoſe number I can truly name my + ſelf) who remember either their having ſeen him make, or their + having read, his Accounts of the Experiments delivered in the following + Tract ſeveral years ſince, and long before the publication of + the Books, wherein they are mentioned. Nay in divers paſſages + (where he could do it without any great inconvenience) he hath ſtruck + out Experiments, which he had tryed many years ago, becauſe he ſince + found them divulged by perſons from whom he had not the leaſt + hint of them; which yet is not touched, with deſign to reflect upon + any Ingenious Man, as if he were a Plagiary: For, though our Generous + Author were not reſerved enough in ſhowing his Experiments to + thoſe that expreſſed a Curioſity to ſee them + (amongſt whom a very Learned Man hath been pleaſed publickly to + acknowledge it ſeveral years ago<a name="LNtA_2" id="LNtA_2_"></a><a + href="#LNt_2"><sup>2</sup></a>; yet the ſame thing may be well enough + lighted on by perſons that know nothing of one another. And eſpecially + Chymical Laboratories may many times afford the ſame <i>Phænomenon</i> + about Colours to ſeveral perſons at the ſame or differing + times. And as for the few <i>Phænomena</i> mentioned in the ſame + Chymical writers, as well as in the following Treatiſe, our Author + hath given an account, why he did not decline rejecting them, in the + Anotations upon the 47<sup>th</sup> Experiment of the third part. Not here + to mention, what he elſewhere ſaith, to ſhew what uſe + may be Juſtifiably made of Experiments not of his own deviſing + by a writer of Natural Hiſtory, if, what he employes of others mens, + be well examined or verified by himſelf. + </p> + <p> + In the mean time, this Treatiſe is ſuch, that there needs no + other invitation to peruſe it, but that tis compoſed by one of + the Deepeſt & Moſt indefatigable ſearchers of Nature, + which, I think the World, as far as I know it, affords. For mine own part, + I feel a Secret Joy within me, to ſee ſuch beginings upon ſuch + <i>Themes</i>, it being demonſtratively true, <i>Mota facilius moveri</i>, + which cauſeth me to entertain ſtrong hopes, that this Illuſtrious + <i>Virtuoſo</i> and Reſtleſs Inquirer into Nature's Secrets + will not ſtop here, but go on and proſper in the Diſquiſition + or the other principal Colours, <i>Green, Red</i>, and <i>Yellow</i>. The + Reaſoning faculty ſet once afloat, will be carried on, and that + with eaſe, eſpecially, when the productions thereof meet, as + they do here, with ſo greedy an Entertainment at home and abroad. I + am confident, that the <b>ROYAL SOCIETY</b>, lately conſtituted by + his <b>MOST EXCELLENT MAJESTY</b> <i>for improving Natural knowledge</i>, + will Judge it their intereſt to exhort our Author to the proſecution + of this Argument, conſidering, how much it is their deſign and + buſineſs to accumulate a good ſtock of ſuch accurate + Obſervations and Experiments, as may afford them and their Offpring + genuine Matter to raiſe a Maſculine Philoſophy upon, + whereby the Mind of Man may be enobled with the Knowledge of ſolid + Truths, and the Life of Man benefited with ampler accommodations, than it + hath been hitherto. + </p> + <p> + Our Great Author, one of the Pillars of that Illuſtrious Corporation, + is conſtantly furniſhing large <i>Symbola</i>'s to this work, + and is now falln, as you ſee, upon ſo comprehenſive and + important a theme, as will, if inſiſted on and compleated, prove + one of the conſiderableſt peeces of that ſtructure. To + which, if he ſhall pleaſe to add his Treatiſe of <i>Heat</i> + and <i>Flame</i>, as he is ready to publiſh his Experimental Accounts + of <i>Cold</i>, I eſteem, the World will be obliged to Him for having + ſhewed them both the <i>Right</i> and <i>Left Hand</i> of Nature, and + the Operations thereof. + </p> + <p> + The conſidering Reader will by this very Treatiſe ſee + abundant cauſe to ſollicit the Author for more; ſure I am, + that of whatever of the Productions of his Ingeny comes into <i>Forein + parts</i> (where I am happy in the acquaintance of many intelligent + friends) is highly valued; And to my knowledge, there are thoſe among + the French, that have lately begun to learn Engliſh, on purpoſe + to enable themſelves to read his Books, being impatient of their + Traduction into Latin. If I durſt ſay all, I know of the Elogies + received by me from abroad concerning Him, I ſhould perhaps make this + Preamble too prolix, and certainly offend the modeſty of our Author. + </p> + <p> + Wherefore I ſhall leave this, and conclude with deſiring the + Reader, that if he meet with other faults beſides thoſe, that + the Errata take notice of (as I believe he may) he will pleaſe to conſider + both the weakneſs of the Authors eyes, for not reviewing, and the + manifold Avocations of the Publiſher for not doing his part; who + taketh his leave with inviting thoſe, that have alſo conſidered + this Nice ſubject experimentally, to follow the Example of our Noble + Author, and impart ſuch and the like performances to the now very + inquiſitive world. <i>Farewell.</i> + </p> + <p class="author"> + <i>H. O.</i> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/018.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:50%;">THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">CONTENTS.</span><br /> + </h2> + <hr /> + <h3> + CHAP. I. + </h3> + <p> + <i>The Author ſhews the Reaſon, first of his Writing on this + Subject</i> (<a href="#LPage_1">1</a>.) <i>Next of his preſent manner + of Handling it, and why he partly declines a Methodical way</i> (<a + href="#LPage_2">2</a>.) <i>and why he has partly made uſe of it in + the Hiſtory of</i> Whiteneſs <i>and</i> Blackneſs. (<a + href="#LPage_3">3</a>.) + </p> + <p> + Chap. 2. <i>Some general Conſiderations are premis'd, firſt of + the Inſignificancy of the Obſervaſion of Colours in many + Bodies</i> (<a href="#LPage_4">4</a>, <a href="#LPage_5">5</a>.) <i>and + the Importance of it in others</i> (<a href="#LPage_5">5</a>.) <i>as + particularly in the Tempering of Steel</i> (<a href="#LPage_6">6</a>, <a + href="#LPage_7">7</a>, <a href="#LPage_8">8</a>.) <i>The reaſon why + other particular Inſtances are in that place omitted</i> (<a + href="#LPage_9">9</a>) <i>A neceſſary diſtinction about + Colour premis'd</i> (<a href="#LPage_10">10</a>, <a href="#LPage_11">11</a>.) + <i>That Colour is not Inherent in the Object</i> (<a href="#LPage_11">11</a>.) + <i>prov'd firſt by the Phantaſms of Colours to</i> Dreaming <i>men, + and</i> Lunaticks; <i>Secondly by the ſenſation or apparition of + Light upon a Blow given the Eye or the Diſtemper of the Brain from + internal Vapours</i> (<a href="#LPage_12">12</a>.) <i>The Author recites a + particular Instance in himſelf; another that hapn'd to an Excellent + Perſon related to him</i> (<a href="#LPage_13">13</a>.) <i>and a + third told him by an Ingenious Phyſician</i> (<a href="#LPage_14">14</a>, + <a href="#LPage_15">15</a>.) <i>Thirdly, from the change of Colours made + by the Senſory Diſaffected</i> (<a href="#LPage_15">15</a>, <a + href="#LPage_16">16</a>.) <i>Some Inſtances of this are related by + the Author, obſerv'd in himſelf</i> (<a href="#LPage_16">16</a>, + <a href="#LPage_17">17</a>.) <i>others told him by a Lady of known + Veracity</i> (<a href="#LPage_18">18</a>.) <i>And others told him by a + very Eminent Man</i> (<a href="#LPage_19">19</a>.) <i>But the ſtrange + Inſtances afforded by ſuch as are Bit by the</i> Tarantula <i>are + omitted, as more properly deliver'd in another place</i>. (<a + href="#LPage_20">20</a>.) + </p> + <p> + Chap. 3. <i>That the Colour of Bodies depends chiefly on the diſpoſition + of the Superficial parts, and partly upon the Variety of the Texture of + the Object</i> (<a href="#LPage_21">21</a>.) <i>The former of theſe + are confirm'd by ſeveral Perſons</i> (<a href="#LPage_22">22</a>.) + <i>and two Inſtances, the firſt of the Steel mention'd before, + the ſecond of melted Lead</i> (<a href="#LPage_23">23</a>, <a + href="#LPage_24">24</a>.) <i>of which laſt ſeveral Obſervables + are noted</i> (<a href="#LPage_25">25</a>.) <i>A third Inſtance is + added of the Porouſneſs of the appearing ſmooth Surface of + Cork</i> (<a href="#LPage_26">26</a>, <a href="#LPage_27">27</a>.) <i>And + that the ſame kind of Porouſneſs may be alſo in the + other Colour'd Bodies; And of what kind of Figures, the Superficial + reflecting Particles of them may be</i> (<a href="#LPage_28">28</a>.) <i>and + of what Bulks, and cloſeneſs of Poſition</i> (<a + href="#LPage_29">29</a>.) <i>How much theſe may conduce to the + Generation of Colour inſtanc'd in the Whiteneſs of Froth, and in + the mixtures of Dry colour'd Powders</i> (<a href="#LPage_30">30</a>.) <i>A + further explication of the Variety that may be in the Superficial parts of + Colour'd Bodies, that may cauſe that Effect, by an example drawn from + the Surface of the Earth</i> (<a href="#LPage_31">31</a>.) <i>An Apology + for that groſs Compariſon</i> (<a href="#LPage_32">32</a>.) <i>That + the appearances of the Superficial aſperities may be Varied from the + poſition of the Eye, and ſeveral Inſtances given of ſuch + appearances</i> (<a href="#LPage_33">33</a>, <a href="#LPage_34">34</a>, + <a href="#LPage_35">35</a>.) <i>That the appearance of the Superficial + particles may be Varied alſo by their Motion, confirm'd by an Inſtance + of the ſmoaking Liquor</i> (<a href="#LPage_35">35</a>.) <i>eſpecially + if the Superficial parts be of ſuch a Nature as to appear divers in + ſeveral Poſtures, explain'd by the variety of Colours exhibited + by the ſhaken Leaves of ſome Plants</i> (<a href="#LPage_36">36</a>.) + <i>and by changeable Taffities</i> (<a href="#LPage_37">37</a>, <a + href="#LPage_38">38</a>, <a href="#LPage_39">39</a>.) <i>The Authors wiſh + that the Variety of Colours in Mother of Pearl were examin'd with a</i> + Microſcope (<a href="#LPage_40">40</a>.) <i>And his Conjectures, that + poſſibly good</i> Microſcopes <i>might diſcover thoſe + Superficial inequalities to be Real, which we now only imagine with his + reaſons drawn partly from the Diſcoveries of the</i> Teleſcope, + <i>and</i> Microſcope (<a href="#LPage_41">41</a>.) <i>And partly alſo + from the Prodigiouſly ſtrange example of a Blind man that could + feel Colours</i> (<a href="#LPage_42">42</a>.) <i>whoſe Hiſtory + is Related</i> (<a href="#LPage_43">43</a>, <a href="#LPage_44">44</a>, <a + href="#LPage_45">45</a>.) <i>The Authors conjecture and thoughts of it</i> + (<a href="#LPage_46">46</a>, <a href="#LPage_47">47</a>, <a + href="#LPage_48">48</a>, <a href="#LPage_49">49</a>.) <i>and ſeveral + Concluſions and Corollaries drawn from it about the Nature of Blackneſs + and Black Bodies</i> (<a href="#LPage_50">50</a>, <a href="#LPage_51">51</a>, + <a href="#LPage_52">52</a>.) <i>and about the Aſperities of ſeveral + other Colour'd Bodies</i> (<a href="#LPage_53">53</a>.) <i>And from theſe, + and ſome premis'd Conſiderations, are propos'd ſome + Conjectures; That the reaſon of the ſeveral Phænomena of + Colours, afterwards to be met with, depends upon the Diſpoſition + of the Seen parts of the Object</i> (<a href="#LPage_54">54</a>.) <i>That + Liquors may alter the Colours of each other, and of other Bodies, first by + their Inſinuating themſelves into the Pores, and filling them, + whence the Aſperity of the Surface of a Body becomes alter'd, + explicated with ſome Inſtances</i> (<a href="#LPage_55">55</a>, + <a href="#LPage_56">56</a>.) <i>Next by removing thoſe Bodies, which + before hindred the appearance of the Genuine Colour, confirm'd by ſeveral + examples</i> (<a href="#LPage_57">57</a>) <i>Thirdly, by making a Fiſſure + or Separation either in the Contiguous or Continued Particles of a Body</i> + (<a href="#LPage_58">58</a>.) <i>Fourthly, by a Union or Conjunction of + the formerly ſeparated Particles; Illuſtrated with divers Inſtances + of precipitated Bodies</i> (<a href="#LPage_59">59</a>.) <i>Fifthly, by Diſlocating + the parts, and putting them both into other Orders and Poſtures, + which is Illuſtrated with Inſtances</i> (<a href="#LPage_60">60</a>, + <a href="#LPage_61">61</a>.) <i>Sixthly, by Motion, which is explain'd</i> + (<a href="#LPage_62">62</a>.) <i>And laſtly, and chiefly, by the + Union of the Saline Bodies, with the Superficial parts of another Body, + whereby both their Bigneſs and Shape muſt neceſſarily + be alter'd</i> (<a href="#LPage_63">63</a>, <a href="#LPage_64">64</a>.) + <i>Explain'd by Experiments</i> (<a href="#LPage_65">65</a>, <a + href="#LPage_66">66</a>.) <i>That the Colour of Bodies may be Chang'd by + the concurrence of two or more of theſe ways</i> (<a href="#LPage_67">67</a>.) + <i>And beſides all theſe, Eight Reflective cauſes of + Colours, there may be in Tranſparent Bodies ſeveral Refractive</i> + (<a href="#LPage_68">68</a>, <a href="#LPage_69">69</a>) <i>Why the Author + thinks the Nature of Colours deſerves yet a further Inquiry</i> (<a + href="#LPage_69">69</a>.) <i>Firſt for that the little Motes of Dust + exhibited very lovely Colours in a darkned Room, whilſt in a + convenient poſture to the Eye, which in other Poſtures and + Lights they did not</i> (<a href="#LPage_70">70</a>.) <i>And that though + the ſmaller Parts of ſome Colour'd Bodies are Tranſparent, + yet of others they are not, ſo that the firſt Doubt's, whether + the Superficial parts create thoſe Colours, and the ſecond, + whether there be any Refraction at all in the later</i> (<a + href="#LPage_71">71</a>, <a href="#LPage_72">72</a>, <a href="#LPage_73">73</a>.) + <i>A famous Controverſie among Philoſophers, about the Nature of + Colour decided</i>. (<a href="#LPage_74">74</a>. <a href="#LPage_75">75</a>.) + </p> + <p> + Chap. 4. <i>The controverſie ſtated about Real and Emphatical + Colours</i> (<a href="#LPage_75">75</a>, <a href="#LPage_76">76</a>.) <i>That + the great Diſparity between them ſeems to be, partly their + Duration in the ſame ſtate, and partly, that Genuine Colours are + produc'd in Opacous Bodies by Reflection, and Emphatical in Tranſparent + by Refraction</i> (<a href="#LPage_78">78</a>.) <i>but that this is not to + be taken in too large a Senſe, the Cautionary inſtance of Froth + is alleged and inſiſted on</i> (<a href="#LPage_78">78</a>, <a + href="#LPage_79">79</a>.) <i>That the Duration is not a ſufficient + Characteristick, exemplify'd by the duration of Froth, and other + Emphatical Colours, and the ſuddain fading of Flowers, and other + Bodies of Real ones</i> (<a href="#LPage_80">80</a>.) <i>That the poſition + of the Eye is not neceſſary to the diſcerning Emphatical + Colours, ſhew'd by the ſeeing white Froth, or an Iris caſt + on the Wall by a Priſm, in what place of the Room ſoever the Eye + be</i> (<a href="#LPage_81">81</a>.) <i>which proceeds from the ſpecular + Reflection of the Wall</i> (<a href="#LPage_82">82</a>.) <i>that + Emphatical Colours may be Compounded, and that the preſent Diſcourſe + is not much concern'd, whether there be, or be not made a diſtinction + between Real and Emphatical Colours</i>. (<a href="#LPage_83">83</a>.) + </p> + <p> + Chap. 5. <i>Six Hypotheſes about Colour recited</i> (<a + href="#LPage_84">84</a>, <a href="#LPage_85">85</a>) <i>Why the Author + cannot more fully Speak of any of theſe</i> (<a href="#LPage_86">86</a>.) + <i>nor Acquieſce in them</i> (<a href="#LPage_87">87</a>, <a + href="#LPage_88">88</a>.) <i>What</i> Pyrophilus <i>is to expect in this + Treatiſe</i> (<a href="#LPage_88">88</a>, <a href="#LPage_89">89</a>.) + <i>What Hypotheſis of Light and Colour the Author most inclines too</i> + (<a href="#LPage_90">90</a>.) <i>Why he thinks neither that nor any other + ſufficient; and what his Difficulties are, that make him decline all + Hypotheſes, and to think it very difficult to ſtick to any.</i> + (<a href="#LPage_91">91</a>, <a href="#LPage_92">92</a>.) + </p> + <hr /> + <h2> + Part the Second. + </h2> + <p class="center"> + <i>Of the Nature of Whiteneſs and Blackneſs.</i> + </p> + <h3> + CHAP. I. + </h3> + <p> + <i>The reaſon why the Author choſe the Explication of Whiteneſs + and Blackneſs</i> (<a href="#LPage_93">93</a>.) <i>Wherein</i> + Democritus <i>thought amiſs of theſe</i> (<a href="#LPage_94">94</a>.) + Gaſſendus <i>his Opinion about them</i> (<a href="#LPage_95">95</a>.) + <i>What the Author approves, and a more full Explication of White, makinig + it a Multiplicity of Light or Reflections</i> (<a href="#LPage_96">96</a>, + <a href="#LPage_97">97</a>.) <i>Confirm'd first by the Whiteneſs of + the</i> Meridian <i>Sun, obſerv'd in Water</i> (<a href="#LPage_98">98</a>.) + <i>and of a piece of Iron glowing Hot</i> (<a href="#LPage_99">99</a>.) <i>Secondly, + by the Offenſiveneſs of Snow to the Travellers eyes, confirm'd + by an example of a Perſon that has Travell'd much in Ruſſia</i> + (<a href="#LPage_100">100</a>.) <i>and by an Obſervation out of</i> + Olaus Magnus (<a href="#LPage_100">100</a>.) <i>and that the Snow does + inlighten and clear the Air in the Night, confirm'd by the Moſco Phyſician, + and Captain</i> James (<a href="#LPage_101">101</a>.) <i>But that Snow has + no inherent Light, prov'd by Experience</i> (<a href="#LPage_102">102</a>.) + <i>Thirdly, by the great ſtore of Reflections, from white Bodies obſerv'd + in a darkned Room, and by their unaptneſs to be Kindled by a + Burning-glaſs</i> (<a href="#LPage_103">103</a>.) <i>Fourthly, the + Specularneſs of White Bodies is confirm'd by the Reflections in a + dark Room from other Bodies</i> (<a href="#LPage_104">104</a>.) <i>and by + the appearance of a River, which both to the Eye and in a darkned Room + appear'd White</i> (<a href="#LPage_105">105</a>, <a href="#LPage_106">106</a>.) + <i>Fifthly, by the Whiteneſs of diſtill'd</i> Mercury, <i>and + that of the</i> Galaxie (<a href="#LPage_107">107</a>, <a href="#LPage_108">108</a>.) + <i>and by the Whiteneſs of Froth, rais'd from whites of Eggs beaten; + that this Whiteneſs comes not from the Air, ſhew'd by + Experiments</i> (<a href="#LPage_109">109</a>, <a href="#LPage_110">110</a>.) + <i>where occaſionally the Whiteneſs of Diſtill'd Oyls, Hot + water, &c. are ſhew'd</i> (<a href="#LPage_111">111</a>.) <i>That + it ſeems not neceſſary the Reflecting Surfaces ſhould + be Sphærical, confirm'd by Experiments</i> (<a href="#LPage_112">112</a>, + <a href="#LPage_113">113</a>.) <i>Sixthly, by the Whiteneſs of the + Powders of tranſparent Bodies</i> (<a href="#LPage_114">114</a>.) <i>Seventhly, + by the Experiment of Whitening and Burniſhing Silver.</i> (<a + href="#LPage_115">115</a>, <a href="#LPage_116">116</a>.) + </p> + <p> + Chap. 2. <i>A Recital of ſome Opinions about Blackneſs, and + which the Author inclines to</i> (<a href="#LPage_117">117</a>.) <i>which + he further inſists on and explicates</i> (<a href="#LPage_118">118</a>, + <a href="#LPage_119">119</a>.) <i>and ſhews for what reaſons he + imbrac'd that Hypotheſis</i> (<a href="#LPage_120">120</a>.) <i>Firſt, + from the contrary Nature of Whiteneſs and Blackneſs, White + reflecting moſt Beams outwards, Black ſhould reflect moſt + inward</i> (<a href="#LPage_120">120</a>.) <i>Next, from the Black + appearance of all Bodies, when Shadow'd; And the manner how this paucity + of Reflection outwards is caus'd, is further explicated, by ſhewing + that the Superficial parts may be Conical and Pyramical</i> (<a + href="#LPage_121">121</a>.) <i>This and other Conſiderations formerly + deliver'd, Illuſtrated by Experiments with black and white Marble</i> + (<a href="#LPage_122">122</a>, <a href="#LPage_123">123</a>.) <i>Thirdly, + from the Black appearance of Holes in white Linnen, and from the + appearance of Velvet ſtroak'd ſeveral ways, and from an Obſervation + of Carrots</i> (<a href="#LPage_124">124</a>, <a href="#LPage_125">125</a>.) + <i>Fourthly, from the ſmall Reflection from Black in a darkned Room</i> + (<a href="#LPage_125">125</a>, <a href="#LPage_126">126</a>.) <i>Fifthly, + from the Experiment of a Checker'd Tile expos'd to the Sun-beams</i> (<a + href="#LPage_127">127</a>.) <i>which is to be preferr'd before a Similar + Experiment try'd in</i> Italy, <i>with black and white Marble</i> (<a + href="#LPage_128">128</a>.) <i>Some other congruous Obſervations</i> + (<a href="#LPage_129">129</a>.) <i>Sixthly, from the Roaſting black'd + Eggs in the Sun</i> (<a href="#LPage_130">130</a>.) <i>Seventhly, by the + Obſervation of the Blind man lately mention'd, and of another + mention'd by</i> Bartholine (<a href="#LPage_130">130</a>.) <i>That + notwithſtanding all theſe Reaſons, the Author is not abſolutely + Poſitive, but remains yet a Seeker after the true Nature of Whiteneſs + and Blackneſs.</i> (<a href="#LPage_131">131</a>, <a href="#LPage_132">132</a>.) + </p> + <p> + Experiments <i>in Conſort, touching</i> Whiteneſs <i>and</i> + Blackneſs. + </p> + <p> + <i>The firſt</i> Experiment, <i>with a Solution of Sublimate, made + White with Spirit of Urine</i>, &c. (<a href="#LPage_133">133</a>, <a + href="#LPage_134">134</a>.) + </p> + <p> + <i>The ſecond</i> Experiment, <i>with an Infuſion of Galls, made + Black with Vitriol</i>, &c. (<a href="#LPage_135">135</a>, <a + href="#LPage_136">136</a>.) <i>further Diſcours'd of</i> (<a + href="#LPage_137">137</a>.) + </p> + <p> + <i>The third</i> Experiment, <i>of the Blacking of Hartſhorn, and + Ivory, and Tartar, and by a further Calcination making them White</i> (<a + href="#LPage_138">138</a>, <a href="#LPage_139">139</a>.) + </p> + <p> + <i>The fourth</i> Experiment, <i>limiting the</i> Chymiſt's <i>principle</i>, + Aduſta nigra ſed peruſta alba, <i>by ſeveral Inſtances + of Calcin'd Alabaſter, Lead, Antimony, Vitriol, and by the Teſtimony + of</i> Bellonius, <i>about the white Charcoles of</i> Oxy-cædar, <i>and by + that of</i> Camphire. (<a href="#LPage_140">140</a>, <a href="#LPage_141">141</a>, + <a href="#LPage_142">142</a>.) <i>That which follows about Inks was miſplac'd + by an Errour of the Printer, for it belongs to what has been formerly + ſaid of Galls</i> (<a href="#LPage_142">142</a>, <a href="#LPage_143">143</a>.) + </p> + <p> + <i>The fifth</i> Experiment, <i>of the black Smoak of Camphire</i> (<a + href="#LPage_144">144</a>.) + </p> + <p> + <i>The ſixth</i> Experiment, <i>of a black</i> Caput Mortuum, <i>of + Oyl of Vitriol, with Oyl of Worm-word, and alſo with Oyl of + Winter-Savory</i> (<a href="#LPage_145">145</a>.) + </p> + <p> + <i>The ſeventh</i> Experiment, <i>of whitening Wax</i> (<a + href="#LPage_146">146</a>.) + </p> + <p> + <i>The eighth</i> Experiment, <i>with Tin-glaſs, and Sublimate</i> (<a + href="#LPage_147">147</a>, <a href="#LPage_148">148</a>.) + </p> + <p> + <i>The ninth</i> Experiment, <i>of a Black powder of Gold in the bottom of</i> + Aqua-fortis, <i>and of the Blacking of Refin'd Gold and Silver</i> (<a + href="#LPage_148">148</a>, <a href="#LPage_149">149</a>.) + </p> + <p> + <i>The tenth</i> Experiment, <i>of the ſtaining Hair, Skin, Ivory</i>, + &c. <i>Black, with Cryſtals of Silver</i> (<a href="#LPage_150">150</a>, + <a href="#LPage_151">151</a>.) + </p> + <p> + <i>The eleventh</i> Experiment, <i>about the Blackneſs of the Skin, + and Hair of</i> Negroes, <i>and Inhabitants of Hot Climates. Several + Objections are made, and the whole Matter more fully diſcours'd and + ſtated from ſeveral notable Hiſtories and Obſervations</i> + (from the <a href="#LPage_151">151</a> to the <a href="#LPage_167">167</a>.) + </p> + <p> + <i>The twelfth</i> Experiment, <i>of the white Powders, afforded by + Precipitating ſeveral Bodies, as Crabs Eyes, Minium, Coral, Silver, + Lead, Tin, Quick-ſilver, Tin-glaſs, Antimony, Benzoin, and Reſinous + Gumms out of Spirit of Wine</i>, &c. <i>but this is not Univerſal, + ſince other Bodies, as Gold, Antimony, Quick-ſilver</i>, &c. + <i>may be Precipitated of other Colours</i> (<a href="#LPage_168">168</a>, + <a href="#LPage_169">169</a>, <a href="#LPage_170">170</a>.) + </p> + <p> + <i>The thirteenth</i> Experiment, <i>of Changing the Blackneſs of + ſome Bodies into other Colours</i> (<a href="#LPage_171">171</a>, <a + href="#LPage_172">172</a>.) <i>and of Whitening what would be Minium, and + Copper, with Tin, and of Copper with Arſnick, which with Coppilling + again Vaniſhes; of covering the Colour of that of</i> 1/3 <i>of Gold + with</i> 2/3 <i>of Silver melted in a Maſs together</i> (<a + href="#LPage_173">173</a>, <a href="#LPage_174">174</a>) + </p> + <p> + <i>The fourteenth</i> Experiment, <i>of turning the black Body of Horn + into a White immediately with Scraping, without changing the Subſtantial + form, or without the Intervention of Salt, Sulphur, or Mercury</i> (<a + href="#LPage_176">176</a>.) + </p> + <p> + <i>The fifteenth</i> Experiment, <i>contains ſeveral Inſtances + againſt the Opinion of the</i> Chymiſts <i>that Sulphur</i> Aduſt + <i>is the cauſe of Blackneſs, and the whole Matter is fully diſcuſs'd + and ſtated</i> (from <a href="#LPage_176">176</a> to <a + href="#LPage_184">184</a>) + </p> + <hr /> + <h2> + Part the Third. + </h2> + <p class="center"> + <i>Concerning Promiſcuous Experiments about Colours.</i> + </p> + <h3> + Experiment the Firſt. + </h3> + <p> + <i>IN confirmation of a former Conjecture about the Generation of Colours + from diverſity of Reflections are ſet down ſeveral Obſervations + made in a Darkned room</i> (<a href="#LPage_186">186</a>, <a + href="#LPage_187">187</a>.) + </p> + <p> + Experiment <i>the ſecond, That white Linnen ſeem'd Ting'd with + the Red of Silk plac'd near it in a light Room</i> (<a href="#LPage_188">188</a>,<a + href="#LPage_189">189</a>.) + </p> + <p> + Experiment <i>the third, Of the Trajection of Light through Colour'd + Papers</i> (<a href="#LPage_189">189</a>, <a href="#LPage_190">190</a>.) + </p> + <p> + Experiment <i>the fourth, Obſervations of a Priſm in a dark Room</i> + (<a href="#LPage_191">191</a>, <a href="#LPage_192">192</a>.) + </p> + <p> + Experiment <i>the fifth, Of the Refracting and Reflecting Priſmatical + Colours in a light Room</i> (<a href="#LPage_193">193</a>.) + </p> + <p> + Experiment <i>the ſixth, On the Vaniſhing of the</i> Iris <i>of + the Priſm, upon the acceſs of a greater adventitious Light</i> (<a + href="#LPage_194">194</a>.) + </p> + <p> + Experiment <i>the ſeventh, Of the appearances of the ſame + Colour'd Papers by Candle-light</i> (<a href="#LPage_195">195</a>, <a + href="#LPage_196">196</a>). + </p> + <p> + Experiment <i>the eighth, Of the Yellowneſs of the Flame of a Candle</i> + (<a href="#LPage_197">197</a>). + </p> + <p> + Experiment <i>the ninth, Of the Greeniſh Blew tranſparency of + Leaf Gold</i> (<a href="#LPage_198">198</a>). + </p> + <p> + Experiment <i>the tenth, Of the curious Tinctures afforded by</i> Lignum + Nephriticum (from <a href="#LPage_199">199</a> to <a href="#LPage_203">203</a>). + <i>Several trials for the Inveſtigation of the Nature of it</i> (from + <a href="#LPage_204">204</a> to <a href="#LPage_206">206</a>.) Kircher's + <i>relation of this Wood ſet down, and examin'd</i> (from <a + href="#LPage_206">206</a> to <a href="#LPage_212">212</a>). <i>A Corollary + on this tenth</i> Experiment, <i>ſhewing how it may be applicable for + the Diſcovering, whether any Salt be of an Acid, or a Sulphureous, + and Alcalizate Nature</i> (from <a href="#LPage_213">213</a> to <a + href="#LPage_216">216</a>). + </p> + <p> + <i>The eleventh</i> Experiment, <i>Of certain pieces of Glaſs that + afforded this Variety of Colours; And of the way of ſo Tinging any + Plate of Glaſs with Silver</i> (from <a href="#LPage_216">216</a> to + <a href="#LPage_219">219</a>). + </p> + <p> + <i>The twelfth</i> Experiment, <i>Of the Mixing and Tempering of Painters + Pigments</i> (<a href="#LPage_219">219</a>, <a href="#LPage_220">220</a>, + <a href="#LPage_221">221</a>). + </p> + <p> + <i>The thirteenth</i> Experiment, <i>Of compounding ſeveral Colours + by Trajecting the Sun-beams through Ting'd Glaſſes</i> (from <a + href="#LPage_221">221</a> to <a href="#LPage_224">224</a>). + </p> + <p> + <i>The fourteenth</i> Experiment, <i>Of the Compounding of Real and Phantaſtical + Colours, and the Reſults</i> (<a href="#LPage_224">224</a>, <a + href="#LPage_225">225</a>, <a href="#LPage_226">226</a>.) <i>as alſo + the ſame of Phantaſtical Colours</i> (<a href="#LPage_226">226</a>, + <a href="#LPage_227">227</a>.) + </p> + <p> + <i>The fifteenth</i> Experiment, <i>Of Varying the Trajected</i> Iris <i>by + a Colour'd Priſm</i> (<a href="#LPage_228">228</a>, <a + href="#LPage_229">229</a>.) + </p> + <p> + <i>The ſixteenth</i> Experiment, <i>Of the Red fumes of Spirit of</i> + Nitre, <i>and, the reſembling Redneſs of the Horizontal + Sun-beams</i> (<a href="#LPage_230">230</a>, <a href="#LPage_231">231</a>.) + </p> + <p> + <i>The ſeventeenth</i> Experiment, <i>Of making a Green by nine Kinds + of Compoſitions</i> (from <a href="#LPage_231">231</a> to <a + href="#LPage_236">236</a>.) <i>And ſome Deductions from them againſt + the neceſſity of recurring to Subſtantial forms and Hypoſtatical + principles for the production of Colours</i> (from <a href="#LPage_237">237</a> + to <a href="#LPage_240">240</a>.) + </p> + <p> + <i>The eighteenth</i> Experiment, <i>Of ſeveral Compoſitions of + Blew and Yellow which produce not a Green, and of the production of a + Green by other Colours</i> (<a href="#LPage_241">241</a>, <a + href="#LPage_242">242</a>.) + </p> + <p> + <i>The nineteenth</i> Experiment, <i>contains ſeveral inſtances + of producing Colours, without the alteration of any Hypoſtatical + principle, by the Priſm, Bubbles, and Feathers</i> ( from <a + href="#LPage_242">242</a> to <a href="#LPage_245">245</a>.) + </p> + <p> + <i>The twentieth</i> Experiment <i>Of turning the Blew of Violets into a + Red by Acid Salts, and to a Green by Alcalizate (<a href="#LPage_245">245</a>, + <a href="#LPage_246">246</a>.) and the uſe of it for Inveſtigating + the Nature of Salts</i> (<a href="#LPage_247">247</a>, <a href="#LPage_248">248</a>.) + </p> + <p> + <i>The one and twentieth</i> Experiment, <i>of the ſame Changes + effected by the ſame means on the Blew Tinctures of Corn-flowers</i> + (<a href="#LPage_249">249</a>, <a href="#LPage_250">250</a>.) <i>And + ſome Reſtrictions to ſhew it not to be ſo general a + propriety as one might imagine</i> (<a href="#LPage_251">251</a>.) + </p> + <p> + <i>The twenty ſecond</i> Experiment, <i>of turning a Solution of + Verdigreaſe into a Blew, with Alcalizate and Urinous Salts</i> (<a + href="#LPage_252">252</a>, <a href="#LPage_253">253</a>, <a + href="#LPage_254">254</a>.) + </p> + <p> + <i>The twenty third</i> Experiment, <i>of taking away the Colour of Roſes + with the Steams of Sulphur, and heightning them with the Steams Condens'd + into Oyl of Sulphur</i> per Campanam (<a href="#LPage_254">254</a>, <a + href="#LPage_255">255</a>.) + </p> + <p> + <i>The twenty fourth</i> Experiment, <i>of Tinging a great quantity of + Liquor with a very little Ting'd Subſtance, Inſtanced in</i> + Cochineel (from <a href="#LPage_255">255</a> to <a href="#LPage_257">257</a>.) + </p> + <p> + <i>The twenty fifth</i> Experiment, <i>of the more general uſe of + Alcalizate and Sulphureous Salts in the Tinctures of Vegetables, further + Inſtanced in the Tincture of Privet Berries, and of the Flowers of Meſereon + and Peaſe</i> (from <a href="#LPage_257">257</a> to <a + href="#LPage_259">259</a>.) <i>An</i> Annotation, <i>ſhewing that of + the three Hypoſtatical principles, Salt according to</i> Paracelſus + <i>is the moſt active about Colours</i> (from <a href="#LPage_259">259</a> + to <a href="#LPage_261">261</a>.) <i>Some things Precurſory premis'd + to three ſeveral Inſtances next following, againſt the + fore-mention'd Operations of Salts</i> (<a href="#LPage_261">261</a>, <a + href="#LPage_262">262</a>.) + </p> + <p> + <i>The twenty ſixth</i> Experiment, <i>containing Trials with Acid + and Sulphureous Salts on the Red Tinctures of Clove-july-flowers, + Buckthorn Berries, Red-Roſes, Braſil</i>, &c. (<a + href="#LPage_262">262</a>, <a href="#LPage_263">263</a>.) + </p> + <p> + <i>The twenty ſeventh</i> Experiment, <i>of the changes of the Colour + of Jaſmin flowers, and Snow drops, by Alcalizate and Sulphureous + Salts</i> (<a href="#LPage_263">263</a>, <a href="#LPage_264">264</a>.) + </p> + <p> + <i>The twenty eighth</i> Experiment, <i>of other differing Effects on + Mary-golds, Prim-roſes, and freſh Madder</i> (<a + href="#LPage_265">265</a>.) <i>with an Admonition, that theſe Salts + may have differing Effects in the changing of the tinctures of divers + other Vegetables</i> (<a href="#LPage_266">266</a>, <a href="#LPage_267">267</a>.) + </p> + <p> + <i>The twenty ninth</i> Experiment, <i>of the differing Effects of theſe + Salts on Ripe and Unripe Juices, inſtanced in Black-berries, and the + Juices of Roſes</i> (from <a href="#LPage_267">267</a> to <a + href="#LPage_270">270</a>.) <i>Two reaſons, why the Author added this + twenty ninth</i> Experiment, <i>the laſt of which is confirm'd by an + Inſtance of Mr.</i> Parkinſon, <i>conſonant to the Confeſſion + of the Makers of ſuch Colours</i> (<a href="#LPage_272">272</a>.) + </p> + <p> + <i>The thirtieth</i> Experiment, <i>of ſeveral changes in Colours by + Digeſtion, exemplify'd by an</i> Amalgam <i>of</i> <img + src="images/gold.png" class="noborder" width="16" height="18" alt="Gold" /> + <i>and</i> <img src="images/mercury.png" class="noborder" width="16" + height="18" alt="Mercury" /> <i>and by Spirit of Harts-horn. And (to ſuch + as believe it) by the changes of the</i> Elixir. + </p> + <p> + <i>The thirty firſt</i> Experiment, <i>ſhewing that moſt + Tinctures drawn by Digeſtion Incline to a Red, inſtanc'd in</i> + Jalap, Guaicum, <i>Amber, Benzoin, Sulphur, Antimony</i>, &c. (<a + href="#LPage_276">276</a>, <a href="#LPage_277">277</a>.) + </p> + <p> + <i>The thirty ſecond</i> Experiment, <i>That ſome Reds with + Diluting turn Yellow, others not, exemplify'd by the Tincture of</i> + Cochineel, <i>and by Balſam of</i> Sulphur, <i>Tinctures of</i> + Amber, &c. (<a href="#LPage_277">277</a>, <a href="#LPage_278">278</a>, + <a href="#LPage_279">279</a>.) + </p> + <p> + <i>The thirty third</i> Experiment, <i>of a Red Tincture of</i> Saccarum + <img src="images/lead.png" class="noborder" width="16" height="20" + alt="Saturni" /> <i>and Oyl of</i> Turpentine <i>made by Digeſtion</i> + (<a href="#LPage_279">279</a>.) + </p> + <p> + <i>The thirty fourth</i> Experiment, <i>of drawing a Volatile red Tincture + of Mercury</i>, <i>whoſe Steams were white, but it would Tinge the + Skin black </i> (<a href="#LPage_279">279</a>, <a href="#LPage_280">280</a>.) + </p> + <p> + <i>The thirty fifth</i> Experiment, <i>of a ſuddain way of making a + Blood red Colour with Oyl of</i> Vitriol, <i>and Oyl of</i> Anniſeeds, + <i>two tranſparent Liquors </i> (<a href="#LPage_280">280</a>, <a + href="#LPage_281">281</a>.) + </p> + <p> + <i>The thirty ſixth</i> Experiment, <i>of the Degenerating of ſeveral + Colours exemplify'd in the laſt mention'd Blood red, and by Mr.</i> + Parkinſons <i>relation of</i> Turnſol, <i>by ſome Trials + with the Juice of Buck-thorn Berries, and other Vegetables, to which + ſeveral notable Conſiderations and Advertiſements back'd + with</i> Experiments <i>are adjoyn'd</i> (from <a href="#LPage_281">281</a> + to <a href="#LPage_288">288</a>.) + </p> + <p> + <i>The thirty ſeventh</i> Experiment, <i>Of Varying the Colour of the + Tinctures of</i> Cochineel, <i>Red-cherries, and Braſil, with Acid + and Sulphureous Salts, and divers Conſiderations thereon</i> (from <a + href="#LPage_288">288</a> to <a href="#LPage_290">290</a>.) + </p> + <p> + <i>The thirty eighth</i> Experiment, <i>About the Red fumes of ſome, + and White of other diſtill'd Bodies, and of their Coalition for the + most part into a tranſparent Liquor</i> (<a href="#LPage_290">290</a>, + <a href="#LPage_291">291</a>.) <i>And of the various Colours of dry + Sublimations, exemplify'd with ſeveral</i> Experiments (<a + href="#LPage_292">292</a>, <a href="#LPage_293">293</a>, <a + href="#LPage_294">294</a>.) + </p> + <p> + <i>The thirty ninth</i> Experiment, <i>Of Varying the Decoction of</i> + Balauſtiums <i>with Acid and Urinous Salts</i> (<a href="#LPage_294">294</a>, + <a href="#LPage_295">295</a>.) <i>Some</i> Annotations <i>wherein two</i> + Experiments <i>of</i> Gaſſendus <i>are Related, Examined, and + Improv'd</i> (from <a href="#LPage_295">295</a> to <a href="#LPage_302">302</a>.) + </p> + <p> + <i>The fortieth</i> Experiment, <i>Of the no leſs Strange than Pleaſant + changes made with a Solution of Sublimate</i> (from <a href="#LPage_301">301</a> + to <a href="#LPage_306">306</a>.) <i>The difference between a Chymical axd + Philoſophical Solution of a</i> Phænomenon (<a href="#LPage_307">307</a>, + <a href="#LPage_308">308</a>.) <i>The Authors Chymical Explication of the</i> + Phænomena, <i>confirm d by ſeveral</i> Experiments <i>made on</i> + Mercury, <i>with ſeveral Saline Liquors</i> (from <a href="#LPage_308">308</a> + to <a href="#LPage_310">310</a>.) <i>An Improvement of the fortieth</i> + Experiment, <i>by a freſh Decoction of</i> Antimony <i>in a</i> + Lixivium (<a href="#LPage_311">311</a>, <a href="#LPage_312">312</a>, <a + href="#LPage_313">313</a>.) <i>Reflections on the tenth, twentieth, and + fortieth</i> Experiments, <i>compar'd together, ſhewing a way with + this Tincture of Sublimate to diſtinguiſh whether any Saline + Body to be examin'd be of a Urinous or Alcalizate Nature</i> (from <a + href="#LPage_314">314</a> to <a href="#LPage_317">317</a>.) <i>The + Examination of Spirit of</i> Sal-armoniack, <i>and Spirit of</i> Oak <i>by + theſe Principles</i> (from <a href="#LPage_316">316</a> to <a + href="#LPage_319">319</a>.) <i>That the Author knows ways of making highly + Operative Saline bodies, that produce none of the before mention'd effects</i> + (<a href="#LPage_319">319</a>, <a href="#LPage_320">320</a>.) <i>Some + notable</i> Experiments <i>about Solutions and Precipitations of Gold and + Silver</i> (<a href="#LPage_320">320</a>, <a href="#LPage_321">321</a>.) + </p> + <p> + <i>The one and fortieth</i> Experiment, <i>Of Depriving a deep Blew + Solution of Copper of its Colour</i> (<a href="#LPage_322">322</a>.) <i>to + which is adjoyn'd the Diſcolouring or making Tranſparent a + Solution of Verdigreaſe, &c. and another of Reſtoring or + Increaſing it</i> (<a href="#LPage_322">322</a>, <a href="#LPage_323">323</a>.) + </p> + <p> + <i>The forty ſecond</i> Experiment, <i>Of changing a Milk white + Precipitate of</i> Mercury <i>into a Yellow, by Affuſion of fair + Water, with ſeveral Conſiderations thereon</i> (from <a + href="#LPage_323">323</a> to <a href="#LPage_326">326</a>.) + </p> + <p> + <i>The forty third</i> Experiment, <i>Of Extracting a Green Solution with + fair Water out of imperfectly Calcin'd Vitriol</i> (<a href="#LPage_327">327</a>.) + </p> + <p> + <i>The forty fourth</i> Experiment, <i>Of the Deepning and Diluting of + ſeveral Tinctures, by the Affuſions of Liquors, and by Conical + Glaſſes that contain'd them, Exemplify'd in the Tinctures of</i> + Cochineel, Braſil, Verdigreaſe, Glaſs, Litmus, <i>of which + laſt on this occaſion ſeveral pleaſant</i> Phænomena + <i>are related</i> (from <a href="#LPage_328">328</a> to <a + href="#LPage_335">335</a>.) <i>To which are adjoyn'd certain Cautional + Corollaries </i> (<a href="#LPage_335">335</a>, <a href="#LPage_336">336</a>.) + <i>The Waterdrinker and ſome of his Legerdemain tricks related.</i>(<a + href="#LPage_337">337</a>.) + </p> + <p> + <i>The forty fifth</i> Experiment, <i>Of the turning Rheniſh and + White Wine into a lovely Green, with a preparation of Steel </i>(<a + href="#LPage_338">338</a>, <a href="#LPage_339">339</a>.) <i>Some further + Trial made about theſe Tinctures, and a Similar</i> Experiment <i>of</i> + Olaus Wormius (<a href="#LPage_340">340</a>.) + </p> + <p> + <i>The forty ſixth</i> Experiment, <i>Of the Internal Colour of + Metalls exhibited by Calcination</i> (<a href="#LPage_341">341</a>, <a + href="#LPage_342">342</a>, <a href="#LPage_343">343</a>.) Annotation <i>the + first, That ſeveral degrees of Fire may diſcloſe a + differing Colour</i> (<a href="#LPage_343">343</a>.) Annotation <i>the + ſecond, That the Glaſſes of Metalls may exhibit alſo + other Kinds of Colours</i> (<a href="#LPage_344">344</a>.) Annotation <i>the + third, That Minerals by ſeveral degrees of Fire may diſcloſe + ſeveral Colours</i>(<a href="#LPage_345">345</a>). + </p> + <p> + Experiment <i>the forty ſeventh, Of the Internal Colours of Metalls + diſclos'd by their Diſſolutions in ſeveral</i> Menſtruums + (from <a href="#LPage_345">345</a> to <a href="#LPage_350">350</a>.) + Annotation <i>the firſt, The Authors Apology for Recording ſome + already known</i> Experiments, <i>without mentioning their Authors</i> + (from <a href="#LPage_350">350</a> to <a href="#LPage_352">352</a>.) + Annotation <i>the ſecond, That ſome Minerals alſo by Diſſolutions + in</i> Menſtruums <i>may exhibit divers Colours</i>. Annotation <i>the + third, That Metalls diſcloſe other Colours by Precipitations, inſtanc'd + in</i> Mercury (from <a href="#LPage_353">353</a> to <a href="#LPage_355">355</a>.) + </p> + <p> + <i>The forty eighth</i> Experiment, <i>Of Tinging Glaſs Blew with + Leaf Silver, and with Calcin'd Copper, and White with Putty</i> (from <a + href="#LPage_355">355</a> to <a href="#LPage_358">358</a>.) Annotation <i>the + firſt, That this white Glaſs is the Baſis of Ammels</i> (<a + href="#LPage_358">358</a>.) Annotion <i>the ſecond, That Colour'd Glaſſes + may be Compounded like Colour'd Liquors in Dying Fats</i> (<a + href="#LPage_359">359</a>.) Annotation <i>the third, Of Tinging Glaſs + with Minerel Subſtances, and of trying what Metalls they contain by + this means</i> (from <a href="#LPage_360">360</a> to <a href="#LPage_362">362</a>.) + Annotation <i>the fourth, That Metalls may be Ting'd by Mineralls</i> (<a + href="#LPage_362">362</a>, <a href="#LPage_363">363</a>.) Annotation <i>the + fifth, Of making ſeveral Kinds of Amauſes or Counterfeit Stones</i> + (from <a href="#LPage_363">363</a> to <a href="#LPage_365">365</a>.) + Annotation <i>the ſixth, Of the Scarlet Dye, of the Stains of diſſolv'd + Gold and Silver</i> (<a href="#LPage_366">366</a>, <a href="#LPage_367">367</a>) + <i>Of the Greenneſs of Salt Beef, and Redneſs of Neats Tongues + from Salts; of Gilding Silver with Bathe Water</i> (<a href="#LPage_368">368</a>, + <a href="#LPage_369">369</a>.) <i>And Tinging the Nails and Skin with</i> + Alcanna (<a href="#LPage_369">369</a>) + </p> + <p> + <i>The forty ninth</i> Experiment, <i>Of making Lakes</i> (<a + href="#LPage_369">369</a>.) <i>A particular example in Turmerick</i> (<a + href="#LPage_370">370</a>, <a href="#LPage_371">371</a>.) Annotation <i>the + first, That in Precipitations wherein Allum is a Coefficient, a great part + of them may conſiſt of the Stony particles of that Compound Body</i> + (from <a href="#LPage_372">372</a> to <a href="#LPage_375">375</a>.) + Annotation <i>the ſecond, That Lakes may be made of other Subſtances, + as Madder, Rue,</i> &c. <i>but that Alcalizate Salts do not Always + Extract the ſame Colour of which the Vegetable appears</i> (from <a + href="#LPage_376">376</a> to <a href="#LPage_378">378</a>.) Annotation <i>the + third, That the</i> Experiments <i>related may Hint divers others</i> (<a + href="#LPage_378">378</a>) Annotation <i>the fourth, That Alum is uſefull + for the preparing other than Vegetable Pigments</i> (<a href="#LPage_379">379</a>.) + </p> + <p> + <i>The fiftieth</i> Experiment, <i>Of the Similar effects of</i> Saccarum + <img src="images/lead.png" class="noborder" width="16" height="20" + alt="Saturni" /> <i>and</i> Alkalies, <i>of Precipitating with Oyl of</i> + Vitriol <i>out of</i> Aqua-fortis, <i>and Spirit of</i> Vinegar; <i>and of + divers Varyings of the Colours, with theſe Compounded</i> (from <a + href="#LPage_380">380</a> to <a href="#LPage_384">384</a>.) <i>Another + very pretty</i> Experiment, <i>with a Solution of</i> Minium (<a + href="#LPage_384">384</a>, <a href="#LPage_385">385</a>.) <i>That theſe</i> + Experiments <i>Skilfully digeſted may hint divers matters about + Colours</i> (<a href="#LPage_386">386</a>.) <i>The Authors Apologetick + concluſion, in which is Curſorily hinted the Bow or Scarlet Dye</i> + (<a href="#LPage_387">387</a>.) <i>The Authors Letter to Sir</i> Robert + Moray, <i>concerning his Obſervations on the Shining Diamond</i> (<a + href="#LPage_391">391</a>. &c.) <i>And the Obſervations themſelves</i>. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/039b.png" alt="Decorative rule" /> + </div> + <!-- Page 1 --> + <p> + <span class="pagenum"><a name="LPage_1" id="LPage_1"></a>[pg 1]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/040a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>EXPERIMENTAL HISTORY</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>OF COLOURS BEGUN.</i></span><br /> + </h2> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE FIRST PART.</i></span><br /> + </h2> + <h2> + <span style="font-size:75%; letter-spacing:6px">CHAP. I.</span><br /> + </h2> + <table> + <tr> + <td valign="top"> + 1 + </td> + <td> + <img width="80" height="80" src="images/040b.png" alt="Illuminated I" /> + </td> + </tr> + </table> + <p> + have ſeen you ſo paſſionately addicted, <i>Pyrophilus</i> + to the delightful Art of Limning and Painting, that I cannot but think my + ſelf obliged to acquaint you with ſome of thoſe things that + have occurred to mee concerning the changes of Colours. And I may expect + that I ſhall as well ſerve the <i>Virtuoſi</i> in general, + as gratifie you in particular, by furniſhing a perſon, who, I + hope, will both improve my Communications, and communicate his + Improvements, with ſuch Experiments and Obſervations as may both + invite you to enquire ſeriouſly into the Nature of Colours, and + aſſiſt you in the Inveſtigation of it. This being the + principal ſcope of the following Tract, I ſhould do that which + might prevent my own deſign, + <!-- Page 2 --> <span class="pagenum"><a name="LPage_2" id="LPage_2"></a>[pg + 2]</span> if I ſhould here attempt to deliver you an accurate and + particular Theory of Colours; for that were to preſent you with what + I deſire to receive from you; and, as farr as in mee lay, to make + that ſtudy needleſs, to which I would engage you. + </p> + <p> + 2 Wherefore my preſent work ſhall be but to divert and recreate, + as well as excite you by the delivery of matters of fact, ſuch as you + may for the moſt part try with much <i>eaſe</i>, and poſſibly + not without ſome <i>delight</i>: And leſt you ſhould expect + any thing of Elaborate or Methodical in what you will meet with here, I muſt + confeſs to you before-hand, that the ſeaſons I was wont to + chuſe to deviſe and try Experiments about Colours, were thoſe + daies, wherein having taken Phyſick, and finding my ſelf as + unfit to ſpeculate, as unwilling to be altogether idle, I choſe + this diverſion, as a kind of Mean betwixt the one and the other. And + I have the leſs ſcrupled to ſet down the following + Experiments, as ſome of them came to my mind, and as the Notes + wherein I had ſet down the reſt, occurr'd to my hands, that by + declining a Methodical way of delivering them, I might leave you and my + ſelf the greater liberty and convenience to add to them, and tranſpoſe + them as ſhall appear expedient. + <!-- Page 3 --> <span class="pagenum"><a name="LPage_3" id="LPage_3"></a>[pg + 3]</span> + </p> + <p> + 3 Yea, that you may not think mee too reſerv'd, or look upon an + Enquiry made up of meer Narratives, as ſomewhat jejune, am content to + <i>premiſe</i> a few conſiderations, that now offer themſelves + to my thoughts, which relate in a more general way, either to the Nature + of Colours, or to the ſtudy of it. And I ſhall <i>inſert</i> + an <i>Eſſay</i>, as well Speculative as Hiſtorical, of the + Nature of Whiteneſs and Blackneſs, that you may have a <i>Specimen</i> + of the Hiſtory of Colours, I have ſometimes had thoughts of; and + if you diſlike not the Method I have made uſe of, I hope, you, + and ſome of the <i>Virtuoſi</i>, your friends, may be thereby + invited to go thorow with <i>Red, Blew, Yellow</i>, and the reſt of + the particular Colours, as I have done with <i>White</i> and <i>Black</i>, + but with farr more ſagacity and ſucceſs. And if I can + invite Ingenious men to undertake ſuch Tasks, I doubt not but the + Curious will quickly obtain a better Account of Colours, than as yet we + have, ſince in our Method the Theorical part of the Enquiry being + attended, and as it were interwoven with the Hiſtorical, whatever + becomes of the diſputable Conjectures, the Philoſophy of Colours + will be promoted by the indiſputable Experiments. + </p> + <!-- Page 4 --> + <p> + <span class="pagenum"><a name="LPage_4" id="LPage_4"></a>[pg 4]</span> + </p> + <hr /> + <h3> + CHAP. II. + </h3> + <p> + 1 To come then in the firſt place to our more general Conſiderations, + I ſhall begin with ſaying ſomething as to the Importance of + examining the Colours of Bodies. For there are ſome, eſpecially + <i>Chymiſts</i>, who think, that a conſiderable diverſity + of Colours does conſtantly argue an equal diverſity of Nature, + in the Bodies wherein it is conſpicuous; but I confeſs I am not + altogether of their mind; for not to mention changeable Taffaties, the + blew and golden necks of Pidgeons, and divers Water-fowl, Rainbows Natural + and Artificial, and other Bodies, whoſe Colours the Philoſophers + have been pleaſed to call not Real, but Apparent and Phantaſtical; + not to inſiſt on theſe, I ſay, (for fear of needleſly + engaging in a Controverſie) we ſee in Parrots, Goldfinches, and + divers other Birds, not only that the contiguous feathers which are + probably as near in properties as place, are ſome of them Red, and + others White, ſome of them Blew, & others Yellow, <i>&c.</i> + but that in the ſeveral parts of the ſelf-ſame feather + there may often be ſeen the greateſt diſparity of Colours; + and ſo in the leaves of Tulips, July-flowers, and ſome other + Vegetables + <!-- Page 5 --> <span class="pagenum"><a name="LPage_5" id="LPage_5"></a>[pg + 5]</span> the ſeveral leaves, and even the ſeveral parts of the + ſame leaf, although no difference have been obſerved in their + other properties, are frequently found painted with very different + Colours. And ſuch a variety we have much more admired in that lovely + plant which is commonly, and not unjuſtly call'd the <i>Marvayl of + Peru</i>; for of divers ſcores of fine Flowers, which in its ſeaſon + that gaudy Plant does almoſt daily produce, I have ſcarce taken + notice of any two that were dyed perfectly alike. But though <i>Pyro</i>: + ſuch things as theſe, among others, keep mee from daring to + affirm, that the Diverſity and change of Colours does <i>alwaies</i> + argue any great difference or alteration, betwixt, or in, the Bodies, + wherein it is to be diſcerned, yet that <i>oftentimes</i> the + Alteration of Colours does ſignifie conſiderable Alterations in + the diſpoſition of parts of Bodies, may appear in the Extraction + of Tinctures, and divers other Chymical Operations, wherein the change of + Colours is the chief, and ſometimes the only thing, by which the Artiſt + regulates his proceeding, and is taught to know when 'tis ſeaſonable + for him to leave off. Inſtances of this ſort are more obvious in + divers ſorts of fruits, as Cherries, Plums, &c. wherein, + according as the Vegetable ſap is ſweetned, or otherwiſe + <!-- Page 6 --> <span class="pagenum"><a name="LPage_6" id="LPage_6"></a>[pg + 6]</span> ripened, by paſſing from one degree to another of + Maturation, the external part of the fruit paſſes likewiſe + from one to another Colour. But one of the nobleſt Inſtances I + have met with of this kind, is not ſo obvious; and that is the way of + tempering Steel to make Gravers, Drills, Springs, and other Mechanical Inſtruments, + which we have divers times both made Artificers practiſe in our preſence, + and tryed our ſelves, after the following manner, Firſt, the + ſlender Steel to be tempered is to be hardened by heating as much of + it as is requiſite among glowing Coals, till it be glowing hot, but + it muſt not be quenched aſſoon as it is taken from the fire + (for that would make it too brittle, and ſpoil it) but muſt be + held over a baſon of water, till it deſcend from a White heat to + a Red one, which aſſoon as ever you perceive, you muſt + immediately quench as much as you deſire to harden in the cold water. + The Steel thus hardened, will, if it be good, look ſomewhat White and + muſt be made bright at the end, that its change of Colours may be + there conſpicuous; and then holding it ſo in the flame of a + Candle, that the bright end may be, for about half an inch, or more, out + of the flame, that the ſmoak do not ſtain or ſully the + brightneſs of it, you ſhall after a + <!-- Page 7 --> <span class="pagenum"><a name="LPage_7" id="LPage_7"></a>[pg + 7]</span> while ſee that clean end, which is almoſt contiguous + to the flame, paſs very nimbly from one Colour to another, as from a + brighter Yellow, to a deeper and reddiſh Yellow, which Artificers + call a <i>ſanguine</i>, and from that to a fainter firſt, and + then a a deeper Blew. And to bring home this Experiment to our preſent + purpoſe, it is found by daily Experience, that each of theſe + ſucceeding Colours argue ſuch a change made in the texture of + the Steel, that if it be taken from the flame, and immediately quenched in + the tallow (whereby it is ſetled in whatever temper it had before) + when it is Yellow, it is of ſuch a hardneſs as makes it fit for + Gravers Drills, and ſuch like tools; but if it be kept a few minutes + longer in the flame till it grow Blew, it becomes much ſofter, and + unfit to make Gravers for Metalls, but fit to make Springs for Watches, + and ſuch like Inſtruments, which are therefore commonly of that + Colour; and if the Steel be kept in the flame, after that this deep Blew + hath diſcloſed it ſelf, it will grow ſo ſoft, as + to need to be new hardened again, before it can be brought to a temper, + fit for Drills or Penknives. And I confeſs <i>Pyro.</i> I have taken + much pleaſure to ſee the Colours run along from the parts of the + Steel contiguous to the flame, to the end of the Inſtrument, + <!-- Page 8 --> <span class="pagenum"><a name="LPage_8" id="LPage_8"></a>[pg + 8]</span> and ſucceed one another ſo faſt, that if a man be + not vigilant, to thruſt the Steel into the tallow at the very nick of + time, at which it has attain'd its due Colour, he ſhall miſs of + giving his tool the right temper. But becauſe the flame of a Candle + is offenſive to my weak eyes, and becauſe it is apt to either + black or ſully the contiguous part of the Steel which is held in it, + and thereby hinder the change of Colours from being ſo long and + clearly diſcern'd, I have ſometimes made this Experiment by + laying the Steel to be tempered upon a heated bar of Iron, which we finde + alſo to be employ'd by ſome Artificers in the tempering of + ſuch great Inſtruments, as are too big to be ſoon heated + ſufficiently by the flame of a Candle. And you may eaſily ſatisfie + your ſelf <i>Pyro</i>: of the differing hardneſs and toughneſs, + which is aſcribed to Steel temper'd at different Colours, if you + break but ſome ſlender wires of Steel ſo temper'd, and obſerve + how they differ in brittleneſs, and if with a file you alſo make + tryal of their various degrees of hardneſs. + </p> + <p> + 2 But <i>Pyrophilus</i>, I muſt not at preſent any further proſecute + the Conſideration of the importance of Experiments about Colours, not + only becauſe you will in the following papers finde ſome inſtances, + that would here + <!-- Page 9 --> <span class="pagenum"><a name="LPage_9" id="LPage_9"></a>[pg + 9]</span> be preſented you out of their due place, of the uſe + that may be made of ſuch Experiments, in diſcovering in divers + bodies, what kind the ſalt is, that is predominant in them; but alſo + becauſe a ſpeculative Naturaliſt might juſtly enough + allege, that as Light is ſo pleaſing an object, as to be well + worth our looking on, though it diſcover'd to us nothing but its + ſelf; ſo modifi'd Light called Colour, were worth our + contemplation, though by underſtanding its Nature we ſhould be + taught nothing elſe. And however, I need not make either you or my + ſelf excuſes for entertaining you on the ſubject I am now + about to treat of, ſince the pleaſure <i>Pyro</i>: takes in + mixing and laying on of Colours, will I preſume keep him, and will (I + am ſure) keep mee from thinking it troubleſome to ſet down, + eſpecially after the tedious proceſſes (about other + matters) wherewith I fear I may have tyr'd him, ſome eaſie, and + not unpleaſant Experiments relating to that ſubject. + </p> + <p> + 3 But, before we deſcend to the more particular conſiderations, + we are to preſent you concerning Colours, I preſume it will be + ſeaſonable to propoſe at the very entrance a Diſtinction; + the ignorance or neglect of which, ſeems to mee to have frequently + enough occaſioned either miſtakes or confuſion + <!-- Page 10 --> <span class="pagenum"><a name="LPage_10" id="LPage_10"></a>[pg + 10]</span> in the Writings of divers Modern Philoſophers; for Colour + may be conſidered, either as it is a quality reſiding in the + body that is ſaid to be coloured, or to modifie the light after + ſuch or ſuch a manner; or elſe as the Light it ſelf, + which ſo modifi'd, ſtrikes upon the organ of ſight, and + ſo cauſes that Senſation which we call Colour; and that + this latter may be look'd upon as the more proper, though not the uſual + acception of the word Colour, will be made probable by divers paſſages + in the inſuing part of our diſcourſe; and indeed it is the + Light it ſelf, which after a certain manner, either mingled with + ſhades, or ſome other waies troubled, ſtrikes our eyes, + that does more immediately produce that motion in the organ, upon whoſe + account men ſay they ſee ſuch or ſuch a Colour in the + object; yet, becauſe there is in the body that is ſaid to be + coloured, a certain diſpoſition of the ſuperficial + particles, whereby it ſends the Light reflected, or refracted, to our + eyes thus and thus alter'd, and not otherwiſe, it may alſo in + ſome ſenſe be ſaid, that Colour depends upon the viſible + body; and therefore we ſhall not be againſt that way of ſpeaking + of Colours that is moſt uſed among the Modern Naturaliſts, + provided we be allowed to have recourſe when occaſion ſhall + <!-- Page 11 --> <span class="pagenum"><a name="LPage_11" id="LPage_11"></a>[pg + 11]</span> require to the premis'd diſtinction, and to take the more + immediate cauſe of Colour to be the modifi'd Light it ſelf, as + it affects the Senſory; though the diſpoſition alſo of + the colour'd body, as that modifies the Light, may be call'd by that name + Metonimically (to borrow a School term) or Efficiently, that is in regard + of its turning the Light, that rebounds from it, or paſſes + thorow it, into this or that particular Colour. + </p> + <p> + 4 I know not whether I may not on this occaſion add, that Colour is + ſo far from being an Inherent quality of the object in the ſenſe + that is wont to be declar'd by the Schools, or even in the ſenſe + of ſome Modern Atomiſts, that, if we conſider the matter + more attentively, we ſhall ſee cauſe to ſuſpect, + if not to conclude, that though Light do more immediately affect the organ + of ſight, than do the bodies that ſend it thither, yet Light it + ſelf produces the ſenſation of a Colour, but as it produces + ſuch a determinate kind of local motion in ſome part of the + brain; which, though it happen moſt commonly from the motion + whereinto the ſlender ſtrings of the <i>Retina</i> are put, by + the appulſe of Light, yet if the like motion happen to be produc'd by + any other cauſe, wherein the Light concurrs not at + <!-- Page 12 --> <span class="pagenum"><a name="LPage_12" id="LPage_12"></a>[pg + 12]</span> all, a man ſhall think he ſees the ſame Colour. + For proof of this, I might put you in mind, that 'tis uſual for + dreaming men to think they ſee the Images that appear to them in + their ſleep, adorn'd ſome with this, and ſome with that + lively Colour, whilſt yet, both the curtains of their bed, and thoſe + of their eyes are cloſe drawn. And I might add the confidence with + which diſtracted perſons do oftentimes, when they are awake, + think, they ſee black fiends in places, where there is no black + object in ſight without them. But I will rather obſerve, that + not only when a man receives a great ſtroak upon his eye, or a very + great one upon ſome other part of his head, he is wont to ſee, + as it were, flaſhes of lightning, and little vivid, but vaniſhing + flames, though perhaps his eyes be ſhut: But the like apparitions may + happen, when the motion proceeds not from ſomething without, but from + ſomething within the body, provided the unwonted fumes that wander up + and down in the head, or the propagated concuſſion of any + internal part in the body, do cauſe about the inward extremities of + the Optick Nerve, ſuch a motion as is wont to be there produc'd, when + the ſtroak of the Light upon the <i>Retina</i> makes us conclude, + that we ſee either Light, or ſuch and ſuch a + <!-- Page 13 --> <span class="pagenum"><a name="LPage_13" id="LPage_13"></a>[pg + 13]</span> Colour: This the moſt ingenious <i>Des Cartes</i> hath + very well obſerv'd, but becauſe he ſeems not to have + exemplifi'd it by any unobvious or peculiar obſervation, I ſhall + indeavour to illuſtrate this doctrine by a few Inſtances. + </p> + <p> + 5 And firſt, I remember, that having, through Gods goodneſs, + been free for ſeveral years, from troubleſome Coughs, being + afterwards, by an accident, ſuddenly caſt into a violent one, I + did often, when I was awaked in the night by my diſtempers, obſerve, + that upon coughing ſtrongly, it would ſeem to mee, that I ſaw + very vivid, but immediately diſappearing flames, which I took + particular notice of, becauſe of the conjecture I am now mentioning. + </p> + <p> + 6 An excellent and very diſcreet perſon, very near ally'd both + to you and mee, was relating to mee, that ſome time ſince, whilſt + ſhe was talking with ſome other Ladies, upon a ſudden, all + the objects, ſhe looked upon, appeared to her dyed with unuſual + Colours, ſome of one kind, and ſome of another, but all ſo + bright and vivid, that ſhe ſhould have been as much delighted, + as ſurpriz'd with them, but that finding the apparition to continue, + ſhe fear'd it portended ſome very great alteration as to her + health: As indeed the day after ſhe was aſſaulted + <!-- Page 14 --> <span class="pagenum"><a name="LPage_14" id="LPage_14"></a>[pg + 14]</span> with ſuch violence by Hyſterical and Hypocondrical Diſtempers, + as both made her rave for ſome daies, and gave her, during that time, + a Baſtard Palſey. + </p> + <p> + 7 Being a while ſince in a Town, where the Plague had made great + havock, and inquiring of an ingenious man, that was ſo bold, as + without much ſcruple to viſit thoſe that were ſick of + it, about the odd ſymptomes of a Diſeaſe that had ſwept + away ſo many there; he told mee, among other things, that he was able + to tell divers Patients, to whom he was called, before they took their + beds, or had any evident ſymptomes of the Plague, that they were + indeed infected upon peculiar obſervations, that being asked, they + would tell him that the neighbouring objects, and particularly his cloths, + appear'd to them beautifi'd with moſt glorious Colours, like thoſe + of the Rainbow, oftentimes ſucceeding one another; and this he + affirm'd to be one of the moſt uſual, as well as the moſt + early ſymptomes, by which this odd Peſtilence diſclos'd it + ſelf: And when I asked how long the Patients were wont to be thus + affected, he anſwered, that it was moſt commonly for about a + day; and when I further inquired whether or no Vomits, which in that Peſtilence + were uſually given, did not remove this ſymptome + <!-- Page 15 --> <span class="pagenum"><a name="LPage_15" id="LPage_15"></a>[pg + 15]</span> (For ſome uſed the taking of a Vomit, when they came + aſhore, to cure themſelves of the obſtinate and troubleſome + giddineſs caus'd by the motion of the ſhip) reply'd, that + generally, upon the evacuation made by the Vomit, that ſtrange + apparition of Colours ceaſed, though the other ſymptomes were + not ſo ſoon abated, yet he added (to take notice of that upon + the by, becauſe the obſervation may perchance do good) that an + excellent Phyſician, in whoſe company he was wont to viſit + the ſick, did give to almoſt all thoſe to whom he was + called, in the beginning before Nature was much weakened, a pretty odd + Vomit conſiſting of eight or ten dramms of Infuſion of <i>Crocus + Metallorum</i>, and about half a dramm, or much more, of White Vitriol, + with ſuch ſucceſs, that ſcarce one of ten to whom it + was ſeaſonably adminiſtred, miſcarried. + </p> + <p> + 8 But to return to the conſideration of Colours: As an apparition of + them may be produced by motions from within, without the aſſiſtance + of an outward object, ſo I have obſerved, that 'tis ſometimes + poſſible that the Colour that would otherwiſe be produced + by an outward object, may be chang'd by ſome motion, or new texture + already produced in the Senſory, as long as that unuſual motion, + or new diſpoſition + <!-- Page 16 --> <span class="pagenum"><a name="LPage_16" id="LPage_16"></a>[pg + 16]</span> laſts; for I have divers times try'd, that after I have + through a Teleſcope look'd upon the Sun, though thorow a thick, red, + or blew glaſs, to make its ſplendor ſupportable to the eye, + the impreſſion upon the <i>Retina</i>, would be not only ſo + vivid, but ſo permanent, that if afterwards I turned my eye towards a + flame, it would appear to mee of a Colour very differing from its uſual + one. And if I did divers times ſucceſſively ſhut and + open the ſame eye, I ſhould ſee the adventitious Colour, + (if I may ſo call it) changed or impair'd by degrees, till at length + (for this unuſual motion of the eye would not preſently ceaſe) + the flame would appear to mee, of the ſame hew that it did to other + beholders; a not unlike effect I found by looking upon the Moon, when + ſhe was near full, thorow an excellent Teleſcope, without + colour'd Glaſs to ſcreen my eye with; But that which I deſire + may be taken notice of, becauſe we may elſewhere have occaſion + to reflect upon it, and becauſe it ſeems not agreeable to what + Anatomiſts and Optical Writers deliver, touching the relation of the + two eyes to each other, is this circumſtance, that though my Right + eye, with which I looked thorow the Teleſcope, were thus affected by + the over-ſtrong impreſſion of the light, yet when the flame + <!-- Page 17 --> <span class="pagenum"><a name="LPage_17" id="LPage_17"></a>[pg + 17]</span> of a Candle, or ſome other bright object appear'd to me of + a very unuſual Colour, whilſt look'd upon with the Diſcompos'd + Eye, or (though not ſo notably) with both eyes at once; yet if I + ſhut that Eye, and looked upon the ſame object with the other, + it would appear with no other than its uſual Colour, though if I + again opened, and made uſe of the Dazled eye, the vivid adventitious + Colour would again appear. And on this occaſion I muſt not + pretermit an Obſervation which may perſwade us, that an + over-vehement ſtroak upon the Senſory, eſpecially if it be + naturally of a weak conſtitution, may make a more laſting impreſſion + than one would imagine, which impreſſion may in ſome caſes, + as it were, mingle with, and vitiate the action of vivid objects for a + long time after. + </p> + <p> + For I know a Lady of unqueſtionable Veracity, who having lately, by a + deſperate fall, receiv'd ſeveral hurts, and particularly a conſiderable + one upon a part of her face near her Eye, had her ſight ſo + troubl'd and diſorder'd, that, as ſhe hath more than once + related to me, not only when the next morning one of her ſervants + came to her bed ſide, to ask how ſhe did, his cloaths appear'd + adorn'd with ſuch variety of dazling Colours, that ſhe was fain + preſently to + <!-- Page 18 --> <span class="pagenum"><a name="LPage_18" id="LPage_18"></a>[pg + 18]</span> command him to withdraw, but the Images in her Hangings, did, + for many daies after, appear to her, if the Room were not extraordinarily + darken'd, embelliſh'd with ſeveral offenſively vivid + Colours, which no body elſe could ſee in them; And when I + enquir'd whether or no White Objects did not appear to her adorn'd with + more luminous Colours than others, and whether ſhe ſaw not + ſome which ſhe could not now well deſcribe to any, whoſe + eyes had never been diſtemper'd, ſhe anſwer'd mee, that + ſometimes ſhe thought ſhe ſaw Colours ſo new and + glorious, that they were of a peculiar kind, and ſuch as ſhe + could not deſcribe by their likeneſs to any ſhe had beheld + either before or ſince, and that White Objects did ſo much diſorder + her ſight, that if ſeveral daies after her fall, ſhe look'd + upon the inſide of a Book, ſhe fanci'd ſhe ſaw there + Colours like thoſe of the Rain-bow, and even when ſhe thought + her ſelf pretty well recover'd, and made bold to leave her Chamber, + the coming into a place where the Walls and Ceeling were whited over, made + thoſe Objects appear to her cloath'd with ſuch glorious and + dazling Colours, as much offended her ſight, and made her repent her + venturouſneſs, and ſhe added, that this Diſtemper of + her Eyes laſted no leſs + <!-- Page 19 --> <span class="pagenum"><a name="LPage_19" id="LPage_19"></a>[pg + 19]</span> than five or ſix weeks, though, ſince that, ſhe + hath been able to read and write much without finding the leaſt + Inconvenience in doing ſo. I would gladly have known, whether if + ſhe had ſhut the Injur'd Eye, the <i>Phænomena</i> would have + been the ſame, when ſhe employ'd only the other, but I heard not + of this accident early enough to ſatisfie that Enquiry. + </p> + <p> + 9 Wherefore, I ſhall now add, that ſome years before, a perſon + exceedingly eminent for his profound Skil in almoſt all kinds of + Philological Learning, coming to adviſe with mee about a Diſtemper + in his Eyes, told me, among other Circumſtances of it, that, having + upon a time looked too fixedly upon the Sun, thorow a Teleſcope, + without any coloured Glaſs, to take off from the dazling ſplendour + of the Object, the exceſs of Light did ſo ſtrongly affect + his Eye, that ever ſince, when he turns it towards a Window, or any + White Object, he fancies, he ſeeth a Globe of Light, of about the + bigneſs the Sun then appeared of to him, to paſs before his + Eyes: And having Inquir'd of him, how long he had been troubled with this + Indiſpoſition, he reply'd, that it was already nine or ten + years, ſince the Accident, that occaſioned it, firſt befel + him. + </p> + <!-- Page 20 --> + <p> + <span class="pagenum"><a name="LPage_20" id="LPage_20"></a>[pg 20]</span> + </p> + <p> + I could here ſubjoyn, <i>Pyrophilus</i>, ſome memorable + Relations that I have met with in the Account given us by the experienc'd + <i>Epiphanius Ferdinandus</i>, of the Symptomes he obſerv'd to be + incident to thoſe that are bitten with the Tarantula, by which + (Relations) I could probably ſhew, that without any change in the + Object, a change in the Inſtruments of Viſion may for a great + while make ſome Colours appear Charming, and make others Provoking, + and both to a high degree, though neither of them produc'd any ſuch + Effects before. Theſe things, I ſay, I could here ſubjoyn + in confirmation of what I have been ſaying, to ſhew, that the Diſpoſition + of the Organ is of great Importance in the Dijudications we make of + Colours, were it not that theſe ſtrange Stories belonging more + properly to another Diſcourſe, I had rather, (contenting my + ſelf to have given you an Intimation of them here) that you ſhould + meet with them fully deliver'd there. + </p> + <hr /> + <h3> + CHAP. III. + </h3> + <p> + But, <i>Pyrophilus</i>, I would not by all that I have hitherto diſcours'd, + be thought to have forgotten the Diſtinction + <!-- Page 21 --> <span class="pagenum"><a name="LPage_21" id="LPage_21"></a>[pg + 21]</span> (of Colour) that I mentioned to you about the beginning of the + third Section of the former Chapter; and therefore, after all I have + ſaid of Colour, as it is modifi'd Light, and immediately affects the + Senſory, I ſhall now re-mind you, that I did not deny, but that + Colour might in ſome ſenſe be conſider'd as a Quality + reſiding in the body that is ſaid to be Colour'd, and indeed the + greateſt part of the following Experiments referr to Colour + principally under that Notion, for there is in the bodyes we call + Colour'd, and chiefly in their Superficial parts, a certain diſpoſition, + whereby they do ſo trouble the Light that comes from them to our Eye, + as that it there makes that diſtinct Impreſſion, upon whoſe + Account we ſay, that the Seen body is either White or Black, or Red + or Yellow, or of any one determinate Colour. But becauſe we ſhall + (God permiting) by the Experiments that are to follow ſome Pages + hence, more fully and particularly ſhew, that the Changes, and conſequently + in divers places the Production and the appearance of Colours depends upon + the continuing or alter'd Texture of the Object, we ſhall in this + place intimate (and that too but as by the way) two or three things about + this Matter. + </p> + <p> + 2. And firſt it is not without ſome Reaſon, + <!-- Page 22 --> <span class="pagenum"><a name="LPage_22" id="LPage_22"></a>[pg + 22]</span> that I aſcribe Colour (in the ſenſe formerly + explan'd) <i>chiefly</i> to the Superficial parts of Bodies, for not to + queſtion how much Opacous Corpuſcles may abound even in thoſe + Bodies we call Diaphanous, it ſeems plain that of Opacous bodies we + do indeed ſee little elſe than the Superficies, for if we found + the beams of Light that rebound from the Object to the Eye, to peirce deep + into the Colour'd body, we ſhould not judge it Opacous, but either + Tranſlucid, or at leaſt Semi-diaphanous, and though the Schools + ſeem to teach us that Colour is a Penetrative Quality, that reaches + to the Innermoſt parts of the Object, as if a piece of Sealing-wax be + broken into never ſo many pieces, the Internal fragments will be as + Red as the External ſurface did appear, yet that is but a Particular + Example that will not overthrow the Reaſon lately offer'd, eſpecially + ſince I can alleage other Examples of a contrary Import, and two or + three Negative Inſtances are ſufficient to overthrow the + Generality of a Poſitive Rule, eſpecially if that be built but + upon One or a Few Examples. Not (then) to mention Cherries, Plums, and I + know not how many other Bodies, wherein the skin is of one Colour, and + what it hides of another, I ſhall name a couple of Inſtances + drawn from the Colours + <!-- Page 23 --> <span class="pagenum"><a name="LPage_23" id="LPage_23"></a>[pg + 23]</span> of Durable bodies that are thought far more Homogeneous, and + have not parts that are either Organical, or of a Nature approaching + thereunto. + </p> + <p> + 3 To give you the firſt Inſtance, I ſhall need but to + remind you of what I told you a little after the beginning of this Eſſay, + touching the Blew and Red and Yellow, that may be produc'd upon a piece of + temper'd Steel, for theſe Colours though they be very Vivid, yet if + you break the Steel they adorn, they will appear to be but Superficial; + not only the innermoſt parts of the Metall, but thoſe that are + within a hairs breadth of the Superficies, having not any of theſe + Colours, but retaining that of the Steel it ſelf. Beſides that, + we may as well confirm this Obſervation, as ſome other + particulars we elſewhere deliver concerning Colours, by the following + Experiment which we purpoſely made. + </p> + <p> + 4 We took a good quantity of clean Lead, and melted it with a ſtrong + Fire, and then immediately pouring it out into a clean Veſſel of + a convenient ſhape and matter, (we us'd one of Iron, that the great + and ſudden Heat might not injure it) and then carefully and nimbly + taking off the Scum that floated on the top, we perceiv'd, as we expected, + the ſmooth and + <!-- Page 24 --> <span class="pagenum"><a name="LPage_24" id="LPage_24"></a>[pg + 24]</span> gloſſie Surface of the melted matter, to be adorn'd + with a very glorious Colour, which being as Tranſitory as + Delightfull, did almoſt immediately give place to another vivid + Colour, and that was as quickly ſucceeded by a third, and this as it + were chas'd away by a fourth, and ſo theſe wonderfully vivid + Colours ſucceſſively appear'd and vaniſh'd, (yet the + ſame now and then appearing the ſecond time) till the Metall ceaſing + to be hot enough to afford any longer this pleaſing Spectacle, the + Colours that chanc'd to adorn the Surface, when the Lead thus began to + cool, remain'd upon it; but were ſo Superficial, that how little + ſoever we ſcrap'd off the Surface of the Lead, we did in ſuch + places ſcrape off all the Colour, and diſcover only that which + is natural to the Metall it ſelf, which receiving its adventitious + Colours, only when the heat was very Intenſe, and in that part which + was expos'd to the comparatively very cold Air, (which by other + Experiments ſeems to abound with ſubtil Saline parts, perhaps + not uncapable of working upon Lead ſo diſpos'd:) Theſe + things I ſay, together with my obſerving that whatever parts of + the ſo ſtrongly melted Lead were expos'd a while to the Air, + turn'd into a kind of Scum or Litharge, + <!-- Page 25 --> <span class="pagenum"><a name="LPage_25" id="LPage_25"></a>[pg + 25]</span> how bright and clean ſoever they appear'd before, ſuggeſted + to me ſome Thoughts or Ravings, which I have not now time to acquaint + You with. One that did not know me, <i>Pyrophilus</i>, would perchance + think I endeavour'd to impoſe upon You by relating this Experiment, + which I have ſeveral times try'd, but the Reaſon why the <i>Phænomena</i> + mention'd have not been taken notice of, may be, that unleſs Lead be + brought to a much higher degree of Fuſion or Fluidity than is uſual, + or than is indeed requiſite to make it melt, the <i>Phænomena</i> I + mention'd will ſcarce at all diſcloſe themſelves; And + we have alſo obſerv'd that this ſucceſſive + appearing and vaniſhing of vivid Colours, was wont to be impair'd or + determin'd whilſt the Metal expos'd to the Air remain'd yet hotter + than one would readily ſuſpect. And one thing I muſt + further Note, of which I leave You to ſearch after the Reaſon, + namely, that the ſame Colours did not always and regularly ſucceed + one another, as is uſually in Steel, but in the diverſify'd + Order mention'd in this following Note, which I was ſcarce able to + write down, the ſucceſſion of the Colours was ſo very + quick, whether that proceeded from the differing degrees of Heat in the + Lead expos'd to the cool Air, or from ſome + <!-- Page 26 --> <span class="pagenum"><a name="LPage_26" id="LPage_26"></a>[pg + 26]</span> other Reaſon, I leave you to examine. + </p> + <blockquote> + <p> + [<i>Blew, Yellow, Purple, Blew; Green, Purple, Blew, Yellow, Red; + Purple, Blew, Yellow and Blew, Yellow, Blew, Purple, Green mixt, Yellow, + Red, Blew, Green, Yellow, Red, Purple, Green</i>.] + </p> + </blockquote> + <p> + 5. The <i>Atomiſts</i> of Old, and ſome Learned men of late, + have attempted to explicate the variety of Colours in Opacous bodies from + the various Figures of their Superficial parts; the attempt is Ingenious, + and the Doctrine ſeems partly True, but I confeſs I think there + are divers other things that muſt be taken in as concurrent to + produce thoſe differing forms of Aſperity, whereon the Colours + of Opacous bodies ſeem to depend. To declare this a little, we muſt + aſſume, that the Surfaces of all ſuch Bodies how Smooth or + polite ſoever they may appear to our Dull Sight and Touch, are + exactly ſmooth only in a popular, or at moſt in a Phyſical + ſenſe, but not in a ſtrict and rigid ſenſe. + </p> + <p> + 6. This, excellent <i>Microſcopes</i> ſhew us in many Bodies, + that ſeem Smooth to our naked Eyes; and this not only as to the + little Hillocks or Protuberancies that ſwell + <!-- Page 27 --> <span class="pagenum"><a name="LPage_27" id="LPage_27"></a>[pg + 27]</span> above that which may be conceiv'd to be the Plain or Level of + the conſider'd Surface, for it is obvious enough to thoſe that + are any thing converſant with ſuch Glaſſes, but as to + numerous Depreſſions beneath that Level, of which ſort of + Cavities by the help of a <i>Microſcope</i>, which the greateſt + Artificer that makes them, judges to be the greateſt Magnifying Glaſs + in <i>Europe</i>, except one that equals it, we have on the Surface of a + thin piece of Cork that appear'd ſmooth to the Eye, obſerv'd + about ſixty in a Row, within the length of leſs then an 31 and + 32 part of an Inch, (for the Glaſs takes in no longer a ſpace at + one view) and theſe Cavities (which made that little piece of Cork + look almoſt like an empty Honey-comb) were not only very diſtinct, + and figur'd like one another, but of a conſiderable bigneſs, and + a ſcarce credible depth; inſomuch that their diſtinct + ſhadows as well as ſides were plainly diſcern'd and eaſiy + to be reckon'd, and might have been well diſtinguiſh'd, though + they had been ten times leſſer than they were; which I thought + it not amiſs to mention to you <i>Pyrophilus</i> upon the by, that + you may thence make ſome Eſtimate, what a ſtrange + Inequality, and what a multitude of little Shades, there may really be, in + a + <!-- Page 28 --> <span class="pagenum"><a name="LPage_28" id="LPage_28"></a>[pg + 28]</span> ſcarce ſenſible part of the Phyſical ſuperficies, + though the naked Eye ſees no ſuch matter. And as Excellent <i>Microſcopes</i> + ſhew us this Ruggedneſs in many Bodies that paſs for + Smooth, ſo there are divers Experiments, though we muſt not now + ſtay to urge them, which ſeem to perſwade us of the ſame + thing as to the reſt of ſuch Bodies as we are now treating off; + So, that there is no ſenſible part of an Opacous body, that may + not be conceiv'd to be made up of a multitude of ſingly inſenſible + Corpuſcles, but in the giving theſe ſurfaces that diſpoſition, + which makes them alter the Light that reflects thence to the Eye after the + manner requiſite to make the Object appear Green, Blew, &c. the + Figures of theſe Particles have <i>a great</i>, but not <i>the only</i> + ſtroak. 'Tis true indeed that the protuberant Particles may be of + very great variety of Figures, Sphærical, Elliptical, Conical, + Cylindrical, Polyedrical, and ſome very irregular, and that according + to the Nature of theſe, and the ſituation of the Lucid body, the + Light muſt be variouſly affected, after one manner from Surfaces + (I now ſpeak of Phyſical Surfaces) conſiſting of + Sphaerical, and in another from thoſe that are made up of Conical or + Cylindrical Corpuſcles; ſome + <!-- Page 29 --> <span class="pagenum"><a name="LPage_29" id="LPage_29"></a>[pg + 29]</span> being fitted to reflect more of the incident Beams of Light, + others leſs, and ſome towards one part, others towards another. + But beſides this difference of Shape, there may be divers other + things that may eminently concurr to vary the forms of Aſperity that + Colours ſo much depend on. For, willingly allowing the Figure of the + Particles in the firſt place, I conſider ſecondly, that the + ſuperficial Corpuſcles, if I may ſo call them, may be + bigger in one Body, and leſs in another, and conſequently fitted + to allay the Light falling on them with greater ſhades. Next, the + protuberant Particles may be ſet more or leſs cloſe + together, that is, there may be a greater or a ſmaller number of them + within the compaſs of one, than within the compaſs of another + ſmall part of the Surface of the ſame Extent, and how much theſe + Qualities may ſerve to produce Colour may be ſomewhat gueſs'd + at, by that which happens in the Agitation of Water; for if the Bubbles + that are thereby made be Great, and but Few, the Water will ſcarce + acquire a ſenſible Colour, but if it be reduc'd to a Froth, conſiſting + of Bubbles, which being very Minute and Contiguous to each other, are a + multitude of them crowded into a narrow Room, the Water (turned to + <!-- Page 30 --> <span class="pagenum"><a name="LPage_30" id="LPage_30"></a>[pg + 30]</span> Froth) does then exhibit a very manifeſt White Colour,<a + name="LNtA_3" id="LNtA_3_"></a><a href="#LNt_3"><sup>3</sup></a> (to which + theſe laſt nam'd Conditions of the Bubbles do as well as their + Convex figure contribute) and that for Reaſons to be mention'd anon. + Beſides, it is not neceſſary that the Superficial particles + that exhibit one Colour, ſhould be all of them Round, or all Conical, + or all of any one Shape, but Corpuſcles of differing Figures may be + mingled on the Surface of the Opacous Body, as when the Corpuſcles + that make a Blew colour, and thoſe that make a Yellow, come to be + Accurately and Skilfully mix'd, they make up a Green, which though it + ſeem one ſimple Colour, yet in this caſe appears to be made + by Corpuſcles of very differing Kinds, duely commix'd. Moreover the + Figure and Bigneſs of the little Depreſſions, Cavities, + Furrows or Pores intercepted betwixt theſe protuberant Corpuſcles, + are as well to be conſider'd as the Sizes and Shapes of the Corpuſcles + themſelves: For we may conceive the Phyſical ſuperficies of + a Body, where (as we ſaid) its Colour does as it were reſide, to + be cut Tranſverſly by a Mathematical plain, which you know is + conceiv'd to be without any Depth or Thickneſs at all, and then as + <!-- Page 31 --> <span class="pagenum"><a name="LPage_31" id="LPage_31"></a>[pg + 31]</span> ſome parts of the Phyſical Superficies will be + Protuberant; or ſwell above this laſt plain, ſo others may + be depreſs'd beneath it; as (to explane my ſelf by a groſs + Compariſon) in divers places of the Surface of the Earth, there are + not only Neighbouring Hills, Trees, &c. that are rais'd above the + Horizontal Level of the Valley, but Rivers, Wells, Pits and other Cavities + that are depreſs'd beneath it, and that ſuch Protuberant and + Concave parts of a Surface may remit the Light ſo differingly, as + much to vary a Colour, ſome examples and other things, that we ſhall + hereafter have occaſion to take notice off in this Tract, will ſufficiently + declare, till when, it may ſuffice to put you in mind, that of two + Flat-ſides of the ſame piece of, for example, red Marble, the + one being diligently Poliſhed, and the other left to its former + Roughneſs, the differing degrees or ſorts of Aſperity, for + the ſide that is ſmooth to the Touch wants not its Roughneſs, + will ſo diverſifie the Light reflected from the ſeveral + Plains to the Eye, that a Painter would employ two differing Colours to + repreſent them. + </p> + <p> + 7. And I hope, <i>Pyrophilus</i>, you will not think it ſtrange or + impertinent, that I employ in divers paſſages of theſe + Papers, + <!-- Page 32 --> <span class="pagenum"><a name="LPage_32" id="LPage_32"></a>[pg + 32]</span> examples drawn from Bodies and Shadows far more Groſs, + than thoſe minute Protuberances and ſhady Pores on which in moſt + caſes the Colour of a Body as 'tis an Inherent Quality or Diſpoſition + of its Surface, ſeems to depend. For ſometimes I employ ſuch + Examples, rather to declare my Meaning, than prove my Conjecture; things, + whom their Smallneſs makes Inſenſible, being better repreſented + to the Imagination by ſuch familiar Objects, as being like them + enough in other reſpects, are of a Viſible bulk. And next, + though the Beams of Light are ſuch ſubtil Bodies, that in reſpect + of them, even Surfaces that are ſenſibly Smooth, are not exactly + ſo, but have their own degree of Roughneſs, conſiſting + of little Protuberances and Depreſſions; and though conſequently + ſuch Inequalities may ſuffice to give Bodies differing Colours, + as we ſee in Marble that appears White or Black, or Red or Blew, even + when the moſt carefully Poliſh'd, yet 'tis plain by the late Inſtance + of Red Marble, and many others, that even bigger Protuberances and greater + Shades may likewiſe ſo Diverſifie the Roughneſs of a + Bodies Superficies, as manifeſtly to concurr to the varying of its + Colour, whereby ſuch Examples appear to be proper enough + <!-- Page 33 --> <span class="pagenum"><a name="LPage_33" id="LPage_33"></a>[pg + 33]</span> to be employ'd in ſuch a Subject as we have now in hand. + And having hinted thus much on this Occaſion, I now proceed. + </p> + <p> + 8. The Situation alſo of the Superficial particles is conſiderable, + which I diſtinguiſh into the Poſture of the ſingle + Corpuſcles, in reſpect of the Light, and of the Eye, and the + Order of them in reference alſo to one another; for a Body may + otherwiſe reflect the Light, when its Superficial particles are more + erected upon the Plain that may be conceiv'd to paſs along their Baſis, + and when the Points or Extremes of ſuch Particles are Obverted to the + Eye, than when thoſe Particles are ſo Inclin'd, that their Sides + are in great part Diſcernable, as the Colour of Pluſh or Velvet + will appear Vary'd to you, if you carefully ſtroak part of it one + way, and part of it another, the poſture of the particular Thrids, in + reference to the Light, or the Eye, becoming thereby different. And you + may obſerve in a Field of ripe Corn blown upon by the Wind, that + there will appear as it were Waves of a Colour (at leaſt Gradually) + differing from that of the reſt of the Field, the Wind by Depreſſing + ſome of the Ears, and not at the ſame time others, making the + one Reflect more from + <!-- Page 34 --> <span class="pagenum"><a name="LPage_34" id="LPage_34"></a>[pg + 34]</span> the Lateral and Strawy parts, than do the reſt. And ſo, + when Doggs are ſo angry, as to Erect the Hairs upon their Necks, and + upon ſome other parts of their Bodies, thoſe Parts ſeem to + acquire a Colour vary'd from that which the ſame Hairs made, when in + their uſual Poſture they did farr more ſtoop. And that the + Order wherein the Superficial Corpuſcles are Rang'd is not to be + neglected, we may gueſs by turning of Water into Froth, the beating + of Glaſs, and the ſcraping of Horns, in which caſes the + Corpuſcles that were before ſo marſhall'd as to be Perſpicuous, + do by the troubling of that Order become Diſpos'd to terminate and + reflect more Light, and thereby to appear Whitiſh. And there are + other ways in which the Order of the Protuberant parts, in reference to + the Eye, may much contribute to the appearing of a particular Colour, for + I have often obſerv'd, that when Peaſe are Planted, or Set in + Parallel Lines, and are Shot up about half a Foot above the Surface of the + Ground, by looking on the Field or Plot of Ground from that part towards + which the Parallel Lines tended, the greater part of the Ground by farr + would appear of its own dirty Colour, but if I look'd upon it Tranſverſly, + the Plot + <!-- Page 35 --> <span class="pagenum"><a name="LPage_35" id="LPage_35"></a>[pg + 35]</span> would appear very Green, the upper parts of the Peaſe + hindering the intercepted parts of the Ground, which as I ſaid + retain'd their wonted Colour, from being diſcover'd by the Eye. And I + know not, <i>Pyrophilus</i>, whether I might not add, that even the Motion + of the Small Parts of a Viſible Object may in ſome caſes + contribute, though it be not ſo eaſie to ſay how, to the + Producing or the Varying of a Colour; for I have ſeveral times made a + Liquor, which when it has well ſettled in a cloſe Vial, is Tranſparent + and Colourleſs, but as ſoon as the Glaſs is unſtopp'd, + begins to fly away very plentifully in a White and Opacous fume; and there + are other Bodies, whoſe Fumes, when they fill a Receiver, would make + one ſuſpect it contains Milk, and yet when theſe Fumes + ſettle into a Liquor, that Liquor is not White, but Tranſparent; + And ſuch White Fumes I have ſeen afforded by unſtopping a + Liquor I know, which yet is it ſelf Diaphanous and Red; Nor are theſe + the only Inſtances of this Kind, that our Tryals can ſupply us + with. And if the Superficial Corpuſcles be of the Groſſer + ſort, and be ſo Framed, that their differing Sides or Faces may + exhibit differing Colours, then the Motion or Reſt of thoſe + Corpuſcles may be + <!-- Page 36 --> <span class="pagenum"><a name="LPage_36" id="LPage_36"></a>[pg + 36]</span> conſiderable, as to the Colour of the Superficies they + compoſe, upon this account, that ſometimes more, ſometimes + fewer of the Sides diſpos'd to exhibit ſuch a Colour may by this + means become or continue more Obverted to the Eye than the reſt, and + compoſe a Phyſical Surface, that will be more or leſs + ſenſibly interrupted; As, to explane my meaning, by propoſing + a groſs Example, I remember, that in ſome ſorts of Leavy + Plants thick ſet by one another, the two ſides of whoſe + Leaves were of ſomewhat differing Colours, there would be a notable + Diſparity as to Colour, if you look'd upon them both when the Leaves + being at Reſt had their upper and commonly expos'd ſides + Obverted to the Eye, and when a breath of Wind paſſing thorow + them, made great Numbers of the uſually Hidden ſides of the + Leaves become conſpicuous. And though the Little Bodies, we were + lately ſpeaking of, may Singly and Apart ſeem almoſt + Colourleſs, yet when Many of them are plac'd by one another, ſo + near, that the Eye does not eaſily diſcern an Interruption, + within a ſenſible ſpace, they may exhibit a Colour; as we + ſee, that though a Slendereſt Thrid of Dy'd Silk do's, whilſt + look'd on Single, ſeem almoſt quite Devoyd of Redneſs, (for + inſtance) + <!-- Page 37 --> <span class="pagenum"><a name="LPage_37" id="LPage_37"></a>[pg + 37]</span> yet when numbers of theſe Thrids are brought together into + one Skein, their Colour becomes notorious. + </p> + <p> + 9. But the ſame Occaſion that invited me to ſay what I have + mention'd concerning the Leaves of Trees, invites me alſo to give you + ſome account of what happens in Changeable Taffities, where we ſee + differing Colours, as it were, Emerge and Vaniſh upon the Ruffling of + the ſame piece of Silk: As I have divers times with Pleaſure obſerv'd, + by the help of ſuch a <i>Microſcope</i>, as, though it do not + very much Magnifie the Object, has in recompence this great Conveniency, + that you may eaſily, as faſt as you pleaſe, remove it from + one part to another of a Large Object, of which the Glaſs taking a + great part at once, you may thereby preſently Survey the Whole. Now + by the help of ſuch a <i>Microſcope</i> I could eaſily (as + I began to ſay) diſcern, that in a piece of Changeable Taffity, + (that appear'd, for Inſtance, ſometimes Red, and ſometimes + Green) the Stuff was compos'd of Red thrids and Green, paſſing + under and over each other, and croſſing one another in almoſt + innumerable points; and if I look'd through the Glaſs upon any conſiderable + portion of the Stuff, that (for example ſake) to the + <!-- Page 38 --> <span class="pagenum"><a name="LPage_38" id="LPage_38"></a>[pg + 38]</span> naked Eye appear'd to be Red, I could plainly ſee, that in + that Poſition, the Red thrids were Conſpicuous, and reflected a + vivid Light; and though I could alſo perceive, that there were Green + ones, yet by reaſon of their diſadvantagious Poſition in + the <i>Phyſical Surface</i> of the Taffity, they were in part hid by + the more Protuberant Thrids of the other Colour; and for the ſame cauſe, + the Reflection from as much of the Green as was diſcover'd, was + comparatively but Dim and Faint. And if, on the contrary, I look'd through + the <i>Microſcope</i> upon any part that appear'd Green, I could + plainly ſee that the Red thrids were leſs fully expos'd to the + Eye, and obſcur'd by the Green ones, which therefore made up the + Predominant Colour. And by obſerving the Texture of the Silken Stuff, + I could eaſiſy ſo expoſe the Thrids either of the one + Colour or of the other to my Eye, as at pleaſure to exhibit an + apparition of Red or Green, or make thoſe Colours ſucceed one + another: So that, when I obſerv'd their Succeſſion by the + help of the Glaſs, I could mark how the Predominant Colour did as it + were ſtart out, when the Thrids that exhibited it came to be + advanagiouſly plac'd; And by making little Folds in the Stuff after a + certain manner, + <!-- Page 39 --> <span class="pagenum"><a name="LPage_39" id="LPage_39"></a>[pg + 39]</span> the Sides that met and terminated in thoſe Folds, would + appear to the naked Eye, one of them Red, and the other Green. When Thrids + of more than two differing Colours chance to be Interwoven, the reſulting + changeableneſs of the Taffity may be alſo ſomewhat + different. But I chooſe to give an Inſtance in the Stuff I have + been ſpeaking off, becauſe the mixture being more Simple, the + way whereby the Changeableneſs is produc'd, may be the more eaſily + apprehended: and though Reaſon alone might readily enough lead a conſidering + Man to gueſs at the Explication, in caſe he knew how Changeable + Taffities are made: yet I thought it not impertinent to mention it, becauſe + both Scholars and Gentlemen are wont to look upon the Inquiry into + Manufactures, as a <i>Mechanick</i> imployment, and conſequently + below Them; and becauſe alſo with ſuch a <i>Microſcope</i> + as I have been mentioning, the diſcovery is as well Pleaſant as + Satisfactory, and may afford Hints of the Solution of other <i>Phænomena</i> + of Colours. And it were not amiſs, that ſome diligent Inquiry + were made, whether the <i>Microſcope</i> would give us an account of + the Variableneſs of Colour, that is ſo Conſpicuous and + ſo Delightfull in Mother of Pearl, in Opalls, and ſome + <!-- Page 40 --> <span class="pagenum"><a name="LPage_40" id="LPage_40"></a>[pg + 40]</span> other reſembling Bodies: For though I remember I did + formerly attempt ſomething of that Kind (fruitleſly enough) upon + Mother of Pearl, yet not having then the advantage of my beſt <i>Microſcope</i>, + nor ſome Conveniences that might have been wiſh'd, I leave it to + you, who have better Eyes, to try what you can do further; ſince + 'twill be <i>Some</i> diſcovery to find, that, in this caſe, the + beſt Eyes and <i>Microſcopes</i> themſelves can make <i>None</i>. + </p> + <p> + 10. I confeſs, <i>Pyrophilus</i>, that a great part of what I have + deliver'd, (or propos'd rather) concerning the differing forms of Aſperity + in Bodies, by which Differences the incident Light either comes to be + Reflected with more or leſs of Shade, and with that Shade more or leſs + Interrupted, or elſe happens to be alſo otherwiſe Modify'd + or Troubl'd, is but Conjectural. But I am not ſure, that if it were + not for the Dullneſs of our Senſes, either theſe or ſome + other Notions of Kin to them, might be better Countenanc'd; for I am apt + to ſuſpect, that if we were Sharp ſighted enough, or had + ſuch perfect <i>Microſcopes</i>, as I fear are more to be wiſh'd + than hop'd for, our promoted Senſe might diſcern in the Phyſical + Surfaces of Bodies, both a great many latent Ruggidneſſes, and + the particular + <!-- Page 41 --> <span class="pagenum"><a name="LPage_41" id="LPage_41"></a>[pg + 41]</span> Sizes, Shapes, and Situations of the extremely little Bodies + that cauſe them, and perhaps might perceive among other Varieties + that we now can but imagine, how thoſe little Protuberances and + Cavities do Interrupt and Dilate the Light, by mingling with it a + multitude of little and ſingly undiſcernable Shades, though + ſome of them more, and ſome of them leſs Minute, ſome + leſs, and ſome more Numerous; according to the Nature and Degree + of the particular Colour we attribute to the Viſible Object; as we + ſee, that in the Moon we can with Excellent <i>Teleſcopes</i> diſcern + many Hills and Vallies, and as it were Pits and other Parts, whereof + ſome are more, and ſome leſs Vividly illuſtrated, and + others have a fainter, others a deeper Shade, though the naked Eye can diſcern + no ſuch matter in that Planet. And with an Excellent <i>Microſcope</i>, + where the <i>Naked</i> Eye did ſee but a Green powder, the <i>Aſſisted</i> + Eye as we noted above, could diſcern particular Granules, ſome + of them of a Blew, and ſome of them of a Yellow colour, which Corpuſcles + we had beforehand caus'd to be exquiſitly mix'd to compound the + Green. + </p> + <p> + 11. And, <i>Pyrophilus</i>, that you may not think me altogether + extravagant in what I + <!-- Page 42 --> <span class="pagenum"><a name="LPage_42" id="LPage_42"></a>[pg + 42]</span> have ſaid of the Poſſibility, (for I ſpeak + of no more) of diſcerning the differing forms of Aſperity in the + Surfaces of Bodies of ſeveral Colours, I'l here ſet down a + Memorable particular that chanc'd to come to my Knowledge, ſince I + writ a good part of this <i>Eſſay</i>; and it is this. Meeting + caſually the other Day with the deſervedly Famous<a name="LNtA_4" + id="LNtA_4_"></a><a href="#LNt_4"><sup>4</sup></a> Dr. <i>J. Finch</i>, + Extraordinary <i>Anatomiſt</i> to that Great Patron of the <i>Virtuoſi</i>, + the now Great Duke of <i>Toſcany</i>, and enquiring of this Ingenious + Perſon, what might be the chief Rarity he had ſeen in his late + return out of <i>Italy</i> into <i>England</i>, he told me, it was a Man + at <i>Maeſtricht</i> in the Low-Countrys, who at certain times can diſcern + and <i>diſtinguiſh Colours by the Touch</i> with his Fingers. + You'l eaſily Conclude, that this is farr more ſtrange, than what + I propos'd but as <i>not Impoſſible</i>; ſince the Senſe + of the <i>Retina</i> ſeeming to be much more Tender and quick than + that of thoſe Groſſer Filaments, Nerves or Membranes of our + Fingers, wherewith we uſe to handle Groſs and Hard Bodies, it + ſeems ſcarce credible, that any Accuſtomance, or Diet, or + peculiarity of Conſtitution, ſhould enable a Man to diſtinguiſh + <!-- Page 43 --> <span class="pagenum"><a name="LPage_43" id="LPage_43"></a>[pg + 43]</span> with ſuch Groſs and Unſuitable Organs, ſuch + Nice and Subtile Differences as thoſe of the forms of Aſperity, + that belong to differing Colours, to receive whoſe Languid and + Delicate Impreſſions by the Intervention of Light, Nature ſeems + to have appointed and contexed into the <i>Retina</i> the tender and + delicate Pith of the Optick Nerve. Wherefore I confeſs, I propos'd + divers Scruples, and particularly whether the Doctor had taken care to + bind a Napkin or Hankerchief over his Eyes ſo carefully, as to be + ſure he could make no uſe of his Sight, though he had but + Counterfeited the want of it, to which I added divers other Queſtions, + to ſatisfie my Self, whether there were any Likelihood of Colluſion + or other Tricks. But I found that the Judicious Doctor having gone farr + out of his way, purpoſely to ſatisfie Himſelf and his + Learned Prince about this Wonder, had been very Watchfull and Circumſpect + to keep <i>Himſelf</i> from being Impos'd upon. And that he might not + through any miſtake in point of Memory mis-inform <i>Me</i>, he did + me the Favour at my Requeſt, to look out the Notes he had Written for + his Own and his Princes Information, the ſumm of which Memorials, as + far as we ſhall mention them here, was this, That the Doctor + <!-- Page 44 --> <span class="pagenum"><a name="LPage_44" id="LPage_44"></a>[pg + 44]</span> having been inform'd at <i>Utrecht</i>, that there Lived one at + ſome Miles diſtance from <i>Maestricht</i>, who could diſtinguiſh + Colours by the Touch, when he came to the laſt nam'd Town, he ſent + a Meſſenger for him, and having Examin'd him, was told upon + Enquiry theſe Particulars: + </p> + <p> + That the Man's name was <i>John Vermaaſen</i>, at that time about 33 + Years of Age; that when he was but two years Old, he had the Small Pox, + which rendred him abſolutely Blind: That at this preſent he is + an <i>Organiſt</i>, and ſerves that Office in a publick Quire. + </p> + <p> + That the Doctor diſcourſing with him over Night, the Blind man + affirm'd, that he could diſtinguiſh Colours by the Touch, but + that he could not do it, unleſs he were Faſting; Any quantity of + Drink taking from him that Exquiſitneſs of Touch, which is requiſite + to ſo Nice a Senſation. + </p> + <p> + That hereupon the Doctor provided againſt the next Morning ſeven + pieces of Ribbon, of theſe ſeven Colours, Black, White, Red, + Blew, Green, Yellow, and Gray, but as for <i>mingled</i> Colours, this <i>Vermaaſen</i> + would not undertake to diſcern them, though if offer'd, he would tell + that they were <i>Mix'd</i>. + </p> + <p> + That to diſcern the Colour of the Ribbon, + <!-- Page 45 --> <span class="pagenum"><a name="LPage_45" id="LPage_45"></a>[pg + 45]</span> he places it betwixt the Thumb and the Fore-finger, but his moſt + exquiſite perception was in his Thumb, and much better in the right + Thumb than in the left. + </p> + <p> + That after the Blind man had four or five times told the Doctor the ſeveral + Colours, (though Blinded with a Napkin for fear he might have ſome + Sight) the Doctor found he was twice miſtaken, for he call'd the + White Black, and the Red Blew, but ſtill, he, before his Errour, + would lay them by in Pairs, ſaying, that though he could eaſily + diſtinguiſh them from all others, yet thoſe two Pairs were + not eaſily diſtinguiſh'd amongſt themſelves, + whereupon the Doctor deſir'd to be told by him what kind of Diſcrimination + he had of Colours by his Touch, to which he gave a reply, for whoſe + ſake chiefly I inſert all this Narrative in this place, namely, + That all the difference was more or leſs Aſperity, for ſays + he, (I give you the Doctor's own words) Black feels as if you were feeling + Needles points, or ſome harſh Sand, and Red feels very Smooth. + </p> + <p> + That the Doctor having deſir'd him to tell in Order the difference of + Colours to his Touch, he did as follows; + </p> + <p> + Black and White are the moſt aſperous + <!-- Page 46 --> <span class="pagenum"><a name="LPage_46" id="LPage_46"></a>[pg + 46]</span> or unequal of all Colours, and ſo like, that 'tis very + hard to diſtinguiſh them, but Black is the moſt Rough of + the two, Green is next in Aſperity, Gray next to Green in Aſperity, + Yellow is the fifth in degree of Aſperity, Red and Blew are ſo + like, that they are as hard to diſtinguiſh as Black and White, + but Red is ſomewhat more Aſperous than Blew, ſo that Red + has the ſixth place, and Blew the ſeventh in Aſperity. + </p> + <p> + 12. To theſe Informations the Obliging Doctor was pleas'd to add the + welcome preſent of three of thoſe very pieces of Ribbon, whoſe + Colours in his preſence the Blind man had diſtinguiſhed, + pronouncing the one Gray, the other Red, and the third Green, which I keep + by me as Rarities, and the rather, becauſe he fear'd the reſt + were miſcarry'd. + </p> + <p> + 13. Before I ſaw the Notes that afforded me the precedent Narrative, + I confeſs I ſuſpected this man might have thus diſcriminated + Colours, rather by the Smell than by the Touch; for ſome of the + Ingredients imployed by Dyers to Colour things, have Sents, that are not + ſo Languid, nor ſo near of Kin, but that I thought it not impoſſible + that a very Critical Noſe might diſtinguiſh them, and this + I the rather ſuſpected, becauſe he requir'd, that the + Ribbons, + <!-- Page 47 --> <span class="pagenum"><a name="LPage_47" id="LPage_47"></a>[pg + 47]</span> whoſe Colours he was to Name, ſhould be offer'd him + Faſting in the morning; for I have obſerv'd in Setting Doggs, + that the feeding of them (especially with ſome ſorts of + Aliments) does very much impair the exquiſite ſent of their Noſes. + And though ſome of the foregoing particulars would have prevented + that Conjecture, yet I confeſs to you (<i>Pyrophilus</i>) that I + would gladly have had the Opportunity of Examining this Man my ſelf, + and of Queſtioning him about divers particulars which I do not find + to have been yet thought upon. And though it be not incredible to me, that + ſince the Liquors that Dyers imploy to tinge, are qualifi'd to do + ſo by multitudes of little Corpuſcles of the Pigment or Dying + ſtuff, which are diſſolved and extracted by the Liquor, and + ſwim to and fro in it, thoſe Corpuſcles of Colour (as the + <i>Atomiſts</i> call them) inſinuating themſelves into, and + filling all the Pores of the Body to be Dyed, may Aſperate its + Superficies more or leſs according to the Bigneſs and Texture of + the Corpuſcles of the Pigment; yet I can ſcarce believe, that + our Blind man could diſtinguiſh all the Colours he did, meerly + by the Ribbons having more or leſs of Aſperity, ſo that I + cannot but think, notwithſtanding this Hiſtory, that the Blind + man + <!-- Page 48 --> <span class="pagenum"><a name="LPage_48" id="LPage_48"></a>[pg + 48]</span> diſtinguiſh'd Colours not only by the <i>Degrees</i> + of Aſperity in the Bodies offer'd to him, but by <i>Forms</i> of it, + though this (latter) would perhaps have been very difficult for him to + make an Intelligible mention of, becauſe thoſe Minute diſparities + having not been taken notice of by men for want of touch as Exquiſite + as our Blind Mans, are things he could not have Intelligibly expreſs'd, + which will eaſily ſeem Probable, if you conſider, that + under the name of Sharp, and Sweet, and Sour, there are abundance of, as + it were, immediate peculiar Reliſhes or Taſts in differing + ſorts of Wine, which though Critical and Experienc'd Palats can eaſily + diſcern themſelves cannot make them be underſtood by + others, ſuch Minute differences not having hitherto any Diſtinct + names aſſign'd them. And it ſeems that there was ſomthing + in the Forms of Aſperity that was requiſite to the Diſtinction + of Colours, beſides the Degree of it, ſince he found it ſo + difficult to diſtinguſh Black and White from one another, though + not from other Colours. For I might urge, that he ſeems not conſonant + to himſelf about the <i>Red</i>, which as you have ſeen in one + place, he repreſents as ſomewhat more Aſperous than the <i>Blew</i>; + and in another, very Smooth: But becauſe he ſpeaks of this + Smoothneſs in that place, + <!-- Page 49 --> <span class="pagenum"><a name="LPage_49" id="LPage_49"></a>[pg + 49]</span> where he mentions the Roughneſs of <i>Black</i>, we may + favourably preſume that he might mean but a <i>comparative Smoothneſs</i>; + and therefore I ſhall not Inſiſt on this, but rather + Countenance my Conjecture by this, that he found it ſo Difficult, not + only, to Diſcriminate Red and Blew, (though the firſt of our + promiſcuous Experiments will inform you, that the Red reflects by + great Odds more Light than the other) but alſo to diſtinguiſh + Black and White from one another, though not from other Colours. And + indeed, though in the Ribbonds that were offer'd him, they might be almoſt + equally Rough, yet in ſuch ſlender Corpuſcles as thoſe + of Colour, there may eaſily enough be Conceiv'd, not only a greater + Cloſeneſs of Parts, or elſe Paucity of Protuberant Corpuſcles, + and the little extant Particles may be otherwiſe Figur'd, and Rang'd + in the White than in the Black, but the Cavities may be much Deeper in the + one than the other. + </p> + <p> + 14. And perhaps, (<i>Pyrophilus</i>) it may prove ſome <i>Illuſtration + of what I mean</i>, and help you to conceive how <i>this may</i> be, if I + Repreſent, that where the Particles are ſo exceeding Slender, we + may allow the Parts expos'd to the Sight and Touch to be a little Convex + in compariſon of the Erected + <!-- Page 50 --> <span class="pagenum"><a name="LPage_50" id="LPage_50"></a>[pg + 50]</span> Particle of Black Bodies, as if there were Wyres I know not how + many times Slenderer than a Hair: whether you ſuppoſe them to be + Figur'd like Needles, or Cylindrically, like the Hairs of a Bruſh, + with Hemiſphærical (or at leaſt Convex) Tops, they will be + ſo very Slender, and conſequently the Points both of the one + ſort and the other ſo very Sharp, that even an exquiſite + Touch will be able to diſtinguiſh no greater Difference between + them, than that which our Blind man allow'd, when comparing Black and + White Bodies, he ſaid, that the latter was the leſs Rough of the + two. Nor is every Kind of Roughneſs, though Senſible enough, + Inconſiſtent with Whiteneſs, there being Caſes, + wherein the Phyſical Superficies of a Body is made by the ſame + Operation both <i>Rough</i> and <i>white</i>, as when the Level Surface of + clear Water being by agitation Aſperated with a multitude of Unequal + Bubbles, do's thereby acquire a Whiteneſs; and as a Smooth piece of + Glaſs, by being Scratch'd with a Diamond, do's in the Aſperated + part of its Surface diſcloſe the ſame Colour. But more + (perchance) of this elſewhere. + </p> + <p> + 15. And therefore, we ſhall here paſs by the Queſtion, + whether any thing might + <!-- Page 51 --> <span class="pagenum"><a name="LPage_51" id="LPage_51"></a>[pg + 51]</span> be conſider'd about the Opacity of the Corpuſcles of + Black Pigments, and the <i>Comparative</i> Diaphaneity of thoſe of + many White Bodies, apply'd to our preſent Caſe; and proceed, to + repreſent, That the newly mention'd Exiguity and Shape of the extant + Particles being ſuppos'd, it will then be conſiderable what we + lately but Hinted, (and therefore muſt now ſomewhat Explane) + That the Depth of the little Cavities, intercepted between the extant + Particles, without being ſo much greater in Black Bodies than in + White ones, as to be perceptibly ſo to the Groſs Organs of + Touch, may be very much greater in reference to their Diſpoſition + of Reflecting the imaginary ſubtile Beams of Light. For in Black + Bodies, thoſe Little intercepted Cavities, and other Depreſſions, + may be ſo Figur'd, ſo Narrow and ſo Deep, that the incident + Beams of Light, which the more extant Parts of the Phyſical + Superficies are diſpos'd to Reflect inwards, may be Detain'd there, + and prove unable to Emerge; whilſt in a White Body, the Slender + Particles may not only by their Figure be fitted to Reflect the Light + copiouſly outwards, but the intercepted Cavities being not Deep, nor + perhaps very Narrow, the Bottoms of them may be ſo Conſtituted, + as to + <!-- Page 52 --> <span class="pagenum"><a name="LPage_52" id="LPage_52"></a>[pg + 52]</span> be fit to Reflect outwards much of the Light that falls even + upon Them; as you may poſſibly better apprehend, when we ſhall + come to treat of Whiteneſs and Blackneſs. In the mean time it + may ſuffice, that you take Notice with me, that the Blind mans + Relations import no neceſſity of Concluding, that, though, becauſe, + according to the Judgment of his Touch, Black was the Rougheſt, as it + is the Darkeſt of Colours, therefore White, which (according to us) + is the Lighteſt, ſhould be alſo the Smootheſt: ſince + I obſerve, that he makes Yellow to be two Degrees more Aſperous + than Blew, and as much leſs Aſperous than Green; whereas indeed, + Yellow do's not only appear to the Eye a Lighter Colour than Blew, but (by + our firſt Experiment hereafter to be mention'd) it will appear, that + Yellow reflected much more Light than Blew, and manifeſtly more than + Green, (which we need not much wonder at, ſince in this Colour and + the two others (Blew and Yellow) 'tis not <i>only</i> the <i>Reflected + Light</i> that is to be conſidered, ſince to produce both theſe, + <i>Refraction</i> ſeems to Intervene, which by its Varieties may much + alter the Caſe:) which both ſeems to ſtrengthen the + Conjecture I was formerly propoſing, that there was ſomething elſe + <!-- Page 53 --> <span class="pagenum"><a name="LPage_53" id="LPage_53"></a>[pg + 53]</span> in the <i>Kinds</i> of Aſperity, as well as in the <i>Degrees</i> + of it, which enabled our Blind man to Diſcriminate Colours, and do's + at leaſt ſhow, that we cannot in all Caſes from the bare + Difference in the Degrees of Aſperity betwixt Colours, ſafely + conclude, that the Rougher of any two always Reflects the leaſt + Light. + </p> + <p> + 16. But this notwithſtanding, (<i>Pyrophilus</i>) and what ever Curioſity + I may have had to move ſome Queſtions to our Sagacious Blind + man, yet thus much I think you will admit us to have gain'd by his Teſtimony, + that ſince many Colours may be felt with the Circumſtances above + related, the Surfaces of ſuch Coloured Bodies muſt certainly + have differing <i>Degrees</i>, and in all probability have differing <i>Forms</i> + or Kinds of Aſperity belonging to them, which is all the Uſe + that my preſent attempt obliges me to make of the Hiſtory above + deliver'd, that being ſufficient to prove, <i>that</i> Colour do's + much depend upon the Diſpoſition of the Superficial parts of + Bodies, and to ſhew in general, <i>wherein</i> 'tis probable that + ſuch a Diſpoſition do's (principally at leaſt) conſiſt. + </p> + <p> + 17. But to return to what I was ſaying before I began to make mention + of our Blind <i>Organiſt</i>, what we have deliver'd + <!-- Page 54 --> <span class="pagenum"><a name="LPage_54" id="LPage_54"></a>[pg + 54]</span> touching the cauſes of the ſeveral Forms or Aſperity + that may Diverſifie the Surfaces of Colour'd Bodies, may perchance + ſomewhat aſſiſt us to make ſome Conjectures in + the general, at ſeveral of the ways whereby 'tis poſſible + for the Experiments hereafter to be mention'd, to produce the ſuddain + changes of Colours that are wont to be Conſequent upon them; for moſt + of theſe <i>Phænomena</i> being produc'd by the Intervention of + Liquors, and theſe for the moſt part abounding with very Minute, + Active, and Variouſly Figur'd Saline Corpuſcles, Liquors ſo + Qualify'd may well enough very Nimbly after the Texture of the Body they + are imploy'd to Work upon, and ſo may change the form of Aſperity, + and thereby make them Remit to the Eye the Light that falls on them, after + another manner than they did before, and by that means Vary the Colour, + ſo farr forth as it depends upon the Texture or Diſpoſition + of the Seen Parts of the Object, which I ſay, <i>Pyrophilus</i>, that + you may not think I would abſolutely exclude all other ways of + Modifying the Beams of Light between their Parting from the Lucid Body, + and their Reception into the common Senſory. + </p> + <p> + 18. Now there ſeem to me divers ways, + <!-- Page 55 --> <span class="pagenum"><a name="LPage_55" id="LPage_55"></a>[pg + 55]</span> by which we may conceive that Liquors may Nimbly alter the + Colour of one another, and of other Bodies, upon which they Act, but my + preſent haſte will allow me to mention but ſome of them, + without Inſiſting ſo much as upon thoſe I ſhall + name. + </p> + <p> + 19. And firſt, the Minute Corpuſcles that compoſe a Liquor + may early inſinuate themſelves into thoſe Pores of Bodies, + whereto their Size and Figure makes them Congruous, and theſe Pores + they may either exactly Fill, or but Inadequately, and in this latter Caſe + they will for the moſt part alter the Number and Figure, and always + the Bigneſs of the former Pores. And in what capacity ſoever theſe + Corpuſcles of a Liquor come to be Lodg'd or Harbour'd in the Pores + that admit them, the Surface of the Body will for the moſt part have + its Aſperity alter'd, and the Incident Light that meets with a Groſſer + Liquor in the little Cavities that before contain'd nothing but Air, or + ſome yet Subtiler Fluid, will have its Beams either Refracted, or + Imbib'd, or elſe Reflected more or leſs Interruptedly, than they + would be, if the Body had been Unmoiſtned, as we ſee, that even + fair Water falling on white Paper, or Linnen, and divers other Bodies + <!-- Page 56 --> <span class="pagenum"><a name="LPage_56" id="LPage_56"></a>[pg + 56]</span> apt to ſoak it in, will for ſome ſuch Reaſons + as thoſe newly mention'd, immediately alter the Colour of them, and + for the moſt part make it Sadder than that of the Unwetted Parts of + the ſame Bodies. And ſo you may ſee, that when in the + Summer the High-ways are Dry and Duſty, if there falls ſtore of + Rain, they will quickly appear of a much Darker Colour than they did + before, and if a Drop of Oyl be let fall upon a Sheet of White Paper, that + part of it, which by the Imbibition of the Liquor acquires a greater + Continuity, and ſome Tranſparency, will appear much Darker than + the reſt, many of the Incident Beams of Light being now Tranſmitted, + that otherwiſe would be Reflected towards the Beholders Eyes. + </p> + <p> + 20. Secondly, A Liquor may alter the Colour of a Body by freeing it from + thoſe things that hindred it from appearing in its Genuine Colour; + and though this may be ſaid to be rather a Reſtauration of a + Body to its own Colour, or a Retection of its native Colour, than a + Change, yet ſtill there Intervenes in it a change of the Colour which + the Body appear'd to be of before this Operation. And ſuch a change a + Liquor may work, either by Diſſolving, or Corroding, or by + ſome ſuch way of + <!-- Page 57 --> <span class="pagenum"><a name="LPage_57" id="LPage_57"></a>[pg + 57]</span> carrying off that Matter, which either Veil'd or Diſguis'd + the Colour that afterwards appears. Thus we reſtore Old pieces of + Dirty Gold to a clean and nitid Yellow, by putting them into the Fire, and + into <i>Aqua-fortis</i>, which take off the adventitious Filth that made + that pure Metall look of a Dirty Colour. And there is alſo an eaſie + way to reſtore Silver Coyns to their due Luſtre, by fetching off + that which Diſcolour'd them. And I know a <i>Chymical</i> Liquor, + which I employ'd to reſtore pieces of Cloath ſpotted with Greaſe + to their proper Colour, by Imbibing the Spotted part with this Liquor, + which Incorporating with the Greaſe, and yet being of a very Volatile + Nature, does eaſily carry it away with it Self. And I have ſometimes + try'd, that by Rubbing upon a good Touch-ſtone a certain <i>Metalline</i> + mixture ſo Compounded, that the Impreſſion it left upon the + Stone appear'd of a very differing Colour from that of Gold, yet a little + of <i>Aqua-fortis</i> would in a Trice make the Golden Colour diſcloſe + it ſelf, by Diſſolving the other <i>Metalline</i> Corpuſcles + that conceal'd thoſe of the Gold, which you know that <i>Menstruum</i> + will leave Untouch'd. + </p> + <p> + 21. Thirdly, A Liquor may alter the + <!-- Page 58 --> <span class="pagenum"><a name="LPage_58" id="LPage_58"></a>[pg + 58]</span> Colour of a Body by making a Comminution of its Parts, and that + principally two ways, the firſt by Diſjoyning and Diſſipating + thoſe Cluſters of Particles, if I may ſo call them, which + ſtuck more Looſely together, being faſtned only by ſome + more eaſily Diſſoluble Ciment, which ſeems to be the + Caſe of ſome of the following Experiments, where you'l find the + Colour of many Corpuſcles brought to cohere by having been + Precipitated together, Deſtroy'd by the Affuſion of very + peircing and inciſive Liquors. The other of the two ways I was ſpeaking + of, is, by Dividing the Groſſer and more Solid Particles into + Minute ones, which will be always Leſſer, and for the moſt + part otherwiſe Shap'd than the Entire Corpuſcle ſo Divided, + as it will happen in a piece of Wood reduc'd into Splinters or Chips, or + as when a piece of Chryſtal heated red Hot and quench'd in Cold water + is crack'd into a multitude of little Fragments, which though they fall + not aſunder, alter the Diſpoſition of the Body of the Chryſtal, + as to its manner of Reflecting the Light, as we ſhall have Occaſion + to ſhew hereafter. + </p> + <p> + 22. There is a fourth way contrary to the third, whereby a Liquor may + change the Colour of another Body, eſpecially of + <!-- Page 59 --> <span class="pagenum"><a name="LPage_59" id="LPage_59"></a>[pg + 59]</span> another Fluid, and that is, by procuring the Coalition of + ſeveral Particles that before lay too Scatter'd and Diſpers'd to + exhibit the Colour that afterwards appears. Thus ſometimes when I + have had a Solution of Gold ſo Dilated, that I doubted whether the + Liquor had really Imbib'd any true Gold or no, by pouring in a little <i>Mercury</i>, + I have been quickly able to ſatisfie my Self, that the Liquor + contain'd Gold, that Mettall after a little while Cloathing the Surface of + the <i>Quick-ſilver</i>, with a Thin Film of its own Livery. And + chiefly, though not only by this way of bringing the Minute parts of + Bodies together in ſuch Numbers as to make them become Notorious to + the Eye, many of theſe Colours ſeem to be Generated which are + produc'd by Precipitations, eſpecially by ſuch as are wont to be + made with fair Water, as when Reſinous Gumms diſſolv'd in + Spirit of Wine, are let fall again, if the Spirit be Copiouſly + diluted with that weakning Liquor. And ſo out of the Rectify'd and + Tranſparent Butter of <i>Antimony</i>, by the bare Mixture of fair + Water, there will be plentifully Precipitated that Milk-white Subſtance, + which by having its Looſer Salts well waſh'd off, is turn'd into + that Medicine, which Vulgar <i>Chymiſts</i> are pleas'd to call <i>Mercurius + Vitæ.</i> + </p> + <!-- Page 60 --> + <p> + <span class="pagenum"><a name="LPage_60" id="LPage_60"></a>[pg 60]</span> + </p> + <p> + 23. A fifth way, by which a Liquor may change the Colour of a Body, is, by + Diſlocating the Parts, and putting them out of their former Order + into another, and perhaps alſo altering the Poſture of the + ſingle Corpuſcles as well as their Order or Situation in reſpect + of one another. What certain Kinds of Commotion or Diſlocation of the + Parts of a Body may do towards the Changing its Colour, is not only + evident in the Mutations of Colour obſervable in <i>Quick-ſilver</i>, + and ſome other Concretes long kept by <i>Chymiſts</i> in a + Convenient Heat, though in cloſe Veſſels, but in the + Obvious Degenerations of Colour, which every Body may take notice of in + Bruis'd Cherries, and other Fruit, by comparing after a while the Colour + of the Injur'd with that of the Sound part of the ſame Fruit. And + that alſo ſuch Liquors, as we have been ſpeaking of, may + greatly Diſcompoſe the Textures of many Bodies, and thereby + alter the Diſpoſition of their Superficial parts, the great + Commotion made in Metalls, and ſeveral other Bodies by <i>Aqua-fortis</i>, + Oyl of <i>Vitriol</i>, and other Saline <i>Menſtruums</i>, may eaſily + perſwade us, and what ſuch Vary'd Situations of Parts may do + towards the Diverſifying of the manner of their Reflecting the Light, + may + <!-- Page 61 --> <span class="pagenum"><a name="LPage_61" id="LPage_61"></a>[pg + 61]</span> be Gueſs'd in ſome Meaſure by the Beating of + Tranſparent Glaſs into a White Powder, but farr better by the + Experiments lately Pointed at, and hereafter Deliver'd, as the Producing + and Deſtroying Colours by the means of ſubtil Saline Liquors, by + whoſe Affuſion the Parts of other Liquors are manifeſtly + both Agitated, and likewiſe Diſpos'd after another manner than + they were before ſuch Affuſion. And in ſome <i>Chymical</i> + Oyls, as particularly that of Lemmon Pills, by barely Shaking the Glaſs, + that holds it, into Bubbles, that Tranſpoſition of the Parts + which is conſequent to the Shaking, will ſhew you on the + Surfaces of the Bubbles exceeding Orient and Lively Colours, which when + the Bubbles relapſe into the reſt of the Oyl, do immediately + Vaniſh. + </p> + <p> + 24. I know not, <i>Pyrophilus</i>, whether I ſhould mention as a Diſtinct + way, becauſe it is of a ſomewhat more General Nature, that + Power, whereby a Liquor may alter the Colour of another Body, by putting + the Parts of it into Motion; For though poſſibly the Motion + ſo produc'd, does, as ſuch, ſeldome ſuddenly change + the Colour of the Body whoſe Parts are Agitated, yet this ſeems + to be one of the moſt General, however not Immediate cauſes of + <!-- Page 62 --> <span class="pagenum"><a name="LPage_62" id="LPage_62"></a>[pg + 62]</span> the Quick change of Colours in Bodies. For the Parts being put + into Motion by the adventitious Liquor, divers of them that were before + United, may become thereby Diſjoyn'd, and when that Motion ceaſes + or decays others of them may ſtick together, and that in a new Order, + by which means the Motion may ſometimes produce Permanent changes of + Colours, as in the Experiment you will meet with hereafter, of preſently + turning a Snowy White Body into a Yellow, by the bare Affuſion of + fair Water, which probably ſo Diſſolves the Saline Corpuſcles + that remain'd in the <i>Calx</i>, and ſets them at Liberty to Act + upon one another, and the Metall, far more Powerfully than the Water + without the Aſſiſtance of ſuch Saline Corpuſcles + could do. And though you rubb Blew <i>Vitriol</i>, how Venereal and Unſophiſticated + ſoever it be, upon the Whetted Blade of a Knife, it will not impart + to the Iron its Latent Colour, but if you moiſten the <i>Vitriol</i> + with your Spittle, or common Water, the Particles of the Liquor diſjoyning + thoſe of the <i>Vitriol</i>, and thereby giving them the Various + Agitation requiſite to Fluid Bodies, the Metalline Corpuſcles of + the thus Diſſolv'd <i>Vitriol</i> will Lodge themſelves in + Throngs in the Small and Congruous + <!-- Page 63 --> <span class="pagenum"><a name="LPage_63" id="LPage_63"></a>[pg + 63]</span> Pores of the Iron they are Rubb'd on, and ſo give the + Surface of it the Genuine Colour of the Copper. + </p> + <p> + 25. There remains yet a way, <i>Pyrophilus</i> to be mention'd, by which a + Liquor may alter the Colour of another Body, and this ſeems the moſt + Important of all, becauſe though it be nam'd but as One, yet it may + indeed comprehend Many, and that is, by Aſſociating the Saline + Corpuſcles, or any other Sort of the more Rigid ones of the Liquor, + with the Particles of the Body that it is employ'd to Work upon. For theſe + Adventitious Corpuſcles Aſſociating themſelves with + the Protuberant Particles of the Surface of a Colour'd Body, muſt + neceſſarily alter their Bigneſs, and will moſt + commonly alter their Shape. And how much the Colours of Bodies depend upon + the Bulk and Figure of their Superficial Particles, you may Gueſs by + this, that eminent antient <i>Philoſophers</i> and divers <i>Moderns</i>, + have thought that all Colours might in a general way be made out by theſe + two; whoſe being Diverſify'd, will in our Caſe be attended + with theſe two Circumſtances, the One, that the Protuberant + Particles being Increas'd in Bulk, they will oftentimes be Vary'd as to + the Cloſneſs or Laxity of + <!-- Page 64 --> <span class="pagenum"><a name="LPage_64" id="LPage_64"></a>[pg + 64]</span> their Order, fewer of them being contain'd within the ſame + Senſible (though Minute) ſpace than before; or elſe by + approaching to one another, they muſt Straighten the Pores, and it + may be too, they will by their manner of Aſſociating themſelves + with the Protuberant Particles, intercept new Pores. And this invites me + to conſider farther, that the Adventitious Corpuſcles, I have + been ſpeaking of, may likewiſe produce a great Change as well in + the Little Cavities or Pores as in the Protuberances of a Colour'd Body; + for beſides what we have juſt now taken notice of, they may by + Lodging themſelves in thoſe little Cavities, fill them up, and + it may well happen, that they may not only fill the Pores they Inſinuate + themſelves into, but likewiſe have their Upper Parts extant + above them; and partly by theſe new Protuberances, partly by Increaſing + the Bulk of the former, theſe Extraneous Corpuſcles may much + alter the Number and Bigneſs of the Surfaces Pores, changing the Old + and Intercepting new ones. And then 'tis Odds, but the Order of the Little + Extancies, and conſequently that of the Little Depreſſions + in point of Situation will be alter'd likewiſe: as if you diſſolve + <i>Quick-ſilver</i> in ſome kind of <i>Aqua-fortis</i>, + <!-- Page 65 --> <span class="pagenum"><a name="LPage_65" id="LPage_65"></a>[pg + 65]</span> the Saline Particles of the <i>Menstruum</i> Aſſociating + themſelves with the Mercurial Corpuſcles, will make a Green + Solution, which afterwards eaſily enough Degenerates. And Red Lead or + <i>Minium</i> being Diſſolv'd in Spirit of Vinegar, yields not a + Red, but a Clear Solution, the Redneſs of the Lead being by the + Liquor Deſtroy'd. But a better Inſtance may be taken from + Copper, for I have try'd, that if upon a Copper-plate you let ſome + Drops of weak <i>Aqua-fortis</i> reſt for a while, the Corpuſcles + of the <i>Menſtruum</i>, joyning with thoſe of the Metall, will + produce a very ſenſible Aſperity upon the Surface of the + Plate, and will Concoagulate that way into very minute Grains of a Pale + Blew <i>Vitriol</i>; whereas if upon another part of the ſame Plate + you ſuffer a little ſtrong Spirit of Urine to reſt a + competent time, you ſhall find the Aſperated Surface adorn'd + with a Deeper and Richer Blew. And the ſame <i>Aqua-fortis</i>, that + will quickly change the Redneſs of Red Lead into a Darker Colour, + will, being put upon Crude Lead, produce a Whitiſh Subſtance, as + with Copper it did a Blewiſh. And as with Iron it will produce a + Reddiſh, and on White Quills a Yellowiſh, ſo much may the + Coalition of the Parts of the ſame + <!-- Page 66 --> <span class="pagenum"><a name="LPage_66" id="LPage_66"></a>[pg + 66]</span> Liquor, with the differingly Figur'd Particles of Stable + Bodies, divers ways Aſperate the differingly Diſpos'd Surfaces, + and to Diverſifie the Colour of thoſe Bodies. And you'l eaſily + believe, that in many changes of Colour, that happen upon the Diſſolutions + of Metalls, and Precipitations made with Oyl of <i>Tartar</i>, and the + like Fix'd Salts, there may Intervene a Coalition of Saline Corpuſcles + with the Particles of the Body Diſſolv'd or Precipitated, if you + examine how much the <i>Vitriol</i> of a Metall may be Heavier than the + Metalline part of it alone, upon the Score of the Saline parts + Concoagulated therewith, and, that in Several Precipitations the weight of + the <i>Calx</i> does for the ſame Reaſon much exceed that of the + Metall, when it was firſt put in to be Diſſolv'd. + </p> + <p> + 26. But, <i>Pyrophilus</i>, to conſider theſe Matters more + particularly would be to forget that I declar'd againſt Adventuring, + at leaſt for this time, at particular Theories of Colours, and that + accordingly you may juſtly expect from me rather Experiments than + Speculations, and therefore I ſhall Diſmiſs this Subject of + the Forms of Superficial Aſperity in Colour'd Bodies, as ſoon as + I ſhall but have nam'd to you by way of Supplement to what we have + <!-- Page 67 --> <span class="pagenum"><a name="LPage_67" id="LPage_67"></a>[pg + 67]</span> hitherto Diſcours'd in this Section, a Couple of + Particulars, (which you'l eaſily grant me) The one, That there are + divers other ways for the ſpeedy Production even of True and + Permanent Colours in Bodies, beſides thoſe Practicable by the + help of Liquors; for proof of which Advertiſement, though ſeveral + Examples might be alleged, yet I ſhall need but Re-mind you of what I + mention'd to you above, touching the change of Colours ſuddenly made + on Temper'd Steel, and on Lead, by the Operation of Heat, without the + Intervention of a Liquor. But the other particular I am to obſerve to + you is of more Importance to our preſent Subject and it is, That + though Nature and Art may in ſome caſes ſo change the Aſperity + of the Superficial parts of a Body, as to change its Colour by either of + the ways I have propos'd Single or Unaſſiſted, yet for the + moſt part 'tis by two or three, or perhaps by more of the + fore-mention'd ways Aſſociated together, that the Effect is + produc'd, and if you conſider how Variouſly thoſe ſeveral + ways and ſome others Ally'd unto them, which I have left unmention'd, + may be Compounded and Apply'd, you will not much wonder that ſuch + fruitfull, whether Principles (or Manners of Diverſification) + <!-- Page 68 --> <span class="pagenum"><a name="LPage_68" id="LPage_68"></a>[pg + 68]</span> ſhould be fitted to Change or Generate no ſmall + ſtore of Differing Colours. + </p> + <p> + 27. Hitherto, <i>Pyrophilus</i>, we have in diſcourſing of the Aſperity + of Bodies conſider'd the little Protuberances of other Superficial + particles which make up that Roughneſs, as if we took it for granted, + that they muſt be perfectly Opacous and Impenetrable by the Beams of + Light, and ſo, muſt contribute to the Variety of Colours as they + terminate more or leſs Light, and reflect it to the Eye mix'd with + more or leſs of thus or thus mingl'd Shades. But to deal Ingenuouſly + with you, <i>Pyrophilus</i>, before I proceed any further, I muſt not + conceal from you, that I have often thought it worth a Serious Enquiry, + whether or no Particles of Matter, each of them ſing'y Inſenſible, + and therefore ſmall enough to be capable of being ſuch Minute + Particles as the <i>Atomiſts</i> both of old and of late have (not abſurdly) + called <i>Corpuſcula Coloris</i>, may not yet conſiſt each + of them of divers yet Minuter Particles, betwixt which we may conceive + little Commiſſures where they Adhere to one another, and, + however, may not be Porous enough to be, at leaſt in ſome + degree, Pervious to the unimaginably ſubtile Corpuſcles that + make up the Beams of + <!-- Page 69 --> <span class="pagenum"><a name="LPage_69" id="LPage_69"></a>[pg + 69]</span> Light, and conſequently to be in ſuch a degree + Diaphanous. For, <i>Pyrophilus</i>, that the propoſed Enquiry may be + of moment to him that ſearches after the Nature of Colour, you'l eaſily + grant, if you conſider, that whereas Perfectly Opacous bodies can but + reflect the incident Beams of Light, thoſe that are Diaphanous are + qualified to refract them too, and that Refraction has ſuch a ſtroak + in the Production of Colours, as you cannot but have taken notice of, and + perhaps admir'd in the Colours generated by the Trajection of Light + through Drops of Water that exhibit a Rain-bow, through Priſmatical + glaſſes, and through divers other Tranſparent bodies. But + 'tis like, <i>Pyrophilus</i>, you'l more eaſily allow that about this + matter 'tis rather Important to have a Certainty, than that 'tis Rational + to entertain a Doubt; wherefore I muſt mention to you ſome of + the Reaſons that make me think it may need a further Enquiry, for I + find that in a Darkned Room, where the Light is permitted to enter but at + One hole, the little wandering Particles of Duſt, that are commonly + called Motes, and, unleſs in the Sunbeams, are not taken notice of by + the unaſſiſted Sight, I have, I ſay, often obſerv'd, + that theſe roving Corpuſcles being look'd on by an Eye plac'd on + one ſide of the + <!-- Page 70 --> <span class="pagenum"><a name="LPage_70" id="LPage_70"></a>[pg + 70]</span> Beams that enter'd the Little hole, and by the Darkneſs + having its Pupill much Enlarg'd, I could diſcern that theſe + Motes as ſoon as they came within the compaſs of the Luminous, + whether Cylinder or Inverted Cone, if I may ſo call it, that was made + up by the Unclouded Beams of the Sun, did in certain poſitions appear + adorn'd with very vivid Colours, like thoſe of the Rain-bow, or + rather like thoſe of very Minute, but Sparkling fragments of + Diamonds; and as ſoon as the Continuance of their Motion had brought + them to an Inconvenient poſition in reference to the Light and the + Eye, they were only viſible without Darting any lively Colours as + before, which ſeems to argue that theſe little Motes, or minute + Fragments, of ſeveral ſorts of bodies reputed Opacous, and only + crumbled as to their Exteriour and Looſer parts into Duſt, did + not barely Reflect the Beams that fell upon them, but remit them to the + Eye Refracted too. We may alſo obſerve, that ſeveral + Bodies, (as well ſome of a Vegetable, as others of an Animal nature) + which are wont to paſs for Opacous, appear in great part Tranſparent, + when they are reduc'd into Thin parts, and held againſt a powerful + Light. This I have not only taken notice of in pieces of Ivory reduc'd but + into Thick leaves, as alſo in divers conſiderable + <!-- Page 71 --> <span class="pagenum"><a name="LPage_71" id="LPage_71"></a>[pg + 71]</span> Thick ſhells of Fiſhes, and in ſhaving of Wood, + but I have alſo found that a piece of Deal, far thicker than one + would eaſily imagine, being purpoſly interpoſed betwixt my + Eye plac'd in a Room, and the clear Daylight, was not only ſomewhat + Tranſparent, but (perhaps by reaſon of its Gummous nature) + appear'd quite through of a lovely Red. And in the Darkned Room above + mention'd, Bodies held againſt the hole at which the Light enter'd, + appear'd far leſs Opacous then they would elſewhere have done, + inſomuch that I could eaſily and plainly ſee through the + whole Thickneſs of my Hand, the Motions of a Body plac'd (at a very + near diſtance indeed, but yet) beyond it. And even in Minerals, the + Opacity is not always ſo great as many think, if the Body be made + Thin, for White Marble though of a pretty Thickneſs, being within a + Due diſtance plac'd betwixt the Eye and a Convenient Light, will + Suffer the Motions of ones Finger to be well diſcern'd through it, + and ſo will pieces, Thick enough, of many common Flints. But above + all, that Inſtance is remarkable, that is afforded us by <i>Muſcovie</i> + glaſs, (which ſome call <i>Selenites</i>, others <i>Lapis + Specularis</i>) for though plates of this Mineral, though but of a + moderate Thickneſs, do often appear Opacous, yet if + <!-- Page 72 --> <span class="pagenum"><a name="LPage_72" id="LPage_72"></a>[pg + 72]</span> one of theſe be Dextrouſly ſplit into the thinneſt + Leaves 'tis made up of, it will yield ſuch a number of them, as + ſcarce any thing but Experience could have perſwaded me, and theſe + Leaves will afford the moſt Tranſparent ſort of conſiſtent + Bodies, that, for ought I have obſerv'd, are yet known; and a ſingle + Leaf or Plate will be ſo far from being Opacous, that 'twill ſcarce + be ſo much as Viſible. And multitudes of Bodies there are, whoſe + Fragments ſeem Opacous to the naked Eye, which yet, when I have + included them in good <i>Microſcopes</i>, appear'd Tranſparent; + but, <i>Pyrophilus</i>, on the other ſide I am not yet ſure that + there are no Bodies, whoſe Minute Particles even in ſuch a <i>Microſcope</i> + as that of mine, which I was lately mentioning, will not appear + Diaphanous. For having conſider'd <i>Mercury</i> Precipitated <i>per + ſe</i>, the little Granules that made up the powder, look'd like + little fragments of Coral beheld by the naked Eye at a Diſtance (for + very Near at hand Coral will ſometimes, eſpecially if it be + Good, ſhew ſome Tranſparency.) Filings likewiſe of + Steel and Copper, though in an excellent <i>Microſcope</i>, and a + fair Day, they ſhow'd like pretty Big Fragments of thoſe + Metalls, and had conſiderable Brightneſs on ſome of their + Surfaces, yet I was not ſatisfi'd, that I perceiv'd + <!-- Page 73 --> <span class="pagenum"><a name="LPage_73" id="LPage_73"></a>[pg + 73]</span> any Reflection from the Inner parts of any of the Filings. Nay, + having look'd in my beſt <i>Microſcope</i> upon the Red <i>Calx</i> + of Lead, (commonly call'd <i>Minium</i>) neither I, nor any I ſhew'd + it to, could diſcern it to be other than Opacous, though the Day were + Clear, and the Object ſtrongly Enlightned. And the deeply Red Colour + of <i>Vitriol</i> appear'd in the ſame <i>Microſcope</i> + (notwithſtanding the great Comminution effected by the Fire) but like + Groſſy beaten Brick. So that, <i>Pyrophilus</i>, I ſhall + willingly reſign you the care of making ſome further Enquiries + into the Subject we have now been conſidering; for I confeſs, as + I told you before, that I think that the Matter may need a further + Scrutiny, nor would I be forward to Determine how far or in what caſes + the Tranſparency or Semi-diaphaniety of the Superficial Corpuſcles + of Bigger Bodies, may have an Intereſt in the Production of their + Colours, eſpecially becauſe that even in divers White bodies, as + Beaten Glaſs, Snow and Froth, where it ſeems manifeſt that + the Superficial parts are ſingly Diaphanous, (being either Water, or + Air, or Glaſs) we ſee not that ſuch Variety of Colours are + produc'd as uſually are by the Refraction of Light, even in thoſe + Bodies, when by their Bigneſs, Shape, &c. they are conveniently + <!-- Page 74 --> <span class="pagenum"><a name="LPage_74" id="LPage_74"></a>[pg + 74]</span> qualify'd to exhibit ſuch Various and Lively Colours as + thoſe of the Rain-bow, and of Priſmatical Glaſſes. + </p> + <p> + 28. By what has been hitherto diſcours'd, <i>Pyrophilus</i>, we may + be aſſiſted to judge of that famous Controverſie which + was of Old diſputed betwixt the <i>Epicureans</i> and other <i>Atomiſts</i> + on the one ſide, and moſt other <i>Philoſophers</i> on the + other ſide. The former Denying Bodies to be Colour'd in the Dark, and + the Latter making Colour to be an Inherent quality, as well as Figure, + Hardneſs; Weight, or the like. For though this Controverſie be + Reviv'd, and hotly Agitated among the <i>Moderns</i>, yet I doubt whether + it be not in great part a Nominal diſpute, and therefore let us, + according to the Doctrine formerly deliver'd, Diſtinguiſh the + Acceptions of the word Colour, and ſay, that if it be taken in the + Stricter Senſe, the <i>Epicureans</i> ſeem to be in the Right, + for if Colour be indeed, though not according to them, but Light Modify'd, + how can we conceive that it can Subſiſt in the Dark, that is, + where it muſt be ſuppos'd there is no Light; but on the other + ſide, if Colour be conſider'd as a certain Conſtant Diſpoſition + of the Superficial parts of the Object to Trouble the Light they Reflect + after ſuch and ſuch a Determinate manner, + <!-- Page 75 --> <span class="pagenum"><a name="LPage_75" id="LPage_75"></a>[pg + 75]</span> this Conſtant, and, if I may ſo ſpeak, Modifying + diſpoſition perſevering in the Object, whether it be Shin'd + upon or no, there ſeems no juſt reaſon to deny, but that in + this Senſe, Bodies retain their Colour as well in the Night as Day; + or, to Speak a little otherwiſe, it may be ſaid, that Bodies are + Potentially Colour'd in the Dark, and Actually in the Light. But of this + Matter diſcourſing more fully elſewhere, as 'tis a + difficulty that concerns Qualities in general, I ſhall forbear to inſiſt + on it here. + </p> + <hr /> + <h3> + CHAP. IV + </h3> + <p> + 1. Of greater Moment in the Inveſtigation of the Nature of Colours is + the Controverſie, Whether thoſe of the Rain-bow, and thoſe + that are often ſeen in Clouds, before the Riſing, or after the + Setting of the Sun; and in a word, Whether thoſe other Colours, that + are wont to be call'd Emphatical, ought or ought not to be accounted True + Colours. I need not tell you that the Negative is the Common Opinion, eſpecially + in the Schools, as may appear by that Vulgar diſtinction of Colours, + whereby theſe under Conſideration are term'd Apparent, by way of + Oppoſition + <!-- Page 76 --> <span class="pagenum"><a name="LPage_76" id="LPage_76"></a>[pg + 76]</span> to thoſe that in the other Member of the Diſtinction + are call'd True or Genuine. This queſtion I ſay ſeems to me + of Importance, upon this Account, that it being commonly Granted, (or + however, eaſie enough to be Prov'd) that Emphatical Colours are Light + it ſelf Modify'd by Refractions chiefly, with a concurrence ſometimes + of Reflections, and perhaps ſome other Accidents depending on theſe + two; if theſe Emphatical Colours be reſolv'd to be Genuine, it + will ſeem conſequent, that Colours, or at leaſt divers of + them, are but Diverſify'd Light, and not ſuch Real and Inherent + qualities as they are commonly thought to be. + </p> + <p> + 2. Now ſince we are wont to eſteem the Echoes and other Sounds + of Bodies, to be True Sounds, all their Odours to be True Odours, and (to + be ſhort) ſince we judge other Senſible Qualities to be + True ones, becauſe they are the proper Objects of ſome or other + of our Senſes, I ſee not why Emphatical Colours, being the + proper and peculiar Objects of the Organ of Sight, and capable to Affect + it as Truly and as Powerfully as other Colours, ſhould be reputed but + Imaginary ones. + </p> + <p> + And if we have (which perchance you'l allow) formerly evinc'd Colour, + (when + <!-- Page 77 --> <span class="pagenum"><a name="LPage_77" id="LPage_77"></a>[pg + 77]</span> the word is taken in its more Proper ſenſe) to be but + Modify'd Light, there will be ſmall Reaſon to deny theſe to + be true Colours, which more manifeſtly than others diſcloſe + themſelves to be produc'd by Diverſifications of the Light. + </p> + <p> + 3. There is indeed taken notice of a Difference betwixt theſe + Apparent colours, and thoſe that are wont to be eſteem'd + Genuine, as to the Duration, which has induc'd ſome Learned Men to + call the former rather Evanid than Fantaſtical. But as the Ingenious + <i>Gaſſendus</i> does ſomewhere Judiciouſly obſerve, + if this way of Arguing were Good, the Greeneſs of a Leaf ought to paſs + for Apparent, becauſe, ſoon Fading into a Yellow, it Scarce laſts + at all, in compariſon of the Greeneſs of an Emerauld. I ſhall + add, that if the Sun-beams be in a convenient manner trajected through a + Glaſs-priſm, and thrown upon ſome well-ſhaded Object + within a Room, the Rain-bow thereby Painted on the Surface of the Body + that Terminates the Beams, may oftentimes laſt longer than Some + Colours I have produc'd in certain Bodies, which would juſtly, and + without ſcruple be accounted Genuine Colours, and yet ſuddenly + Degenerate, and loſe their Nature. + </p> + <p> + 4. A greater Diſparity betwixt Emphatical + <!-- Page 78 --> <span class="pagenum"><a name="LPage_78" id="LPage_78"></a>[pg + 78]</span> Colours, and others, may perhaps be taken from this, that + Genuine Colours ſeem to be produc'd in Opacous Bodies by Reflection, + but Apparent ones in Diaphanous Bodies, and principally by Refraction, I + ſay Principally rather than Solely, becauſe in ſome caſes + Reflection alſo may concurr, but ſtill this ſeems not to + conclude theſe Latter Colours not to be True ones. Nor muſt what + has been newly ſaid of the Differences of True and Apparent Colours, + be interpreted in too Unlimited a Senſe, and therefore it may perhaps + ſomewhat Aſſiſt you, both to Reflect upon the two + fore-going Objections, and to judge of ſome other Paſſages + which you'l meet with in this Tract, if I take this Occaſion to obſerve + to you, that if Water be Agitated into Froth, it exhibits you know a White + colour, which ſoon after it Loſes upon the Reſolution of + the Bubbles into Air and Water, now in this caſe either the Whiteneſs + of the Froth is a True Colour or not, if it be, then True Colours, ſuppoſing + the Water pure and free from Mixtures of any thing Tenacious, may be as + Short-liv'd as thoſe of the Rain-bow; alſo the Matter, wherein + the Whiteneſs did Reſide, may in a few moments perfectly Loſe + all foot-ſteps or remains of it. And + <!-- Page 79 --> <span class="pagenum"><a name="LPage_79" id="LPage_79"></a>[pg + 79]</span> beſides, even Diaphanous Bodies may be capable of + exhibiting True Colours by Reflection, for that Whiteneſs is ſo + produc'd, we ſhall anon make it probable. But if on the other ſide + it be ſaid, that the Whiteneſs of Froth is an Emphatical Colour, + then it muſt no longer be ſaid, that Fantaſtical Colours + require a certain Poſition of the Luminary and the Eye, and muſt + be Vary'd or Deſtroy'd by the Change thereof, ſince Froth + appears White, whether the Sun be Riſing or Setting, or in the + Meridian, or any where between it and the Horizon, and from what + (Neighbouring) place ſoever the Beholders Eye looks upon it. And + ſince by making a Liquor Tenacious enough, yet without Deſtroying + its Tranſparency, or Staining it with any Colour, you may give the + Little Films, whereof the Bubbles conſiſt, ſuch a Texture, + as may make the Froth laſt very many Hours, if not ſome Days, or + even Weeks, it will render it ſomewhat Improper to aſſign + Duration for the Diſtinguiſhing Character to Diſcriminate + Genuine from Fantaſtical Colours. For ſuch Froth may much outlaſt + the Undoubtedly true Colours of ſome of Nature's Productions, as in + that Gaudy Plant not undeſervedly call'd the Mervail of <i>Peru</i>, + the Flowers do often Fade, the + <!-- Page 80 --> <span class="pagenum"><a name="LPage_80" id="LPage_80"></a>[pg + 80]</span> ſame Day they are Blown; And I have often ſeen a <i>Virginian</i> + Flower, which uſually Withers within the compaſs of a Day; and I + am credibly Inform'd, that not far from hence a curious Herboriſt has + a Plant, whoſe Flowers periſh in about an Hour. But if the + Whiteneſs of Water turn'd into Froth muſt therefore be reputed + Emphatical, becauſe it appears not that the Nature of the Body is + Alter'd, but only that the Diſpoſition of its Parts in reference + to the Incident Light is Chang'd, why may not the Whiteneſs be + accounted Emphatical too, which I ſhall ſhew anon to be + Producible, barely by ſuch another change in Black Horn? and yet this + ſo eaſily acquir'd Whiteneſs ſeems to be as truly its + Colour as the Blackneſs was before, and at leaſt is more + Permanent than the Greenneſs of Leaves, the Redneſs of Roſes, + and, in ſhort, than the Genuine Colours of the moſt part of + Nature's Productions. It may indeed be further Objected, that according as + the Sun or other Luminous Body changes place, theſe Emphatical + Colours alter or vaniſh. But not to repeat what I have juſt now + ſaid, I ſhall add, that if a piece of Cloath in a Drapers Shop + (in ſuch the Light being ſeldome Primary) be variouſly + Folded, it will appear of differing + <!-- Page 81 --> <span class="pagenum"><a name="LPage_81" id="LPage_81"></a>[pg + 81]</span> Colours, as the Parts happen to be more Illuminated or more + Shaded, and if you ſtretch it Flat, it will commonly exhibit ſome + one Uniform Colour, and yet theſe are not wont to be reputed + Emphatical, ſo that the Difference ſeems to be chiefly this, + that in the Caſe of the Rain-bow, and the like, the Poſition of + the Luminary Varies the Colour, and in the Cloath I have been mentioning, + the Poſition of the Object does it. Nor am I forward to allow that in + all Caſes the Apparition of Emphatical Colours requires a Determinate + poſition of the Eye, for if Men will have the Whiteneſs of Froth + Emphatical, you know what we have already Inferr'd from thence. Beſides, + the Sun-beams trajected through a Triangular Glaſs, after the manner + lately mention'd, will, upon the Body that Terminates them, Paint a + Rain-bow, that may be ſeen whether the Eye be plac'd on the Right + Hand of it or the Left, or Above or Beneath it, or Before or Behind it; + and though there may appear ſome Little Variation in the Colours of + the Rain-bow, beheld from Differing parts of the Room, yet ſuch a + Diverſity may be alſo obſerv'd by an Attentive Eye in Real + Colours, look'd upon under the like Circumſtances, Nor will it + follow, + <!-- Page 82 --> <span class="pagenum"><a name="LPage_82" id="LPage_82"></a>[pg + 82]</span> that becauſe there remains no Footſteps of the Colour + upon the Object, when the Priſm is Remov'd, that therefore the Colour + was not Real, ſince the Light was truly Modify'd by the Refraction + and Reflection it Suffer'd in its Trajection through the Priſm; and + the Object in our caſe ſerv'd for a Specular Body, to Reflect + that Colour to the Eye. And that you may not be Startled, <i>Pyrophilus</i>, + that I ſhould Venture to ſay, that a Rough and Coiour'd Object + may ſerve for a <i>Speculum</i> to Reflect the Artificial Rain-bow I + have been mentioning, conſider what uſually happens in Darkned + Rooms, where a Wall, or other Body conveniently Situated within, may + ſo Reflect the Colours of Bodies, without the Room, that they may + very clearly be Diſcern'd and Diſtinguiſh'd, and yet 'tis + taken for granted, that the Colours ſeen in a Darkned Room, though + they leave no Traces of themſelves upon the Wall or Body that + Receives them, are the True Colours of the External Objects, together with + which the Colours of the Images are Mov'd or do Reſt. And the Errour + is not in the Eye, whoſe Office is only to perceive the Appearances + of things, and which does Truly ſo, but in the Judging or Eſtimative + faculty, which Miſtakingly + <!-- Page 83 --> <span class="pagenum"><a name="LPage_83" id="LPage_83"></a>[pg + 83]</span> concludes that Colour to belong to the Wall, which does indeed + belong to the Object, becauſe the Wall is that from whence the Beams + of Light that carry the Viſible <i>Species</i>, do come in Straight + Lines directly to the Eye, as for the ſame Reaſon we are wont at + a certain Diſtance from Concave Sphærical Glaſſes, to perſwade + our Selves that we ſee the Image come forth to Meet us, and Hang in + the Air betwixt the Glaſs and Us, becauſe the Reflected Beams + that Compoſe the image croſs in that place, where the Image + ſeems to be, and thence, and not from the Glaſs, do in Direct + Lines take their Courſe to the Eye, and upon the like Cauſe it + is, that divers Deceptions in Sounds and other Senſible Objects do + depend, as we elſewhere declare. + </p> + <p> + 5. I know not, whether I need add, that I have purpoſely Try'd, (as + you'l find ſome Pages hence, and will perhaps think ſomewhat + ſtrange) that Colours that are call'd Emphatical, becauſe not + Inherent in, the Bodies in which they Appear, may be Compounded with one + another, as thoſe that are confeſſedly Genuine may. But + when all this is ſaid, <i>Pyrophilus</i>, I muſt Advertiſe + you, that it is but Problematically Spoken, and that though I think the + Opinion + <!-- Page 84 --> <span class="pagenum"><a name="LPage_84" id="LPage_84"></a>[pg + 84]</span> I have endeavour'd to fortifie Probable, yet a great part of + our Diſcourſe concerning Colours may be True, whether that + Opinion be ſo or not. + </p> + <hr /> + <h3> + CHAP. V. + </h3> + <p> + 1. There are you know, <i>Pyrophilus</i>, beſides thoſe Obſolete + Opinions about Colours which have been long ſince Rejected, very + Various Theories that have each of them, even at this day, Eminent Men for + its Abetters; for the Peripatetick Schools, though they diſpute amongſt + themſelves divers particulars concerning Colours, yet in this they + ſeem Unanimouſly enough to Agree, that Colours are Inherent and + Real Qualities, which the Light doth but Diſcloſe, and not + concurr to Produce. Beſides there are <i>Moderns</i>, who with a + ſlight Variation adopt the Opinion of <i>Plato</i>, and as he would + have Colour to be nothing but a Kind of Flame conſiſting of + Minute Corpuſcles as it were Darted by the Object againſt the + Eye, to whoſe Pores their Littleneſs and Figure made them + congruous, ſo theſe would have Colour to be an Internal Light of + the more Lucid parts of the Object, Darkned and conſequently Alter'd + by the Various Mixtures of the leſs Luminous + <!-- Page 85 --> <span class="pagenum"><a name="LPage_85" id="LPage_85"></a>[pg + 85]</span> parts. There are alſo others, who in imitation of ſome + of the Ancient <i>Atomiſts</i>, make Colour not to be Lucid ſteam, + but yet a Corporeal <i>Effluvium</i> iſſuing out of the Colour'd + Body, but the Knowingſt of theſe have of late Reform'd their + Hypotheſis, by acknowledging and adding that ſome External Light + is neceſſary to Excite, and as <i>they</i> ſpeak, Sollicit + theſe Corpuſcles of Colour as <i>they</i> call them, and Bring + them to the Eye. Another and more principal Opinion of the <i>Modern</i> + Philoſophers, to which this laſt nam'd may by a Favourable + explication be reconcil'd, is that which derives Colours from the Mixture + of Light and Darkneſs, or rather Light and Shadows. And as for the <i>Chymiſts</i> + 'tis known, that the generality of them aſcribes the Origine of + Colours to the Sulphureous Principle in Bodies, though I find, as I elſewhere + largely ſhew, that ſome of the Chiefeſt of them derive + Colours rather from Salt than Sulphur, and others, from the third Hypoſtatical + Principle, <i>Mercury</i>. And as for the <i>Carteſians</i> I need + not tell you, that they, ſuppoſing the Senſation of Light + to bee produc'd by the Impulſe made upon the Organs of Sight, by + certain extremely Minute and Solid Globules, to which the Pores of the Air + and other Diaphanous + <!-- Page 86 --> <span class="pagenum"><a name="LPage_86" id="LPage_86"></a>[pg + 86]</span> bodies are pervious, endeavour to derive the Varieties of + Colours from the Various Proportion of the Direct Progreſs or Motion + of theſe Globules to their Circumvolution or Motion about their own + Centre, by which Varying Proportion they are by this Hypotheſis + ſuppos'd qualify'd to ſtrike the Optick Nerve after ſeveral + Diſtinct manners, ſo to produce the perception of Differing + Colours. + </p> + <p> + 2. Beſides theſe ſix principal Hypotheſes, <i>Pyrophilus</i>, + there may be ſome others, which though Leſs known, may perhaps + as well as theſc deſerve to be taken into conſideration by + you; but that I ſhould copiouſly debate any of them at preſent, + I preſume you will not expect, if you conſider the Scope of theſe + Papers, and the Brevity I have deſign'd in them, and therefore I + ſhall at this time only take notice to you in the general of two or + three things that do more peculiarly concern the Treatiſe you have + now in your hands. + </p> + <p> + 3. And firſt, though the Embracers of the Several Hypotheſes I + have been naming to you, by undertaking each Sect of them to explicate + Colours indefinitely, by the particular Hypotheſes they maintain, + ſeem to hold it forth as the only Needful Theory about that Subject, + yet for my part I doubt + <!-- Page 87 --> <span class="pagenum"><a name="LPage_87" id="LPage_87"></a>[pg + 87]</span> whether any one of all theſe Hypotheſes have a right + to be admitted Excluſively to all others, for I think it Probable, + that Whiteneſs and Blackneſs may be explicated by Reflection + alone without Refraction, as you'l find endeavour'd in the Diſcourſe + you'l meet with e're long Of the Origine of Whiteneſs and Blackneſs, + and on the other ſide, ſince I have not found that by any + Mixture of White and True Black, (for there is a Blewiſh Black which + many miſtake for a Genuine) there can be a Blew, a Yellow, or a Red, + to name no other Colours, produced, and ſince we do find that theſe + Colours may be produc'd in the Glaſs-priſm and other Tranſparent + bodies, by the help of Refractions, it ſeems that Refraction is to be + taken in into the Explication of ſome Colours, to whoſe + Generation they ſeem to concurr, either by making a further or other + Commixture of Shades with the Refracted Light, or by ſome other way + not now to be diſcours'd. And as it ſeems not improbable, that + in caſe the Pores of the Air, and other Diaphanous bodies be every + where almoſt fill'd with ſuch <i>Globuli</i> as the <i>Carteſians</i> + ſuppoſe, the Various kind of Motion of theſe <i>Globuli</i>, + may in many caſes have no ſmall ſtroak in Varying our + Perception of Colour, ſo + <!-- Page 88 --> <span class="pagenum"><a name="LPage_88" id="LPage_88"></a>[pg + 88]</span> without the Suppoſition of theſe <i>Globuli</i>, + which 'tis not ſo eaſie to evince, I think we may probably + enough conceive in general, that the Eye may be Variouſly affected, + not only by the Entire Beams of Light that fall upon it as they are ſuch, + but by the Order, and by the Degree of Swiftneſs, and in a word by + the Manner according to which the Particles that compoſe each + Particular Beam arrive at the Senſory, ſo that whatever be the + Figure of the Little Corpuſcles, of which the Beams of Light conſiſt, + not only the Celerity or Slowneſs of their Revolution or Rotation in + reference to their Progreſſive Motion, but their more Abſolute + Celerity, their Direct or Undulating Motion, and other Accidents, which + may attend their Appulſe to the Eye, may fit them to make Differing + Impreſſions on it. + </p> + <p> + 4. Secondly, For theſe and the like Conſiderations, <i>Pyrophilus</i>, + I muſt deſire that you would look upon this little Treatiſe, + not as a Diſcourſe written Principally to maintain any of the + fore-mention'd Theories, Excluſively to all others, or ſubſtitute + a New one of my Own, but as the beginning of a Hiſtory of Colours, + upon which, when you and your Ingenious friends ſhall have Enrich'd + it, a Solid Theory may be + <!-- Page 89 --> <span class="pagenum"><a name="LPage_89" id="LPage_89"></a>[pg + 89]</span> ſafely built. But yet becauſe this Hiſtory is + not meant barely for a Regiſter of the things recorded in it, but for + an <i>Apparatus</i> to a ſound and comprehenſitive Hypotheſis, + I thought fit, ſo to temper the whole Diſcourſe, as to make + it as conducible, as conveniently I can to that End, and therefore I have + not ſcrupled to let you ſee that I was willing, as to ſave + you the labour of Cultivating ſome Theories that I thought would + never enable you to reach the Ends you aim at, ſo to contract your + Enquiries into a Narrow compaſs, for both which purpoſes I + thought it requiſite to do theſe two things, the <i>One</i>, to + ſet down ſome Experiments which by the help of the Reflections + and Inſinuations that attend them, may aſſiſt you to + diſcover the Infirmneſs and Inſufficiency both of the + common Peripatetick Doctrine, and of the now more applauded Theory of the + <i>Chymists</i> about Colour, becauſe thoſe two Doctrines having + Poſſeſs'd themſelves, the one of the moſt part of + the Schools, and the other of the Eſteem of the Generality ef Phyſicians + and other Learned Men, whoſe Profeſſions and Ways of Study + do not exact that they ſhould Scrupulouſly examine the very Firſt + and Simpleſt Principles of Nature, I fear'd it would be to + <!-- Page 90 --> <span class="pagenum"><a name="LPage_90" id="LPage_90"></a>[pg + 90]</span> little purpoſe, without doing ſomething to diſcover + the Inſufficiency of theſe Hypotheſes, that I ſhould, + (which was the <i>Other</i> thing I thought requiſite for me to do) + ſet down among my other Experiments thoſe in the greateſt + Number, that may let you ſee, that, till I ſhall be Better + Inform'd, I encline to take Colour to be a Modification of Light, and + would invite you chiefly to Cultivate that Hypotheſis, and Improve it + to the making out of the Generation of Particular Colours, as I have + Endeavour'd to apply it to the Explication of Whiteneſs and Blackneſs. + </p> + <p> + 5. Thirdly. But, <i>Pyrophilus</i>, though this be at preſent the + Hypotheſis I preferr, yet I propoſe it but in a General Senſe, + teaching only that the Beams of Light, Modify'd by the Bodies whence they + are ſent (Reflected or Refracted) to the Eye, produce there that Kind + of Senſation, Men commonly call Colour; But whether I think this + Modification of the Light to be perform'd by Mixing it with Shades, or by + Varying the Proportion of the Progreſs and Rotation of the <i>Carteſian + Globuli Cæleſtes</i>, or by ſome other way which I am not now to + mention, I pretend not here to Declare. Much leſs do I pretend to + Determine, or ſcarce ſo much as to Hope to + <!-- Page 91 --> <span class="pagenum"><a name="LPage_91" id="LPage_91"></a>[pg + 91]</span> know all that were requiſite to be Known, to give You, or + even my Self, a perfect account of the Theory of Viſion and Colours, + for in Order to ſuch an undertaking I would firſt Know what + Light is, and if it be a Body (as a Body or the Motion of a Body it ſeems + to be) what Kind of Corpuſcles for Size and Shape it conſiſts + of, with what Swiftneſs they move Forwards, and Whirl about their own + Centres. Then I would Know the Nature of Refraction, which I take to be + one of the Abſtruſeſt things (not to explicate Plauſibly, + but to explicate Satisfactorily) that I have met with in Phyſicks; I + would further Know what Kind and what Degree of Commixture of Darkneſs + or Shades is made by Refractions or Reflections, or both, in the + Superficial particles of thoſe Bodies, that being Shin'd upon, conſtantly + exhibit the one, for Inſtance, a Blew, the other a Yellow, the third + a Red Colour; I would further Know why this Contemperation of Light and + Shade, that is made, for Example, by the Skin of a Ripe Cherry, ſhould + exhibit a Red, and not a Green, and the Leaf of the ſame Tree ſhould + exhibit a Green rather than a Red; and indeed, Laſtly, why ſince + the Light that is Modify'd into theſe Colours conſiſts but + of Corpuſcles + <!-- Page 92 --> <span class="pagenum"><a name="LPage_92" id="LPage_92"></a>[pg + 92]</span> moved againſt the <i>Retina</i> or Pith of the Optick + Nerve, it ſhould there not barely give a Stroak, but produce a + Colour, whereas a Needle wounding likewiſe the Eye, would not produce + Colour but Pain. Theſe, and perhaps other things I ſhould think + requiſite to be Known, before I ſhould judge my Self to have + fully Comprehended the True and Whole Nature of Colours; and therefore, + though by making the Experiments and Reflections deliver'd in this Paper, + I have endeavour'd ſomewhat to Leſſen my Ignorance in this + Matter, and think it far more Deſireable to diſcover a Little, + than to diſcover Nothing, yet I pretend but to make it Probable by + the Experiments I mention, that ſome Colours may be Plauſibly + enough Explicated in the General by the Doctrine here propos'd; For whenſoever + I would Deſcend to the Minute and Accurate Explication of + Particulars, I find my Self very Senſible of the great Obſcurity + of things, without excepting thoſe which we never ſee but when + they are Enlightned, and confeſs with <i>Scaliger</i><a name="LNtA_5" + id="LNtA_5_"></a><a href="#LNt_5"><sup>5</sup></a>, <i>Latet natura hæc</i>, + (ſays he, Speaking of that of Colour) <i>& ſicut aliarum + rerum ſpecies in profundiſſima caligine inſcitiæ + humanæ.</i> + </p> + <!-- Page 93 --> + <p> + <span class="pagenum"><a name="LPage_93" id="LPage_93"></a>[pg 93]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/132a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px"><i>THE</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>EXPERIMENTAL HISTORY</i></span><br /> + <span style="font-size:75%; letter-spacing:6px"><i>OF COLOURS.</i></span><br /> + </h2> + <hr /> + <h2> + <span style="font-size:75%; letter-spacing:6px">PART. II.</span><br /> + </h2> + <p class="center"> + <i>Of the Nature of Whiteneſs and Blackneſs</i>. + </p> + <h2> + <span style="font-size:75%; letter-spacing:6px">CHAP. I.</span><br /> + </h2> + <table> + <tr> + <td valign="top"> + 1. + </td> + <td> + <img width="80" height="80" src="images/132b.png" + alt="Illuminated T in Though" /> + </td> + </tr> + </table> + <p> + Hough after what I have acknowledged, <i>Pyrophilus</i>, of the Abſtruſe + Nature of Colours in <i>particular</i>, you will eaſily believe, that + I pretend not to give you a Satisfactory account of Whiteneſs and + Blackneſs; Yet not wholly to fruſtrate your Expectation of my + offering ſomething by way of Specimen towards the Explication of + ſome Colours in particular, + <!-- Page 94 --> <span class="pagenum"><a name="LPage_94" id="LPage_94"></a>[pg + 94]</span> I ſhall make choice of Theſe as the moſt Simple + Ones, (and by reaſon of their mutual Oppoſition the Leaſt + hardly explicable) about which to preſent you my Thoughts, upon + condition you will take them at moſt to be my Conjectures, not my + Opinions. + </p> + <p> + 2. When I apply'd my Self to conſider, how the cauſe of Whiteneſs + might be explan'd by Intelligible and Mechanical Principles, I remembred + not to have met with any thing among the Antient <i>Corpuſcularian</i> + Philoſophers, touching the Quality we call Whiteneſs, ſave + that <i>Democritus</i> is by <i>Ariſtotle</i> ſaid to have aſcrib'd + the Whiteneſs of Bodies to their Smoothneſs, and on the contrary + their Blackneſs to their Aſperity.<a name="LNtA_6" id="LNtA_6_"></a><a + href="#LNt_6"><sup>6</sup></a> But though about the Latter of thoſe + Qualities his Opinion be allowable, as we ſhall ſee anon, yet + that he heeds a Favourable Interpretation in what is Deliver'd concerning + the Firſt, (at leaſt if his Doctrine be not Mis-repreſented + in this point, as it has been in many others) we ſhall quickly have + Occaſion to manifeſt. But amongſt the <i>Moderns</i>, the + moſt Learned <i>Gaſſendus</i> in his Ingenious Epiſtle + publiſh'd in the Year 1642. <i>De apparente + <!-- Page 95 --> <span class="pagenum"><a name="LPage_95" id="LPage_95"></a>[pg + 95]</span> Magnitudine ſolis humilis & ſublimis</i>, + reviving the <i>Atomical</i> Philoſophy, has, though but + Incidentally, deliver'd ſomething towards the Explication of Whiteneſs + upon Mechanical Principles: And becauſe no Man that I know of, has + done ſo before him, I ſhall, to be ſure to do him Right, + give you his Senſe in his own Words:<a name="LNtA_7" id="LNtA_7_"></a><a + href="#LNt_7"><sup>7</sup></a> <i>Cogites velim</i> (ſays he) <i>lucem + quidem in Diaphano nullius coloris videri, ſed in Opaco tamen + terminante Candicare, ac tantò magis, quantò denſior ſeu + collectior fuerit. Deinde aquam non eſſe quidem coloris ex + ſe candidi & radium tamen ex eâ reflexum verſus oculum + candicare. Rurſus cum plana aquæ Superficies non niſi ex una + parte eam reflexionem faciat: ſi contigerit tamen illam in aliquot + bullas intumeſcere, bullam unamquamque reflectionem facere, & + candoris ſpeciem creare certa Superficiei parte. Ad hæc Spumam ex + aqua pura non alia ratione videri candeſcere & albeſcerere + quam quod ſit congeries confertiſſima minutiſſimarum + bullarum, quarum unaquæque ſuum radium reflectit, unde continens + candor alborve apparet. Denique Nivem nihil aliud videri quam ſpeciem + puriſſimæ ſpumæ ex bullulis quam minutiſſimis + & confertiſſimis cohærentis. Sed ridiculam me exhibeam, + ſi tales meas nugas uberius proponem.</i> + </p> + <!-- Page 96 --> + <p> + <span class="pagenum"><a name="LPage_96" id="LPage_96"></a>[pg 96]</span> + </p> + <p> + 3. But though in this paſſage, that very Ingenous Perſon + has Anticipated part of what I ſhould ſay; Yet I preſume + you will for all that expect, that I ſhould give you a fuller Account + of that Notion of Whiteneſs, which I have the leaſt Exceptions + to, and of the Particulars whence I deduce it, which to do, I muſt + mention to you the following Experiments and Obſervations. + </p> + <p> + Whiteneſs then conſider'd as a Quality in the Object, ſeems + chiefly to depend upon this, That the Superficies of the Body that is + call'd White, is Aſperated by almoſt innumerable Small Surfaces, + which being of an almoſt Specular Nature, are alſo ſo + Plac'd, that ſome Looking this way, and ſome that way, they yet + Reflect the Rays of Light that fall on them, not towards one another, but + outwards towards the Spectators Eye. In this Rude and General account of + Whiteneſs, it ſeems that beſides thoſe Qualities, + which are common to Bodies of other Colours, as for inſtance the + Minuteneſs and Number of the Superficial parts, the two chief things + attributed to Bodies as White are made to be, Firſt, that its Little + Protuberances and Superficial parts be of ſomewhat a Specular Nature, + that they may as little Looking-glaſſes each of them Reflect the + Beams it + <!-- Page 97 --> <span class="pagenum"><a name="LPage_97" id="LPage_97"></a>[pg + 97]</span> receives, (or the little Picture of the Sun made on it) without + otherwiſe conſiderably Altering them; whereas in moſt other + Colours, they are wont to be much Chang'd, by being alſo Refracted, + or by being Return'd to the Eye, mixt with Shades or otherwiſe. And + next, that its Superficial parts be ſo Situated, that they Retain not + the Incident Rays of Light by Reflecting them Inwards, but Send them almoſt + all Back, ſo that the Outermoſt Corpuſcles of a White Body, + having their Various Little Surfaces of a Specular Nature, a Man can from + no place Behold the Body, but that there will be among thoſe + Innumerable <i>Superficieculæ</i>, that Look ſome one way, and ſome + another, enough of them Obverted to his Eye, to afford like a broken + Looking-glaſs, a confuſed Idæa, or Repreſentation of Light, + and make ſuch an Impreſſion on the Organ, as that for which + Men are wont to call a Body White. But this Notion will perhaps be beſt + Explan'd by the ſame Experiments and Obſervations, on which it + is Built, And therefore I ſhall now advance to <i>Them</i>. + </p> + <p> + 4. And in the firſt place I conſider, that the Sun and other + Powerfully Lucid Bodies, are not only wont to Offend, which we call to + Dazle our Eyes, but that if any + <!-- Page 98 --> <span class="pagenum"><a name="LPage_98" id="LPage_98"></a>[pg + 98]</span> Colour be to be Aſcrib'd to them as they are Lucid, it + ſeems it ſhould be Whiteneſs: For the Sun at Noon-day, and + in Clear weather, and when his Face is leſs Troubled, and as it were + Stained by the Steams of Sublunary Bodies, and when his Beams have much leſs + of the Atmoſphere to Traject in their Paſſage to our Eyes, + appears of a Colour more approaching to White, than when nearer the + Horizon, the Interpoſition of certain Sorts of Fumes and Vapours make + him oftentimes appear either Red, or at leaſt more Yellow. And when + the Sun Shines upon that Natural Looking-glaſs, a Smooth water, that + part of it, which appears to this or that particular Beholder, the moſt + Shin'd on, does to his Eye ſeem far Whiter than the reſt. And + here I ſhall add, that I have ſometimes had the Opportunity to + obſerve a thing, that may make to my preſent purpoſe, + namely, that when the Sun was Veil'd over as it were, with a Thin White + Cloud, and yet was too Bright to be Look'd upon Directly without Dazling, + by caſting my Eyes upon a Smooth water, as we ſometimes do to obſerve + Eclipſes without prejudice to our Eyes, the Sun then not far from the + Meridian, appear'd to me not Red, but ſo White, that 'twas + <!-- Page 99 --> <span class="pagenum"><a name="LPage_99" id="LPage_99"></a>[pg + 99]</span> not without ſome Wonder, that I made the Obſervation. + Beſides, though we in <i>Engliſh</i> are wont to ſay, a + thing is Red hot, as an Expreſſion of its being Superlatively <i>Ignitum</i>, + (if I may ſo Speak for want of a proper <i>Engliſh</i> word) yet + in the Forges of Smiths, and the Furnaces of other Artificers, by that + which they call a White heat, they mean a further Degree of <i>Ignition</i>, + than by that which both they and we call a Red heat. + </p> + <p> + 5. Secondly, I conſider, that common Experience informs us, that as + much Light Over-powers the Eye, ſo when the Ground is covered with + Snow, (a Body extremely White) thoſe that have Weak Eyes are wont to + complain of too much Light: And even thoſe that have not, are + generally Senſible of an Extraordinary meaſure of Light in the + Air; and if they are fain to Look very long upon the Snow, find their + Sight Offended by it. On which occaſion we may call to mind what <i>Xenophon</i> + relates, that his <i>Cyrus</i> marching his Army for divers days through + Mountains covered with Snow, the Dazling ſplendor of its Whiteneſs + prejudic'd the Sight of very many of his Souldiers, and Blinded ſome + of them; and other Stories of that Nature be met with in Writers of good + <!-- Page 100 --> <span class="pagenum"><a name="LPage_100" + id="LPage_100"></a>[pg 100]</span> Note. And the like has been affirm'd to + me by credible Perſons of my own Acquaintance, and eſpecially by + one who though Skill'd in Phyſick and not Ancient confeſs'd to + me when I purpoſely ask'd him, that not only during his ſtay in + <i>Muſcovy</i>, he found his Eyes much Impair'd, by being reduc'd + frequently to Travel in the Snow, but that the Weakneſs of his Eyes + did not Leave him when he left that Country, but has follow'd him into theſe + Parts, and yet continues to Trouble him. And to this doth agree what I as + well as others have obſerv'd, namely, that when I Travell'd by Night, + when the Ground was all cover'd with Snow, though the Night otherwiſe + would not have been Lightſome, yet I could very well ſee to Chooſe + my way. But much more Remarkable to my preſent purpoſe is that, + which I have met with in <i>Olaus Magnus</i>,<a name="LNtA_8" id="LNtA_8_"></a><a + href="#LNt_8"><sup>8</sup></a> concerning the way of Travelling in Winter + in the <i>Northern</i> Regions, where the Days of that Seaſon are + ſo very Short; for after other things not needfull to be here Tranſcribed: + <i>Iter</i>, ſays he, <i>Diurnum duo ſcilicet montana milliaria + (quæ 12 Italica ſunt) conſiciunt. Nocte verò ſub ſplendiſſima + luna, duplatum iter conſumunt aut triplatum. Neque id incommodè fit, + <!-- Page 101 --> <span class="pagenum"><a name="LPage_101" + id="LPage_101"></a>[pg 101]</span> cum nivium reverberatione lunaris + ſplendo<sup>ris</sup> ſublimes & declives campos illuſtret, + ac etiam montium præcipitia ac noxias feras à lorgè proſpiciant + evitandas</i>. Which Teſtimony I the leſs Scruple to allege, + becauſe that it agrees very well with what has been Affirm'd to me by + a Phyſician of <i>Moſco</i>, whom the Notion I have been + Treating of concerning Whiteneſs invited me to ask whether he could + not See much farther when he Travell'd by Night in <i>Ruſſia</i> + than he could do in <i>England</i>, or elſewhere, when there was no + Snow upon the Ground; For this Ingenious Perſon inform'd me, that he + could See Things at a farr greater Diſtance, and with more Clearneſs, + when he Travell'd by Night on the <i>Ruſſian</i> Snow, though + without the Aſſiſtance of Moon-ſhine, than we in theſe + Parts would eaſily be perſwaded. Though it ſeems not + unlikely to me, that the Intenſeneſs of the Cold may contribute + ſomething to the conſiderableneſs of the Effect, by much + Clearing the Air of Darkiſh Steams, which in theſe more + Temperate Climates are wont to Thicken it in Snowy weather: For having + purpoſely inquir'd of this Doctor, and conſulted that Ingenious + Navigator Captain <i>James</i>'s Voyage hereafter to be further mention'd, + I find both their Relations + <!-- Page 102 --> <span class="pagenum"><a name="LPage_102" + id="LPage_102"></a>[pg 102]</span> agree in this, that in Dark Froſty + Nights they could Diſcover more Stars, and See the reſt Clearer + than we in <i>England</i> are wont to do. + </p> + <p> + 6. I know indeed that divers Learned Men think, that Snow ſo ſtrongly + Affects our Eye, not by a Borrow'd, but a Native Light; But I venture to + give it as a Proof, that White Bodies reflect more Light than Others, + becauſe having once purpoſely plac'd a parcel of Snow in a Room + carefully Darkned, that no Celeſtial Light might come to fall upon + it; neither I, nor an ingenous Perſon, (Skill'd in Opticks) whom I deſir'd + for a Witneſs, could find, that it had any other Light than what it + receiv'd. And however, 'tis uſual among thoſe that Travel in + Dark Nights, that the Guides wear ſomething of White to be Diſcern'd + by, there being ſcarce any Night ſo Dark, but that in the Free + Air there remains ſome Light, though Broken and Debilitated perhaps + by a thouſand Reflections from the Opacous Corpuſcles that Swim + in the Air, and lend it to one another before it comes to arrive at the + Eye. + </p> + <p> + 7. Thirdly, And the better to ſhew that White Bodies reflect ſtore + of Light, in comparſon of thoſe that are otherwiſe + Colour'd, I did in the Darkn'd Room, + <!-- Page 103 --> <span class="pagenum"><a name="LPage_103" + id="LPage_103"></a>[pg 103]</span> formerly mention'd, hold not far from + the Hole, at which the Light was admitted, a Sheet only of White Paper, + from whence caſting the Sun-beams upon a White Wall, whereunto it was + Obverted, it manifeſtly appear'd both to Me, and to the Perſon I + took for a Witneſs of the Experiment, that it Reflected a far greater + Light, than any of the other Colours formerly mention'd, the Light ſo + thrown upon one Wall notably Enlightning it, and by it a good part of the + Room. And yet further to ſhow you, that White Bodies Reflect the + Beams From them, and not Towards themſelves, Let me add, that + Ordinary Burning-glaſſes, ſuch as are wont to be employ'd + to light Tobacco, will not in a great while Burn, or ſo much as Diſcolour + a Sheet of White Paper. Inſomuch that even when I was a Boy, and + Lov'd to make Tryals with Burning-glaſſes, I could not but + wonder at this Odd <i>Phænomenon</i>, which ſet me very Early upon + Gueſſing at the Nature of Whiteneſs, eſpecially becauſe + I took notice, that the Image of the Sun upon a White Paper was not ſo + well Defin'd (the Light ſeeming too Diffus'd) as upon Black, and + becauſe I try'd, that Blacking over the Paper with Ink, not only the + Ink would be quickly Dry'd up, but the + <!-- Page 104 --> <span class="pagenum"><a name="LPage_104" + id="LPage_104"></a>[pg 104]</span> Paper that I could not Burn before, + would be quickly ſet on Fire. I have alſo try'd, that by expoſing + my Hand with a Thin Black Glove over it to the Warm Sun, it was thereby + very quickly and conſiderably more Heated, than if I took off the + Glove, and held my Hand Naked, or put on it another Glove of Thin but + White Leather. And having thus ſhewn you, <i>Pyrophilus</i>, that + White Bodies reflect the moſt Light of any, let us now proceed, to + conſider what is further to be taken notice of in them, in order to + our preſent Enquiry. + </p> + <p> + 8. And Fourthly, whereas among the Diſpoſitions we attributed to + White Bodies, we alſo intimated this, That ſuch Bodies are apt, + like <i>Speculums</i>, though but Imperfect ones, to Reflect the Light + that falls on them Untroubled or Unſtain'd, we ſhall beſides + other particulars to be met with in theſe Papers, offer you this in + favour of the Conjecture; That in the Darkned Room ſeveral times + mention'd in this Treatſe, we try'd that the Sun-beams being caſt + from a Coloured Body upon a neighbouring White Wall, the Determinate + Colour of the Body was from the Wall reflected to the Eye; whereas we + could in divers caſes manifeſtly Alter the Colour arriving at + the Eye, by Subſtituting + <!-- Page 105 --> <span class="pagenum"><a name="LPage_105" + id="LPage_105"></a>[pg 105]</span> at a convenient Diſtance, a + (conveniently) Colour'd (and Gloſſy) Body inſtead of the + White Wall. As by throwing the Beams from a Yellow Body upon a Blew, there + would be Exhibited a kind of Green, as in the Experiments about Colours is + more fully Declar'd. + </p> + <p> + 9. I know not whether I ſhould on this Occaſion take notice, + that when, as when looking upon the Calm and Smooth Surface of a River + betwixt my Eye and the Sun, it appear'd to be a natural <i>Speculum</i>, + wherein that Part which Reflected to my Eye the Entire and defin'd Image + of the Sun, and the Beams leſs remote from thoſe which exhibited + That Image, appear'd indeed of a great and Whitiſh Brightneſs, + but the reſt Comparatively Dark enough: if afterwards the Superficies + chanc'd to be a little, but not much troubled, by a gentle Breath of Wind, + and thereby reduc'd into a Multitude of Small and Smooth <i>Speculums</i>, + the Surface of the River would ſuitably to the Doctrine lately + deliver'd, at a Diſtance appear very much of Kin to White, though it + would loſe that Brightneſs or Whiteneſs upon the Return of + the Surface to Calmneſs and an Uniform Level. And I have ſometimes + for Tryals ſake brought in by a Lenticular Glaſs, the Image of a + River, Shin'd upon + <!-- Page 106 --> <span class="pagenum"><a name="LPage_106" + id="LPage_106"></a>[pg 106]</span> by the Sun, into an Upper Room Darkn'd, + and Diſtant about a Quarter of a Mile from the River, by which means + the Numerous Declining Surfaces of the Water appear'd ſo Contracted, + that upon the Body that receiv'd the Images, the whole River appear'd a + very White Object at two or three paces diſtance. But if we drew Near + it, this Whiteneſs appear'd to proceed from an Innumerable company of + Lucid Reflections, from the ſeveral Gently wav'd Superficies of the + Water, which look'd Near at hand like a Multitude of very Little, but + Shining Scales of Fiſh, of which many did every moment Diſappear, + and as many were by the Sun, Wind and River generated anew. But though + this Obſervation ſeem'd Sufficiently to diſcover, how the + Appearing Whiteneſs in that caſe was Produc'd, yet in ſome + other caſes Water may have the Same, though not ſo Vivid a + Colour upon other Accounts; for oftentimes it happens that the Smooth + Surface of the Water does appear Bright or Whitiſh, by reaſon of + the Reflection not immediatly of the Images of the Sun, but of the + Brightneſs of the Sky; and in ſuch caſes a Convenient Wind + may where it paſſes along make the Surface look Black, by cauſing + many ſuch Furrows and Cavities, as may make the Inflected Superficies + <!-- Page 107 --> <span class="pagenum"><a name="LPage_107" + id="LPage_107"></a>[pg 107]</span> of the Water reflect the Brightneſs + of the Sky rather Inward than Outward. And again if the Wind increaſe + into a Storm, the Water may appear White, eſpecially near the Shore + and the Ship, namely becauſe the Rude Agitation Breaks it into Fome + or Froth. So much do Whiteneſs and Blackneſs depend upon the Diſpoſition + of the Superficial parts of a Body to Reflect the Beams of Light Inward or + Outward. But that as White Bodies reflect the moſt Light of any, + ſo there Superficial Particles are, in the Senſe newly + Deliver'd, of a Specular Nature, I ſhall now further endeavour to + ſhew both by the making of Specular bodies White, and the making of a + White body Specular. + </p> + <p> + 10. In the Fifth place then, I will inform You, that (not to repeat what + <i>Gaſſendus</i> obſerves concerning Water) I have for + Curioſity ſake Diſtill'd Quickſilver in a Cucurbit, + fitted with a Capacious Glaſs-head, and obſerv'd that when the + Operation was perform'd by the Degrees of Fire requiſite for my purpoſe, + there would ſtick to the Inſide of the Alembick a multitude of + Little round drops of <i>Mercury</i>. And as you know that <i>Mercury</i> + is a Specular Body, ſo each of theſe Little drops was a ſmall + round Looking-glaſs, + <!-- Page 108 --> <span class="pagenum"><a name="LPage_108" + id="LPage_108"></a>[pg 108]</span> and a Multitude of them lying Thick and + Near one another, they did both in my Judgment, and that of thoſe I + Invited to ſee it, make the Glaſs they were faſtened to, + appear manifeſtly a White Body. And yet as I ſaid, this Whiteneſs + depended upon the Minuteneſs and Nearneſs of the Little + Mercurial <i>Globuli</i>, the Convexity of whoſe Surfaces fitted them + to repreſent in a Narrow compaſs a Multitude of Little Lucid + Images to differingly ſituated Beholders. And here let me obſerve + a thing that ſeems much to countenance the Notion I have been + recommending: namely, that whereas divers parts of the Sky, and eſpecially + the Milky-way, do to the naked Eye appear White, (as the name it ſelf + imports) yet the Galaxie look'd upon through the Teleſcope, does not + ſhew White, but appears to be made up of a Vaſt multitude of + Little Starrs; ſo that a Multitude of Lucid Bodies, if they be ſo + Small that they cannot Singly or apart be diſcern'd by the Eye, and + if they be ſufficiently Thick ſet by one another, may by their + confus'd beams appear to the Eye One White Body. And why it is not poſſible, + that the like may be done, when a Multitude of Bright and Little Corpuſcles + being crowded together, are made to ſend together Vivid beams to the + Eye, + <!-- Page 109 --> <span class="pagenum"><a name="LPage_109" + id="LPage_109"></a>[pg 109]</span> though they Shine but as the Planets by + a Borrow'd Light? + </p> + <p> + 11. But to return to our Experiments. We may take notice, That the White + of an Egg, though in part Tranſparent, yet by its power of Reflecting + ſome Incident Rays of Light, is in ſome meaſure a Natural + <i>Speculum</i>, being long agitated with a Whisk or Spoon, loſes its + Tranſparency, and becomes very White, by being turn'd into Froth, + that is into an Aggregate of Numerous ſmall Bubbles, whoſe + Convex Superficies fits them to Reflect the Light every way Outwards. And + 'tis worth Noting, that when Water, for inſtance, is Agitated into + Froth, if the Bubbles be Great and Few, the Whiteneſs will be but + Faint, becauſe the number of <i>Specula</i> within a Narrow compaſs + is but Small, and they are not Thick ſet enough to Reflect ſo + Many Little Images or Beams of the Lucid Body, as are requiſite to + produce a Vigorous ſenſation of Whiteneſs: And partly leaſt + it ſhould be ſaid, that the Whiteneſs of ſuch + Globulous Particles proceeds from the Air Included in the Froth; (which to + make good, it ſhould be prov'd that the Air it ſelf is White) + and partly to illuſtrate the better the Notion we have propos'd of + Whiteneſs, I ſhall add, that I purpoſely made this + Experiment, I took a quantity + <!-- Page 110 --> <span class="pagenum"><a name="LPage_110" + id="LPage_110"></a>[pg 110]</span> Fair water, & put to it in a clear + Glaſs phial, a convenient quantity of Oyl or Spirit of Turpentine, + becauſe that Liquor will not incorporate with Water, and yet is almoſt + as Clear and Colourleſs as it; theſe being Gently Shaken + together, the Agitation breaks the Oyl (which as I ſaid, is Indiſpos'd + to Mix like Wine or Milk <i>per minima</i> with the Water) into a + Multitude of Little Globes, which each of them Reflecting Outwards a Lucid + Image, make the Imperfect Mixture of the two Liquors appear Whitiſh; + but if by Vehemently Shaking the Glaſs for a competent time you make + a further Comminution of the Oyl into far more Numerous and Smaller <i>Globuli</i>, + and thereby confound it alſo better with the Water, the Mixture will + appear of a Much greater Whiteneſs, and almoſt like Milk; + whereas if the Glaſs be a while let alone, the Colour will by degrees + Impair, as the Oyly globes grow Fewer and Bigger, and at length will quite + Vaniſh, leaving both the Liquors Diſtinct and Diaphanous as + before. And ſuch a Tryal hath not ill ſucceeded, when inſteed + of the Colourleſs Oyl of Turpentine I took a Yellow Mixture made of a + good Proportion of Crude Turpentine diſſolv'd in that Liquor; + and (if I mis-remember not) it alſo Succeeded better than one would + <!-- Page 111 --> <span class="pagenum"><a name="LPage_111" + id="LPage_111"></a>[pg 111]</span> expect, when I employ'd an Oyl brought + by Filings of Copper infuſed in it, to a deep Green. And this (by the + way) may be the Reaſon, why often times when the Oyls of ſome + Spices and of Anniſeeds &c. are Diſtilled in a Limbec with + Water, the Water (as I have ſeveral times obſerv'd) comes over + Whitiſh, and will perhaps continue ſo for a good while, becauſe + if the Fire be made too Strong, the ſubtile Chymical Oyl is thereby + much Agitated and Broken, and Blended with the Water in ſuch Numerous + and Minute Globules, as cannot eaſily in a ſhort time Emerge to + the Top of the Water, and whilſt they Remain in it, make it, for the + Reaſon newly intimated, look Whitiſh; and perhaps upon the + ſame Ground a cauſe may be rendred, why Hot water is obſerv'd + to be uſually more Opacous and Whitiſh, than the ſame Water + Cold, the Agitation turning the more Spirituous or otherwiſe + Conveniently Diſpos'd Particles of the Water into Vapours, thereby + Producing in the Body of the Liquor a Multitude of Small Bubbles, which + interrupt the Free paſſage, that the Beams of Light would elſe + have Every way, and from the Innermoſt parts of the Water Reflect + many of them Outwards. Theſe and the like Examples, <i>Pyrophilus</i>, + <!-- Page 112 --> <span class="pagenum"><a name="LPage_112" + id="LPage_112"></a>[pg 112]</span> have induc'd me to Suſpect, that + the Superficial Particles of White bodies, may for the Moſt part be + as well Convex as Smooth; I content my ſelf to ſay <i>Suſpect</i> + and <i>for the moſt part</i>, becauſe it ſeems not Eaſie + to prove, that when Diaphanous bodies, as we ſhall ſee by and + by, are reduc'd into White Powders, each Corpuſcle muſt needs be + of a Convex Superficies, ſince perhaps it may Suffice that Specular + Surfaces look ſeverally ways. For (as we have ſeen) when a + Diaphanous Body comes to be reduc'd to very Minute parts, it thereby + requires a Multitude of Little Surfaces within a Narrow compaſs. And + though each of theſe ſhould not be of a Figure Convenient to + Reflect a Round Image of the Sun, yet even from ſuch an + Inconveniently Figur'd body, there may be Reflected ſome (either + Streight or Crooked) Phyſical Line of Light, which Line I call Phyſical, + becauſe it has ſome Breadth in it, and in which Line in many caſes + ſome Refraction of the Light falling upon the Body it depends on, may + contribute to the Brightneſs, as if a Slender Wire, or Solid Cylinder + of Glaſs be expos'd to the Light, you ſhall ſee in ſome + part of it a vivid Line of Light, and if we were able to draw out and lay + together a Multitude of theſe Little + <!-- Page 113 --> <span class="pagenum"><a name="LPage_113" + id="LPage_113"></a>[pg 113]</span> Wires or Thrids of Glaſs, ſo + Slender, that the Eye could not diſcern a Diſtance betwixt the + Luminous Lines, there is little doubt (as far as I can gueſs by a + Tryal purpoſely made with very Slender, but far leſs Slender + Thrids of Glaſs, whoſe Aggregate was Look'd upon one way White) + but the whole Phyſical Superficies compos'd of them, would to the Eye + appear White, and if ſo, it will not be always neceſſary + that the Figure of thoſe Corpuſcles, that make a Body appear + White, ſhould be <i>Globulous</i>. And as for Snow it ſelf, + though the Learned <i>Gaſſendus</i> (as we have ſeen above) + makes it to ſeem nothing elſe but a pure Frozen Froth, conſiſting + of exceedingly Minute and Thickſet Bubbles; yet I ſee no neceſſity + of Admitting that, ſince not only by the Variouſly and Curiouſly + Figur'd Snow, that I have divers times had the Opportunity with Pleaſure + to obſerve, but alſo by the Common Snow, it rather doth appear + both to the Naked Eye, and in a <i>Microſcope</i>, often, if not moſt + commonly, to conſiſt principally of Little Slender Icicles of + ſeveral Shapes, which afford ſuch Numerous Lines of Light, as we + have been newly Speaking of. + </p> + <p> + 12. Sixthly, If you take a Diaphanous Body, as for inſtance a Piece + of Glaſs, and + <!-- Page 114 --> <span class="pagenum"><a name="LPage_114" + id="LPage_114"></a>[pg 114]</span> reduce it to Powder, the ſame + Body, which when it was Entire, freely Tranſmitted the Beams of + Light, acquiring by Contuſion a multitude of Minute Surfaces, each of + which is as it were a Little, but Imperfect <i>Speculum</i>, is qualify'd + to Reflect in a Confus'd manner, ſo many either Beams, or Little and + Singly Unobſervable Images of the Lucid Body, that from a Diaphanous + it Degenerates into a White Body. And I remember, I have for Trials ſake + taken Lumps of Rock Cryſtal, and Heating them Red hot in a Crucible, + I found according to my Expectation, that being Quench'd in Fair water, + even thoſe that remain'd in ſeemingly entire Lumps exchang'd + their Tranſlucency for Whiteneſs, the Ignition and Extinction + having as it were Crack'd each Lump into a multitude of Minute Bodies, and + thereby given it a great multitude of new Surfaces. And ev'n with + Diaphanous Bodies, that are Colour'd, there may be this way a Greater + Degree of Whiteneſs produced, than one would lightly think; as I + remember, I have by Contuſion obtain'd Whitiſh Powders of <i>Granates</i>, + Glaſs of <i>Antimony</i>, and <i>Emeralds</i> finely Beaten, and you + may more eaſily make the Experiment, by taking Good Venereal <i>Vitriol</i> + of a Deep Blew, + <!-- Page 115 --> <span class="pagenum"><a name="LPage_115" + id="LPage_115"></a>[pg 115]</span> and comparing with ſome of the + Entire Cryſtalls purpoſely reſerv'd, ſome of the + Subtile Powder of the ſame Salt, which will Comparatively exhibit a + very conſiderable degree of Whitiſhneſs. + </p> + <p> + 13. Seventhly, And as by a Change of Poſition in the Parts, a Body + that is not White, may be made White, ſo by a Slight change of the + Texture of its Surface, a White Body may be Depriv'd of its Whiteneſs. + For if, (as I have try'd in Gold-ſmiths Shops) you take a piece of + Silver that has been freſhly Boyl'd, as the Artificers call it, + (which is done by, firſt Bruſhing, and then Decocting it with + Salt and Tartar, and perhaps ſome other Ingredients) you ſhall + find it to be of a Lovely White. But if you take a piece of Smooth Steel, + and therewith Burniſh a part of it, which may be preſently done, + you ſhall find that Part will Loſe its Whiteneſs, and turn + a <i>Speculum</i>, looking almoſt every where Dark, as other + Looking-glaſſes do, which may not a little confirm our Doctrine. + For by this we may gueſs, what it is chiefly that made the Body White + before, by conſidering that all that was done to deprive it of that + Whiteneſs, was only to Depreſs the Little Protuberances that + were before on the Surface of the Silver + <!-- Page 116 --> <span class="pagenum"><a name="LPage_116" + id="LPage_116"></a>[pg 116]</span> into one Continu'd Superficies, and + thereby effect this, that now the Image of the Lucid Body, and conſequently + a Kind of Whiteneſs ſhall appear to your Eye, but in ſome + place of the greater Silver Looking-glaſs (whence the Beams reflected + at an Angle Equal to that wherewith they fall on it, may reach your Eye) + whilſt the Aſperity remain'd Undeſtroy'd, the Light falling + on innumerable Little <i>Specula</i> Obverted ſome one way, and + ſome another, did from all Senſibly Diſtinguiſhable + parts of the Superficies reflect confus'd Beams or Repreſentations of + Light to the Beholders Eye, from whence ſoever he chance to Look upon + it. And among the Experiments annex'd to this Diſcourſe, you + will find One, wherein by the Change of Texture in Bodies, Whiteneſs + is in a Trice both Generated and Deſtroy'd. + </p> + <hr /> + <h3> + CHAP. II. + </h3> + <p> + 1. What we have Diſcours'd of Whiteneſs, may ſomewhat Aſſiſt + us to form a Notion of Blackneſs, thoſe two Qualities being + Contrary enough to Illuſtrate each other. Yet among the Antient <i>Philoſophers</i> + I find leſs Aſſiſtance + <!-- Page 117 --> <span class="pagenum"><a name="LPage_117" + id="LPage_117"></a>[pg 117]</span> to form a Notion of Blackneſs than + of Whiteneſs, only <i>Democritus</i> in the paſſage above + Recited out of <i>Aristotle</i> has given a General Hint of the Cauſe + of this Colour, by referring the Blackneſs of Bodies to their Aſperity. + But this I call but a General Hint, becauſe thoſe Bodies that + are Green, and Purple, and Blew, ſeem to be ſo as well as Black + ones, upon the Account of their Superficial Aſperity. But among the + <i>Moderns</i>, the formerly mention'd <i>Gaſſendus</i>, perhaps + invited by this Hint of <i>Democritus</i>, has Incidentally in another Epiſtle + given us, though a very Short, yet a ſomewhat Clearer account of the + Nature of Blackneſs in theſe words: <i>Existimare par est + corpora ſuâpte Naturâ nigra constare ex particulis, quarum + Superficieculæ ſcabræ ſint, nec facilè lucem extrorſum + reflectant.</i> I wiſh this Ingenious Man had enlarg'd himſelf + upon this Subject; For indeed it ſeems, that as that which makes a + Body White, is chiefly ſuch a Diſpoſition of its Parts, + that it Reflects (I mean without much Interruption) more of the Light that + falls on it, than Bodies of any other Colour do, ſo that which makes + a Body Black is principally a Peculiar kind of Texture, chiefly of its + Superficial Particle, whereby it does as it were Dead the Light + <!-- Page 118 --> <span class="pagenum"><a name="LPage_118" + id="LPage_118"></a>[pg 118]</span> that falls on it, ſo that very + little is Reflected Outwards to the Eye. + </p> + <p> + 2. And this Texture may be Explicated two, and perhaps more than two + ſeveral ways, whereof the firſt is by Suppoſing in the + Superficies of the Black Body a Particular kind of Aſperity, whereby + the Superficial Particles reflect but Few of the Incident Beams Outwards, + and the reſt Inwards towards the Body it ſelf. As if for Inſtance, + we ſhould conceive the Surface of a Black Body to be Aſperated + by an almoſt Numberleſs throng of Little Cylinders, Pyramids, + Cones, and other ſuch Corpuſcles, which by their being Thick Set + and <i>Erected</i>, reflect the Beams of Light from one to another + Inwards, and ſend them too and fro ſo often, that at length they + are Loſt before they can come to Rebound out again to the Eye. And + this is the firſt of the two mention'd ways of Explicating Blackneſs. + The other way is by Suppoſing the Texture of Black Bodies to be + ſuch, that either by their Yielding to the Beams of Light, or upon + ſome other Account, they do as it were Dead the Beams of Light, and + keep them from being Reflected in any Plenty, or with any Conſiderable + Vigour of Motion, Outwards. According to this Notion it may be ſaid, + that + <!-- Page 119 --> <span class="pagenum"><a name="LPage_119" + id="LPage_119"></a>[pg 119]</span> the Corpuſcles that make up the + Beams of Light, whether they be Solary <i>Effluviums</i>, or Minute + Particles of ſome Ætherial Subſtance, Thruſting on one + another from the Lucid Body, do, falling on Black Bodies, meet with ſuch + a Texture, that ſuch Bodies receive Into themſelves, and Retain + almoſt all the Motion communicated to them by the Corpuſcles + that make up the Beams of Light, and conſequently Reflect but Few of + them, or thoſe but Languidly, towards the Eye, it happening here almoſt + in like manner as to a ball, which thrown againſt a Stone or Floor, + would Rebound a great way Upwards, but Rebounds very Little or not at all, + when it is thrown againſt Water, or Mud, or a Looſe Net, becauſe + the Parts yield, and receive into themſelves the Motion, on whoſe + Account the Ball ſhould be Reflected Outwards. But this Laſt way + of Explicating Blackneſs, I ſhall content my Self to have + Propos'd, without either Adopting it, or abſolutely Rejecting it. For + the Hardneſs of Touchſtones, Black Marble and other Bodies, that + being Black are Solid, ſeem to make it ſomewhat Improbable, that + ſuch Bodies ſhould be of ſo Yielding a Texture, unleſs + we ſhould ſay, that ſome Bodies may be more Diſpos'd + to Yield to the Impulſes of + <!-- Page 120 --> <span class="pagenum"><a name="LPage_120" + id="LPage_120"></a>[pg 120]</span> the Corpuſcles of Light by reaſon + of a Peculiar Texture, than other Bodies, that in other Tryals appear to + be Softer than they. But though the Former of theſe two Explications + of Blackneſs be that, by which we ſhall Endeavour to give an + Account of it, yet as we ſaid, we ſhall not Abſolutely + Reject this Latter, partly becauſe they both Agree in this, that + Black Bodies Reflect but Little of the Light that falls on them, and + partly becauſe it is not Impoſſible, that in ſome Caſes + both the Diſpoſition of the Superficial particles, as to Figure + and Poſition, and the Yielding of the Body, or ſome of its + Parts, may joyntly, though not in an Equal meaſure concurr to the + rendring of a Body Black. The Conſiderations that induc'd me to propoſe + this Notion of Blackneſs, as I Explan'd it, are principally theſe: + </p> + <p> + 3. Firſt, That as I lately ſaid, Whiteneſs and Blackneſs + being generally reputed to be Contrary Qualities, Whiteneſs depending + as I ſaid upon the Diſpoſition of the Parts of a Body to + Reflect much Light, it ſeems likely, that Blackneſs may depend + upon a Contrary Diſpoſition of the Black Bodies Surface; But + upon this I ſhall not Inſiſt. + </p> + <p> + 4. Next then we ſee, that if a Body of + <!-- Page 121 --> <span class="pagenum"><a name="LPage_121" + id="LPage_121"></a>[pg 121]</span> One and the ſame Colour be plac'd, + part in the Sun-beams, and part in the Shade, that part which is not + Shin'd on will appear more of Kin to Blackneſs than the other, from + which more Light Rebounds to the Eye; And Dark Colours ſeem the + Blacker, the leſs Light they are Look'd upon in, and we think all + Things Black in the Dark, when they ſend no Beams to make Impreſſions + on our Organs of Sight, ſo that Shadows and Darkneſs are near of + Kin, and Shaddow we know is but a Privation of Light; and accordingly + Blackneſs ſeems to proceed from the Paucity of Beams Reflected + from the Black Body to the Eye, I ſay the Paucity of Beams, becauſe + thoſe Bodies that we call Black, as Marble, Jeat, &c. are Short + of being perfectly ſo, elſe we ſhould not See them at all. + But though the Beams that fall on the Sides of thoſe Erected + Particles that we have been mentioning, do Few of them return Outwards, + yet thoſe that fall upon the Points of thoſe Cylinders, Cones, + or Pyramids, may thence Rebound to the Eye, though they make there but a + Faint Impreſſion, becauſe they Arrive not there, but + Mingl'd with a great Proportion of Little Shades. This may be Confirm'd by + my having procur'd a Large piece of Black + <!-- Page 122 --> <span class="pagenum"><a name="LPage_122" + id="LPage_122"></a>[pg 122]</span> Marble well Poliſh'd, and brought + to the Form of a Large Sphærical and Concave <i>Speculum</i>; For on the + Inſide this Marble being well Poliſh'd, was a kind of Dark + Looking-glaſs, wherein I could plainly ſee a Little Image of the + Sun, when that Shin'd upon it. But this Image was very far from Offending + and Dazling my Eyes, as it would have done from another <i>Speculum</i>; + Nor, though the <i>Speculum</i> were Large, could I in a Long time, or in + a Hot Sun ſet a piece of Wood on Fire, though a far leſs <i>Speculum</i> + of the ſame Form, and of a more Reflecting Matter, would have made it + Flame in a Trice. + </p> + <p> + 5. And on this Occaſion we may as well in Reference to ſomething + formerly deliver'd concerning Whiteneſs, as in Reference to what has + been newly ſaid, Subjoyn what we further obſerv'd touching the + Differing Reflections of Light from White and Black Marble, namely, that + having taking a pretty Large Mortar of White Marble, New and Poliſh'd + in the Inſide, and Expos'd it to the Sun, we found that it Reflected + a great deal of Glaring Light, but ſo Diſpers'd, that we could + not make the Reflected Beams concurr in any ſuch Conſpicuous <i>Focus</i>, + as that newly taken notice of in the Black Marble, though + <!-- Page 123 --> <span class="pagenum"><a name="LPage_123" + id="LPage_123"></a>[pg 123]</span> perhaps there may enough of them be + made to meet near the Bottom, to make ſome Kind of <i>Focus</i>, eſpecially + ſince by holding in the Night-time a Candle at a convenient Diſtance, + we were able to procure a Concourſe of ſome, though not many of + the Reflected Beams, at about two Inches diſtant from the Bottom of + the Mortar: But we found the Heat even of the Sunbeams ſo Diſperſedly + Reflected to be very Languid, even in Compariſon of the Black Marbles + <i>Focus</i>. And the Little Picture of the Sun, that appear'd upon the + White Marble as a <i>Speculum</i>, was but very Faint and exceeding ill + Defin'd. Secondly, That taking two pieces of Plain and Poliſh'd + Surfaces, and caſting on them Succeſſively the Beams of the + Same Candle, In ſuch manner, as that the Neighbouring Superficies + being Shaded by an Opacous and Perforated Body, the Incident Beams were + permitted to paſs but through a Round Hole of about Half an Inch + Diameter, the Circle of Light that appear'd on the White Marble was in + Compariſon very Bright, but very ill Defin'd; whereas that on the + Black Marble was far leſs Luminous, but much more preciſely + Defin'd. + </p> + <p> + 6. Thirdly, When you Look upon a piece of Linnen that has Small Holes in + it, + <!-- Page 124 --> <span class="pagenum"><a name="LPage_124" + id="LPage_124"></a>[pg 124]</span> thoſe Holes appear very Black, and + Men are often deceiv'd in taking Holes for Spots of Ink; And Painters to + repreſent Holes, make uſe of Black, the Reaſon of which + ſeems to be, that the Beams that fall on thoſe Holes, fall into + them So Deep, that none of them is Reflected back to the Eye. And in + narrow Wells part of the Mouth ſeems Black, becauſe the Incident + Beams are Reflected Downwards from one ſide to another, till they can + no more Rebound to the Eye. + </p> + <p> + We may conſider too, that if Differing parts of the ſame piece + of Black Velvet be ſtroak'd Oppoſite ways, the piece of Velvet + will appear of two Diſtinct kinds of Blackneſs, the one far + Darker than the other, of which Diſparity the Reaſon Seems to + be, that in the Leſs obſcure part of the Velvet, the Little + Silken Piles whereof 'tis made up, being Inclin'd, there is a Greater part + of each of them Obverted to the Eye, whereas in the other part the Piles + of Silk being more Erected, there are far Fewer Beams Reflected Outwards + from the Lateral parts of each Pile, So that moſt of thoſe that + Rebound to the Eye, come from the Tops of the Piles, which make but a + ſmall part of the whole Superficies, that may be cover'd by the piece + of Velvet. + <!-- Page 125 --> <span class="pagenum"><a name="LPage_125" + id="LPage_125"></a>[pg 125]</span> Which Explication I propoſe, not + that I think the Blackneſs of the Velvet proceeds from the Cauſe + aſſign'd, ſince each Single Pile of Silk is Black by reaſon + of its Texture, in what Poſition ſoever you Look upon it; But + that the Greater Blackneſs of one of theſe Tuffts ſeems to + proceed from the Greater Paucity of Beams Reflected from it, and that from + the Fewneſs of thoſe Parts of a Surface that Reflect Beams, and + the Multitude of thoſe Shaded Parts that Reflect none. And I + remember, that I have oftentimes obſerv'd, that the Poſition of + Particular Bodies far greater than Piles of Silk in reference to the Eye, + may notwithſtanding their having each of them a Colour of its own, + make one part of their Aggregate appear far Darker than the other; For I + have near Great Towns often taken notice, that a Cart-load of Carrots + pack'd up, appear'd of a much Darker Colour when Look'd upon, where the + Points of the Carrots were Obverted to the Eye, than where the Sides of + them were ſo. + </p> + <p> + 7. Fourthly, In a Darkned Room, I purpoſely obſerv'd, that if + the Sun-beams, which came in at the Hole were receiv'd upon White or any + other Colour, and directed to a Convenient place of the Room, + <!-- Page 126 --> <span class="pagenum"><a name="LPage_126" + id="LPage_126"></a>[pg 126]</span> they would Manifeſtly, though not + all Equally, Encreaſe the Light of that Part; whereas if we Subſtituted, + either a piece of Black Cloth or Black Velvet, it would ſo Dead the + Incident Beams, that the place (newly mention'd) whereto I Obverted the + Black Body, would be Leſs Enlightned than it was before, when it + received its Light but from the Weak and Oblique Reflections of the Floor + and Walls of a pretty Large Room, through which the Beams that came in at + the Hole were Confuſedly and Brokenly Diſpers'd. + </p> + <p> + 8. Fifthly, And to ſhew that the Beams that fall on Black Bodies, as + they do not Rebound Outwards to the Eye, ſo they are Reflected + towards the Body it ſelf, as the Nature of thoſe Erected + Particles to which we have imputed Blackneſs, requires, we will add + an Experiment that will alſo confirm our Doctrine touching Whiteneſs; + Namely, that we took a Broad and Large Tile, and having Whitened over one + half of the Superficies of it, and Black'd the other, we expos'd it to the + Summer Sun; And having let it lye there a convenient time (for the + Difference is more Apparent, if it have not lain there too long) we found, + as we expected, that whilſt the Whited part of the Tile remained Cool + enough, the + <!-- Page 127 --> <span class="pagenum"><a name="LPage_127" + id="LPage_127"></a>[pg 127]</span> Black'd part of the ſame Tile was + grown not only Senſible, but very Hot, (ſometimes to a ſtrong + Degree.) And to ſatisfie ſome of our Friends the more, we have + ſometimes left upon the Surface of the Tile, beſides the White + and Black parts thereof, a part that Retain'd the native Red of the Tile + it ſelf, and Expoſing them to the Sun, we obſerv'd this Laſt + mention'd to have Contracted a Heat in compariſon of the White, but a + Heat Inferiour to that of the Black, of which the Reaſon ſeems + to be, that the Superficial Particles of Black Bodies, being, as we ſaid, + more Erected, than thoſe of White or Red ones, the Corpuſcles of + Light falling on their ſides, being for the moſt part Reflected + Inwards from one Particle to another, and thereby engag'd as it were and + kept from Rebounding Upwards, they communicate their brisk Motion, + wherewith they were impell'd againſt the Black Body, (upon whoſe + account had they fallen upon a White Body, they would have been Reflected + Outwards) to the Small parts of the Black Body, and thereby Produce in thoſe + Small parts ſuch an Agitation, as (when we feel it) we are wont to + call Heat. I have been lately inform'd, that an Obſervation near of + Kin to Ours, has been made by ſome Learned Men in <i>France</i> and + <!-- Page 128 --> <span class="pagenum"><a name="LPage_128" + id="LPage_128"></a>[pg 128]</span> <i>Italy</i>, by long Expoſing to + a very Hot Sun, two pieces of Marble, the one White, the other Black; But + though the Obſervation be worthy of them, and may confirm the ſame + Truth with Our Experiment, yet beſides that our Tryal needs not the + Summer, nor any Great Heat to ſucceed, It ſeems to have this + Advantage above the other, that whereas Bodies more Solid, and of a Cloſer + Texture, though they uſe to be more Slowly Heated, are wont to + receive a Greater Degree of Heat from the Sun or Fire, than (<i>Cæteris + paribus</i>) Bodies of a Slightest Texture; I have found by the + Information of Stone-cutters, and by other ways of Enquiry, that Black + Marble is much Solider and Harder than White, ſo that poſſibly + the Difference betwixt the Degrees of Heat they receive from the Sunbeams + will by many be aſcrib'd to the Difference of their Texture, rather + than to that of their Colour, though I think our Experiment will make it + Probable enough that the greater part of that Difference may well be aſcrib'd + to that Diſpoſition of Parts, which makes the one Reflect the + Sunbeams Inward; and the other Outwards. And with this Doctrine accords + very well, that Rooms hung with Black, are not only Darker than elſe + they would be, but are + <!-- Page 129 --> <span class="pagenum"><a name="LPage_129" + id="LPage_129"></a>[pg 129]</span> wont to be Warmer too; Inſomuch + that I have known a great Lady, whoſe Conſtitution was ſomewhat + Tender, complain that ſhe was wont to catch Cold, when ſhe went + out into the Air, after having made any long Viſits to Perſons, + whoſe Rooms were hung with Black. And this is not the only Lady I + have heard complain of the Warmth of ſuch Rooms, which though perhaps + it may be partly imputed to the <i>Effluvia</i> of thoſe Materials + wherewith the hangings were Dy'd, yet probably the Warmth of ſuch + Rooms depends chiefly upon the ſame Cauſe that the Darkneſs + does; As (not to repeat what I formerly Noted touching my Gloves,) to + ſatisfie ſome Curious Perſons of that Sex, I have convinc'd + them, by Tryall, that of two Pieces of Silken Stuff given me by themſelves, + and expos'd in their Preſence, to the ſame Window, Shin'd on by + that Sun, the White was <i>conſiderably</i> Heated, when the Black + was not ſo much as <i>Senſibly</i> ſo. + </p> + <p> + 9. Sixthly, I remember, that Acquainting one Day a <i>Virtuoſo</i> of + Unſuſpected Credit, that had Viſited Hot Countries, with + part of what I have here Deliver'd concerning Blackneſs, he Related + to me by way of Confirmation of it, a very notable + <!-- Page 130 --> <span class="pagenum"><a name="LPage_130" + id="LPage_130"></a>[pg 130]</span> Experiment, which he had both others + make, and Made himſelf in a Warm Climate, namely, that having + carefully Black'd over Eggs, and Expos'd them to the Hot Sun, they were + thereby in no very Long time well Roaſted, to which Effect I conceive + the Heat of the Climate muſt have Concurr'd with the Diſpoſition + of the Black Surface to Reflect the Sunbeams Inward, for I remember, that + having made that among other Tryals in <i>England</i>, though in + Summer-time, the Eggs I Expos'd, acquir'd indeed a conſiderable + Degree of Heat, but yet not ſo Intenſe a One, as prov'd + Sufficient to Roaſt them. + </p> + <p> + 10. Seventhly, and Laſtly, Our Conjectures at the Nature of Blackneſs + may be ſomewhat Confirm'd by the (formerly mention'd) Obſervation + of the Blind <i>Dutch-man</i>, that Diſcerns Colours with his + Fingers; for he Says, that he Feels a greater Roughneſs upon the + Surfaces of Black Bodies, than upon thoſe of Red, or Yellow, or + Green. And I remember, that the Diligent <i>Bartholinus</i> ſays,<a + name="LNtA_9" id="LNtA_9_"></a><a href="#LNt_9"><sup>9</sup></a> that a Blind + Earl of <i>Mansfield</i> could Diſtinguiſh White from Black only + by the Touch, which would Sufficiently Argue a great Diſparity in the + Aſperities, or other + <!-- Page 131 --> <span class="pagenum"><a name="LPage_131" + id="LPage_131"></a>[pg 131]</span> Superficial Textures of Bodies of thoſe + two Colours, if the Learn'd Relator had Affirm'd the Matter upon his own + Knowledge. + </p> + <p> + II. Theſe, <i>Pyrophilus</i>, are the chief things that Occurr to me + at preſent, about the Nature of Whiteneſs and Blackneſs, + which it they have Rendred it ſo much as Probable, that in <i>Moſt</i>; + or at leaſt <i>Many</i> Caſes, the Cauſes of theſe + Qualities may be ſuch as I have Adventur'd to Deliver, it is as much + as I Pretend to; for till I have Opportunity to Examine the Matter by + ſome further Tryals, I am not ſure, but that in ſome White + and Black Bodies, there may Concurr to the Colour ſome peculiar + Texture or Diſpoſition of the Body, whereby the Motion of the + Small Corpuſcles that make up the Incident Beams of Light, may be + Differingly Modify'd, before they reach the Eye, eſpecially in this, + that White Bodies do not only Copiouſly Reflect thoſe Incident + Corpuſcles Outwards, but Reflect them Briskly, and do not otherwiſe + Alter them in the manner of their Motion. Nor ſhall I now ſtay + to Enquire, whether ſome of thoſe other ways, (as a Diſpoſition + to Alter the Velocity, the Rotation, or the Order and Manner of Appulſe + ſo the Eye of the Reflected Corpuſcles + <!-- Page 132 --> <span class="pagenum"><a name="LPage_132" + id="LPage_132"></a>[pg 132]</span> that Compos'd the Incident Beams of + Light) which we mention'd when we conſider'd the Production of + Colours in General, may not in ſome Caſes be Applicable to thoſe + of White and Black Bodies: For I am yet ſo much a <i>Seeker</i> in + this Matter, and ſo little Wedded to the Opinions I have propos'd, + that what I am to add ſhall be but the Beginning of a Collection of + Experiments and Obſervation towards the Hiſtory of Whiteneſs + and Blackneſs, without at preſent interpoſing my + Explications of them, that ſo, I may aſſiſt your + Enquires without much Fore-ſtalling or Biaſſing your + Judgment. + </p> + <hr /> + <!-- Page 133 --> + <p> + <span class="pagenum"><a name="LPage_133" id="LPage_133"></a>[pg 133]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/172a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:100%; letter-spacing:10px">EXPERIMENT</span><br /> + <span style="font-size:75%; letter-spacing:6px">IN</span><br /> <span + style="font-size:100%; letter-spacing:10px">CONSORT,</span><br /> <span + style="font-size:50%;">Touching</span><br /> <span style="font-size:100%;">Whiteneſs + & Blackneſs.</span><br /> + </h2> + <hr /> + <h3> + EXPERIMENT I. + </h3> + <p> + <img width="80" height="80" src="images/172b.png" + alt="Illuminated H in Having" /> Aving promis'd in the <a href="#LPage_114">114</a>, + and <a href="#LPage_115">115</a>. Pages of the foregoing Diſcourſe + of Whiteneſs and Blackneſs, to ſhew, that thoſe two + Colours may by a change of Texture in bodies, each of them apart + Diaphanous and Colourleſs, be at pleaſure and in a trice as well + Generated as Deſtroy'd, We ſhall begin with Experiments that may + acquit us of that promiſe. + </p> + <p> + Take then what Quantity you pleaſe of Fair Water, and having Heated + it, put into it as much good Common Sublimate, as it is able to Diſſolve, + and (to be ſure of having + <!-- Page 134 --> <span class="pagenum"><a name="LPage_134" + id="LPage_134"></a>[pg 134]</span> it well glutted:) continue putting in + the Sublimate, till ſome of it lye Untouch'd in the bottom of the + Liquor, Filter this Solution through Cap-paper, to have it cleer and + limpid, and into a ſpoonfull or two thereof, (put into a clean glaſs + veſſel,) ſhake about four or five drops (according as you + took more or leſs of this Solution) of good limpid Spirits of Urine, + and immediately the whole mixture will appear White like Milk, to which + mixture if you preſently add a convenient proportion of Rectifi'd <i>Aqua + Fortis</i> (for the number of drops is hard to determine, becauſe of + the Differing Strength of the liquor, but eaſily found by tryal) the + Whiteneſs will preſently diſappear, and the whole mixture + become Tranſparent, which you may, if you pleaſe, again reduce + to a good degree of Whiteneſs (though inferiour to the firſt) + onely by a more copious affuſion of freſh Spirit of Urine. <i>N</i>. + Firſt, That it is not ſo neceſſary to employ either <i>Aqua + Fortis</i> or Spirit of Urine about this Experiment, but that we have made + it with other liquors inſtead of theſe, of which perhaps more elſewhere. + Secondly, That this Experiment, though not made with the ſame <i>Menſtruums</i>, + nor producing the ſame Colour is yet much of Kin to that other to be + <!-- Page 135 --> <span class="pagenum"><a name="LPage_135" + id="LPage_135"></a>[pg 135]</span> mentioned in this Tract among our other + Experiments of Colours, about turning a Solution of Præcipitate into an + Orange-colour, and the Chymical Reaſon being much alike in both, the + annexing it to one of them may ſuffice FOR both. + </p> + <h3> + <i>EXPERIMENT II.</i> + </h3> + <p> + Make a ſtrong Infuſion of broken Galls in Fair Water, and having + Filtred it into a clean Vial, add more of the ſame liquor to it, till + you have made it ſomewhat Tranſparent, and ſufficiently + diluted the Colour, for the credit of the Experiment, leſt otherwiſe + the Darkneſs of the liquor might make it be objected, that 'twas + already almoſt Ink; Into this Infuſion ſhake a convenient + quantity of a Cleer, but very ſtrong Solution of Vitriol, and you + ſhall immediately ſee the mixture turn Black almoſt like + Ink, and ſuch a way of producing Blackneſs is vulgar enough; but + if preſently after you doe upon this mixture drop a ſmall + quantity of good oyl of Vitriol, and, by ſhaking the Vial diſperſe + it nimbly through the two other liquors, you ſhall (if you perform + your part well, and have employ'd oyl of Vitriol Cleer and Strong enough) + ſee the Darkneſs of the liquor preſently begin + <!-- Page 136 --> <span class="pagenum"><a name="LPage_136" + id="LPage_136"></a>[pg 136]</span> to be diſcuſs'd, and grow + pretty Cleer and Tranſparent, loſing its Inky Blackneſs, + which you may again reſtore to it by the affuſion of a ſmall + quantity of a very ſtrong Solution of Salt of Tartar. And though + neither of theſe Atramentous liquors will ſeem other than very + Pale Ink, if you write with a clean Pen dipt in them, yet that is common + to them with ſome ſorts of Ink that prove very good when Dry, as + I have alſo found, that when I made theſe carefully, what I + wrote with either of them, eſpecially with the Former, would when + throughly Dry grow Black enough not to appear bad Ink. This Experiment of + taking away and reſtoring Blackneſs from and to the liquors, we + have likewiſe tryed in Common Ink; but there it ſucceeds not + ſo well, and but very ſlowly, by reaſon that the Gum wont + to be employed in the making it, does by its Tenacity oppoſe the + operations of the above mention'd Saline liquors. But to conſider Gum + no more, what ſome kind of Præcipitation may have to do in the + producing and deſtroying of Inks without it, I have elſewhere + given you ſome occaſion and aſſiſtance to + enquire; But I muſt not now ſtay to do ſo my ſelf, + only I ſhall take notice to you, that though it be taken for granted + that bodies will not be Præcipitated by Alcalizat Salts, + <!-- Page 137 --> <span class="pagenum"><a name="LPage_137" + id="LPage_137"></a>[pg 137]</span> that have not firſt been diſſolved + in ſome Acid <i>Menſtruums</i>, yet I have found upon tryals, + which my conjectures lead me to make on purpoſe, That divers + Vegetables <i>barely infus'd</i>, or, <i>but ſlightly decocted in + common water</i>, would, upon the affuſion of a Strong and Cleer <i>Lixivium</i> + of Potaſhes, and much more of ſome other Præcipitating liquors + that I ſometimes employ, afford good ſtore of a Crudled matter, + ſuch as I have had in the Præcipitations of Vegetable ſubſtances, + by the intervention of Acid things, and that this matter was eaſily + ſeparable from the reſt of the liquor, being left behind by it + in the Filtre; and in making the firſt Ink mention'd in this + Experiment, I found that I could by Filtration ſeparate pretty ſtore + of a very Black pulverable ſubſtance, that remain'd in the + Filtre, and when the Ink was made Cleer again by the Oyl of Vitriol, the + affuſion of diſſolv'd <i>Sal Tartari</i> ſeem'd but to + Præcipitate, and thereby to Unite and render Conſpicuous the + particles of the Black mixture that had before been diſpers'd into + very Minute and ſingly Inviſible particles by the Inciſive + and reſolving power of the highly Corroſive Oyl of Vitriol. + </p> + <p> + <!-- Erratum: insert: --> + And to manifeſt, <i>Pyrophilus</i>, that Galls are not ſo requiſite + as many ſuppoſe to the making Atramentous Liquors, we have + ſometimes made the following Experiment, We took dryed Roſe + leaves and Decocted them for a while in Fair Water, into two or three + ſpoonfulls of this Decoction we ſhook a few drops of a ſtrong + and well filtrated Solution of Vitriol (which perhaps had it been Green + would have done as well) and immediately the mixture did turn Black, and + when into this mixture preſently after it was made, we ſhook a + juſt Proportion of <i>Aqua Fortis</i>, we turn'd it from a Black Ink + to a deep Red one, which by the affuſion of a little Spirit of Urine + may be reduc'd immediately to an Opacous and Blackiſh Colour. And in + regard, <i>Pyrophilus</i>, that in the former Experiments, both the Infuſion + of Galls, and the Decoction of Roſes, and the Solution of Copperis + employ'd about them, are endow'd each of them with its own Colour, there + may be a more noble Experiment of the ſudden production of Blackneſs + made by the way mention'd in the Second Section of the Second Part of our + Eſſays, for though upon the Confuſion of the two Liquors + there mention'd, there do immediately emerge a very Black mixture, yet + both the Infuſion of <i>Orpiment</i> and the Solution of <i>Minium</i> + were before their being joyn'd together, Limpid and Colourleſs. + <!-- end insert --> + </p> + <!-- Page 138 --> + <p> + <span class="pagenum"><a name="LPage_138" id="LPage_138"></a>[pg 138]</span> + </p> + <h3> + <i>EXPERIMENT III.</i> + </h3> + <p> + If pieces of White Harts-horn be with a competent degree of Fire diſtill'd + in a Glaſs-retort, they will, after the avolation of the Flegm, + Spirit, Volatile Salt, and the looſer and lighter parts of the + Oleagenous ſubſtance, remain behind of a Cole-black colour. And + even Ivory it ſelf being skilfully Burnt (how I am wont to do it, I + have elſewhere ſet down) affords Painters one of the beſt + and deepeſt Blacks they have, and yet in the Inſtance of diſtill'd + Harts-horn, the operation being made in Glaſs-veſſels + carefully clos'd, it appears there is no Extraneous Black ſubſtance + that Inſinuates it ſelf into White Harts-horn, and thereby makes + it turn Black; but that the Whiteneſs is deſtroy'd, and the + Blackneſs generated, only by a Change of Texture, made in the burnt + Body, by the Receſs of ſome parts and the Tranſpoſition + of others. And though I remember not that in many Diſtillations of + Harts-horn I ever ſound the <i>Cap. Mort</i>. to paſs from Black + to a true Whiteneſs, whilſt it continu'd in Clos'd veſſels, + yet having taken out the Cole-black fragments, and Calcin'd them in Open + veſſels, I could in few hours quite deſtroy that Blackneſs, + & without + <!-- Page 139 --> <span class="pagenum"><a name="LPage_139" + id="LPage_139"></a>[pg 139]</span> ſenſibly changing their Bulk + or Figure, reduce them to great Whiteneſs. So much do theſe two + Colours depend upon the Diſpoſition of the little parts, that + the Bodies wherein they are to be met with do conſiſt of. And we + find, that if Whitewine Tartar, or even the white Cryſtalls of ſuch + Tartar be burnt without being truly Calcin'd, the <i>Cap. Mortuum</i> (as + the Chymiſts call the more Fixt part) will be Black. But if you + further continue the Calcination till you have perfectly Incinerated the + Tartar, & kept it long enough in a Strong fire, the remaining <i>Calx</i> + will be White. And ſo we ſee that not only other Vegetable + ſubſtances, but even White woods, as the Hazel, will yield a + Black Charcoal, and afterwards Whitiſh aſhes; And ſo Animal + ſubſtances naturally White, as Bones and Eggſhels, will + grow Black upon the being Burnt, and White again when they are perfectly + Calcin'd. + </p> + <h3> + <i>EXPERIMENT IV.</i> + </h3> + <p> + But yet I much Queſtion whether that Rule delivered by divers, as + well Philoſophers as Chymiſts, <i>aduſta nigra, ſed + peruſta alba</i>, will hold as Univerſally as is preſum'd, + ſince I have ſeveral Examples to allege againſt + <!-- Page 140 --> <span class="pagenum"><a name="LPage_140" + id="LPage_140"></a>[pg 140]</span> it: For I have found that by burning + Alablaſter, ſo as both to make it appear to boyl almoſt + like Milk, and to reduce it to a very fine Powder, it would not at all + grow Black, but retain its Pure and Native Whiteneſs, and though by + keeping it longer than is uſual in the fire, I produced but a faint + Yellow, even in that part of the Powder that lay neareſt the top of + the Crucible, yet having purpoſely enquired of an Experienced + Stone-cutter, who is Curious enough in tryng Concluſions in his own + Trade, he told me he had found that if Alabaſter or Plaſter of + Paris be very long kept in a Strong fire, the whole heap of burnt Powder + would exchange its Whiteneſs for a much deeper Colour than the Yellow + I obſerv'd. Lead being Calcin'd with a Strong fire turns (after + having purhaps run thorough divers other Colour) into <i>Minium</i>, whoſe + Colour we know is a deep red; and if you urge this <i>Minium</i>, as I + have purpoſely done with a Strong fire, you may much eaſier find + a Glaſſie and Brittle Body darker than <i>Minium</i>, than any + white <i>Calx</i> or Glaſs. 'Tis known among Chymiſts, that the + white <i>Calx</i> of Antimony, by the further and more vehement operation + of the fire, may be melted into Glaſs, which we have obtain'd of a + Red Colour, which is + <!-- Page 141 --> <span class="pagenum"><a name="LPage_141" + id="LPage_141"></a>[pg 141]</span> far deeper than that of the <i>Calx</i> + of Burnt Antimony, and though common Glafs of Antimony being uſually + Adulterated with <i>Borax</i>, have its Colour thereby diluted, oftentimes + to a very pale Yellow; yet not onely ours made more ſincerily, was, + as we ſaid, of a Colour leſs remote from Black, than was the <i>Calx</i>; + but we obſerv'd, that by Melting it once or twice more, and ſo + expoſing it to the further operation of the Fire, we had, as we + expected, the Colour heightned. To which we ſhall add but this one Inſtance, + (which is worth the taking notice of in Reference to Colours:) That, if + you take Blew, but Unſophiſticated, Vitriol, and burn it very + ſlowly, and with a Gentle degree of Heat, you may obſerve, that + when it has Burnt but a Little, and yet ſo far as that you may rub it + to Powder betwixt your fingers, it will be of a White or Whitiſh + Colour; But if you Proſecute the Calcination, this Body which by a + light Aduſtion was made White, will paſs through other Colours, + as Gray, Yellowiſh, and Red; and if you further burn it with a Long + and Vehement fire, by that time it comes to be <i>Peruſtum</i>, it + will be of a dark purple, nearer to Black, not only than the firſt <i>Calx</i>, + but than the Vitriol before it at all felt the fire. I might add that <i>Crocus</i> + <!-- Page 142 --> <span class="pagenum"><a name="LPage_142" + id="LPage_142"></a>[pg 142]</span> <i>Martis</i> (<i>per ſe</i> as + they call it) made by the Laſting violence of the Reverberated flames + is not ſo near a Kin to White, as the Iron or Steel that afforded it + was before its Calcinations; but that I ſuppoſe, theſe Inſtances + may Suffice to ſatisfie you, that Minerals are to be excepted out of + the forementioned Rule, which perhaps, though it ſeldome fail in + ſubſtances belonging to the Vegetable or Animal Kingdome, may + yet be Queſtion'd even in ſome of theſe, if that be true, + which the Judicious Traveller <i>Bellonius</i> affirms, that Charcoales + made out of the Wood of <i>Oxycæder</i> are White; And I could not find + that though in Retorts Hartſhorn and other White Bodies will be + Denigrated by Heat, yet Camphire would not at all loſe its Whiteneſs, + though I have purpoſely kept it in ſuch a heat, as made it melt + and boyl. + </p> + <!-- Erratum: delete: And to manifeſt, <i>Pyrophilus</i>, that Galls + are not ſo requiſite as many ſuppoſe to the making + Atramentous Liquors, we have ſometimes made the following Experiment, + We took dryed Roſe leaves and Decocted them for a while in Fair + Water, into two or three ſpoonfulls of this Decoction we ſhook a + few drops of a ſtrong and well filtrated Solution of Vitriol (which + perhaps had it been Green would have done as well) and immediately the + mixture did turn Black, and when into this mixture preſently after it + was made, we ſhook a juſt Proportion of <i>Aqua Fortis</i>, we + turn'd it from a Black Ink to a deep Red one, which by the affuſion + of a little Spirit of Urine may be reduc'd immediately to an Opacous and + Blackiſh Colour. And in regard, <i>Pyrophilus</i>, that in the former + Experiments, both the Infuſion of Galls, and the Decoction of + Roſes, and the Solution of Copperis employ'd about them, are endow'd + each of them with its own Colour, there may be a more noble Experiment of + the ſudden production of Blackneſs made by the way mention'd in + the Second Section of the Second Part of our Eſſays, for though + upon the Confuſion of the two Liquors there mention'd, there do + immediately emerge a very Black mixture, yet both the Infuſion of + <i>Orpiment</i> and the Solution of <i>Minium</i> were before their being + joyn'd together, Limpid and Colourleſs. --> + <!-- Page 143 --> + <p> + <span class="pagenum"><a name="LPage_143" id="LPage_143"></a>[pg 143]</span> + </p> + <h3> + <i>EXPERIMENT V.</i> + </h3> + <p> + And now I ſpeak of Camphire, it puts me in mind of adding this + Experiment, That, though as I ſaid in Clos'd Glaſſes, I + could not Denigrate it by Heat, but it would Sublime to the ſides and + top of the Glaſs, + <!-- Page 144 --> <span class="pagenum"><a name="LPage_144" + id="LPage_144"></a>[pg 144]</span> as it was before, yet not only it will, + being ſet on fire in the Free Air, ſend forth a Copious ſmoak, + but having purpoſely upon ſome of it that was Flaming, clapt a + Large Glaſs, almoſt in the form of a Hive, (but more Slender + only) with a Hole at the top, (which I caus'd to be made to trye + Experiments of Fire and Flame in) it continued ſo long burning that + it Lin'd all the Inſide of the Glaſs with a Soot as Black as + Ink, and ſo Copious, that the Cloſeneſs of the Veſſel + conſider'd, almoſt all that part of the White Camphire that did + take Fire, ſeem'd to have been chang'd into that deep Black Subſtance. + </p> + <h3> + <i>EXPERIMENT VI</i> + </h3> + <p> + And this alſo brings into my mind another Experiment that I made + about the production of Blackneſs, whereof, for Reaſons too long + to be here deduced, I expected and found a good Succeſs, an it was + this: I took Rectifi'd Oyl of Vitriol (that I might have the Liquor Clean + as well as Strong) and by degrees mixt with it a convenient proportion of + the Eſſential Oyl, as Chymiſts call it, of Wormwood, drawn + over with ſtore of Water in a Limbec, and warily Diſtilling the + mixture in a Retort, there remain'd + <!-- Page 145 --> <span class="pagenum"><a name="LPage_145" + id="LPage_145"></a>[pg 145]</span> a ſcarce credible quantity of dry + Matter + <!-- Erratum: delete: s -->, Black as a Coal. And becauſe the Oyl of + Wormwood, though a Chymical Oyl drawn by a <i>Virtuoſo</i>, ſeem'd + to have ſomewhat in it of the Colour of the Plant, I Subſtituted + in its Room, the Pure and Subtile Eſſential Oyl of + Winter-Savory, and mixing little by little this Liquor, with (if I + mis-remember not) an Equal weight of the formerly mention'd Rectifi'd Oyl + of Vitriol, and Diſtilling them as before in a Retort, beſides + what there paſs'd over into the Receiver, even theſe two clear + Liquors left me a Conſiderable Proportion, (though not ſo great + as the two former) of a Subſtance Black as Pitch, which I yet Keep by + me as a Rarity. + </p> + <h3> + <i>EXPERIMENT VII.</i> + </h3> + <p> + A way of Whiting Wax Cheaply and in Great Quantity may be a thing of good + Oeconomical Uſe, and we have elſewhere ſet down the + Practice of Trades-men that Blanch it; But here Treating of Whiteneſs + only in Order to the Philoſophy of Colours, I ſhall not Examine + which of the Slow wayes may be beſt Employ'd, to free Wax from the + Yellow Melleous parts, but ſhall rather ſet down a Quick + <!-- Page 146 --> <span class="pagenum"><a name="LPage_146" + id="LPage_146"></a>[pg 146]</span> way of making it White, though but in + very Small Quantities. Take then a little Yellow Wax, ſcraped or + thinly ſliced, and putting it into a + <!-- Erratum: was C... -->Bolts-head or ſome other Convenient Glaſs, + pour to it a pretty deal of Spirit of Wine, and placing the Veſſel + in Warm Sand, Encreaſe the Heat by degrees, till the Spirit of Wine + begin to Simper or to Boyl a little; and continuing that degree of Fire, + if you have put Liquor enough, you will quickly have the Wax diſſolv'd, + then taking it off the fire, you may either ſuffer it to Cool as haſtily + as with Safety to the Glaſs you can, or Pour it whilſt 'tis yet + Hot into a Filtre of Paper, and either in the Glaſs where it Cools, + or in the Filtre, you will ſoon find the Wax and <i>Menſtruum</i> + together reduc'd into a White Subſtance, almoſt like Butter, + which by letting the Spirit Exhale will ſhrink into a much Leſſer + Bulk, but ſtill retaining its Whiteneſs. And that which is + pretty in the working of this Magiſtery of Wax, is, that the Yellowneſs + vaniſhes, neither appearing in the Spirit of Wine that paſſes + Limpid through the Filtre, nor in the Butter of Wax, if I may ſo call + it, that, as I ſaid, is White. + <!-- Page 147 --> <span class="pagenum"><a name="LPage_147" + id="LPage_147"></a>[pg 147]</span> + </p> + <h3> + <i>EXPERIMENT VIII.</i> + </h3> + <p> + There is an Experiment, <i>Pyrophilus</i>, which though I do not ſo + exactly remember, and though it be ſomewhat Nice to make, yet I am + willing to Acquaint You with, becauſe the thing Produc'd, though it + be but a Curioſity, is wont not a little to pleaſe the + Beholders, and it is a way of turning by the help of a Dry Subſtance, + an almoſt Golden-Colour'd Concrete, into a White one, the Several + Tryals are not at preſent ſo freſh in my Memory to enable + me to tell you Certainly, whether an Equal onely or a Double weight of + Common Sublimate muſt be taken in reference to the Tinglaſs, but + if I miſtake not, there was in the Experiment that ſucceeded beſt, + Two parts of the Former taken to One of the Latter. Theſe Ingredients + being finely Powdred and Exactly mix'd, we Sublim'd together by degrees of + fire (the due Gradation of which is in this Experiment a thing of main + Importance) there aſcended a matter of a very peculiar Texture, for + it was for the moſt part made up of very Thin, Smooth, Soft and + Slippery Plates, almoſt like the fineſt ſort of the Scales + of Fiſhes, but of ſo Lovely a White Inclining to + <!-- Page 148 --> <span class="pagenum"><a name="LPage_148" + id="LPage_148"></a>[pg 148]</span> Pearl-Colour, and of ſo Curious + and Shining a Gloſs, that they appear'd in ſome reſpect + little Inferiour to Orient Pearls, and in other Regards, they ſeem'd + to Surpaſs them, and were Applauded for a ſort of the Prettieſt + Trifles that we had ever prepar'd to Amuſe the Eye. I will not + undertake that though you'l hardly miſs changing the Colour of your + ſhining Tinglaſs, yet you will the firſt or perhaps the + ſecond time hit Right upon the way of making the Gliſtring + Sublimate I have been mentioning. + </p> + <h3> + <i>EXPERIMENT IX.</i> + </h3> + <p> + When we Diſſolve in <i>Aqua Fortis</i> a mixture of Gold and + Silver melted into one Lump, it uſually happens that the Powder of + Gold that falls to the bottom, as not being Diſſoluble by that + <i>Menſtruum</i>, will not have its own Yellow, but appear of a Black + Colour, though neither the Gold, nor the Silver, nor the <i>Aqua Fortis</i> + did before manifeſt any Blackneſs. And divers Alchymiſts, + when they make Solutions of Minerals they would Examine, are very Glad, if + they ſee a Black Powder Præcipitated to the Bottom, taking it for a + Hopefull Sign, that thoſe Particles are of a Golden Nature, + <!-- Page 149 --> <span class="pagenum"><a name="LPage_149" + id="LPage_149"></a>[pg 149]</span> which appear in a Colour ſo + ordinary to Gold parted from other Metalls by <i>Aqua Fortis</i>, that it + is a trouble to the Refiner to Reduce the Præcipitated <i>Calx</i> to its + Native Colour. For though, (as we have try'd,) that may be Quickly enough + done by Fire, which will make this Gold look very Gloriouſly (as + indeed 'tis at leaſt one of the Beſt wayes that is Practis'd for + the Refining of Gold,) yet it requires both Watchfulneſs and Skill, + to give it ſuch a Degree of Fire as will ſerve to Reſtore + it to its Luſtre, without giving it ſuch a One, as may bring it + to Fuſion, to which the Minuteneſs of the <i>Corpuſeles</i> + it conſiſts of makes the Powder very apt. And this brings into + my Mind, that having taken a Flat and Bright piece of Gold, that was + Refin'd by a Curious and Skilfull Perſon on purpoſe to Trye to + what height of Purity Gold could be brought by Art, I found that this very + piece, as Glorious as it look'd, being rubb'd a little upon a piece of + fine clean Linnen, did ſully it with a kind of Black; and the like I + have obſerv'd in Refin'd Silver, which I therefore mention, becauſe + I formerly ſuſpected that the Impurity of the Metall might have + been the only Cauſe of what I have divers times obferv'd in wearing + Silver-hilted Swords, Namely, that + <!-- Page 150 --> <span class="pagenum"><a name="LPage_150" + id="LPage_150"></a>[pg 150]</span> where they rubb'd upon my Clothes, if + they were of a Light-Colour'd Cloath, the Affriction would quickly Black + them; and Congruouſly hereunto I have found Pens Blackt almoſt + all over, when I had a while carri'd them about me in a Silver Ink-caſe. + To which I ſhall only add, that whereas in theſe ſeveral Inſtances + of Denigration, the Metalls are worn off, or otherwiſe Reduc'd into + very Minute Parts, that Circumſtance may prove not Unworthy your + Notice. + </p> + <h3> + <i>EXPERIMENT X.</i> + </h3> + <p> + That a Solution of Silver does Dye Hair of a Black Colour, is a Known + Experiment, which ſome perſons more Curious than Dextrous, have + ſo Unluckily made upon themſelves as to make their Friends very + Merry. And I remember that the other day, I made my ſelf ſome + Sport by an Improvement of this Obſervation, for having diſſolv'd + ſome Pure Silver in <i>Aqua Fortis</i>, and Evaporated the <i>Menſtruum + ad ſiccitatem</i>, as they ſpeak, I caus'd a Quantity of fair + Water to be pour'd upon the <i>Calx</i> two or three ſeveral times, + and to be at each Evaporated, till the <i>Calx</i> was very Drye, and all + the Greeniſh Blewneſs that is wont to appear in Common Cryſtals + of Silver, + <!-- Page 151 --> <span class="pagenum"><a name="LPage_151" + id="LPage_151"></a>[pg 151]</span> was quite carry'd away. Then I made thoſe + I meant to Deceive, Moiſten ſome part of their Skin with their + own Spittle, and ſlightly Rub the moiſtned parts with a little + of this Prepar'd Silver, Whereupon they Admir'd to ſee, that a + Snow-white Body laid upon the White Skin ſhould preſently + produce a deep Blackneſs, as if the ſtains had been made with + Ink, eſpecially conſidering that this Blackneſs could not, + like that produc'd by ordinary Ink, be readily Waſh'd off, but + requir'd many Hours, and part of it ſome dayes to its Obliteration. + And with the ſame White <i>Calx</i> and a little Fair Water we likewiſe + Stain'd the White Hafts of Knives, with a laſting Black in thoſe + parts where the <i>Calx</i> was Plentifully enough laid on, for where it + was laid on but very Thinly, the Stain was not quite of ſo Deep a + Colour. + </p> + <h3> + <i>EXPERIMENT XI</i> + </h3> + <p> + The Cauſe of the Blackneſs of thoſe many Nations, which by + one common Name we are wont to call <i>Negroes</i>, has been long ſince + Diſputed of by Learned Men, who poſſibly had not done amiſs, + if they had alſo taken into Conſideration, why ſome whole + races of other Animals beſides Men, as + <!-- Page 152 --> <span class="pagenum"><a name="LPage_152" + id="LPage_152"></a>[pg 152]</span> Foxes and Hares, are Diſtinguiſh'd + by a Blackneſs not familiar to the Generality of Animals of the + ſame Species; The General Opinion (to be mention'd a little lower) + has been rejected even by ſome of the Antient Geographers, and among + our Moderns <i>Ortelius</i> and divers other Learned Men have Queſtion'd + it. But this is no place to mention what thoughts I have had to and fro + about theſe Matters: Only as I ſhall freely Acknowledge, that to + me the inquiry ſeems more Abſtruſe than it does to many + others, and that becauſe conſulting with Authors, and with Books + of Voyages, and with Travellers, to ſatisfie my ſelf in matters + of Fact, I have met with ſome things among them, which ſeem not + to agree very well with the Notions of the moſt Claſſick + Authors concerning theſe things; for it being my Preſent Work to + deliver rather matters Hiſtorical than Theorys, I ſhall Annex + Some few of my Collections, inſtead of a Solemn Diſputation. It + is commonly preſum'd that the Heat of the Climate wherein they live, + is the reaſon, why ſo many Inhabitants of the Scorching Regions + of <i>Africa</i> are Black; and there is this familiar Obſervation to + Countenance this Conjecture, That we plainly ſee that Mowers, + Reapers, and other Countrey-people, + <!-- Page 153 --> <span class="pagenum"><a name="LPage_153" + id="LPage_153"></a>[pg 153]</span> who ſpend the moſt part of + the Hot Summer dayes expos'd to the Sun, have the skin of their Hands and + Faces, which are the parts immediately Expos'd to the Sun and Air, made of + a Darker Colour than before, and conſequently tending to Blackneſs; + And Contrarywiſe we obſerve that the <i>Danes</i> and ſome + other people that Inhabit Cold Climates, and even the <i>Engliſh</i> + who feel not ſo Rigorous a Cold, have uſually Whiter faces than + the <i>Spaniards</i>, <i>Portugalls</i> and other European Inhabitants of + Hotter Climates. But this Argument I take to be far more Specious than + Convincing; for though the Heat of the Sun may Darken the Colour of the + Skin, by that Operation, which we in <i>Engliſh</i> call Sun-burning, + yet Experience doth not Evince, that I remember, That that Heat alone can + produce a Diſcolouring that ſhall amount to a true Blackneſs, + like that of <i>Negroes</i>, and we ſhall ſee by and by that + even the Children of ſome <i>Negroes</i> not yet 10. dayes Old + (perhaps not ſo much by three quarters of that time) will notwithſtanding + their Infancy be of the ſame Hue with their Parents. Beſides, + there is this ſtrong Argument to be alleg'd againſt the Vulgar + Opinion, that in divers places in <i>Aſia</i> under the ſame + Parallel, or even of the ſame + <!-- Page 154 --> <span class="pagenum"><a name="LPage_154" + id="LPage_154"></a>[pg 154]</span> Degree of Latitude with the <i>African</i> + Regions Inhabited by Blacks, the People are at moſt but Tawny;<a + name="LNtA_10" id="LNtA_10_"></a><a href="#LNt_10"><sup>10</sup></a> And in + <i>Africa</i> it ſelf divers Nations in the Empire of <i>Ethiopia</i> + are not <i>Negroes</i>, though Situated in the Torrid Zone, and as neer + the Æquinoctial, as other Nations that are ſo (as the Black + Inhabitants of <i>Zeylan</i> and <i>Malabar</i> are not in our Globes + plac'd ſo near the Line as <i>Amara</i> the Famouſeſt place + in <i>Ethiopia</i>.) Moreover, (that which is of no ſmall Moment in + our preſent Diſquiſition) I find not by the beſt + Navigators and Travellers to the <i>Weſt-Indies</i>, whoſe Books + or themſelves I have conſulted on this Subject, that excepting + perhaps one place or two of ſmall extent, there are any Blacks + Originally Natives of any part of <i>America</i> (for the Blacks now there + have been by the <i>Europeans</i> long Tranſplanted thither) though + the New World contain in it ſo great a Variety of Climates, and + particularly reach quite Croſs the Torri'd Zone from one Tropick to + another. And enough it be true that the <i>Danes</i> be a Whiter People + than the <i>Spaniards</i>, yet that may proceed rather from other cauſes + (not here to be enquired into) than from the Coldneſs of the Climate, + ſince not onely the + <!-- Page 155 --> <span class="pagenum"><a name="LPage_155" + id="LPage_155"></a>[pg 155]</span> <i>Swedes</i> and other Inhabitants of + thoſe Cold Countreys, are not uſually ſo White as the <i>Danes</i>, + nor Whiter than other Nations in proportion to their Vicinity to the Pole. + [And ſince the Writing of the former part of this Eſſay, + having an opportunity on a Solemn occaſion to take Notice of the + Numerous Train of Some Extraordinary Embaſſadours ſent from + the <i>Ruſſian</i> Emperour to a great Monarch, obſerv'd, + that (though it were then Winter) the Colour of their Hair and Skin was + far leſs Whitiſh than the <i>Danes</i> who Inhabit a milder + Region is wont to be, but rather for the moſt part of a Darkiſh + Brown; And the Phyſician to the Embaſſadour with whom thoſe + <i>Ruſſes</i> came, being ask'd by me whether in <i>Muſcovy</i> + it ſelf the Generality of the People were more inclin'd to have + Dark-colour'd Hair than Flaxen, he anſwer'd Affirmatively; but ſeem'd + to ſuſpect that the True and Antient <i>Ruſſians</i>, + a Sept of whom he told me he had met with in one of the Provinces of that + vaſt Empire, were rather White like the <i>Danes</i>, than any thing + near ſo Brown as the preſent <i>Muſcovites</i> whom he gueſſes + to be deſcended of the <i>Tartars</i>, and to have inherited their + Colour from them.] But to Proſecute our former Diſcourſe, I + ſhall add for further Proof of the Conjecture I was + <!-- Page 156 --> <span class="pagenum"><a name="LPage_156" + id="LPage_156"></a>[pg 156]</span> countenancing that good Authors inform + us that there are <i>Negroes</i> in <i>Africa</i> not far from the <i>Cape + of good Hope</i>, and conſequently beyond the Southern Tropick, and + without the Torrid Zone, much about the ſame Northern Latitude (or + very little more) wherein there are divers <i>American</i> Nations that + are not <i>Negroes</i>, and wherein the Inhabitants of <i>Candia</i>, + ſome parts of <i>Sicily</i>, and even of <i>Spain</i> are not ſo + much as Tawny-Mores. But (which is a freſh and ſtrong Argument + againſt the common Opinion,) I find by our recent Relations of <i>Greenland</i> + (our Accounts whereof we owe to the Curioſity of that Royal <i>Virtuoſo</i> + the preſent King of <i>Denmark</i>,) that the Inhabitants are + Olive-colour'd, or rather of a Darker Hiew. But if the Caſe were the + ſame with Men, and thoſe other kinds of Animals I formerly + nam'd, I ſhould offer ſomething as a conſiderable proof, + That, Cold may do much towards the making Men White or Black, and however + I ſhall let down the Obſervation as I have met with it, as + worthy to come into the Hiſtory of Whiteneſs and Blackneſs, + and it is, that in ſome parts of <i>Ruſſia</i> and of <i>Livonia</i> + it is affirm'd by <i>Olaus Magnus</i> and others, that Hares and Foxes (ſome + add Partridges) which before were Black, or Red, or + <!-- Page 157 --> <span class="pagenum"><a name="LPage_157" + id="LPage_157"></a>[pg 157]</span> Gray, do in the depth of Winter become + White by reaſon of the great Cold; (for that it ſhould be, as + ſome conceive, by Looking upon the Snow, ſeems improbable upon + divers accounts) And I remember that having purpoſely enquir'd of a + <i>Virtuoſo</i> who lately Travell'd through <i>Livonia</i> to <i>Moſco</i> + concerning the Truth of this Tradition, he both told me, he believ'd it, + and added, that he ſaw divers of thoſe lately nam'd Animals + either in <i>Ruſſia</i> or <i>Livonia</i>, (for I do not very + well remember whether of the two) which, though White when he ſaw + them in Winter, they aſſur'd him had been Black, or of other + Colours before the Winter began, and would be ſo again when it was + over. But for further ſatisfaction, I alſo conſulted one + that had for ſome years been an Eminent Phyſician in <i>Ruſſia</i>, + who though he rejected ſome other Traditions that are generally + enough believ'd concerning that Countrey, told me nevertheleſs, that + he ſaw no cauſe to doubt of this Tradition of <i>Olaus Magnus</i> + as to Foxes and Hares, not onely becauſe 'tis the common and + uncontroul'd Aſſertion of the Natives, but alſo becauſe + he himſelf in the Winter could never that he remember'd ſee + Foxes and Hares of any other Colour than White; And I my ſelf having + ſeen a ſmall White + <!-- Page 158 --> <span class="pagenum"><a name="LPage_158" + id="LPage_158"></a>[pg 158]</span> Fox brought out of <i>Ruſſia</i> + into <i>England</i> towards the latter end of Winter, foretold thoſe + that ſhew'd him me, that he would change Colour in Summer, and + accordingly coming to look upon him again in <i>July</i>, I found that the + Back and Sides, together with the upper part of the Head and Tayl were + already grown of a Dark Colour, the lower part of the Head and Belly + containing as yet a Whiteneſs. Let me add, that were it not for + ſome ſcruple I have, I ſhould think more than what <i>Olaus</i> + relates, confirm'd by the judicious <i>Olearius</i>, who was twice + employ'd into thoſe parts as a Publick Miniſter, who in his + Account of <i>Moſcovy</i> has this Paſſage: <i>The Hares + there are Gray; but in ſome Provinces they grow white in the Winter</i>. + And within ſome few Lines after: <i>It is not very Difficult to find + the Cauſe of this Change, which certainly proceeds only from the + Outward Cold, ſince I know that even in Summer, Hares will change + Colour, if they be kept a competent time in a Cellar</i>; I ſay, were + it not for Some Scruple, becauſe I take notice, that in the ſame + Page the Author Affirms, that the like change of Colour that happens to + Hares in ſome Provinces of <i>Muſcovy</i>, happens to them alſo + in <i>Livonia</i>, and yet immediately ſubjoyns, that in <i>Curland</i> + the Hares vary not their Colour in Winter, + <!-- Page 159 --> <span class="pagenum"><a name="LPage_159" + id="LPage_159"></a>[pg 159]</span> though theſe two laſt named + Countries be contiguous, (that is) ſever'd only by the River of <i>Dugna</i>; + For it is ſcarce conceivable how Cold alone ſhould have, in + Countries ſo near, ſo ſtrangely differing an operation, + though no leſs ſtrange a thing is confeſs'd by many, that aſcribe + the Complexion of <i>Negroes</i> to the Heat of the Sun, when they would + have the River of <i>Cenega</i> ſo to bound the <i>Moors</i>, that + though on the North-ſide they are but Tawny, on the other ſide + they are Black. + </p> + <p> + There is another Opinion concerning the Complexion of <i>Negroes</i>, that + is not only embrac'd by many of the more Vulgar Writers, but likewiſe + by that ingenious Traveller Mr. <i>Sandys</i>, and by a late moſt + learned Critick, beſides other men of Note, and theſe would have + the Blackneſs of <i>Negroes</i> an effect of <i>Noah's</i> Curſe + ratify'd by God's, upon <i>Cham</i>; But though I think that even a + Naturaliſt may without diſparagement believe all the Miracles + atteſted by the Holy Scriptures, yet in this caſe to flye to a + Supernatural Cauſe, will, I fear, look like Shifting off the + Difficulty, inſtead of Reſolving it; for we enquire not the Firſt + and Univerſal, but the Proper, Immediate, and Phyſical Cauſe + of the Jetty Colour of <i>Negroes</i>; And not only we do not find expreſſed + in the + <!-- Page 160 --> <span class="pagenum"><a name="LPage_160" + id="LPage_160"></a>[pg 160]</span> Scripture, that the Curſe meant by + <i>Noah</i> to <i>Cham</i>, was the Blackneſs of his Poſterity, + but we do find plainly enough there that the Curſe was quite another + thing, namely that he ſhould be a Servant of Servants, that is by an + Ebraiſm, a very Abject Servant to his Brethren, which accordingly did + in part come to paſs, when the <i>Iſraelites</i> of the poſterity + of <i>Sem</i>, ſubdued the <i>Canaanites</i>, that deſcended + from <i>Cham</i>, and kept them in great Subjection. Nor is it evident + that Blackneſs is a Curſe, for Navigators tell us of Black + Nations, who think ſo much otherwiſe of their own condition, + that they paint the Devil White. Nor is Blackneſs inconſiſtent + with Beauty, which even to our European Eyes conſiſts not ſo + much in Colour, as an Advantageous Stature, a Comely Symmetry of the parts + of the Body, and Good Features in the Face. So that I ſee not why + Blackneſs ſhould be thought ſuch a Curſe to the <i>Negroes</i>, + unleſs perhaps it be, that being wont to go Naked in thoſe Hot + Climates, the Colour of their Skin does probably, according to the + Doctrine above deliver'd, make the Sun-beams more Scorching to them, than + they would prove to a people of a White Complexion. + </p> + <p> + Greater probability there is, That the Principal Cauſe (for I would + not exclude + <!-- Page 161 --> <span class="pagenum"><a name="LPage_161" + id="LPage_161"></a>[pg 161]</span> all concurrent ones) of the Blackneſs + of <i>Negroes</i> is ſome Peculiar and Seminal Impreſſion, + for not onely we ſee that <i>Blackmore</i> boyes brought over into + theſe Colder Climates loſe not their Colour; But good Authors + inform us, That the Off-ſpring of <i>Negroes</i> Tranſplanted + out of <i>Africa</i>, above a hundred years ago, retain ſtill the + Complexion of their Progenitors, though poſſibly in Tract of + time it will decay; As on the other ſide, the White people removing + into very Hot Climates, have their Skins by the Heat of the Sun ſcorch'd + into Dark Colours; yet neither they, nor their Children have been obſerv'd, + even in the Countreys of <i>Negroes</i>, to deſcend to a Colour + amounting to that of the Natives; whereas I remember I have Read in <i>Piſos</i><a + name="LNtA_11" id="LNtA_11_"></a><a href="#LNt_11"><sup>11</sup></a> + excellent account of <i>Braſile</i>, that betwixt the <i>Americans</i> + and <i>Negroes</i> are generated a diſtinct ſort of Men, which + they call <i>Cabocles</i>, and betwixt <i>Portugalls</i> and <i>Æthiopian</i> + women, He tells us, he has ſometimes ſeen Twins, whereof one had + a White skin, the other a Black; not to mention here ſome other inſtances, + he gives, that the productions of the mixtures of differing people, that + is (indeed,) the effects of Seminal Impreſſions which they + <!-- Page 162 --> <span class="pagenum"><a name="LPage_162" + id="LPage_162"></a>[pg 162]</span> conſequently argue to have been + their Cauſes; and we ſhall not much ſcruple at this, if we + conſider, that even Organical parts may receive great Differences + from ſuch peculiar Impreſſions, upon what account ſoever + they came to be ſetled in the firſt Individual perſons, + from whom they are Propogated to Poſterity, as we ſee in the + Blobber-Lips and Flat-Noſes of moſt Nations of <i>Negroes</i>. + And if we may Credit what Learned men deliver concerning the Little Feet + of the <i>Chineſses</i>, the <i>Macrocephali</i> taken notice of by + <i>Hippocrates</i>, will not be the only Inſtance we might apply to + our preſent purpoſe. And on this occaſion it will not + perchance be Impertinent to add ſomething of what I have obſerv'd + in other Animals, as that there is a ſort of Hens that want Rumps; + And that (not to mention that in ſeveral places there is a ſort + of Crows or Daws that are not Cole-black as ours, but partly of a Whitiſh + Colour) in ſpight of <i>Porphyries</i> examples of Inſeparable + Accidents, I have ſeen a perfectly White Raven, as to Bill as well as + Feathers, which I attentively conſidered, for fear of being impos'd + upon. And this recalls into my Memory, what a very Ingenious Phyſician + has divers times related to me of a young Lady, to whom being call'd, he + found that though + <!-- Page 163 --> <span class="pagenum"><a name="LPage_163" + id="LPage_163"></a>[pg 163]</span> ſhe much complain'd of want of + Health, yet there appear'd ſo little cauſe either in her Body, + or her Condition to Gueſs that She did any more than fancy her ſelf + Sick, that ſcrupling to give her Phyſick, he perſwaded her + Friends rather to divert her Mind by little Journeys of Pleaſure, in + one of which going to Viſit St. <i>Winifrids</i> Well, this Lady, who + was a <i>Catholick</i>, and devout in her Religion, and a pretty while in + the Water to perform ſome Devotions, and had occaſion to fix her + Eyes very attentively upon the Red pipple-ſtones, which in a ſcatter'd + order made up a good part of thoſe that appear'd through the water, + and a while after growing Bigg, ſhe was deliver'd of a Child, whoſe + White Skin was Copiouſly ſpeckl'd with ſpots of the Colour + and Bigneſſs of thoſe Stones, and though now this Child + have already liv'd ſeveral years, yet ſhe ſtill retains + them. I have but two things to add concerning the Blackneſs of <i>Negroes</i>, + the one is, that the Seat of that Colour ſeems to be but the thin <i>Epidermes</i>, + or outward Skin, for I knew a young <i>Negroe</i>, who having been lightly + Sick of the Small Pox or Meaſles, (for it was doubted which of the + two was his Diſeaſe) I found by enquiry of a perſon that + was concern'd for him, that in thoſe places + <!-- Erratum: insert --> where the little Tumors + <!-- Page 164 --> <span class="pagenum"><a name="LPage_164" + id="LPage_164"></a>[pg 164]</span> + <!-- Erratum: dele. that --> had broke their paſſage through + the Skin, when they were gone, they left Within ſpecks behind them; + And the lately commended <i>Piſo</i> aſſures us, that + having the opportunity in <i>Braſil</i> to Diſſect many <i>Negroes</i>, + he cleerly found that their Blackneſs went no deeper than the very + outward Skin, which <i>Cuticula</i> or <i>Epidermis</i> + <!-- Erratum: for Epiderms --> being remov'd, the undermoſt Skin or + <i>Cutis</i> appear'd juſt as White as that of <i>Europæan</i> + Bodyes. And the like has been affirmed to me by a Phyſician of our + own, whom, hearing he had Diſſectcd a <i>Negroe</i> here in <i>England</i>, + I conſulted about this particular. The other thing to be here taken + notice of concerning <i>Negroes</i> is, That having enquir'd of an + Intelligent acquaintance of mine (who keeps in the <i>Indies</i> about + 300. + <!-- Erratum: for 200. --> of them as well Women as Men to work in his + Plantations,) whether their Children come Black into the world; he anſwer'd, + That they did not, but were brought forth of almoſt the like Reddiſh + Colour with our <i>European</i> Children; and having further enquir'd, how + long it was before theſe Infants appear'd Black, be reply'd, that + 'twas not wont to be many daies. And agreeable to this account I find + that, given us in a freſhly publiſh'd French Book written by a + <i>Jeſuit</i>, that had good opportunity + <!-- Page 165 --> <span class="pagenum"><a name="LPage_165" + id="LPage_165"></a>[pg 165]</span> of Knowing the Truth of what he + Delivers, for being one of the Miſſionaries of his Order into + the Southern <i>America</i> upon the Laudable Deſign of Converting + Infidels to Chriſtianity, he Baptiz'd ſeveral Infants, which + when newly Born, were much of the ſame Colour with <i>European</i> + Babes, but within about a Week began to appear of the Hue of their + Parents. But more Pregnant is the Teſtimony of our Countrey-man <i>Andrew + Battel</i>, who being ſent Priſoner by the <i>Portugalls</i> to + <i>Angola</i>, liv'd there, and in the adjoyning Regions, partly as a Priſoner, + partly as a Pilot, and partly as a Souldier, near 18. years, and he + mentioning the <i>African</i> Kingdom of <i>Longo</i>, peopl'd with + Blacks, has this paſſage:<a name="LNtA_12" id="LNtA_12_"></a><a + href="#LNt_12"><sup>12</sup></a> <i>The Children in this Countrey are Born + White, and change their Colour in two dayes to a Perfect Black</i>. As for + Example, <i>The</i> Portugalls <i>which dwell in the Kingdome of</i> Longo + <i>have ſometimes Children by the</i> Negroe<i>-women, and many times + the Fathers are deceived, thinking, when the Child is Born, that it is + theirs, and within two dayes it proves the Son or Daughter of a</i> + Negroe,<i> which the</i> Portugalls <i>greatly grieve at</i>; And the + ſame perſon has elſewhere a Relation, which, if he have + made no uſe at all of the + <!-- Page 166 --> <span class="pagenum"><a name="LPage_166" + id="LPage_166"></a>[pg 166]</span> liberty of a Traveller, is very well + worth our Notice, ſince this, together with that we have formerly + mention'd of Seminal Impreſſions, ſhews a poſſibility, + that a Race of <i>Negroes</i> might be begun, though none of the Sons of + <i>Adam</i>, for many Precedent Generations were of that Complexion. For I + ſee not why it ſhould not be at leaſt as poſſible, + that White Parents may ſometimes have Black Children, as that <i>African + Negroes</i> ſhould ſometimes have laſtingly White ones, eſpecially + ſince concurrent cauſes may eaſily more befriend the + Productions of the Former kind, than under the ſcorching Heat of <i>Africa</i> + thoſe of the Latter. And I remember on the occaſion of what he + delivers, that of the White Raven formerly mention'd, the Poſſeſſor + affirm'd to me, that in the Neſt out of which he was taken White, + they found with him but one other Young one, and that he was of as Jetty a + Black as any common Raven. But let us hear our Author himſelf<a + name="LNtA_13" id="LNtA_13_"></a><a href="#LNt_13"><sup>13</sup></a>; <i>Here + are</i> (ſayes he, ſpeaking of the formerly mention'd Regions) + <i>Born in this Countrey White Children, which is very rare among them, + for their Parents are</i> Negroes; <i>And when any of them are Born, they + are preſented to the King, and are call'd</i> Dondos; <i>theſe + are as White as any + <!-- Page 167 --> <span class="pagenum"><a name="LPage_167" + id="LPage_167"></a>[pg 167]</span> White Men. Theſe are the Kings + Witches, and are brought up in Witchcraft, and alwayes wait on the King: + There is no man that dare meddle with theſe</i> Dondos, <i>if they go + to the Market they may take what they lift, for all Men ſtand in awe + of them. The King of</i> Longo <i>hath four of them</i>. And yet this + Countrey in our Globes is plac'd almoſt in the midſt of the + Torrid Zone (four or five Degrees Southward of the Line.) And our Author + elſewhere tells us of the Inhabitants, that they are ſo fond of + their Blackneſs, that they will not ſuffer any that is not of + that Colour (as the <i>Portugalls</i> that come to Trade thither) to be + ſo much as Buri'd in their Land, of which he annexes a particular + example,<a name="LNtA_14" id="LNtA_14_"></a><a href="#LNt_14"><sup>14</sup></a> + that may be ſeen in his Voyage preſerv'd by our Induſtrious + Countreyman Mr. <i>Purchas</i>. But it is high time for me to diſmiſs + Obſervations, and go on with Experiments. + </p> + <h3> + <i>EXPERIMENT XII.</i> + </h3> + <p> + The way, <i>Pyrophilus,</i> of producing Whiteneſs by Chymical + Præcipitations is very well worth our obſerving, for thereby Bodyes + of very Differing Colours as well as Natures, though diſſolv'd + in Several Liquors, + <!-- Page 168 --> <span class="pagenum"><a name="LPage_168" + id="LPage_168"></a>[pg 168]</span> are all brought into <i>Calces</i> or + Powders that are White. Thus we find that not only Crabs-eyes, that are of + themſelves White, and Pearls that are almoſt ſo, but <i>Coral</i> + and <i>Minium</i> that are Red, being diſſolv'd in Spirit of + Vinegar, may be uniformly Præcipitated by Oyl of <i>Tartar</i> into White + Powders. Thus Silver and Tin ſeparately diſſolv'd in <i>Aqua + Fortis</i>, will the one Præcipitate it ſelf, and the other be + Præcipitated by common Salt-water into a White <i>Calx</i>, and ſo + will Crude Lead and Quickſilver firſt diſſolv'd likewiſe + in <i>Aqua Fortis</i>. The like <i>Calx</i> will be afforded as I have + try'd by a Solution of that ſhining Mineral Tinglaſs diſſolv'd + in <i>Aqua Fortis</i>, and Præcipitated out of it; and divers of theſe + <i>Calces</i> may be made at leaſt as Fair and White, if not better + Colour'd, if inſtead of Oyl of <i>Tartar</i> they were Præcipitated + with Oyl of <i>Vitriol</i>, or with another Liquor I could Name. Nay, that + Black Mineral <i>Antimony</i> it ſelf, being reduc'd by and with the + Salts that concurr to the Compoſition of common Sublimate, into that + Cleer though Unctuous Liquor that Chymiſts commonly call Rectifi'd + Butter of <i>Antimony</i>, will by the bare affuſion of ſtore of + Fair Water be ſtruck down into that Snow-white Powder, which when the + adhering Saltneſs is well waſh'd + <!-- Page 169 --> <span class="pagenum"><a name="LPage_169" + id="LPage_169"></a>[pg 169]</span> off, Chymiſts are pleas'd to call + <i>Mercurius Vitæ</i>, though the like Powder may be made of <i>Antimony</i>, + without the addition of any <i>Mercury</i> at all. And this Lacteſcence + if I may ſo call it, does alſo commonly enſue when Spirit + of Wine, being Impregnated with thoſe parts of Gums or other + Vegetable Concretions, that are ſuppos'd to abound with Sulphureous + Corpuſcles, fair Water is ſuddenly pour'd upon the Tincture or + Solution. And I remember that very lately I did, for Tryal ſake, on a + Tincture of <i>Benjamin</i> drawn with Spirit of Wine, and brought to be + as Red as Blood, pour ſome fair Water, which preſently mingling + with the Liquor, immediately turn'd the whole Mixture White. But if ſuch + Seeming Milks be ſuffer'd to ſtand unſtirr'd for a + convenient while, they are wont to let fall to the bottome a Reſinous + Subſtance, which the Spirit of Wine Diluted and Weakned by the Water + pour'd into it + <!-- Erratum: for into it -->, was unable to ſupport any longer. + And ſomething of Kin to this change of Colour in Vegetables is that, + which Chymiſts are wont to obſerve upon the pouring of Acid + Spirits upon the Red Solution of <i>Sulphur</i>, diſſolv'd in an + Infuſion of Pot-aſhes, or in ſome other ſharp <i>Lixivium</i>, + the Præcipitated <i>Sulphur</i> before it ſubſides, immediately + turning the Red Liquor + <!-- Page 170 --> <span class="pagenum"><a name="LPage_170" + id="LPage_170"></a>[pg 170]</span> into a White one. And other Examples + might be added of this way of producing Whiteneſs in Bodyes by + Præcipitating them out of the Liquors wherein they have been Diſſolv'd; + but I think it may be more uſefull to admoniſh you, <i>Pyrophilus</i>, + that this obſervation admits of Reſtrictions, and is not ſo + Univerſal, as by this time perhaps you have begun to think it; For + though moſt Præcipitated Bodyes are White, yet I know ſome that + are not; For Gold Diſſolv'd in <i>Aqua Regis</i>, whether you + Præcipitate it with Oyl of <i>Tartar</i>, or with Spirit of <i>Sal + Armoniack</i>, will not afford a White but a Yellow <i>Calx</i>. <i>Mercury</i> + alſo though reduc'd into Sublimate, and Præcipitated with Liquors + abounding with Volatile Salts, as the Spirits drawn from Urine, + Harts-horn, and other Animal ſubſtances, yet will afford, as we + Noted in our firſt Experiment about Whiteneſs and Blackneſs, + a White Præcipitate, yet with + <!-- Erratum for: the Solution of Pot-aſhes and other Lixiviate + Salts read: --> ſome Solutions hereafter to be mentioned, it will + let fall an Orange-Tawny Powder. And ſo will Crude <i>Antimony</i>, + if, being diſſolv'd in a ſtrong Lye, you pour (as farr as I + remember) any Acid Liquor upon the Solution newly Filtrated, whilſt + it is yet Warm. And if upon the Filtrated Solution of <i>Vitriol</i>, you + pour a Solution of + <!-- Page 171 --> <span class="pagenum"><a name="LPage_171" + id="LPage_171"></a>[pg 171]</span> one of theſe fix'd Salts, there + will ſubſide a Copious ſubſtance, very farr from + having any Whiteneſs, which the Chymiſts are pleas'd to call, + how properly I have elſewhere examin'd, the <i>Sulphur of Vitriol</i>. + So that moſt + <!-- Erratum: insert --> part of Diſſolv'd Bodyes being by + Præcipitation brought to White Powders, and yet ſome affording + Præcipitates of other Colours, the reaſon of both the Phænomena may + deſerve to be enquir'd into. + </p> + <h3> + <i>EXPERIMENT XIII.</i> + </h3> + <p> + Some Learned Modern Writers<a name="LNtA_15" id="LNtA_15_"></a><a + href="#LNt_15"><sup>15</sup></a> are of Opinion, that the Account upon + which Whiteneſs and Blackneſs ought to be call'd, as they + commonly are, the two Extreme Colours, is, That Blackneſs (by which I + preſume is meant the Bodyes endow'd with it) receives no other + Colours; but Whiteneſs very eaſily receives them all; whence + ſome of them compare Whiteneſs to the <i>Aristotelian Materia + prima</i>, that being capable of any ſort of Forms, as they ſuppoſe + White Bodyes to be of every kind of Colour. But not to Diſpute about + Names or Expreſſions, the thing it ſelf that is affirm'd as + Matter of Fact, ſeems to be True enough in moſt Caſes, not + in all, or ſo, + <!-- Page 172 --> <span class="pagenum"><a name="LPage_172" + id="LPage_172"></a>[pg 172]</span> as to hold Univerſally. For though + it be a common obſervation among Dyers, That Clothes, which have once + been throughly imbu'd with Black, cannot ſo well afterwards be Dy'd + into Lighter Colours, the præexiſtent Dark Colour infecting the + Ingredients, that carry the Lighter Colour to be introduc'd, and making it + degenerate into Some more Sad one; Yet the Experiments lately mention'd + may ſhew us, that where the change of Colour in Black Bodies is + attempted, not by mingling Bodyes of Lighter Colours with them, but by + Addition of ſuch things as are proper to alter the Texture of thoſe + Corpuſcles that contain the Black Colour, 'tis no ſuch difficult + matter, as the lately mention'd Learned Men imagine, to alter the Colour + of Black Bodyes. For we ſaw that Inks of ſeveral Kinds might in + a trice be depriv'd of all their Blackneſs; and thoſe made with + Logwood and Red-Roſes might alſo be chang'd, the one into a Red, + the other into a Reddiſh Liquor; and with Oyl of <i>Vitriol</i> I + have ſometimes turn'd Black pieces of Silk into a kind of Yellow, and + though the Taffaty were thereby made Rotten, yet the ſpoyling of that + does no way prejudice the Experiment, the change of Black Silk into + Yellow, being never the leſs True, becauſe + <!-- Page 173 --> <span class="pagenum"><a name="LPage_173" + id="LPage_173"></a>[pg 173]</span> the Yellow Silk is the leſs good. + And as for Whiteneſs, I think the general affirmation of its being + ſo eaſily Deſtroy'd or Tranſmuted by any other Colour, + ought not to be receiv'd without ſome Cautions and Reſtrictions. + For whereas, according to what I formerly Noted, Lead is by Calcination + turned into that Red Powder we call <i>Minium</i>; And Tin by Calcination + reduc'd to a White <i>Calx</i>, the common Putty that is ſold and + us'd ſo much in Shops, inſtead of being, as it is pretended and + ought to be, only the <i>Calx</i> of Tin, is, by the Artificers that make + it, to ſave the charge of Tin, made, (as ſome, of themſelves + have confeſs'd, and as I long ſuſpected by the Cheap rate + it may be bought for) but of half Tin and half Lead, if not far more Lead + than Tin, and yet the Putty in ſpight of ſo much Lead is a very + White Powder, without diſcloſing any mixture of <i>Minium</i>. + And ſo if you take two parts of Copper, which is a High-colour'd + Metall, to but one of Tin, you may by Fuſion bring them into one Maſs, + wherein the Whiteneſs of the Tin is much more Conſpicuous and + Predominant than the Reddiſhneſs of the Copper. And on this occaſion + it may not be Impertinent to mention an Experiment, which I relate upon + the Credit of a very Honeſt man, + <!-- Page 174 --> <span class="pagenum"><a name="LPage_174" + id="LPage_174"></a>[pg 174]</span> whom I purpoſely enquir'd of about + it, being my ſelf not very fond of making Tryals with <i>Arſenick</i>, + the Experiment is this, That if you Colliquate <i>Arſenick</i> and + Copper in a due proportion, the <i>Arſenick</i> will Blanch the + Copper both within and without, which is an Experiment well enough Known; + but when I enquir'd, whether or no this White mixture being skilfully kept + a while upon the Cupel would not let go its <i>Arſenick</i>, which + made Whiteneſs its prædominant Colour, and return to the Reddiſhneſs + of Copper, I was aſſur'd of the Affirmative; ſo that among + Mineral Bodyes, ſome of thoſe that are White, may be far more + capable, than thoſe I am reaſoning with ſeem to have known, + of Eclipſing others, and of making their Colour Prædominant in + Mixtures. In further Confirmation of which may be added, that I remember + that I alſo took a lump of Silver and Gold melted together, wherein + by the Æſtimate of a very Experienced Refiner, there might be about a + fourth or third part of Gold, and yet the Yellow Colour of the Gold was + ſo hid by the White of the Silver, that the whole Maſs appear'd + to be but Silver, and when it was rubb'd upon the Touchſtone, an + ordinary beholder could ſcarce have diſtinguiſh'd it from + the Touch of common + <!-- Page 175 --> <span class="pagenum"><a name="LPage_175" + id="LPage_175"></a>[pg 175]</span> Silver; though if I put a little <i>Aqua + Fortis</i> upon any part of the White Surface it had given the Touchſtone, + the Silver in the moiſtned part being immediately taken up and + conceal'd by the Liquor, the Golden Particles would preſently diſcloſe + that native Yellow, and look rather as if Gold, than if the above + mention'd mixture, had been rubb'd upon the Stone. + </p> + <h3> + <i>EXPERIMENT XIV.</i> + </h3> + <p> + I took a piece of Black-horn, (poliſh'd as being part of a Comb) this + with a piece of broken glaſs I ſcrap'd into many thin and + curdled flakes, ſome ſhorter and ſome longer, and having + laid a pretty Quantity of theſe ſcrapings together, I found, as + I look'd for, that the heap they compos'd was White, and though, if I laid + it upon a clean piece of White Paper, its Colour ſeem'd ſomewhat + Eclips'd by the greater Whiteneſs of the Body it was compar'd with, + looking ſomewhat like Linnen that had been ſulli'd by a little + wearing, yet if I laid it upon a very Black Body, as upon a Beaver Hatt, + it then appear'd to be of a good White, which Experiment, that you may in + a trice make when you pleaſe, ſeems very much to Disfavour both + their Doctrine + <!-- Page 176 --> <span class="pagenum"><a name="LPage_176" + id="LPage_176"></a>[pg 176]</span> that would have Colours to flow from + the Subſtantial Forms of Bodyes, and that of the Chymiſts alſo, + who aſcribe them to one or other of their three Hypoſtatical + Principles; for though in our Caſe there was ſo great a Change + made, that the ſame Body without being ſubſtantially either + Increas'd or Leſſened, paſſes immediately from one + extreme Colour to another (and that too from Black to White) yet this + ſo great and ſudden change is effected by a ſlight + Mechanical Tranſpoſition of parts, there being no Salt or <i>Sulphur</i> + or <i>Mercury</i> that can be pretended to be Added or Taken away, nor yet + any ſubſtantial Form that can reaſonably be ſuppos'd + to be Generated and Deſtroy'd, the Effect proceeding only from a + Local Motion of the parts which ſo vary'd their Poſition as to + multiply their diſtinct Surfaces, and to Qualifie them to Reflect far + more Light to the Eye, than they could before they were ſcrap'd off + from the entire piece of Black horn. + </p> + <h3> + <i>EXPERIMENT XV.</i> + </h3> + <p> + And now, <i>Pyrophilus</i>, it will not be improper for us to take ſome + notice of an Opinion touching the cauſe of Blackneſs, which I + judged + <!-- Erratum: insert --> it not ſo ſeaſonable to Queſtion, + till I + <!-- Page 177 --> <span class="pagenum"><a name="LPage_177" + id="LPage_177"></a>[pg 177]</span> I had ſet down ſome of the + Experiments, that might juſtifie my diſſent from it. You + know that of late divers Learned Men, having adopted the three Hypoſtatical + Principles, beſides other Notions of the Chymiſts, are very + inclinable to reduce all Qualities of Bodies to one or other of thoſe + three Principles, and Particularly aſſign for the cauſe of + Blackneſs the Sootie ſteam of <i>adust</i> or <i>torrifi'd + Sulphur</i>. But I hope that what we have deliver'd above to countenance + the Opinion we have propos'd about the Cauſe of Blackneſs, will + ſo eaſily ſupply you with ſeveral Particulars that may + be made uſe of againſt this Opinion, that I ſhall now repreſent + to You but two things concerning it. + </p> + <p> + And Firſt it ſeems that the favourers of the Chymicall Theories + might have pitcht upon ſome more proper term, to expreſs the + Efficient of Blackneſs than <i>Sulphur adust</i>; for we know that <i>common + Sulphur</i>, not only when Melted, but even when Sublim'd, does not grow + Black by ſuffering the Action of the fire, but continues and aſcends + Yellow, and rather more than leſs White, than it was before its being + expos'd to the fire. And if it be ſet on fire, as when we make that + acid Liquor, that Chymiſts call <i>Oleum Sulphuris per campanam</i>, + it affords + <!-- Page 178 --> <span class="pagenum"><a name="LPage_178" + id="LPage_178"></a>[pg 178]</span> very little Soot, and indeed the flame + yeelds ſo little, that it will ſcarce in any degree Black a + ſheet of White Paper, held a pretty while over the flame and ſmoak + of it, which is obſerved rather to Whiten than Infect linnen, and + which does plainly make Red Roſes grow very Pale, but not at all + Black, as far as the Smoak is permitted to reach the leaves. And I can + ſhew you of a ſort of fixt Sulphur made by an Induſtrious + Laborant of your acquaintance, who aſſur'd me that he was wont + to keep it for divers weeks together night and day in a naked and Violent + fire, almoſt like that of the Glaſs-houſe, and when, to + ſatisfie my Curioſity, I made him take out a lump of it, though + it were glowing hot (and yet not melted,) it did not, when I had ſuffered + it to cool, appear Black, the true Colour of it being a true Red. I know + it may be ſaid, that <i>Chymiſts</i> in the Opinion above + recited mean the <i>Principle of Sulphur</i>, and not <i>common Sulphur</i> + which receives its name, not from its being <i>all</i> perfectly of a + Sulphureous Nature, but for that <i>plenty</i> and <i>Predominancy</i> of + the Sulphureous Principle in it. But allowing this, 'tis eaſie to + reply, that ſtill according to this very Reaſon, torrifi'd + Sulphur ſhould afford more Blackneſs, than moſt other + concretes, + <!-- Page 179 --> <span class="pagenum"><a name="LPage_179" + id="LPage_179"></a>[pg 179]</span> wherein that Principle is confeſs'd + to be far leſs copious. Alſo when I have expos'd Camphire to the + fire in Cloſe Veſſels, as Inflamable, and conſequenly + (according to the Chymiſts) as Sulphureous a Body as it is, I could + not by ſuch a degree of Heat, as brought it to Fuſion, and made + it Boyl in the glaſs, impreſs any thing of Blackneſs, or of + any other Colour, than its own pure White, upon this Vegetable concrete. + But what ſhall we ſay to Spirit of Wine, which being made by a + Chymical Analyſis of the Liquor that affords it, and being totally + Inflamable, ſeems to have a full right to the title they give it of + <i>Sulphur Vegetabile</i>, & yet this fluid Sulphur not only contracts + not any degree of Blackneſs by being often ſo heated, as to be + made to Boyl, but when it burns away with an Actual flame, I have not + found that it would diſcolour a piece of White Paper held over it, + with any diſcernable ſoot. Tin alſo, that wants not, + according to the Chymiſts, a <i>Sulphur Joviale</i>, when throughly + burned by the fire into a <i>Calx</i>, is not Black, but eminently White. + And I lately noted to you out of <i>Bellonius</i>, that the Charcoals of + Oxy-cedar are not of the former of theſe two Colours, but of the + latter. And the Smoak of our Tinby coals here in <i>England</i>, has been + <!-- Page 180 --> <span class="pagenum"><a name="LPage_180" + id="LPage_180"></a>[pg 180]</span> uſually obſerv'd, rather to + Blanch linnen then to Black it. To all which, other Particulars of the + like nature might be added, but I rather chooſe to put you in mind of + the third Experiment, about making Black Liquors, or Inks, of Bodies that + were non of them Black before. For how can it be ſaid, that when thoſe + Liquors are put together actually Cold, and continue ſo after their + mixture, there intervenes any new <i>Adustion of Sulphur</i> to produce + the emergent Blackneſs? (and the ſame queſtion will be + appliable to the Blackneſs produc'd upon the blade of a Knife, that + has cut Lemmons and ſome kind of Sowr apples, if the juyce (though + both Actually and Potentially Cold) be not quickly wip'd of) And when by + the inſtilling either of a few drops of Oyl of Vitriol as in the + ſecond Experiment, or of a little of the Liquor mention'd in the Paſſage + pointed at in the fourth Experiment, (where I teach at once to Deſtroy + one black Ink, and make another) the Blackneſs produc'd by thoſe + Experiments is preſently deſtroy'd; if the Colour proceeded only + from the Plenty of Sulphurous parts, torrify'd in the Black Bodies, I + demand, what becomes of them, when the Colour ſo ſuddenly diſſappears? + For it cannot Reaſonably be ſaid, that all thoſe that + <!-- Page 181 --> <span class="pagenum"><a name="LPage_181" + id="LPage_181"></a>[pg 181]</span> ſuffic'd to make ſo great a + quantity of Black Matter, ſhould reſort to ſo very ſmall + a proportion of the Clarifying Liquor, (if I may ſo call it) as to be + deluted by it, with out at all Denigrating it. And if it be ſaid that + the Inſtill'd Liquor diſpers'd thoſe Black Corpuſcles, + I demand, how that Diſperſion comes to deſtroy their + Blackneſs, but by making ſuch a Local Motion of their parts, as + deſtroys their former Texture? which may be a Matter of ſuch + moment in caſes like ours, that I remember that I have in few houres, + without addition, from Soot it ſelf, attain'd pretty ſtore of + Cryſtalline Salt, and good ſtore of Tranſparent Liquor, and + (which I have on another occaſion noted as remarkable) this ſo + Black Subſtance had its Colour ſo alter'd, by the change of + Texture it receiv'd from the fire, wherewith it was diſtill'd, that + it did for a great while afford ſuch plenty of very white + Exhalations, that the Receiver, though large, ſeem'd to be almoſt + fill'd with Milk. + </p> + <p> + Secondly, But were it granted, as it is in ſome caſes not + Improbable, that divers Bodies may receive a Blackneſs from a Sootie + Exhalation, occaſion'd by the Aduſtion of their Sulphur, which + (for the Reaſons lately mention'd I ſhould rather call their + Oyly parts;) yet ſtill this account + <!-- Page 182 --> <span class="pagenum"><a name="LPage_182" + id="LPage_182"></a>[pg 182]</span> is applicable but to ſome + Particular Bodies, and will afford us no General Theory of Blackneſs. + For if, for example, White Harts-horn, being, in Veſſels well + luted to each other, expos'd to the fire, be ſaid to turn Black by + the Infection of its own Smoak, I think I may juſtly demand, what it + is that makes the Smoak or Soot it ſelf Black, ſince no Such + Colour, but its contrary, appear'd before in the Harts-horn? And with the + ſame Reaſon, when we are told, that torrify'd Sulphur makes + bodies Black, I deſire to be told alſo, why Torrefaction makes + Sulphur it ſelf Black? nor will there be any Satisfactory Reaſon + aſſign'd of theſe Quæries, without taking in thoſe + Fertile as well as intelligible Mechanical Principles of the Poſition + and Texture of the Minute parts of the body in reference to the Light and + the Eye; and theſe applicable Principles may Serve the turn in many + caſes, where the Aduſtion of Sulphur cannot be pretended; as in + the appearing Blackneſs of an Open window, lookt upon at a ſomewhat + remote diſtance from the houſe, as alſo in the Blackneſs + Men think they ſee in the Holes that happen to be in White linnen, or + Paper of the like Colour; and in the Increaſing Blackneſs + immediatly Produc'd barely by ſo rubbing Velvet, + <!-- Page 183 --> <span class="pagenum"><a name="LPage_183" + id="LPage_183"></a>[pg 183]</span> whoſe Piles were Inclin'd before, + as to reduce them to a more Erected poſture, in which and in many + other caſes formerly alleg'd, there appears nothing requiſite to + the Production of <i>the</i> Blackneſs, but the hindering of the + incident Beams of Light from rebounding plentifully enough to the Eye. To + be ſhort, thoſe I reaſon with, do concerning Blackneſs, + what the Chymiſts are wont alſo to do concerning other + Qualities, namely to content themſelves to tell us, in what + Ingredient of a Mixt Body, the Quality enquir'd after, does reſide, + inſtead of explicating the Nature of it, which (to borrow a compariſon + from their own Laboratories) is much as if in an enquiry after the cauſe + of Salivation, they ſhould think it enough to tell us, that the + ſeveral Kinds of Præcipitates of Gold and <i>Mercury</i>) as likewiſe + of Quick-ſilver and Silver (for I know that make and uſe of + ſuch Precipitates alſo) do Salivate upon the account of the <i>Mercury</i>, + which though Diſguis'd abounds in them, whereas the Difficulty is as + much to know upon what account <i>Mercury</i> it ſelf, rather than + other Bodies, has that power of working by Salivation. Which I ſay + not, as though it were not <i>ſomething</i> (and too often the moſt + we can arrive at) to diſcover in which of the + <!-- Page 184 --> <span class="pagenum"><a name="LPage_184" + id="LPage_184"></a>[pg 184]</span> Ingredients of a Compounded Body, the + Quality, whoſe Nature is ſought, reſides, but becauſe, + though this Diſcovery it ſelf may paſs for <i>ſomething</i>, + and is oftentimes more than what is taught us about the ſame ſubjects + in the Schools, yet we ought not to think it <i>enough</i>, when more + Clear and Particular accounts are to be had. + </p> + <!-- Page 185 --> + <p> + <span class="pagenum"><a name="LPage_185" id="LPage_185"></a>[pg 185]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/224a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:50%;">THE</span><br /> <span style="font-size:75%;">Experimental + Hiſtory</span><br /> <span style="font-size:50%;">OF</span><br /> <span + style="font-size:150%; letter-spacing:6px">COLOURS.</span><br /> <span + style="font-size:75%;">Begun.</span> + </h2> + <hr /> + <h2> + The Third PART. + </h2> + <hr /> + <h2> + <span style="font-size:50%;">Containing</span><br /> <span + style="font-size:75%;">Promiſcuous Experiments</span><br /> <span + style="font-size:50%;">About</span><br /> <span + style="font-size:100%; letter-spacing:6px">COLOURS.</span> + </h2> + <hr /> + <h3> + EXPERIMENT I. + </h3> + <p> + <img width="80" height="80" src="images/224b.png" + alt="Illuminated B in Because" /> Ecauſe that, according to the + Conjectures I have above propos'd, one of the moſt General Cauſes + of the Diverſity of Colours in Opacous Bodyes, is, that ſome + reflect the Light mingl'd with more, others with leſs of Shade + (either + <!-- Page 186 --> <span class="pagenum"><a name="LPage_186" + id="LPage_186"></a>[pg 186]</span> as to Quantity, or as to Interruption) + I hold it not unfit to mention in the firſt place, the Experiments + that I thought upon to examine this Conjecture. And though coming to tranſcribe + them out of ſome Phyſiological <i>Adverſaria</i> I had + written in looſe Papers, I cannot find one of the chief Records I had + of my Tryals of this Nature, yet the Papers that ſcap'd miſcarrying, + will, I preſume, ſuffice to manifeſt the main thing for + which I now allege them; I find then Among my <i>Adverſaria</i>, the + following Narrative. + </p> + <p> + <i>October</i> the 11. About ten in the Morning in Sun-ſhiny Weather, + (but not without fleeting Clouds) we took ſeveral ſorts of Paper + Stain'd, ſome of one Colour, and ſome of another; and in a + Darken'd Room whoſe Window look'd Southward, we caſt the Beams + that came in at a hole about three Inches and a half in Diameter, upon a + White wall that was plac'd on one ſide, about five foot diſtance + from them. + </p> + <p> + The White gave much the Brighteſt Reflection. + </p> + <p> + The Green, Red, and Blew being Compar'd together, the Red gave much the + ſtrongeſt Reflection, and manifeſtly enough alſo threw + its <i>Colour</i> upon the Wall; The Green and Blew were ſcarce Diſcernable + <!-- Page 187 --> <span class="pagenum"><a name="LPage_187" + id="LPage_187"></a>[pg 187]</span> by their Colours, and ſeem'd to + reflect an almoſt Equal Light. + </p> + <p> + The Yellow Compar'd with the two laſt nam'd, Reflected ſomewhat + more Light. + </p> + <p> + The Red and Purple being Compar'd together, the former manifeſtly + Reflected a good deal more Light. + </p> + <p> + The Blew and Purple Compar'd together, the former ſeem'd to Reflect a + little more Light, though the Purple Colour were more manifeſtly + ſeen. + </p> + <p> + A Sheet of very well fleck'd Marbl'd Paper being Apply'd as the others, + did not caſt any or its Diſtinct Colours upon the Wall; nor + throw its Light upon it with an Equal Diffuſion, but threw the Beams + Unſtain'd and Bright to this and that part of the Wall, as if it's + Poliſh had given it the Nature of a ſpecular Body. But comparing + it with a ſheet of White Paper, we found the Reflection of the latter + to be much Stronger, it diffuſing almoſt as much Light to a <i>good + Extent</i> as the Marble Paper did to <i>one part</i> of the Wall. + </p> + <p> + The Green and Purple left us ſomewhat in ſuſpence which + Reflected the moſt Light; only the Purple ſeem'd to have ſome + little Advantage over the Green, which was Dark in its kind. + </p> + <p> + Thus much I find in our above mention'd + <!-- Page 188 --> <span class="pagenum"><a name="LPage_188" + id="LPage_188"></a>[pg 188]</span> <i>Collections</i>, among which there + are alſo ſome Notes concerning the Production of <i>Compounded + Colours</i>, <i>by Reflection</i> from Bodyes differingly Colour'd. And + theſe Notes we intended ſhould ſupply us with what we + ſhould mention as our ſecond Experiment: but having loſt + the Paper that contain'd the Particulars, and remembring onely in General, + that if the Objects which Reflected the Light were not Strongly Colour'd + and ſomewhat Gloſſy, the Reflected Beams would not manifeſtly + make a Compounded Colour upon the Wall, and even then but very Faintly, we + ſhall now ſay no more of that Matter, only reſerving our + ſelves to mention hereafter the Compoſition of a Green, which we + ſtill retain in Memory. + </p> + <h3> + <i>EXPERIMENT II.</i> + </h3> + <p> + We may add, <i>Pyrophilus</i>, on this Occaſion, that though a + Darken'd Room be Generally thought requiſite to make the Colour of a + Body appear by Reflection from another Body, that is not one of thoſe + that are commonly agreed upon to be Specular (as Poliſh'd Metall, + Quick ſilver, Glaſs, Water, &c.) Yet I have often obſerv'd + that when I wore Doublets Lin'd with ſome ſilken + <!-- Page 189 --> <span class="pagenum"><a name="LPage_189" + id="LPage_189"></a>[pg 189]</span> Stuff that was very Gloſſy + and Vividly Colour'd, eſpecially Red, I could in an Inlightned Room + plainly enough Diſcern the Colour, upon the Pure White Linnen that + came out at my Sleeve and reach'd to my Cufs; as if that Fine White Body + were more Specular, than Colour'd and Unpoliſh'd Bodyes are thought + Capable of being. + </p> + <h3> + <i>EXPERIMENT III.</i> + </h3> + <p> + Whilſt we were making the newly mention'd Experiments, we thought fit + to try alſo what Compoſition of Colours might be made by + Altering the Light in its Paſſage to the Eye by the Interpoſition + not of Perfectly Diaphanous Bodies, (that having been already try'd by + others as well as by us (as we ſhall ſoon have occaſion to + take notice) but of Semi-opacous Bodyes, and thoſe ſuch as + look'd upon in an ordinary Light, and not held betwixt it and the Eye, are + not wont to be Diſcriminated from the reſt of Opacous Bodyes; of + this Tryal, our mention'd <i>Adverſaria</i> preſent us the + following Account. + </p> + <p> + Holding theſe Sheets, ſometimes one ſometimes the other of + them, before the Hole betwixt the Sun and the Eye, with + <!-- Page 190 --> <span class="pagenum"><a name="LPage_190" + id="LPage_190"></a>[pg 190]</span> the Colour'd ſides obverted to the + Sun; we found them <i>ſingle</i> to be ſomewhat Tranſparent, + and appear of the ſame Colour as before, onely a little alter'd by + the great Light they were plac'd in; but laying <i>two</i> of them one + over another and applying them ſo to the Hole, the Colours were + compounded as follows. + </p> + <p> + The Blew and Yellow ſcarce exhibited any thing but a Darker Yellow, + which we aſcrib'd to the Coarſeneſs of the Blew Papers, and + its Darkneſs in its Kind. For applying the Blew parts of the Marbl'd + Paper with the Yellow Paper after the ſame manner, they exhibited a + good Green. + </p> + <p> + The Yellow and Red look'd upon together gave us but a Dark Red, ſomewhat + (and but a little,) inclining to an Orange Colour. + </p> + <p> + The Purple and Red look'd on together appear'd more Scarlet. + </p> + <p> + The Purple and Yellow made an Orange. + </p> + <p> + The Green and Red made a Dark Orange Tawny. + </p> + <p> + The Green and Purple made the Purple appear more Dirty. + </p> + <p> + The Blew and Purple made the Purple more Lovely, and far more Deep. + </p> + <p> + The Red parts of the Marbl'd Paper look'd upon with the Yellow appear'd of + a + <!-- Page 191 --> <span class="pagenum"><a name="LPage_191" + id="LPage_191"></a>[pg 191]</span> Red far more like Scarlet than without + it. + </p> + <p> + But the Fineneſs or Coarſeneſs of the Papers, their being + carefully or ſlightly Colour'd, and divers other Circumſtances, + may ſo vary the Events of ſuch Experiments as theſe, that + if, <i>Pyrophilus</i>, you would Build much on them, you muſt + carefully Repeat them. + </p> + <h3> + <i>EXPERIMENT IV.</i> + </h3> + <p> + The Triangular Priſmatical Glaſs being the Inſtrument upon + whoſe Effects we may the moſt Commodiouſly ſpeculate + the Nature of Emphatical Colours, (and perhaps that of Others too;) we + thought it might be uſefull to obſerve the ſeveral + Reflections and Refractions which the Incident Beams of Light ſuffer + in Rebounding from it, and Paſſing through it. And this we + thought might be Beſt done, not (as is uſual,) in an ordinary + Inlightn'd Room, where (by reaſon of the Difficulty of doing otherwiſe) + ev'n the Curious have left Particulars Unheeded, which may in a convenient + place be eaſily taken notice of; but in a Darken'd Room, where by + placing the Glaſs in a convenient Poſture, the Various + Reflections and Refractions may be Diſtinctly obſerv'd; and + where it may appear <i>what</i> Beams are Unting'd; + <!-- Page 192 --> <span class="pagenum"><a name="LPage_192" + id="LPage_192"></a>[pg 192]</span> and <i>which</i> they are, that upon + the Bodyes that terminate them, do Paint either the Primary or Secondary + Iris. In purſuance of this we did in the above mention'd Darken'd + Room, make obſervation of no leſs than four Reflections, and + three Refractions that were afforded us by the ſame Priſm, and + thought that notwithſtanding what was taught us by the Rules of + Catoptricks and Dioptricks, it would not be amiſs to find alſo, + by hiding ſometimes one part of the Priſm, and ſometimes + another, and obſerving where the Light or Colour Vaniſh'd + thereupon, by which Reflection and by which Refraction each of the ſeveral + places whereon the Light rebounding from, or paſſing through, + the Priſm appear'd either Sincere or Tincted, was produc'd. But becauſe + it would be Tedious and not ſo Intelligible to deliver this in Words, + I have thought fit to Referr You to the Annexed Scheme where the Newly + mention'd particulars may be at one View taken Notice of. + </p> + <h3> + <i>EXPERIMENT V.</i> + </h3> + <table width="100%" cellpadding="5"> + <tr> + <td> + <a href="images/232.png"><img width="400" height="418" + src="images/232.png" alt="The Explication of the Scheme." /></a><br /> + <h3> + The Explication of the Scheme. + </h3> + </td> + <td valign="top"> + <p> + <i>PPP</i>. An Aequilaterotriangular Cryſtalline Priſm, + one of whoſe edges <i>P</i>. is placed directly towards the + Sun. + </p> + <p> + <i>A B</i> & α β Two rays from the Sun falling on the + Priſm at <i>B</i> β. and thence partly reflected towards + <i>C</i> & γ. and partly refracted towards <i>D</i> & + δ. + </p> + <p> + <i>B C</i> & β γ. Thoſe reflected Rays. + </p> + <p> + <i>B D</i> & β δ. Thoſe refracted Rays which are + partly refracted towards <i>E</i> & ε. and there paint + an Iris 1 2 3 4 5. denoting the five conſecutions of colours + Red, Yellow, Green, Blew, and Purple; and are partly reflected + towards <i>F</i> & ζ. + </p> + <p> + <i>D F</i> & δ ζ. Thoſe Reflected Rays which are + partly refracted towards <i>G</i> & η. colourleſs, and + partly reflected, towards <i>H</i> & θ. + </p> + <p> + <i>F H</i> & ζ θ. Thoſe reflected Rays which are + refracted towards <i>I</i> & ι. and there paint an other + fainter Iris, the colours of which are contrary to the former 5 4 3 + 2 1. ſignifying Purple, Blew, Green, Yellow, Red, ſo that + the Priſm in this poſture exhibits four Rainbows. + </p> + </td> + </tr> + </table> + <!-- Page 193 --> + <p> + <span class="pagenum"><a name="LPage_193" id="LPage_193"></a>[pg 193]</span> + </p> + <p> + I know not whether you will think it Inconſiderable to annex to this + Experiment, That we obſerv'd in a Room not Darken'd, that the Priſmatical + Iris (if I may ſo call it) might be Reflected without loſing any + of its ſeveral <i>Colours</i> (for we now conſider not their <i>Order</i>) + not onely from a plain Looking-glaſs and from the calm Surface of + Fair Water, but alſo from a Concave Looking-glaſs; and that + Refraction did as little Deſtroy thoſe Colours as Reflection. + For by the help of a large (double Convex) Burning-glaſs through + which we Refracted the Suns Beams, we found that one part of the Iris + might be made to appear either beyond, or on this ſide of the other + Parts of the ſame Iris; but yet the ſame Vivid Colours would + appear in the Diſplac'd part (if I may ſo term it) as in the + other. To which I ſhall add, that having, by hiding the ſide of + the Priſm, obverted to the Sun with an Opacous Body, wherein only one + ſmall hole was left for the Light to paſs through, reduc'd the + Priſmatical Iris (caſt upon White Paper) into a very narrow + compaſs, and look'd upon it througn a Microſcope; the Colours + appear'd the ſame as to kind that they did to the naked Eye. + </p> + <!-- Page 194 --> + <p> + <span class="pagenum"><a name="LPage_194" id="LPage_194"></a>[pg 194]</span> + </p> + <h3> + <i>EXPERIMENT VI.</i> + </h3> + <p> + It may afford matter of Speculation to the Inquiſitive, ſuch as + you, <i>Prophilus</i>, that as the Colours of outward Objects brought into + a Darken'd Room, do ſo much depend for their Viſibility upon the + Dimneſs of the Light they are there beheld by; that the ordinary + Light of the day being freely let in upon them, they immediately diſappear: + ſo our Tryals have inform'd us, that as to the Priſmatical Iris + painted on the Floor by the beams of the Sun Trajected through a + Triangular-glaſs; though the Colours of it appear very Vivid ev'n at + Noon-day, and in Sun ſhiny Weather, yet by a more Powerfull Light + they may be made to diſappear. For having ſometimes, (in proſecution + of ſome Conjectures of mine not now to be Inſiſted on,) + taken a large Metalline Concave <i>Speculum</i>, and with it caſt the + converging Beams of the Sun upon a Priſmatical Iris which I had + caus'd to be projected upon the Floor, I found that the over-powerfull + Light made the Colours of the Iris diſappear. And if I ſo + Reflected the Light as that it croſs'd but the middle of the Iris, in + that part only the Colours vaniſh'd or were made Inviſible; thoſe + <!-- Page 195 --> <span class="pagenum"><a name="LPage_195" + id="LPage_195"></a>[pg 195]</span> parts of the Iris that were on the + right and left hand of the Reflected Light (which ſeem'd to divide + them, and cut the Iris aſunder) continuing to exhibit the ſame + Colours as before. But upon this we muſt not now ſtay to + Speculate. + </p> + <h3> + <i>EXPERIMENT VII.</i> + </h3> + <p> + I have ſometimes thought it worth while to take notice, whether or no + the Colours of Opacous Bodies might not appear to the Eye ſomewhat + Diverſify'd, not only by the Diſpoſition of the Superficial + parts of the Bodyes themſelves and by the Poſition of the Eye in + Reference to the Object and the Light, (for theſe things are + Notorious enough;) but according alſo to the Nature of the Lucid Body + that ſhines upon them. And I remember that in Proſecution of + this Curioſity, I obſerv'd a manifeſt Difference in ſome + Kinds of Colour'd Bodyes look'd on by Day-light, and afterwards by the + light of the Moon; either directly falling on them or Reflected upon them + from a Concave Looking-glaſs. But not finding at preſent in my + Collections about Colours any thing ſet down of this Kind, I ſhall, + till I have opportunity to repeat them, content my ſelf to add what I + find Regiſter'd concerning + <!-- Page 196 --> <span class="pagenum"><a name="LPage_196" + id="LPage_196"></a>[pg 196]</span> Colours look'd on by Candle-light, in + regard that not only the Experiment is more eaſie to be repeated, but + the Objects being the Same Sorts of Colour'd Paper laſtly mention'd, + the Collation of the two Experiments may help to make the Conjectures they + will ſuggeſt ſomewhat the leſs uncertain. + </p> + <p> + Within a few dayes of the time above mention'd, divers Sheets of Colour'd + Paper that had been look'd upon before in the Sunſhine were look'd + upon at night by the light of a pretty big Candle, (ſnuff'd) and the + Changes that were obſerv'd were theſe. + </p> + <p> + The Yellow ſeem'd much fainter than in the Day, and inclinable to a + pale Straw Colour. + </p> + <p> + The Red ſeem'd little Chang'd; but ſeem'd to Reflect Light more + ſtrongly than any other Colour (for White was none of them.) + </p> + <p> + A fair Deep Green look'd upon by it ſelf ſeem'd to be a Dark + Blew: But being look'd upon together with a Dark Blew, appear'd Greeniſh; + and beheld together with a Yellow appear'd more Blew than at firſt. + </p> + <p> + The Blew look'd more like a Deep Purple or Murray than it had done in the + Daylight. + </p> + <!-- Page 197 --> + <p> + <span class="pagenum"><a name="LPage_197" id="LPage_197"></a>[pg 197]</span> + The Purple ſeem'd very little alter'd. + </p> + <p> + The Red look'd upon with the Yellow made the Yellow look almoſt like + Brown Cap-paper. + </p> + <p> + <i>N</i>. The Caution Subjoyned to the third Experiments is alſo + Applicable to this. + </p> + <h3> + <i>EXPERIMENT VIII.</i> + </h3> + <p> + But here I muſt not omit to ſubjoyn, that to ſatisfie our + Selves, whether or no the Light of a Candle were not made unſincere, + and as it were Ting'd with a Yellow Colour by the Admixtion of the Corpuſcles + it aſſumes from its Fuel; we did not content our ſelves + with what appears to the Naked Eye, but taking a pretty thick Rod or + Cylinder (for thin Peeces would not ſerve the turn) of deep Blew Glaſs, + and looking upon the Candles flame at a Convenient diſtance througn + it, we perceiv'd as we expected, the Flame to look Green; which as we + often note, is the Colour wont to emerge from the Compoſition of + Opacous Bodies, which were apart one of them Blew, and the other Yellow. + And this perchance may be the main Reaſon of that which ſome obſerve, + that a ſheet of very White Paper being look'd upon by Candle light, + 'tis not eaſie at firſt to diſcern it from + <!-- Page 198 --> <span class="pagenum"><a name="LPage_198" + id="LPage_198"></a>[pg 198]</span> a light Yellow or Lemon Colour; White + Bodyes (as we have elſewhere obſerv'd) having more than thoſe + that are otherwiſe Colour'd, of a Specular Nature; in regard that + though they exhibit not, (unleſs they be Poliſh'd,) the ſhape + of the Luminary that ſhines on them, yet they Reflect its Light more + Sincere and Untroubl'd, by either Shades or Refractions, than Bodyes of + other Colours (as Blew, or Green, or Yellow or the like.) + </p> + <h3> + <i>EXPERIMENT IX.</i> + </h3> + <p> + We took a Leaf of Such Foliated Gold as Apothecaries are wont to Gild + their Pills with; and with the Edge of a Knife, (lightly moyſten'd by + drawing it over the Surface of the Tongue, and afterwards) laid upon the + edge of the Gold Leaf; we ſo faſten'd it to the Knife, that + being held againſt the light, it conctinu'd extended like a little + Flagg. This Leaf being held very near the Eye, and obverted to the Light, + appear'd ſo full of Pores, that it ſeem'd to have ſuch a + kind of Tranſparency as that of a Sive, or a piece of Cyprus, or a + Love-Hood; but the Light that paſs'd by theſe Pores was in its + Paſſages So Temper'd with Shadow, and Modify'd, that the Eye diſcern'd + <!-- Page 199 --> <span class="pagenum"><a name="LPage_199" + id="LPage_199"></a>[pg 199]</span> no more a Golden Colour, but a Greeniſh + Blew. And for other's ſatisfaction, we did in the Night look upon a + Candle through ſuch a Leaf of Gold; and by trying the Effect of + Several Proportions of Diſtance betwixt the Leaf, the Eye and the + Light, we quickly hit upon ſuch a Poſition for the Leaf of Gold, + as that the flame, look'd on through it, appear'd of a Greeniſh Blew, + as we have ſeen in the Day time. The like Experiment try'd with a + Leaf of Silver ſucceeded not well. + </p> + <hr /> + <h3> + <i>EXPERIMENT X.</i> + </h3> + <p> + We have ſometimes found in the Shops of our Druggiſts, a certain + Wood, which is there called <i>Lignum Nephriticum</i>, becauſe the + Inhabitants of the Country where it grows, are wont to uſe the Infuſion + of it made in fair Water againſt the Stone of the Kidneys, and indeed + an Eminent Phyſician of our Acquaintance, who has very Particularly + enquir'd into that Diſeaſe, aſſures me, that he has + found ſuch an Infuſion one of the moſt effectual Remedyes, + which he has ever tried againſt that formidable Diſeaſe. + The ancienteſt Account I have met with of this Simple, is given us by + the Experienc'd <i>Monardes</i> in theſe Words. + <!-- Page 200 --> <span class="pagenum"><a name="LPage_200" + id="LPage_200"></a>[pg 200]</span> <i>Nobis,</i> ſays he,<a + name="LNtA_16" id="LNtA_16_"></a><a href="#LNt_16"><sup>16</sup></a> <i>Nova + Hiſpania mittit quoddam ligni genus craſſum & enode, + cujus uſus jam diu receptus fuit in his Regionibus ad Renum vitia + & urinæ difficultates ac arenulas pellendas. Fit autem hac ratione, + Lignum aſſulatim & minutim conciſum in limpidiſſima + aqua fontana maceratur, inque ea relinquitur, donec aqua à bibentibus abſumpta + ſit, dimidia hora post injectum lignum aqua cæruleum colorem + contrabit, qui ſenſim intenditur pro temporis diuturnitate, + tametſi lignum candidum fit</i>. This Wood, <i>Pyrophilus</i>, may + afford us an Experiment, which beſides the ſingularity of it, + may give no ſmall aſſiſtance to an attentive Conſiderer + towards the detection of the Nature of Colours. The Experiment as we made + it is this. Take <i>Lignum Nephriticum</i>, and with a Knife cut it into + thin Slices, put about a handfull of theſe Slices into two three or + four pound of the pureſt Spring-water, let them infuſe there a + night, but if you be in haſt, a much ſhorter time may ſuffice; + <i>decant</i> this Impregnated Water into a clear Glaſs Vial, and if + you hold it directly between the Light and your Eye, you ſhall ſee + it wholly Tincted (excepting the very top of the Liquor, wherein you will + ſome times diſcern a Sky-colour'd Circle) with + <!-- Page 201 --> <span class="pagenum"><a name="LPage_201" + id="LPage_201"></a>[pg 201]</span> an almoſt Golden Colour, unleſs + your Infuſion have been made too Strong of the Wood, for in that caſe + it will againſt the Light appear ſomewhat Dark and Reddiſh, + and requires to be diluted by the addition of a convenient quantity of + fair Water. But if you hold this Vial from the Light, ſo that your + Eye be plac'd betwixt the Window and the Vial, the Liquor will appear of a + deep and lovely Cæruleous Colour, of which alſo the drops, if any be + lying on the outſide of the Glaſs, will ſeem to be very + perfectly; And thus far we have try'd the Experiment, and found it to + Succeed even by the Light of Candles of the larger ſize. If you + ſo hold the Vial over againſt your Eyes, that it may have a + Window on one ſide of it, and a Dark part of the Room both before it + and on the other ſide, you ſhall ſee the Liquor partly of a + Blewiſh and partly of a Golden Colour. If turning your back to the + Window, you powr out ſome of the Liquor towards the Light and towards + your Eyes, it will ſeem at the comming out of the Glaſs to be + perfectly Cæruleous, but when it is fallen down a little way, the drops + may ſeem Particolour'd, according as the Beams of Light do more or leſs + fully Penetrate and Illuſtrate them. If you take a Baſon about + <!-- Page 202 --> <span class="pagenum"><a name="LPage_202" + id="LPage_202"></a>[pg 202]</span> half full of Water, and having plac'd + it ſo in the Sun-beams Shining into a Room, that one part of the + Water may be freely illuſtrated by the Beams of Light, and the other + part of it Darkned by the ſhadow of the Brim of the Baſon, if + then I ſay you drop of our Tincture, made ſomewhat ſtrong, + both into the Shaded and Illuminated parts of the Water, you may by + looking upon it from ſeveral places, and by a little Agitation of the + water, obſerve divers pleaſing Phænomena which were tedious to + particularize. If you powr a little of this Tincture upon a ſheet of + White Paper, ſo as the Liquor may remain of ſome depth upon it, + you may perceive the Neighbouring drops to be partly of one Colour, and + partly of the other, according to the poſition of your Eye in + reference to the Light when it looks upon them, but if you powr off all + the Liquor, the Paper will ſeem Dy'd of an almoſt Yellow Colour. + And if a ſheet of Paper with ſome of this Liquor in it be plac'd + in a window where the Sunbeams may ſhine freely on it, then if you + turn your back to the Sun and take a Pen or ſome ſuch ſlender + Body, and hold it over-thwart betwixt the Sun and the Liquor, you may + perceive that the Shadow projected by the Pen upon the Liquor, will not + all of it be a vulgar + <!-- Page 203 --> <span class="pagenum"><a name="LPage_203" + id="LPage_203"></a>[pg 203]</span> and Dark, but in part a curiouſly + Colour'd ſhadow, that edge of it, which is next the Body that makes + it, being almoſt of a lively Golden Colour, and the remoter verge of + a Cæruleous one. + </p> + <p> + Theſe and other Phænomena, which I have obſerv'd in this + delightfull Experiment, divers of my friends have look'd upon not without + ſome wonder, and I remember an excellent Oculiſt finding by + accident in a friends Chamber a fine Vial full of this Liquor, which I had + given that friend, and having never heard any thing of the Experiment, nor + having any Body near him that could tell him what this ſtrange Liquor + might be, was a great while apprehenſive, as he preſently after + told me, that ſome ſtrange new diſtemper was invading his + Eyes. And I confeſs that the unuſualneſs of the Phænomena + made me very ſollicitous to find out the Cauſe of this + Experiment, and though I am far from pretending to have found it, yet my + enquiries have, I ſuppoſe, enabled me to give ſuch hints, + as may lead your greater ſagacity to the diſcovery of the Cauſe + of this wonder. And firſt finding that this Tincture, if it were too + copious in the water, Kept the Colours from being ſo lively, and + their Change from being ſo diſcernable, and + <!-- Page 204 --> <span class="pagenum"><a name="LPage_204" + id="LPage_204"></a>[pg 204]</span> finding alſo that the Impregnating + Virtue of this Wood did by its being frequently Infus'd in New Water by + degrees Decay, I Conjectur'd that the Tincture afforded by the Wood muſt + proceed from ſome Subtiler parts of it drawn forth by the Water, + which ſwimming too and fro in it did ſo Modifie the Light, as to + exhibit ſuch and ſuch Colours; and becauſe theſe + Subtile parts were ſo eaſily Soluble even in Cold water, I + concluded that they muſt abound with Salts, and perhaps contain much + of the Eſſential Salt, as the <i>Chymiſts</i> call it, of + the Wood. And to try whether theſe Subtile parts were Volatile enough + to be Diſtill'd, without the Diſſolution of their Texture, + I carefully Diſtill'd ſome of the Tincted Liquor in very low Veſſels, + and the gentle heat of a Lamp Furnace; but found all that came over to be + as Limpid and Colourleſs as Rock-water, and the Liquor remaining in + the Veſſel to be ſo deeply Cæruleous, that it requir'd to + be oppos'd to a very ſtrong Light to appear of any other Colour. I + took likewiſe a Vial with Spirit of Wine, and a little Salt of + Harts-horn, and found that there was a certain proportion to be met with + betwixt the Liquor and the Salt, which made the Mixture fit to exhibit + ſome little Variety + <!-- Page 205 --> <span class="pagenum"><a name="LPage_205" + id="LPage_205"></a>[pg 205]</span> of Colours not Obſervable in + ordinary Liquors, as it was variouſly directed in reference to the + Light and the Eye, but this Change of Colour was very far ſhort from + that which we had admir'd in our Tincture. But however, I ſuſpected + that the Tinging Particles did abound with ſuch Salts, whoſe + Texture, and the Colour ſpringing from it, would probably be alter'd + by peircing Acid Salts, which would in likelihood either make ſome Diſſipation + of their Parts, or Aſſociate themſelves to the like Bodies, + and either way alter the Colour exhibited by them; whereupon Pouring into + a ſmall Vial full of Impregnated Water, a very little Spirit of + Vinegar, I found that according to my Expectation, the Cæruleous Colour + immediately vaniſh'd, but was deceiv'd in the Expectation I had, that + the Golden Colour would do ſo too; for, which way ſoever I + turned the Vial, either to or from the Light, I found the Liquor to appear + always of a Yellowiſh Colour and no other: Upon this I imagin'd that + the Acid Salts of the Vinegar having been able to deprive the Liquor of + its Cæruleous Colour, a Sulphureous Salt being of a contrary Nature, would + be able to Mortifie the Saline Particles of Vinegar, and Deſtroy + their + <!-- Page 206 --> <span class="pagenum"><a name="LPage_206" + id="LPage_206"></a>[pg 206]</span> Effects; And accordingly having plac'd + my Self betwixt the Window, and the Vial, and into the Same Liquor dropt a + few drops of Oyl of Tartar <i>per Deliquium</i>, (as <i>Chymiſts</i> + call it) I obſerv'd with pleaſure, that immediately upon the + Diffuſion of this Liquor, the Impregnated Water was reſtor'd to + its former Cæruleous Colour; And this Liquor of <i>Tartar</i> being very + Ponderous, and falling at firſt to the Bottom of the Vial, it was eaſie + to obſerve that for a little while the Lower part of the Liquor + appear'd deeply Cæruleous; whilſt all the Upper part retain'd its + former Yellowneſs, which it immediately loſt as ſoon as + either Agitation or Time had made a competent Diffuſion of the Liquor + of <i>Tartar</i> through the Body of the former Tincture; and this reſtored + Liquor did, as it was Look'd upon againſt or from the Light, exhibit + the Same <i>Phænomena</i> as the Tincted Water did, before either of the + Adventitious Liquors was pour'd into it. + </p> + <p> + Having made, <i>Pyrophilus</i>, divers Tryals upon this Nephritick Wood, + we found mention made of it by the Induſtrious Jeſuit <i>Kircherus</i>, + who having received a Cup Turned of it from the <i>Mexican</i> Procurator + of his Society, has probably receiv'd alſo from him the Information + he gives us concerning + <!-- Page 207 --> <span class="pagenum"><a name="LPage_207" + id="LPage_207"></a>[pg 207]</span> that <i>Exotick</i> Plant, and + therefore partly for that Reaſon, and partly becauſe what he + Writes concerning it, does not perfectly agree with what we have + deliver'd, we ſhall not Scruple to acquaint you in his own Words, + with as much of what he writes concerning our Wood, as is requiſite + to our preſent purpoſe. <i>Hoc loco</i> (ſays he)<a + name="LNtA_17" id="LNtA_17_"></a><a href="#LNt_17"><sup>17</sup></a> <i>neutiquam + omittendum duximus quoddam ligni candidi Mexicani genus, quod Indigenæ + Coalle & Tlapazatli vocant, quod etſi experientia hucuſque + non niſi Cæruleo aquam colore tingere docuerit, nos tamen continua + experientia invenimus id aquam in omne Colorum genus transformare, quod + merito cuipiam Paradoxum videri poſſet; Ligni frutex grandis, ut + aiunt, non rarò in molem arboris excreſcit, truncus illius eft craſſus, + enodis, inſtar piri arboris, folia ciceris foliis, aut rutæ haud abſimilia, + flores exigui, oblongi, lutei & ſpicatim digeſti; eſt + frigida & humida planta, licet parum recedat à medio temperamento. + Hujus itaque deſcriptæ arboris lignum in poculum efformatum, aquam + eidem infuſam primo in aquam intenſe Cæruleam, colore floris + Bugloſſæ; tingit, & quo diutius in eo ſteterit, tanto + intenſiorem colorem acquirit. Hanc igitur aquam si Vitreæ Sphæræ + infuderis, lucique expoſueris, ne ullum quidem Cærulei coloris + <!-- Page 208 --> <span class="pagenum"><a name="LPage_208" + id="LPage_208"></a>[pg 208]</span> veſtigium apparebit, ſed inſtar + aquæ puræ putæ fontanæ limpidam claramque aspicientibus ſe præbebit. + Porro ſi hanc phialam vitream verſus locum magis umbroſum + direxeris, totus humor gratiſſimum virorem referet; ſi + adhuc umbroſioribus locis, ſubrubrum, & ſic pro rerum + objectarum conditione, mirum dictu, colorem mutabit; in tenebris verò vel + in vaſe opaco poſita, Cæruleum colorem ſuum reſumet.</i> + </p> + <p> + In this paſſage we may take notice of the following Particulars. + And firſt, he calls it a White <i>Mexican</i> Wood, whereas (not to + mention that <i>Mornardes</i> informs us that it is brought out of <i>Nova + Hiſpania</i>) the Wood that we have met with in ſeveral places, + and employ'd as <i>Lignum Nephriticum</i>, was not White, but for the moſt + part of a much Darker Colour, not unlike that of the Sadder Colour'd Wood + of Juniper. 'Tis true, that <i>Monardes</i> himſelf alſo ſays, + that the Wood is White; and it is affirm'd, that the Wood which is of a + Sadder Colour is Adulterated by being Imbu'd with the Tincture of a + Vegetable, in whoſe Decoction it is ſteep'd. But having purpoſely + enquir'd of the Eminenteſt of our <i>Engliſh</i> Druggiſts, + he peremptorily deny'd it. And indeed, having conſider'd ſome of + the faireſt Round pieces of this + <!-- Page 209 --> <span class="pagenum"><a name="LPage_209" + id="LPage_209"></a>[pg 209]</span> Wood that I could meet with in theſe + Parts, I had Opportunity to take notice that in one or two of them it was + the External part of the Wood that was White, and the more Inward part + that was of the other Colour, the contrary of which would probably have + appear'd, if the Wood had been Adulterated after the afore-mention'd + manner. And I have at preſent by me a piece of ſuch Wood, which + for about an Inch next the Bark is White, and then as it were abruptly paſſes + to the above-mention'd Colour, and yet this Wood by the Tincture, it + afforded us in Water, appears to have its Colour'd part Genuine enough; + for as for the White part, it appears upon tryal of both at once, much leſs + enrich'd with the tingent Property. + </p> + <p> + Next, whereas our Author tells us, that the Infuſion of this Wood + expos'd in a Vial to the Light, looks like Spring-water, in which he + afterwards adds, that there is no Tincture to be ſeen in it, our Obſervation + and his agree not, for the Liquor, which oppoſed to the Darker part + of a Room exhibits a Sky-colour, did conſtantly, when held againſt + the Light, appear Yellowiſh or Reddiſh, according as its + Tincture was more Dilute or Deep; and + <!-- Page 210 --> <span class="pagenum"><a name="LPage_210" + id="LPage_210"></a>[pg 210]</span> then, whereas it has been already + ſaid, that the Cæruleous Colour was by Acid Salts aboliſhed, + this Yellowiſh one ſurviv'd without any conſiderable + Alteration, ſo that unleſs our Author's Words be taken in a very + Limited Senſe, we muſt conclude, that either his Memory + mis-inform'd him, or that his White <i>Nephritick</i> Wood, and the Sadder + Colour'd one which we employ'd, were not altogether of the ſame + Nature: What he mentions of the Cup made of <i>Lignum Nephriticum</i>, we + have not had Opportunity to try, not having been able to procure pieces of + that Wood great enough, and otherwiſe fit to be turned into Cups; but + as for what he ſays in the Title of his Experiment, that this Wood + tinges the Water with all Sorts of Colours, that is much more than any of + thoſe pieces of Nephritick Wood that we have hitherto employ'd, was + able to make good; The change of Colours diſcernable in a Vial full + of Water, Impregnated by any of them, as it is directed towards a place + more Lightſome or Obſcure, being far from affording a Variety anſwerable + to ſo promiſing a Title. And as for what he tells us, that in + the Dark the Infuſion of our Wood will reſume a Cæruleous + Colour, I wiſh he had Inform'd us how he Try'd it. + </p> + <!-- Page 211 --> + <p> + <span class="pagenum"><a name="LPage_211" id="LPage_211"></a>[pg 211]</span> + </p> + <p> + But this brings into my mind, that having ſometimes for Curioſity + ſake, brought a round Vial with a long Neck fill'd with the Tincture + of <i>Lignum Nephriticum</i> into the Darken'd Room already often + mention'd, and holding it ſometimes in, ſometimes near the + Sun-beams that enter'd at the hole, and ſometimes partly in them, and + partly out of them, the Glaſs being held in ſeveral poſtures, + and look'd upon from ſeveral Neighbouring parts of the Room, diſclos'd + a much greater Variety of Colours than in ordinary inlightn'd Rooms it is + wont to do; exhibiting, beſides the uſual Colours, a Red in + ſome parts, and a Green in others, beſides Intermediate Colours + produc'd by the differing Degrees, and odd mixtures of Light and Shade. + </p> + <p> + By all this You may ſee, <i>Pyrophilus</i>, the reaſonableneſs + of what we elſewhere had occaſion to mention, when we have + divers times told you, that it is uſefull to have New Experiments + try'd over again, though they were, at firſt, made by Knowing and + Candid Men, ſuch Reiterations of Experiments commonly exhibiting + ſome New Phænomena, detecting ſome Miſtake or hinting + ſome Truth, in reference to them, that was not formerly taken notice + of. And ſome of our friends have been pleas'd to + <!-- Page 212 --> <span class="pagenum"><a name="LPage_212" + id="LPage_212"></a>[pg 212]</span> think, that we have made no unuſefull + addition to this Experiment, by ſhewing a way, how in a moment our + Liquor may be depriv'd of its Blewneſs, and reſtor'd to it again + by the affuſion of a very few drops of Liquors, which have neither of + them any Colour at all of their own. And that which deſerves ſome + particular wonder, is, that the Cæruleous Tincture of our Wood is ſubject + by the former Method to be Deſtroy'd or Reſtor'd, the Yellowiſh + or Reddiſh Tincture continuing what it was. And that you may ſee, + that Salts are of a conſiderable uſe in the ſtriking of + Colours, let me add to the many Experiments which may be afforded us to + this purpoſe by the Dyers Trade, this Obſervation; That as far + as we have hitherto try'd, thoſe Liquors in general that are ſtrong + of Acid Salts have the Power of Deſtroying the Blewneſs of the + Infuſion of our Wood, and thoſe Liquors indiſcriminatly + that abound with Sulphureous Salts, (under which I comprehend the Urinous + and Volatile Salts of Animal Subſtances, and the Alcaliſate or + fixed Salts that are made by Incineration) have the vertue of Reſtoring + it. + </p> + <!-- Page 213 --> + <p> + <span class="pagenum"><a name="LPage_213" id="LPage_213"></a>[pg 213]</span> + </p> + <p> + <i>A Corollary of the Tenth Experiment.</i> + </p> + <p> + That this Experiment, <i>Pyrophilus</i>, may be as well Uſefull as + Delightfull to You, I muſt mind You, <i>Pyrophilus</i>, that in the + newly mention'd Obſervation, I have hinted to You a New and Eaſie + way of Diſcovering in many Liquors (for I dare not ſay in all) + whether it be an Acid or Sulphureous Salt, that is Predominant; and that + ſuch a Diſcovery is oftentimes of great Difficulty, and may + frequently be of great Uſe, he that is not a Stranger to the various + Properties and Effects of Salts, and of how great moment it is to be able + to diſtinguiſh their Tribes, may readily conceive. But to + proceed to the way of trying other Liquors by an Infuſion of our + Wood, take it briefly thus. Suppoſe I have a mind to try whether I + conjecture aright, when I imagine that Allom, though it be plainly a Mixt + Body, does abound rather with Acid than Sulphureous Salt. To ſatisfie + my ſelf herein, I turn my back to the Light, and holding a ſmall + Vial full of the Tincture of <i>Lignum Nephriticum</i>, which look'd upon + in that Poſition, appears Cæruleous, I drop into it a little of a + ſtrong Solution of Allom made in Fair Water, and finding upon the + <!-- Page 214 --> <span class="pagenum"><a name="LPage_214" + id="LPage_214"></a>[pg 214]</span> Affuſion and ſhaking of this + New liquor, that the Blewneſs formerly conſpicuous in our + Tincture does preſently vaniſh, I am thereby incited to ſuppoſe, + that the Salt Prædominant in Allom belongs to the Family of Sour Salts; + but if on the other ſide I have a mind to examine whether or no I + rightly conceive that Salt of Urine, or of Harts-horn is rather of a + Saline Sulphureous (if I may ſo ſpeak) than of an Acid Nature, I + drop a little of the Saline Spirit of either into the Nephritick Tincture, + and finding that the Cæruleous Colour is rather thereby Deepned than Deſtroy'd, + I collect that the Salts, which conſtitute theſe Spirits, are + rather Sulphureous than Acid. And to ſatisfie my ſelf yet + farther in this particular, I take a ſmall Vial of freſh + Tincture, and placing both it and my ſelf in reference to the Light + as formerly, I drop into the Infuſion juſt as much Diſtill'd + Vinegar, or other Acid liquor as will ſerve to Deprive it of its + Blewneſs (which a few drops, if the Sour Liquor be ſtrong, and + the Vial ſmall will ſuffice to do) then without changing my Poſture, + I drop and ſhake into the ſame Vial a ſmall proportion of + Spirit of Hartſhorn or Urine, and finding that upon this affuſion, + the Tincture immediately recovers its Cæruleous Colour, I am thereby + confirm'd + <!-- Page 215 --> <span class="pagenum"><a name="LPage_215" + id="LPage_215"></a>[pg 215]</span> firm'd in my former Opinion, of the + Sulphureous Nature of theſe Salts. And ſo, whereas it is much + doubted by Some Modern Chymiſts to what ſort of Salt, that which + is Prædominant in Quick-lime belongs, we have been perſwaded to + referr it rather to Lixiviate than Acid Salts, by having obſerv'd, + that though an Evaporated Infuſion of it will ſcarce yield + ſuch a Salt, as Aſhes and other Alcalizate Bodyes are wont to + do, yet if we deprive our Nephritick Tincture of its Blewneſs by juſt + ſo much Diſtill'd Vinegar as is requiſite to make that + Colour Vaniſh, the <i>Lixivium</i> of Quick-lime will immediately + upon its Affuſion recall the Baniſhed Colour; but not ſo + Powerfully as either of the Sulphureous Liquors formerly mention'd. And + therefore I allow my ſelf to gueſs at the <i>Strength</i> of the + Liquors examin'd by this Experiment, by the <i>Quantity</i> of them which + is ſufficient to Deſtroy or Reſtore the Cæruleous Colour of + our Tincture. But whether concerning Liquors, wherein neither Acid nor + Alcaliſate Salts are Eminently Prædominant, our Tincture will enable + us to conjecture any thing more than that ſuch Salts are not + Prædominant in them, I take not upon me to determine here, but leave to + further Tryal; For I find not that Spirit of + <!-- Page 216 --> <span class="pagenum"><a name="LPage_216" + id="LPage_216"></a>[pg 216]</span> Wine, Spirit of Tartar freed from + Acidity, or Chymical Oyl of Turpentine, (although Liquors which muſt + be conceiv'd very Saline, if Chymiſts have, which is here no place to + Diſpute, rightly aſcrib'd taſts to the Saline Principle of + Bodyes,) have any Remarkable Power either to deprive our Tincture of its + Cæruleous Colour, or reſtore it, when upon the Affuſion of + Spirit of Vinegar it has diſappear'd. + </p> + <h3> + <i>EXPERIMENT XI.</i> + </h3> + <p> + And here I muſt not omit, <i>Pyrophilus</i>, to inform You, that we + can ſhew You even in a Mineral Body ſomething that may ſeem + very near of Kin to the Changeable Quality of the Tincture of <i>Lignum + Nephriticum</i>, for we have ſeveral flat pieces of Glaſs, of + the thickneſs of ordinary Panes for Windows one of which being + interpoſed betwixt the Eye and a clear Light, appears of a Golden + Colour, not much unlike that of the moderate Tincture of our Wood, but + being ſo look'd upon as that the Beams of light are not ſo much + Trajected thorough it as Reflected from it to the Eye, that Yellow ſeems + to degenerate into a pale Blew, ſomewhat like that of a Turquoiſe. + And what which may alſo appear ſtrange, is this, + <!-- Page 217 --> <span class="pagenum"><a name="LPage_217" + id="LPage_217"></a>[pg 217]</span> that if in a certain poſture you + hold one of theſe Plates Perpendicular to the Horizon, ſo that + the Sun-beams ſhine upon half of it, the other half being Shaded, You + may ſee that the part Shin'd upon will be of a much Diluter Yellow + than the Shaded part which will appear much more Richly Colour'd; and if + You alter the Poſture of the Glaſs, ſo that it be not held + Perpendicular, but Parallel in reference to the Horizon, You may ſee, + (which perhaps you will admire) the Shaded part look of a Golden Colour, + but the other that the Sun ſhines freely on, will appear conſiderably + Blew, and as you remove any part of the Glaſs thus held Horizontally + into the Sun-beams or Shade, it will in the twinkling of an Eye ſeem + to paſs from one of the above mention'd Colours to the other, the + Sun-beams Trajected through it upon a ſheet of White Paper held near + it, do colour it with a Yellow, ſomewhat bordering upon a Red, but + yet the Glaſs may be ſo oppos'd to the Sun, that it may upon + Paper project a mix'd Colour here and there more inclin'd to Yellow, and + here and there more to Blew. The other Phænomena of this odd Glaſs, I + fear it would be ſcarce worth while to Record, and therefore I ſhall + rather advertiſe You, <i>Firſt</i> that in the trying of theſe + Experiments + <!-- Page 218 --> <span class="pagenum"><a name="LPage_218" + id="LPage_218"></a>[pg 218]</span> with it, you muſt take notice that + one of the ſides has either alone, or at leaſt principally its + Superficial parts diſpos'd to the Reflection of the Blew Colour above + nam'd, and that therefore you muſt have a care to keep that ſide + neareſt to the Eye. And next, that we have our ſelves made Glaſſes + not unfit to exhibit an Experiment not unlike that I have been ſpeaking + of, by laying upon pieces of Glaſs ſome very finely foliated + Silver, and giving it by degrees a much ſtronger Fire than is requiſite + or uſual for the Tinging of Glaſſes of other Colours. And + this Experiment, not to mention that it was made without a Furnace in + which Artificers that Paint Glaſs are wont to be very Curious, is the + more conſiderable, becauſe, that though a Skilfull Painter could + not deny to me that 'twas with Silver he Colour'd his Glaſſes + Yellow; yet he told me, that when to Burn them (as they ſpeak) he + layes on the plates of Glaſs nothing but a <i>Calx</i> of Silver + Calcin'd without Corroſive Liquors, and Temper'd with Fair Water, the + Plates are Ting'd of a fine Yellow that looks of a Golden Colour, which + part ſoever of it you turn to or from the Light; whereas (whether it + be what an Artificer would call Over-doing, or Burning, or elſe the + imploying the Silver + <!-- Page 219 --> <span class="pagenum"><a name="LPage_219" + id="LPage_219"></a>[pg 219]</span> Crude that makes the Difference,) we + have found more than once, that ſome Pieces of Glaſs prepar'd as + we have related, though held againſt the Light they appear'd of a + Tranſparent Yellow, yet look'd on with ones back turn'd to the Light + they exhibited an Untranſparent Blew. + </p> + <h3> + <i>EXPERIMENT XII.</i> + </h3> + <p> + If you will allow me, <i>Pyrophilus</i>, for the avoiding of Ambiguity, to + imploy the Word Pigments, to ſignifie ſuch prepared materials + (as Cochinele, Vermilion, Orpiment,) as Painters, Dyers and other + Artificers make uſe of to impart or imitate particular Colours, I + ſhall be the better underſtood in divers paſſages of + the following papers, and particularly when I tell you, That the mixing of + Pigments being no inconſiderable part of the Painters Art, it may + ſeem an Incroachment in me to meddle with it. But I think I may eaſily + be excus'd (though I do not altogether paſs it by) if I reſtrain + my ſelf to the making of a Tranſient mention of ſome few of + their Practices about this matter; and that only ſo far forth, as may + warrant me to obſerve to you, that there are but few Simple and + Primary Colours (if I may ſo call them) + <!-- Page 220 --> <span class="pagenum"><a name="LPage_220" + id="LPage_220"></a>[pg 220]</span> from whoſe Various Compoſitions + all the reſt do as it were Reſult. For though Painters can + imitate the Hues (though not always the Splendor) of thoſe almoſt + Numberleſs differing Colours that are to be met with in the Works of + Nature, and of Art, I have not yet found, that to exhibit this ſtrange + Variety they need imploy any more than <i>White</i>, and <i>Black</i>, and + <i>Red</i>, and <i>Blew</i>, and <i>Yellow</i>; theſe <i>five</i>, + Variouſly <i>Compounded</i>, and (if I may ſo ſpeak) <i>Decompounded</i>, + being ſufficient to exhibit a Variety and Number of Colours, ſuch, + as thoſe that are altogether Strangers to the Painters Pallets, can + hardly imagine. + </p> + <p> + Thus (for Inſtance) Black and White differingly mix'd, make a Vaſt + company of Lighter and Darker Grays. + </p> + <p> + Blew and Yellow make a huge Variety of Greens. + </p> + <p> + Red and Yellow make Orange Tawny. + </p> + <p> + Red with a little White makes a Carnation. + </p> + <p> + Red with an Eye of Blew, makes a Purple; and by theſe ſimple + Compoſitions again Compounded among themſelves, the Skilfull + Painter can produce what kind of Colour he pleaſes, and a great many + more than we have yet Names for. But, as I intimated above, 'tis not my Deſign + <!-- Page 221 --> <span class="pagenum"><a name="LPage_221" + id="LPage_221"></a>[pg 221]</span> to proſecute this Subject, though + I thought it not unfit to take ſome Notice of it, becauſe we may + hereafter have occaſion to make uſe of what has been now + deliver'd, to illuſtrate the Generation of Intermediate Colours; + concerning which we muſt yet ſubjoyn this Caution, that to make + the Rules about the Emergency of Colours, fit to be Relied upon, the Corpuſcles + whereof the Pigments conſiſt muſt be ſuch as do not Deſtroy + one anothers Texture, for in caſe they do, the produced Colour may be + very Different from that which would Reſult from the Mixture of other + harmleſs Pigments of the ſame Colours, as I ſhall have Occaſion + to ſhew ere long. + </p> + <h3> + <i>EXPERIMENT XIII.</i> + </h3> + <p> + It may alſo give much light to an Enquirer into the Nature of + Colours, to know that not only in Green, but in many (if not all) other + Colours, the Light of the Sun paſſing through Diaphanous Bodies + of differing Hues may be tinged of the ſame Compound Colour, as if it + came from ſome Painters Colours of the ſame Denomination, though + this later be exhibited by Reflection, and be (as the + <!-- Page 222 --> <span class="pagenum"><a name="LPage_222" + id="LPage_222"></a>[pg 222]</span> former Experiment declares) manifeſtly + Compounded of material Pigments. Wherefore to try the Compoſition of + Colours by Trajection, we provided ſeveral Plates of Tinged Glaſs, + which being laid two at a time one on the top of another, the Object + look'd upon through them both, appear'd of a Compounded Colour, which + agrees well with what we have obſerv'd in the ſecond Experiment, + of Looking againſt the Light through differingly Colour'd Papers. But + we thought the Experiment would be more Satisfactory, if we procur'd the + Sun-beams to be ſo Ting'd in their paſſage through Plates + of Glaſs, as to exhibit the Compounded Colour upon a Sheet of White + Paper. And though by reaſon of the Thickneſs of the Glaſſes, + the Effect was but Faint, even when the Sun was High and Shin'd forth + clear, yet, we eaſily remedied that by Contracting the Beams we caſt + on them by means of a Convex Burning-glaſs, which where it made the + Beams much converge Increas'd the Light enough to make the Compounded + Colour very manifeſt upon the Paper. By this means we obſerv'd, + that the Beams trajected through Blew and Yellow compos'd a Green, that an + intenſe and moderate Red did with Yellow make differing + <!-- Page 223 --> <span class="pagenum"><a name="LPage_223" + id="LPage_223"></a>[pg 223]</span> degrees of Saffron, and Orange Tawny + Colours, that Green and Blew made a Colour partaking of both, ſuch as + that which ſome Latin Writers call <i>Pavonaceus</i>, that Red and + Blew made a Purple, to which we might add other Colours, that we produc'd + by the Combinations of Glaſſes differingly Ting'd, but that I + want proper Words to expreſs them in our Language, and had not when + we made the Tryals, the Opportunity of conſulting with a Painter, who + perchance might have Suppli'd me with ſome of the terms I wanted. + </p> + <p> + I know not whether it will be requiſite to ſubjoyn on this Occaſion, + what I tried concerning Reflections from Colour'd Glaſſes, and + other Tranſparent Bodies, namely, that having expos'd four or five + ſorts of them to the Sun, and caſt the Reflected Beams upon + White Paper held near at hand, the Light appear'd not manifeſtly + Ting'd, but as if it had been Reflected from the Impervious parts of a + Colourleſs Glaſs, only that Reflected from the Yellow was here + and there ſtain'd with the ſame Colour, as if thoſe Beams + were not all Reflected from the Superficial, but ſome from the + Internal parts of the Glaſs; upon which Occaſion you may take + notice, that a Skilfull Tradeſman, who makes ſuch Colour'd + <!-- Page 224 --> <span class="pagenum"><a name="LPage_224" + id="LPage_224"></a>[pg 224]</span> Glaſs told me, that where as the + Red Pigment was but Superficial, the Yellow penetrated to the very midſt + of the Plate. But for further Satisfaction, not having the Opportunity to + Foliate thoſe Plates, and ſo turn them into Looking-glaſſes, + we Foliated a Plate of <i>Muſcovy</i> Glaſs, and then laying on + it a little Tranſparent Varniſh of a Gold Colour, we expos'd it + to the Sun-beams, ſo as to caſt them upon a Body fit to receive + them, on which the Reflected Light, appearing, as we expected, Yellow, + manifeſted that Rebounding from the Specular part of the <i>Selenitis</i>, + it was Ting'd in its return with the Colour of the Tranſparent Varniſh + through which it paſs'd. + </p> + <h3> + <i>EXPERIMENT XIV.</i> + </h3> + <p> + After what we have ſaid of the Compoſition of Colours, it will + now be ſeaſonable to annex ſome Experiments that we made in + favour of thoſe Colours, that are taught in the Schools not to be + Real, but only Apparent and Phantaſtical; For we found by Tryals, + that theſe Colours might be Compounded, both with True and Stable + Colours, and with one another, as well as unqueſtionably Genuine and + Laſting Colours, and that the Colours + <!-- Page 225 --> <span class="pagenum"><a name="LPage_225" + id="LPage_225"></a>[pg 225]</span> reſulting from ſuch Compoſitions, + would reſpectively deſerve the ſame Denominations. + </p> + <p> + For firſt, having by the Trajection of the Sun-beams through a Glaſs-priſm + thrown an Iris on the Floor, I found that by placing a Blew Glaſs at + a convenient diſtance betwixt the Priſm and the Iris, that part + of the Iris that was before Yellow, might be made to appear Green, though + not of a Graſs Green, but of one more Dilute and Yellowiſh. And + it ſeems not improbable, that the narrow Greeniſh Liſt (if + I may ſo call it) that is wont to be ſeen between the Yellow and + Blew parts of the Iris, is made by the Confuſion of thoſe two + Bordering Colours. + </p> + <p> + Next, I found, that though the want of a ſufficient Livelineſs + in either of the Compounding Colours, or a light Error in the manner of + making the following Tryals, was enough to render ſome of them Unſucceſsfull, + yet when all neceſſary Circumſtances were duely obſerv'd, + the Event was anſwerable to our Expectation and Deſire. + </p> + <p> + And (as I formerly Noted) that Red and Blew compound a Purple, ſo I + could produce this laſt nam'd Colour, by caſting at ſome Diſtance + from the Glaſs the Blew + <!-- Page 226 --> <span class="pagenum"><a name="LPage_226" + id="LPage_226"></a>[pg 226]</span> part of the Priſmatical Iris (as I + think it may be call'd for Diſtinction ſake) upon a Lively Red, + (for elſe the Experiment ſucceeds not ſo well.) And I + remember, that ſometimes when I try'd this upon a piece of Red + Cloath, <i>that</i> part of the Iris which would have been Blew, (as I + try'd by covering that part of the Cloath with a piece of White Paper) and + Compounded with the Red, wherewith the Cloath was Imbued before, appear'd + of a fair Purple, did, when I came to View it near at hand, look very + Odly, as if there were ſome ſtrange Reflection or Refraction or + both made in the Hairs of which that Cloath was compoſed. + </p> + <p> + Calling likewiſe the Priſmatical Iris upon a very Vivid Blew, I + found that part of it, which would elſe have been the Yellow, appear + Green. (Another ſomewhat differing Tryal, and yet fit to confirm + this, you will find in the fifteenth Experiment.) + </p> + <p> + But it may ſeem ſomewhat more ſtrange, that though the Priſmatical + Iris being made by the Refraction of Light through a Body that has no + Colour at all, muſt according to the Doctrine of the Schools conſiſt + of as purely Emphatical Colours, as may be, yet even theſe may be + Compounded with one another, as well as Real Colours in + <!-- Page 227 --> <span class="pagenum"><a name="LPage_227" + id="LPage_227"></a>[pg 227]</span> the Groſſeſt Pigments. + For I took at once two Triangular Glaſſes, and one of them being + kept fixt in the ſame Poſture, that the Iris it projected on the + Floor might not Waver, I caſt on the ſame Floor another Iris + with the other Priſm, and Moving it too and fro to bring what part of + the ſecond Iris I pleas'd, to fall upon what part of the firſt I + thought fit, we did ſometimes (for a ſmall Errour ſuffices + to hinder the Succeſs) obtain by this means a Green Colour in that + part of the more Stable Iris, that before was Yellow, or Blew, and + frequently by caſting thoſe Beams that in one of the Iris's made + the Blew upon the Red parts of the other Iris, we were able to produce a + lovely Purple, which we can Deſtroy or Recompoſe at pleaſure, + by Severing and Reapproaching the Edges of the two Iris's. + </p> + <h3> + <i>EXPERIMENT XV.</i> + </h3> + <p> + On this occaſion, <i>Pyrophilus</i>, I ſhall add, that finding + the Glaſs-priſm to be the uſefulleſt Inſtrument + Men have yet imploy'd about the Contemplation of Colours, and conſidering + that Priſms hitherto in uſe are made of Glaſs, Tranſparent + and Colourleſs, I thought it would not be amiſs to try, + <!-- Page 228 --> <span class="pagenum"><a name="LPage_228" + id="LPage_228"></a>[pg 228]</span> what change the Superinduction of a + Colour, without the Deſtruction of the Diaphaneity, would produce in + the Colours exhibited by the Priſm. But being unable to procure one + to be made of Colour'd Glaſs, and fearing alſo that if it were + not carefully made, the Thickneſs of it would render it too Opacous, + I endeavoured to ſubſtitute one made of Clarify'd Roſin, or + of Turpentine brought (as I elſewhere teach) to the conſiſtence + of a Tranſparent Gum. But though theſe Endeavours were not + wholly loſt, yet we found it ſo difficult to give theſe + Materials their true Shape, that we choſe rather to Varniſh over + an ordinary Priſm with ſome of theſe few Pigments that are + to be had Tranſparent; as accordingly we did firſt with Yellow, + and then with Red, or rather Crimſon, made with Lake temper'd with a + convenient Oyl, and the Event was, That for want of good Tranſparent + Colours, (of which you know there are but very few) both the Yellow and + the Red made the Glaſs ſo Opacous, (though the Pigment were laid + on but upon two Sides of the Glaſs, no more being abſolutely + neceſſary) that unleſs I look'd upon an Inlightned Window, + or the Flame of a Candle, or ſome other Luminous or very Vivid + object, + <!-- Page 229 --> <span class="pagenum"><a name="LPage_229" + id="LPage_229"></a>[pg 229]</span> I could ſcarce diſcern any + Colours at all, eſpecially when the Glaſs was cover'd with Red. + But when I did look on ſuch Objects, it appear'd (as I expected) that + the Colour of the Pigment had Vitiated or Drown'd ſome of thoſe + which the Priſm would according to its wont have exhibited, and + mingling with others, Alter'd them: as I remember, that both to my Eyes, + and others to whom I ſhow'd it, when the Priſm was cover'd with + Yellow, it made thoſe Parts of bright Objects, where the Blew would + elſe have been Conſpicuous, appear of a light Green. But, <i>Pyrophilus</i>, + both the Nature of the Colours, and the Degree of Tranſparency, or of + Darkneſs in the Pigment, beſides divers other Circumſtances, + did ſo vary the <i>Phænomena</i> of theſe Tryals, that till I + can procure ſmall Colour'd Priſms, or Hollow ones that may be + filled with Tincted Liquor, or obtain Some better Pigments than thoſe + I was reduc'd to imploy, I ſhall forbear to Build any thing upon what + has been delivered, and ſhall make no other uſe of it, than to + invite you to proſecute the Inquiry further. + </p> + <!-- Page 230 --> + <p> + <span class="pagenum"><a name="LPage_230" id="LPage_230"></a>[pg 230]</span> + </p> + <h3> + <i>EXPERIMENT XVI.</i> + </h3> + <p> + And here, <i>Pyrophilus</i>, ſince we are treating of Emphatical + Colours, we ſhall add what we think not unworthy your Obſervation, + and not unfit to afford ſome Exerciſe to the Speculative. For + there are ſome Liquors, which though Colourleſs themſelves, + when they come to be Elevated, and Diſpers'd into Exhalations, + exhibit a conſpicuous Colour, which they loſe again, when they + come to be Reconjoyn'd into a Liquor, as good Spirit of <i>Nitre</i>; or + upon its account ſtrong <i>Aqua-fortis</i>, though devoid of all + appearance of Redneſs whilſt they continue in the form of a + Liquor, if a little Heat chance to turn the Minute parts of them into + Vapour, the Steam will appear of a Reddiſh or deep Yellow Colour, + which will Vaniſh when thoſe Exhalations come to reſume the + form of Liquor. + </p> + <p> + And not only if you look upon a Glaſs half full of <i>Aqua-fortis</i>, + or Spirit of <i>Nitre</i>, and half full of <i>Nitrous</i> ſteams + proceeding from it, you will ſee the Upper part of the Glaſs of + the Colour freſhly mention'd, if through it you look upon the Light. + But which is much more conſiderable, I + <!-- Page 231 --> <span class="pagenum"><a name="LPage_231" + id="LPage_231"></a>[pg 231]</span> have tried, that putting <i>Aqua-fortis</i> + in a long clear Glaſs, and adding a little Copper or ſome ſuch + open Metall to it, to excite Heat and Fumes, the Light trajected through + thoſe Fumes, and caſt upon a ſheet of White Paper, did upon + that appear of the Colour that the Fumes did, when directly Look'd upon, + as if the Light were as well Ting'd in its paſſage through theſe + Fumes, as it would have been by paſſing through ſome Glaſs + or Liquor in which the ſame Colour was Inherent. + </p> + <p> + To which I ſhall further add, that having ſometimes had the + Curioſity to obſerve whether the Beams of the Sun near the + Horizon trajected through a very Red Sky, would not (though ſuch + redneſſes are taken to be but Emphatical Colours) exhibit the + like Colour, I found that the Beams falling within a Room upon a very + White Object, plac'd directly oppoſite to the Sun, diſclos'd a + manifeſt Redneſs, as if they had paſs'd through a Colour'd + <i>Medium</i>. + </p> + <h3> + <i>EXPERIMENT XVII.</i> + </h3> + <p> + The emergency, <i>Pyrophilus</i>, of Colours upon the Coalition of the + Particles of ſuch Bodies as were neither of them of the Colour of + that Mixture whereof they are the + <!-- Page 232 --> <span class="pagenum"><a name="LPage_232" + id="LPage_232"></a>[pg 232]</span> Ingredients, is very well worth our + attentive Obſervation, as being of good uſe both Speculative and + Practical; For much of the Mechanical uſe of Colours among Painters + and Dyers, doth depend upon the Knowledge of what Colours may be produc'd + by the Mixtures of Pigments ſo and ſo Colour'd. And (as we + lately intimated) 'tis of advantage to the contemplative Naturaliſt, + to know how many and which Colours are Primitive (if I may ſo call + them) and Simple, becauſe it both eaſes his Labour by confining + his moſt ſollicitous Enquiry to a ſmall Number of Colours + upon which the reſt depend, and aſſiſts him to judge + of the nature of particular compounded Colours, by ſhewing him from + the Mixture of what more Simple ones, and of what Proportions of them to + one another, the particular Colour to be conſider'd does reſult. + But becauſe to inſiſt on the Proportions, the Manner and + the Effects of ſuch Mixtures would oblige me to conſider a + greater part of the Painters Art and Dyers Trade, than I am well + acquainted with, I confin'd my ſelf to make Trial of <i>ſeveral + ways to produce Green</i>, by the compoſition of Blew and Yellow. And + ſhall in this place both Recapitulate moſt of the things I have + Diſperſedly deliver'd + <!-- Page 233 --> <span class="pagenum"><a name="LPage_233" + id="LPage_233"></a>[pg 233]</span> already concerning that Subject, and + Recruit them. + </p> + <p> + And firſt, whereas Painters (as I noted above) are wont to make Green + by tempering Blew and Yellow, both of them made into a ſoft Conſiſtence, + with either Water or Oyl, or ſome Liquor of Kin to one of thoſe + two, according as the Picture is to be Drawn with thoſe they call <i>water + Colours</i>, or thoſe they term <i>Oyl Colours</i>, I found that by + chooſing fit Ingredients, and mixing them in the form of Dry Powders, + I could do, what I could not if the Ingredients were temper'd up with a + Liquor; But the Blew and Yellow Powders muſt not only be finely + Ground, but ſuch as that the Corpuſcles of the one may not be + too unequal to thoſe of the other, leſt by their Diſproportionate + Minuteneſs the Smaller cover and hide the Greater. We us'd with good + ſucceſs a ſlight Mixture of the fine Powder of Biſe, + with that of Orpiment, or that of good Yellow Oker, I ſay a <i>ſlight</i> + Mixture, becauſe we found that an <i>exquiſite</i> Mixture did + not do ſo well, but by lightly mingling the two Pigments in ſeveral + little Parcels, thoſe of them in which the Proportion and Manner of + Mixture was more Lucky, afforded us a good Green. + </p> + <!-- Page 234 --> + <p> + <span class="pagenum"><a name="LPage_234" id="LPage_234"></a>[pg 234]</span> + </p> + <p> + 2. We alſo learn'd in the Dye-houſes, that Cloth being Dy'd Blew + with Woad, is afterwards by the Yellow Decoction of <i>Luteola</i> or + <!-- Erratum: insert --> Woud-wax or Wood-wax Dy'd into a Green Colour. + </p> + <p> + 3. You may alſo remember what we above Related, where we intimated, + that having in a Darkn'd Room taken two Bodies, a Blew and a Yellow, and + caſt the Light Reflected from the one upon the other, we likewiſe + obtain'd a Green. + </p> + <p> + 4. And you may remember, that we obſerv'd a Green to be produc'd, + when in the ſame Darkn'd Room we look'd at the Hole at which alone + the Light enter'd, through the Green and Yellow parts of a ſheet of + Marbl'd Paper laid over one another. + </p> + <p> + 5. We found too, that the Beams of the Sun being trajected through two + pieces of Glaſs, the one Blew and the other Yellow, laid over one + another, did upon a ſheet of White paper on which they were made to + fall, exhibit a lovely Green. + </p> + <p> + 6. I hope alſo, that you have not already forgot, what was ſo + lately deliver'd, concerning the compoſition of a Green, with a Blew + and Yellow; of which moſt Authors would call the one a <i>Real</i>, + and the other an <i>Emphatical</i>. + </p> + <!-- Page 235 --> + <p> + <span class="pagenum"><a name="LPage_235" id="LPage_235"></a>[pg 235]</span> + </p> + <p> + 7. And I preſume, you may have yet freſh in your memory, what + the fourteenth Experiment informs you, concerning the exhibiting of a + Green, by the help of a Blew and Yellow, that were both of them + Emphatical. + </p> + <p> + 8. Wherefore we will proceed to take notice, that we alſo devis'd a + way of trying whether or no Metalline Solutions though one of them at leaſt + had its Colour Adventitious, by the mixture of the <i>Menstruum</i> + employ'd to diſſolve it, might not be made to compound a Green + after the manner of other Bodies. And though this ſeem'd not eaſie + to be perform'd by reaſon of the Difficulty of finding Metalline + Solutions of the Colour requiſite, that would mix without + Præcipitating each other; yet after a while having conſider'd the + matter, the firſt Tryal afforded me the following Experiment. I took + a High Yellow Solution of good Gold in <i>Aqua-Regis</i>, (made of <i>Aqua-fortis</i>, + and as I remember half its weight of Spirit of Salt) To this I put a due + Proportion of a deep and lovely Blew Solution of Crude Copper, (which I + have elſewhere taught to be readily Diſſoluble in ſtrong + Spirit of Urine) and theſe two Liquors though at firſt they + ſeem'd a little to Curdle one another, yet being throughly mingl'd by + Shaking, + <!-- Page 236 --> <span class="pagenum"><a name="LPage_236" + id="LPage_236"></a>[pg 236]</span> they preſently, as had been + Conjectur'd, united into a Tranſparent Green Liquor, which continu'd + ſo for divers days that I kept it in a ſmall Glaſs wherein + 'twas made, only letting fall a little Blackiſh Powder to the Bottom. + The other <i>Phænomena</i> of this Experiment belong not to this place, + where it may ſuffice to take notice of the Production of a Green, and + that the Experiment was more than once repeated with Succeſs. + </p> + <p> + 9. And laſtly, to try whether this way of compounding Colours would + hold ev'n in Ingredients actually melted by the Violence of the Fire, + provided their Texture were capable of ſafely induring Fuſion, + we caus'd ſome Blew and Yellow Ammel to be long and well wrought + together in the Flame of a Lamp, which being Strongly and Inceſſantly + blown on them kept them in ſome degree of Fuſion, and at length + (for the Experiment requires ſome Patience as well as Skil) we + obtain'd the expected Ammel of a Green Colour. + </p> + <p> + I know not, <i>Pyrophilus</i>, whether it be worth while to acquaint you + with the ways that came into my Thoughts, whereby in ſome meaſure + to explicate the firſt of the mention'd ways of making a Green; for I + have ſometimes Conjectur'd, that the mixture + <!-- Page 237 --> <span class="pagenum"><a name="LPage_237" + id="LPage_237"></a>[pg 237]</span> of the Biſe and the Orpiment + produc'd a Green by ſo altering the Superficial Aſperity, which + each of thoſe Ingredients had apart, that the Light Incident on the + mixture was Reflected with differing Shades, as to Quantity, or Order, or + both, from thoſe of either of the Ingredients, and ſuch as the + Light is wont to be Modify'd with, when it Reflects from Graſs, or + Leaves, or ſome of thoſe other Bodies that we are wont to call + Green. And ſometimes too I have doubted, whether the produced Green + might not be partly at leaſt deriv'd from this, That the Beams that + Rebound from the Corpuſcles of the Orpiment, giving one kind of + ſtroak upon the <i>Retina</i>, whoſe Perception we call Yellow, + and the Beams Reflected from the Corpuſcles of the Biſe, giving + another ſtroak upon the ſame <i>Retina</i>, like to Objects that + are Blew, the Contiguity and Minuteneſs of theſe Corpuſcles + may make the Appulſe of the Reflected Light fall upon the <i>Retina</i> + within ſo narrow a Compaſs, that the part they Beat upon being + but as it were a Phyſical point, they may give a Compounded ſtroak, + which may conſequently exhibit a Compounded and new Kind of Senſation, + as we ſee that two Strings of a Muſical Inſtrument being + ſtruck together, making two + <!-- Page 238 --> <span class="pagenum"><a name="LPage_238" + id="LPage_238"></a>[pg 238]</span> Noiſes that arrive at the Ear at + the ſame time as to Senſe, yield a Sound differing from either + of them, and as it were Compounded of both; Inſomuch that if they be + Diſcordantly ton'd, though each of them ſtruck apart would yield + a Pleaſing Sound, yet being ſtruck together they make but a Harſh + and troubleſome Noiſe. But this not being ſo fit a place to + proſecute Speculations, I ſhall not inſiſt, neither + upon theſe Conjectures nor any others, which the Experiment we have + been mentioning may have ſuggeſted to me. And I ſhall leave + it to you, <i>Pyrophilus</i>, to derive what Inſtruction you can from + comparing together the Various ways whereby a Yellow and a Blew can be + made to Compound a Green. That which I now pretend to, being only to + ſhew that the firſt of thoſe mention'd ways, (not to take + at preſent notice of the reſt) does far better agree with our + Conjectures about Colours, than either with the Doctrine of the Schools, + or with that of the <i>Chymiſts</i>, both which ſeem to be very + much Disfavour'd by it. + </p> + <p> + For firſt, ſince in the Mixture of the two mention'd Powders I + could by the help of a very excellent <i>Microſcope</i> (for ordinary + ones will ſcarce ſerve the turn) diſcover that which ſeem'd + to the naked Eye a Green + <!-- Page 239 --> <span class="pagenum"><a name="LPage_239" + id="LPage_239"></a>[pg 239]</span> Body, to be but a heap of Diſtinct, + though very ſmall Grains of Yellow Orpiment and Blew Biſe confuſedly + enough Blended together, it appears that the Colour'd Corpuſcles of + either kind did each retain its own Nature and Colour; By which it may be + gueſs'd, what meer Tranſpoſition and Juxtapoſition of + Minute and Singly unchang'd Particles of Matter can do to produce a new + Colour; For that this Local Motion and new Diſpoſition of the + ſmall parts of the Orpiment did Intervene is much more manifeſt + than it is eaſie to Explicate how they ſhould produce this new + Green otherwiſe than by the new Manner of their being put together, + and conſequently by their new Diſpoſition to Modifie the + Incident Light by Reflecting it otherwiſe than they did before they + were Mingl'd together. + </p> + <p> + Secondly, The Green thus made being (if I may ſo ſpeak) + Mechanically produc'd, there is no pretence to derive it from I know not + what incomprehenſible Subſtantial Form, from which yet many + would have us believe that Colours muſt flow; Nor does this Green, + though a Real and Permanent, not a Phantaſtical and Vanid Colour, + ſeem to be ſuch an Inherent Quality as they would have it, + ſince not only each part of + <!-- Page 240 --> <span class="pagenum"><a name="LPage_240" + id="LPage_240"></a>[pg 240]</span> the Mixture remains unalter'd in + Colour, and conſequently of a differing Colour from the Heap they + Compoſe, but if the Eye be aſſiſted by a <i>Microſcope</i> + to diſcern things better and more diſtinctly than before it + could, it ſees not a Green Body, but a Heap of Blew and Yellow Corpuſcles. + </p> + <p> + And in the third place, I demand what either Sulphur, or Salt, or Mercury + has to do in the Production of this Green; For neither the Biſe nor + the Orpiment were indu'd with that Colour before, and the bare Juxtapoſition + of the Corpuſcles of the two Powders that work not upon each other, + but might if we had convenient Inſtruments be ſeparated, + unalter'd, cannot with any probability be imagin'd either to Increaſe + or Diminiſh any of the three Hypoſtatical Principles, (to which + of them ſoever the <i>Chymiſts</i> are pleas'd to aſcribe + Colours) nor does there here Intervene ſo much as Heat to afford them + any colour to pretend, that at leaſt there is made an Extraverſion + (as the <i>Helmontians</i> ſpeak) of the Sulphur or of any of the two + other ſuppoſed Principles; But upon this Experiment we have + already Reflected enough, if not more than enough for once. + </p> + <!-- Page 241 --> + <p> + <span class="pagenum"><a name="LPage_241" id="LPage_241"></a>[pg 241]</span> + </p> + <h3> + <i>EXPERIMENT XVIII.</i> + </h3> + <p> + But here, <i>Pyrophilus</i>, I muſt advertiſe you, that 'tis not + every Yellow and every Blew that being mingl'd will afford a Green; For in + caſe one of the Ingredients do not Act only as endow'd with ſuch + a Colour, but as having a power to alter the Texture of the Corpuſcles + of the other, ſo as to Indiſpoſe them to Reflect the Light, + as Corpuſcles that exhibit a Blew or a Yellow are wont to Reflect it, + the emergent Colour may be not Green, but ſuch as the change of + Texture in the Corpuſcles of one or both of the Ingredients qualifies + them to ſhew forth; as for inſtance, if you let fall a few Drops + of Syrrup of Violets upon a piece of White Paper, though the Syrrup being + ſpread will appear Blew, yet mingling with it two or three Drops of + the lately mention'd Solution of Gold, I obtain'd not a Green but a Reddiſh + mixture, which I expected from the remaining Power of the Acid Salts + abounding in the Solution, ſuch Salts or Saline Spirits being wont, + as we ſhall ſee anon, though weakn'd, ſo to work upon that + Syrrup as to change it into a Red or Reddiſh Colour. And to confirm + that for which I allege the former + <!-- Page 242 --> <span class="pagenum"><a name="LPage_242" + id="LPage_242"></a>[pg 242]</span> Experiment, I ſhall add this + other, that having made a very ſtrong and high-colour'd Solution of + Filings of Copper with Spirit of Urine, though the <i>Menſtruum</i> + ſeem'd Glutted with the Metall, becauſe I put in ſo much + Filings that many of them remain'd for divers days Undiſſolv'd + at the Bottom, yet having put three or four Drops of Syrrup of Violets + upon White Paper, I found that the deep Blew Solution proportionably + mingl'd with this other Blew Liquor did not make a Blew mixture, but, as I + expected, a fair Green, upon the account of the Urinous Salt that was in + the <i>Menſtruum</i>. + </p> + <h3> + <i>EXPERIMENT XIX.</i> + </h3> + <p> + To ſhew the <i>Chymiſts</i>, that Colours may be made to Appear + or Vaniſh, where there intervenes no Acceſſion or Change + either of the Sulphureous, or the Saline, or the Mercurial principle (as + they ſpeak) of Bodies: I ſhall not make uſe of the Iris + afforded by the Glaſs-priſm, nor of the Colours to be ſeen + in a fair Morning in thoſe drops of Dew that do in a convenient + manner Reflect and Refract the Beams of Light to the Eye; But I will + rather mind them of what they may obſerve in their + <!-- Page 243 --> <span class="pagenum"><a name="LPage_243" + id="LPage_243"></a>[pg 243]</span> own Laboratories, namely, that divers, + if not all, Chymical Eſſential Oyls, as alſo good Spirit of + Wine, being ſhaken till they have good ſtore of Bubbles, thoſe + Bubbles will (if attentively conſider'd) appear adorn'd with various + and lovely Colours, which all immediately Vaniſh, upon the relapſing + of the Liquor that affords thoſe Bubbles their Skins, into the reſt + of the Oyl, or Spirit of Wine, ſo that a Colourleſs Liquor may + be made in a trice to exhibit variety of Colours, and may loſe them + in a moment without the Acceſſion or Diminution of any of its + Hypoſtatical Principles. And, by the way, 'tis not unworthy our + notice, that ſome Bodies, as well Colourleſs, as Colour'd, by + being brought to a great Thinneſs of parts, acquire Colours though + they had none before, or Colours differing from them they were before + endued with: For, not to inſiſt on the Variety of Colours, that + Water, made ſomewhat Glutinous by Sope, acquires, when 'tis blown + into ſuch Sphærical Bubbles as Boys are wont to make and play with; + Turpentine (though it have a Colour deep enough of its own) may (by being + blown into after a certain manner) be brought to afford Bubbles adorn'd + with variety of Orient Colours, which though + <!-- Page 244 --> <span class="pagenum"><a name="LPage_244" + id="LPage_244"></a>[pg 244]</span> they Vaniſh after ſome while + upon the breaking of the Bubbles, yet they would in likelihood always + exhibit Colours upon their <i>Superfices</i>, (though not always the + ſame in the ſame Parts of them, but Vary'd according to the + Incidence of the Sight, and the Poſition of the Eye) if their Texture + were durable enough: For I have ſeen one that was Skill'd at faſhioning + Glaſſes by the help of a Lamp, blowing ſome of them ſo + ſtrongly as to burſt them, whereupon it was found, that the + Tenacity of the Metall was ſuch, that before it broke it ſuffer'd + it ſelf to be reduc'd into Films ſo extremely thin, that being + kept clean they conſtantly ſhew'd on their Surfaces (but after + the manner newly mention'd) the varying Colours of the Rain-bow, which + were exceedingly Vivid, as I had often opportunity to obſerve in + ſome, that I caus'd purpoſely to be made, to keep by me. + </p> + <p> + But leſt it ſhould be objected, that the above mentioned Inſtances + are drawn from Tranſparent Liquors, it may poſſibly appear, + not impertinent to add, what I have ſometimes thought upon, and + ſeveral times tried, when I was conſidering the Opinions of the + <i>Chymiſts</i> about Colours, I took then a Feather of a convenient + Bigneſs + <!-- Page 245 --> <span class="pagenum"><a name="LPage_245" + id="LPage_245"></a>[pg 245]</span> and Shape, and holding it at a fit diſtance + betwixt my Eye and the Sun when he was near the Horizon, me thought there + appear'd to me a Variety of little Rain-bows, with differing and very + vivid Colours, of which none was conſtantly to be ſeen in the + Feather; the like <i>Phænomenon</i> I have at other times (though not with + altogether ſo good ſucceſs) produc'd, by interpoſing + at a due diſtance a piece of Black Ribband betwixt the almoſt + ſetting Sun and my Eye, not to mention the Trials I have made to the + ſame purpoſe, with other Bodies. + </p> + <h3> + <i>EXPERIMENT XX.</i> + </h3> + <p> + Take good Syrrup of Violets, Imprægnated with the Tincture of the flowers, + drop a little of it upon a White Paper (for by that means the Change of + Colour will be more conſpicuous, and the Experiment may be practis'd + in ſmaller Quantities) and on this Liquor let fall two or three drops + of Spirit either of Salt or Vinegar, or almoſt any other eminently + Acid Liquor, and upon the Mixture of theſe you ſhall find the + Syrrup immediatly turn'd Red, and the way of Effecting ſuch a Change + has not been unknown to divers Perſons + <!-- Page 246 --> <span class="pagenum"><a name="LPage_246" + id="LPage_246"></a>[pg 246]</span> who have produc'd the like, by Spirit + of Vitriol, or juice of Limmons, but have Groundleſsly aſcrib'd + the Effect to ſome Peculiar Quality of thoſe two Liquors, + whereas, (as we have already intimated) almoſt any Acid Salt will + turn Syrrup of Violets Red. But to improve the Experiment, let me add what + has not (that I know of) been hitherto obſerv'd, and has, when we firſt + ſhew'd it them, appear'd ſomething ſtrange, even to thoſe + that have been inquiſitive into the Nature of Colours; namely, that + if inſtead of Spirit of Salt, or that of Vinegar, you drop upon the + Syrrup of Violets a little Oyl of Tartar <i>per Deliquium</i>, or the like + quantity of Solution of Potaſhes, and rubb them together with your + finger, you ſhall find the Blew Colour of the Syrrup turn'd in a + moment into a perfect Green, and the like may be perform'd by divers other + Liquors, as we may have occaſion elſewhere to Inform you. + </p> + <p class="center"> + <i>Annotation upon the twentieth Experiment</i>. + </p> + <p> + The uſe of what we lately deliver'd concerning the way of turning + Syrrup of Violets, Red or Green, may be this; That, though it be a far + more common and procurable + <!-- Page 247 --> <span class="pagenum"><a name="LPage_247" + id="LPage_247"></a>[pg 247]</span> Liquor than the Infuſion of <i>Lignum + Nephriticum</i>, it may yet be eaſily ſubſtituted in its + Room, when we have a mind to examine, whether or no the Salt predominant + in a Liquor or other Body, wherein 'tis Looſe and Abundant, belong to + the Tribe of <i>Acid</i> Salts or not. For if ſuch a Body turn the + Syrrup of a Red or Reddiſh Purple Colour, it does for the moſt + part argue the Body (eſpecially if it be a diſtill'd Liquor) to + abound with Acid Salt. But if the Syrrup be made Green, that argues the + Predominant Salt to be of a Nature repugnant to that of the Tribe of + Acids. For, as I find that either Spirit of Salt, or Oyl of Vitriol, or <i>Aqua-fortis</i>, + or Spirit of Vinegar, or Juice of Lemmons, or any of the Acid Liquors I + have yet had occaſion to try, will turn Syrrup of Violets, of a <i>Red</i>, + (or at leaſt, of a <i>Reddiſh</i> Colour, ſo I have found, + that not only the Volatile Salts of all Animal Subſtances I have + us'd, as Spirit of Harts-horn, of Urine, of Sal-Armoniack, of Blood, &c. + but alſo all the Alcalizate Salts I have imploy'd, as the Solution of + Salt of Tartar, of Pot-aſhes, of common Wood-aſhes, Lime-water, + &c. will immediately change the Blew Syrrup, into a perfect Green. And + by the ſame way (to hint that upon + <!-- Page 248 --> <span class="pagenum"><a name="LPage_248" + id="LPage_248"></a>[pg 248]</span> the by) I elſewhere ſhow you, + both the changes that Nature and Time produce, in the more Saline parts of + ſome Bodies, may be diſcover'd, and alſo how ev'n ſuch + Chymically prepar'd Bodies, as belong not either to the Animal Kingdome, + or to the Tribe of <i>Alcali's</i>, may have their new and ſuperinduc'd + Nature ſucceſsfully Examin'd. In this place I ſhall only + add, that not alone the Changing the Colour of the Syrrup, requires, that + the Changing Body be more ſtrong, of the Acid, or other ſort of + Salt that is Predominant in it, than is requiſite for the working + upon the Tincture of <i>Lignum Nephriticum</i>; but that in this is alſo, + the Operation of the formerly mention'd Salts upon our Syrrup, differs + from their Operation upon our Tinctures, that in this Liquor, if the + Cæruleous Colour be <i>Deſtroy'd</i> by an Acid Salt, it may be <i>Restor'd</i> + by one that is either Volatile, or Lixiviate; whereas in Syrrup of + Violets, though one of theſe contrary Salts will <i>destroy</i> the + Action of the other, yet neither of them will <i>reſtore</i> the + Syrrup to its native Blew; but each of them will Change it into the Colour + which it ſelf doth (if I may ſo ſpeak) affect, as we ſhall + have Occaſion to ſhow in the Notes on the twenty fifth + Experiment. + </p> + <!-- Page 249 --> + <p> + <span class="pagenum"><a name="LPage_249" id="LPage_249"></a>[pg 249]</span> + </p> + <h3> + <i>EXPERIMENT XXI.</i> + </h3> + <p> + There is a Weed, more known to Plowmen than belov'd by them, whoſe + Flowers from their Colour are commonly call'd <i>Blew-bottles</i>, and <i>Corn-weed</i> + from their Growing among Corn<a name="LNtA_18" id="LNtA_18_"></a><a + href="#LNt_18"><sup>18</sup></a>. Theſe Flowers ſome Ladies do, + upon the account of their Lovely Colour, think worth the being Candied, + which when they are, they will long retain ſo fair a Colour, as makes + them a very fine Sallad in the Winter. But I have try'd, that when they + are freſhly gather'd, they will afford a Juice, which when newly + expreſs'd, (for in ſome caſes 'twill ſoon enough + degenerate) affords a very deep and pleaſant Blew. Now, (to draw this + to our preſent Scope) by dropping on this freſh Juice, a little + Spirit of Salt, (that being the Acid Spirit I had then at hand) it + immediately turn'd (as I predicted) into a Red. And if inſtead of the + Sowr Spirit I mingled with it a little ſtrong Solution of an + Alcalizate Salt, it did preſently diſcloſe a lovely Green; + the ſame Changes being by thoſe differing ſorts of Saline + Liquors, producible in this <i>Natural juice</i>, that we lately mention'd + to + <!-- Page 250 --> <span class="pagenum"><a name="LPage_250" + id="LPage_250"></a>[pg 250]</span> have happen'd to that <i>factitious + Mixture</i>, the Syrrup of Violets. And I remember, that finding this Blew + Liquor, when freſhly made, to be capable of ſerving in a Pen for + an Ink of that Colour, I attempted by moiſtning one part of a piece + of White Paper with the Spirit of Salt I have been mentioning, and another + with ſome Alcalizate or Volatile Liquor, to draw a Line on the leiſurely + dry'd Paper, that ſhould, e'vn before the Ink was dry, appear partly + Blew, partly Red, and partly Green: But though the latter part of the + Experiment ſucceeded not well, (whether becauſe Volatile Salts + are too Fugitive to be retain'd in the Paper, and Alcalizate ones are too + Unctuous, or ſo apt to draw Moiſture from the Air, that they + keep the Paper from drying well) yet the former Part ſucceeded well + enough; the Blew and Red being Conſpicuous enough to afford a ſurprizing + Spectacle to thoſe, I acquaint not with (what I willingly allow you + to call) the <i>Trick</i>. + </p> + <p class="center"> + <i>Annotation upon the one and twentieth Experiment.</i> + </p> + <p> + But leſt you ſhould be tempted to think (<i>Pyrophilus</i>) that + Volatile or Alcalizate + <!-- Page 251 --> <span class="pagenum"><a name="LPage_251" + id="LPage_251"></a>[pg 251]</span> Salts change Blews into Green, rather + upon the ſcore of the eaſie Tranſition of the former Colour + into the latter, than upon the account of the Texture, wherein moſt + Vegetables, that afford a Blew, ſeem, though otherwiſe + differing, to be Allied, I will add, that when I purpoſely diſſolv'd + Blew Vitriol in fair Water, and thereby imbu'd ſufficiently that + Liquor with that Colour, a Lixiviate Liquor, and a Urinous Salt being + Copiouſly pour'd upon diſtinct Parcels of it, did each of them, + though perhaps with ſome Difference, turn the Liquor not Green, but + of a deep Yellowiſh Colour, almoſt like that of Yellow Oker, + which Colour the Precipitated Corpuſcles retain'd, when they had Leiſurely + ſubſided to the Bottom. What this Precipitated Subſtance + is, it is not needfull now to Enquire in this place, and in another, I + have ſhown you, that notwithſtanding its Colour, and its being + Obtainable from an Acid <i>Menſtruum</i> by the help of Salt of + Tartar, it is yet far enough from being the true Sulphur of Vitriol. + </p> + <h3> + <i>EXPERIMENT XXII.</i> + </h3> + <p> + Our next Experiment (<i>Pyrophilus</i>) will perhaps ſeem to be of a + contrary Nature + <!-- Page 252 --> <span class="pagenum"><a name="LPage_252" + id="LPage_252"></a>[pg 252]</span> to the two former, made upon Syrrup of + Violets, and Juice of Blew-bottles. For as in them by the Affuſion of + Oyl of Tartar, a Blewiſh Liquor is made Green, ſo in this, by + the ſole Mixture of the ſame Oyl, a Greeniſh Liquor becomes + Blew. The hint of this Experiment was given us by the practice of ſome + <i>Italian</i> Painters, who being wont to Counterfeit <i>Ultra-marine + Azure</i> (as they call it) by Grinding Verdigreaſe with + Sal-Armoniack, and ſome other Saline Ingredients, and letting them + Rot (as they imagine) for a good while together in a Dunghill, we ſuppos'd, + that the change of Colour wrought in the Verdigreaſe by this way of + Preparation, muſt proceed from the Action of certain Volatile and + Alcalizate Salts, abounding in ſome of the mingled Concretes, and + brought to make a further Diſſolution of the Copper abounding in + the Verdigreaſe, and therefore we Conjectur'd, that if both the + Verdigreaſe, and ſuch Salts were diſſolv'd in fair + Water, the ſmall Parts of both being therein more ſubdivided, + and ſet at liberty, would have better acceſs to each other, and + thereby Incorporate much the more ſuddenly; And accordingly we found, + that if upon a ſtrong Solution of good French Verdigreaſe (for + 'tis that we + <!-- Page 253 --> <span class="pagenum"><a name="LPage_253" + id="LPage_253"></a>[pg 253]</span> are wont to imploy, as the beſt) + you pour a juſt quantity of Oyl of Tartar, and ſhake them well + together, you ſhall immediately ſee a notable Change of Colour, + and the Mixture will grow thick, and not tranſparent, but if you + ſtay a while, till the Groſſer part be Precipitated to, and + ſetled in the Bottom, you may obtain a clear Liquor of a very lovely + Colour, and exceeding delightfull to the Eye. But, you muſt have a + care to drop in a competent Quantity of Oyl of Tartar, for elſe the + Colour will not be ſo Deep, and Rich; and if inſtead of this Oyl + you imploy a clear <i>Lixivium</i> of Pot-aſhes, you may have an + Azure ſomewhat Lighter or Paler than, and therefore differing from, + the former. And if inſtead of either of theſe Liquors, you make + uſe of Spirit of Urine, or of Harts-horn, you may according to the + Quantity and Quality of the Spirit you pour in, obtain ſome further + Variety (though ſcarce conſiderable) of Cæruleous Liquors. And + yet lately by the help of this Urinous Spirit we made a Blew Liquor, which + not a few Ingenious Perſons, and among them, ſome, whoſe + Profeſſion makes them very Converſant with Colours, have + looked upon with ſome wonder. But theſe Azure Colour'd Liquors + <!-- Page 254 --> <span class="pagenum"><a name="LPage_254" + id="LPage_254"></a>[pg 254]</span> ſhould be freed from the Subſiding + matter, which the Salts of Tartar or Urine precipitate out of them, rather + by being Decanted, than by Filtration. For by the latter of theſe + ways we have ſometimes found, the Colour of them very much Impair'd, + and little Superiour to that of the groſſer Subſtance, that + it left in the Filtre. + </p> + <h3> + <i>EXPERIMENT XXIII.</i> + </h3> + <p> + That Roſes held over the Fume of Sulphur, may quickly by it be + depriv'd of their Colour, and have as much of their Leaves, as the Fume + works upon, burn'd pale, is an Experiment, that divers others have tried, + as well as I. But (<i>Pyrophilus</i>) it may ſeem ſomewhat + ſtrange to one that has never conſider'd the Compounded nature + of Brimſtone, That, whereas the Fume of Sulphur will, as we have + ſaid, Whiten the Leaves of Roſes; That Liquor, which is commonly + call'd Oyl of Sulphur <i>per Campanam</i>, becauſe it is ſuppos'd + to be made by the Condenſation of theſe Fumes in Glaſſes + ſhap't like Bells, into a Liquor, does powerfully heighten the + Tincture of Red Roſes, and make it more Red and Vivid, as we have eaſily + tried by putting ſome Red-Roſe Leaves, + <!-- Page 255 --> <span class="pagenum"><a name="LPage_255" + id="LPage_255"></a>[pg 255]</span> that had been long dried, (and ſo + had loſt much of their Colour) into a Vial of fair Water. For a while + after the Affuſion of a convenient Quantity of the Liquor we are + ſpeaking of, both the Leaves themſelves, and the Water they were + Steep'd in, diſcover'd a very freſh and lovely Colour. + </p> + <h3> + <i>EXPERIMENT XXIV.</i> + </h3> + <p> + It may (<i>Pyrophilus</i>) ſomewhat ſerve to Illuſtrate, + not only the Doctrine of <i>Pigments</i>, and of <i>Colours</i>, but + divers other Parts of the <i>Corpuſcular Philoſophy</i>; as that + explicates Odours, and many other things, not as the Schools by Aery + Qualities, but by Real, though extremely Minute Bodies; to examine, how + much of a Colourleſs Liquor, a very ſmall Parcel of a Pigment + may Imbue with a <i>diſcernable</i> Colour. And though there be + ſcarce any thing of Preciſeneſs to be expected from ſuch + Trials, yet I preſum'd, that (at leaſt) I ſhould be able to + ſhow a much further Subdiviſion of the Parts of Matter into <i>Viſible</i> + Particles, than I have hitherto found taken notice of, and than moſt + men would imagine; no Body, that I know of, having yet attempted to reduce + this Matter to any Meaſure. + </p> + <!-- Page 256 --> + <p> + <span class="pagenum"><a name="LPage_256" id="LPage_256"></a>[pg 256]</span> + </p> + <p> + The Bodies, the moſt promiſing for ſuch a purpoſe, + might ſeem to be the Metalls, eſpecially Gold, becauſe of + the Multitude, and Minuteneſs of its Parts, which might be argu'd + from the incomparable Cloſeneſs of its Texture: But though we + tried a Solution of Gold made in <i>Aqua Regia</i> firſt, and then in + fair Water; yet in regard we were to determine the Pigment we imploy'd, + not by <i>Bulk</i> but <i>Weight</i>, and becauſe alſo, that the + Yellow Colour of Gold is but a faint one in Compariſon of the deep + Colour of <i>Cochineel</i>, we rather choſe this to make our Trials + with. But among divers of theſe it will ſuffice to ſet down + one, which was carefully made in Veſſels conveniently Shap'd; + (and that in the preſence of a Witneſs, and an Aſſiſtant) + the Sum whereof I find among my <i>Adverſaria</i>, Regiſtred in + the following Words. To which I ſhall only premiſe, (to leſſen + the wonder of ſo ſtrange a diffuſion of the Pigment) That + <i>Cochineel</i> will be better Diſſolv'd, and have its Colour + far more heightn'd by Spirit of Urine, than (I ſay not by common + Water, but) by Rectify'd Spirit of Wine it ſelf. + </p> + <p> + The Note I ſpoke off is this. [One Grain of <i>Cochineel</i> diſſolv'd + in a pretty Quantity of Spirit of Urine, and then diſſolv'd + <!-- Page 257 --> <span class="pagenum"><a name="LPage_257" + id="LPage_257"></a>[pg 257]</span> further by degrees in fair Water, + imparted a diſcernable, though but a very faint Colour, to about + ſix Glaſs-fulls of Water, each of them containing about forty + three Ounces and an half, which amounts to above a hundred twenty five + thouſand times its own Weight.] + </p> + <h3> + <i>EXPERIMENT XXV.</i> + </h3> + <p> + It may afford a conſiderable Hint (<i>Pyrophilus</i>) to him, that + would improve the Art of Dying, to know what change of Colours may be + produc'd by the three ſeveral ſorts of Salts already often + mention'd, (ſome or other of which may be procur'd in Quantity at reaſonable + Rates) in the Juices, Decoctions, Infuſions, and (in a word) the more + ſoluble parts of Vegetables. And, though the deſign of this Diſcourſe + be the Improvement of Knowledge, not of Trades: yet thus much I ſhall + not ſcruple to intimate here, That the Blew Liquors, mention'd in the + twentieth and one and twentieth Experiments, are far from being the only + Vegetable Subſtances, upon which Acid, Urinous, and Alcalizate Salts + have the like Operations to thoſe recited in thoſe two + Experiments. For Ripe <i>Privet Berries</i> (for inſtance) being cruſh'd + <!-- Page 258 --> <span class="pagenum"><a name="LPage_258" + id="LPage_258"></a>[pg 258]</span> upon White Paper, though they ſtain + it with a Purpliſh Colour, yet if we let fall on ſome part of it + two or three drops of Spirit of Salt, and on the other part a little more + of the Strong Solution of Pot-aſhes, the former Liquor immediately + turn'd that part of the Thick juice or Pulp, on which it fell, into a + lovely Red, and the latter turn'd the other part of it into a delightfull + Green. Though I will not undertake, that thoſe Colours in that Subſtance + ſhall not be much more Orient, than Laſting; and though (<i>Pyrophilus</i>) + this Experiment may ſeem to be almoſt the ſame with thoſe + already deliver'd concerning Syrrup of Violets, and the Juice of + Blew-bottles, yet I think it not amiſs to take this Occaſion to + inform you, that this Experiment reaches much farther, than perhaps you + yet imagine, and may be of good Uſe to thoſe, whom it concerns + to know, how Dying Stuffs may be wrought upon by Saline Liquors. For, I + have found this Experiment to ſucceed in ſo many Various + Berries, Flowers, Bloſſoms, and other finer Parts of Vegetables, + that neither my Memory, nor my Leiſure ſerves me to enumerate + them. And it is ſomewhat ſurprizing to ſee, by how + Differingly-colour'd Flowers, or Bloſſoms, (for example) the + Paper being + <!-- Page 259 --> <span class="pagenum"><a name="LPage_259" + id="LPage_259"></a>[pg 259]</span> ſtain'd, will by an Acid Spirit be + immediately turn'd Red, and by any <i>Alcaly</i> or any Urinous Spirit + turn'd Green; inſomuch that ev'n the cruſh'd Bloſſoms + of <i>Meſerion</i>, (which I gather'd in Winter and froſty + Weather) and thoſe of Peaſe, cruſh'd upon White Paper, how + remote ſoever their Colours be from Green, would in a moment paſs + into a deep Degree of that Colour, upon the Touch of an Alcalizate Liquor. + To which let us add, That either of thoſe new Pigments (if I may + ſo call them) may by the Affuſion of enough of a contrary + Liquor, be preſently chang'd from Red into Green, and from Green into + Red, which Obſervation will hold alſo in Syrrup of Violets, + Juices of Blew-bottles, &c. + </p> + <p class="center"> + <i>Annotation.</i> + </p> + <p> + After what I have formerly deliver'd to evince, That there are many Inſtances, + wherein new Colours are produc'd or acquir'd by Bodies, which <i>Chymiſts</i> + are wont to think deſtitute of Salt, or to whoſe change of + Colours no new Acceſſion of Saline Particles does appear to + contribute, I think we may ſafely enough acknowledge, + <!-- Page 260 --> <span class="pagenum"><a name="LPage_260" + id="LPage_260"></a>[pg 260]</span> that we have taken notice of ſo + many Changes made by the Intervention of Salts in the Colours of Mix'd + Bodies, that it has leſſen'd our Wonder, That though <i>many + Chymiſts</i> are wont to aſcribe the Colours of Such Bodies to + their Sulphureous, and <i>the reſt</i> to their Mercurial Principle; + yet <i>Paracelſus</i> himſelf directs us in the Indagation of + Colours, to have an Eye principally upon Salts, as we find in that paſſage + of his, wherein he takes upon him to Oblige his Readers much by Inſtructing + them, of what things they are to expect the Knowledge from each of the + three diſtinct Principles of Bodies. <i>Alias</i> (ſays he) <i>Colorum + ſimilis ratio eſt: De quibus brevem inſtitutionem hanc + attendite, quod ſcilicet colores omnes ex Sale prodeant. Sal enim dat + colorem, dat Balſamum.</i><a name="LNtA_19" id="LNtA_19_"></a><a + href="#LNt_19"><sup>19</sup></a> And a little beneath. <i> Iam natura Ipſa + colores protrathit ex ſale, cuique ſpeciei dans illum, qui ipſi + competit</i>, &c. After which he concludes; <i>Itaque qui rerum omnium + corpora cognoſcere vult, huic opus eſt, ut ante omnia cognoſcat + Sulphur, Ab hoc, qui deſiderat noviſſe Colores is ſcientiam + iſtorum petat à Sale, Qui ſcire vult Virtutes, is ſcrutetur + arcana Mercurii. Sic nimirum fundamentum hauſerit Myſteriorum, + in quolibet creſcenti indagandorum, + <!-- Page 261 --> <span class="pagenum"><a name="LPage_261" + id="LPage_261"></a>[pg 261]</span> prout natura cuilibet ſpeciei ea + ingeſſit</i>. But though <i>Paracelſus</i> aſcribes to + each of his belov'd Hypoſtatical Principles, much more than I fear + will be found to belong to it; yet if we pleaſe to conſider + Colours, not as <i>Philoſophers</i>, but as <i>Dyers</i>, the + concurrence of Salts to the ſtriking and change of Colours, and their + Efficacy, will, I ſuppoſe, appear ſo conſiderable, + that we ſhall not need to quarrel much with <i>Paracelſus</i>, + for aſcribing in this place (for I dare not affirm that he uſes + to be ſtill of one Mind) the Colours of Bodies to their Salts, if by + Salts he here underſtood, not only Elementary Salts, but ſuch alſo + as are commonly taken for Salts, as Allom, Cryſtals of Tartar, + Vitriol, &c. becauſe the Saline principle does chiefly abound in + them, though indeed they be, as we elſewhere declare, mix'd Bodies, + and have moſt of them, beſides what is Saline, both Sulphureous, + Aqueous, and Groſs or Earthy parts. + </p> + <p> + But though (<i>Pyrophilus</i>) I have obſerv'd a Red and Green to be + produc'd, the former, by Acid Salts, the later by Salts not Acid, in the + expreſs Juices of ſo many differing Vegetable Subſtances, + that the Obſervation, if perſued, may prove (as I ſaid) of + good Uſe: yet to ſhow you how much e'vn theſe Effects + depend upon the + <!-- Page 262 --> <span class="pagenum"><a name="LPage_262" + id="LPage_262"></a>[pg 262]</span> particular Texture of Bodies, I muſt + ſubjoyn ſome caſes wherein I (who am ſomewhat + backwards to admit Obſervations for Univerſal) had the Curioſity + to diſcover, that the Experiments would not Uniformly ſucceed, + and of theſe Exceptions, the chief that I now remember, are reducible + to the following three. + </p> + <h3> + <i>EXPERIMENT XXVI.</i> + </h3> + <p> + And, (firſt) I thought fit to try the Operation of Acid Salts upon + Vegetable Subſtances, that are already and by their own Nature Red. + And accordingly I made Trial upon Syrrup of Clove-july-flowers, the clear + expreſs'd Juice of the ſucculent Berries of <i>Spina Cervina</i>, + or Buckthorn (which I had long kept by me for the ſake of its deep + Colour) upon Red Roſes, Infuſion of Brazil, and divers other + Vegetable Subſtances, on ſome of which cruſh'd (as is often + mention'd) upon White Paper, (which is alſo to be underſtood in + moſt of theſe Experiments, if no Circumſtance of them argue + otherwiſe) Spirit of Salt either made no conſiderable Change, or + alter'd the Colour but from a Darker to a Lighter Red. How it will ſucceed + in many other Vegetable Juices, + <!-- Page 263 --> <span class="pagenum"><a name="LPage_263" + id="LPage_263"></a>[pg 263]</span> and Infuſions of the ſame + Colour, I have at preſent ſo few at hand, that I muſt leave + you to find it out your ſelf. But as for the Operation of the other + ſorts of Salts upon theſe Red Subſtances, I found it not + very Uniform, ſome Red, or Reddiſh Infuſions, as of Roſes, + being turn'd thereby into a dirty Colour, but yet inclining to Green. Nor + was the Syrrup of Clove-july-flowers turn'd by the ſolution of Pot-aſhes + to a much better, though ſomewhat a Greener, Colour. Another ſort + of Red Infuſions was by an <i>Alcaly</i> not turn'd into a Green, but + advanc'd into a Crimſon, as I ſhall have occaſion to note + ere long. But there were other ſorts, as particularly the lovely + Colour'd juice of Buckthorn Berries, that readily paſs'd into a + lovely Green. + </p> + <h3> + <i>EXPERIMENT XXVII.</i> + </h3> + <p> + Among other Vegetables, which we thought likely to afford Exceptions to + the General Obſervation about the differing Changes of Colours + produc'd by Acid and Sulphureous Salts, we thought fit to make Trial upon + the Flowers of <i>Jaſmin</i>, they being both White as to Colour, and + eſteem'd to be of a more Oyly nature than other Flowers. Whereupon + having taken + <!-- Page 264 --> <span class="pagenum"><a name="LPage_264" + id="LPage_264"></a>[pg 264]</span> the White parts only of the Flowers, + and rubb'd them ſomewhat hard with my Finger upon a piece of clean + Paper, it appear'd very little Diſcolour'd. Nor had Spirit of Salt, + wherewith I moiſten'd one part of it, any conſiderable Operation + upon it. But Spirit of Urine, and ſomewhat more effectually a ſtrong + Alcalizate Solution, did immediately turn the almoſt Colourleſs + Paper moiſten'd by the Juice of the <i>Jaſmin</i>, not as thoſe + Liquors are wont to do, when put upon the Juices of other Flowers, of a + good Green, but of a Deep, though ſomewhat Greeniſh Yellow, + which Experiment I did afterwards at ſeveral times repeat with the + like ſucceſs. But it ſeems not that a great degree of + Unctuouſneſs is neceſſary to the Production of the + like Effects, for when we try'd the Experiment with the Leaves of thoſe + purely White Flowers that appear about the end of Winter, and are commonly + call'd <i>Snow drops</i>, the event, was not much unlike that, which, we + have been newly mentioning. + </p> + <h3> + <i>EXPERIMENT XXVIII.</i> + </h3> + <p> + Another ſort of Inſtances to ſhow, how much changes of + Colour effected by Salts, depend upon the particular Texture of the + <!-- Page 265 --> <span class="pagenum"><a name="LPage_265" + id="LPage_265"></a>[pg 265]</span> Colour'd Bodies, has been afforded me + by ſeveral <i>Yellow</i> Flowers, and other Vegetables, as Mary-gold + Leaves, early Prim-roſes, freſh Madder, &c. For being rubb'd + upon White Paper, till they imbued it with their Colour, I found not, that + by the addition of Alcalizate Liquors, nor yet by that of an Urinous + Spirit, they would be turn'd either Green or Red: nor did ſo Acid a + Spirit, as that of Salt, conſiderably alter their Colour, ſave + that it ſeem'd a little to Dilute it. Only in ſome early Prim-roſes + it deſtroy'd the greateſt part of the Colour, and made the Paper + almoſt White agen. And Madder alſo afforded ſome thing + peculiar, and very differing from what we have newly mention'd: For having + gather'd Some Roots of it, and, (whilſt they were recent) expreſs'd + upon White Paper the Yellow Juice, an Alcalizate Solution drop'd upon it + did not turn it either Green or White, but Red. And the bruis'd Madder it + ſelf being drench'd with the like Alcalizate Solution, exchang'd alſo + its Yellowiſhneſs for a Redneſs. + </p> + <!-- Page 266 --> + <p> + <span class="pagenum"><a name="LPage_266" id="LPage_266"></a>[pg 266]</span> + </p> + <p class="center"> + <i>An admonition touching the four preceding Experiments.</i> + </p> + <p> + Having thus (<i>Pyrophilus</i>) given you divers Inſtances, to + countenance the General obſervation deliver'd in the twenty fifth + Experiment, and divers Exceptions whereby it ought to be Limited; I muſt + leave the further Inquiry into theſe Matters to your own Induſtry. + For not remembring at preſent many of thoſe other Trials, long + ſince made to ſatisfie my ſelf about Particulars, and not + having now the Opportunity to repeat them, I muſt content my Self to + have given you the Hint, and the ways of proſecuting the ſearch + your Self; and only declare to you in general, that, As I have made many + Trials, unmention'd in this Treatiſe, whoſe Events were + agreeable to thoſe mention'd in the twenty fifth Experiment, ſo + (to name now no other Inſtances) what I have try'd with Acid and + Sulphureous Salts upon the Pulp of Juniper Berries, rubb'd upon White + Paper, inclines me to think, That among that vaſt Multitude, and + ſtrange Variety of Plants that adorn the face of the Earth, perhaps + many other Vegetables may be found, on which ſuch <i>Menſtruums</i> + may not + <!-- Page 267 --> <span class="pagenum"><a name="LPage_267" + id="LPage_267"></a>[pg 267]</span> have ſuch Operations, as upon the + Juice of Violets, Peaſe-bloſſoms, &c. no nor upon any + of thoſe three other ſorts of Vegetables, that I have taken + notice of in the three fore-going Experiments. It ſufficiently + appearing ev'n by theſe, that the effects of a Salt upon the Juices + of particular Vegetables do very much depend upon their particular + Textures. + </p> + <h3> + <i>EXPERIMENT XXIX.</i> + </h3> + <p> + It may be of ſome Uſe towards the diſcovery of the nature + of theſe Changes, which the Alimental Juice receives in ſome + Vegetables, according to the differing degrees of their Maturity, and + according to the differing kinds of Plants of the ſame Denomination, + to obſerve what Operation Acid, Urinous, and Alcalizate Salts will + have upon the Juices of the ſeveral ſorts of the Vegetable + ſubſtances I have been mentioning. + </p> + <p> + To declare my meaning by an Example, I took from the ſame Cluſter, + one Blackberry full Ripe, and another that had not yet gone beyond a Redneſs, + and rubbing apiece of white Paper, with the former, I obſerv'd, that + the Juice adhering to it was of adark Reddiſh Colour, full of little + <!-- Page 268 --> <span class="pagenum"><a name="LPage_268" + id="LPage_268"></a>[pg 268]</span> Black Specks; and that this Juice by a + drop of a ſtrong <i>Lixivium</i>, was immediately turn'd into a + Greeniſh Colour deep enough, by as much Urinous Spirit into a Colour + much of Kin to the former, though ſomewhat differing, and fainter; + and by a drop of Spirit of Salt into a fine and lightſome Red: where + as the Red Berry being in like manner rubb'd upon Paper, left on it a Red + Colour, which was very little alter'd by the Acid Spirit newly nam'd, and + by the Urinous and Lixiviate Salts receiv'd changes of Colour differing + from thoſe that had been juſt before produc'd in the dark Juice + of the Ripe Blackberry. + </p> + <p> + I remember alſo, that though the Infuſion of Damask-Roſes + would as well, though not ſo much, as that of Red, be heightned by + Acid Spirits to an intenſe degree of Redneſs, and by Lixiviate + Salts be brought to a Darkiſh Green; yet having for Trials ſake + taken a Roſe, whoſe Leaves, which were large and numerous, like + thoſe of a Province Roſe, were perfectly Yellow, though in a + Solution of Salt of Tartar, they afforded a Green Blewiſh Tincture, + yet I did not by an Acid Liquor obtain a Red one; all that the Saline + Spirit I imploy'd, perform'd, being (if I much miſremember + <!-- Page 269 --> <span class="pagenum"><a name="LPage_269" + id="LPage_269"></a>[pg 269]</span> not) to Dilute Somewhat the Yellowneſs + of the Leaves. I would alſo have tried the Tincture of Yellow + Violets, but could procure none. And if I were in thoſe Iſlands + of <i>Banda</i>, which are made Famous as well as Rich, by being the almoſt + only places, where Cloves will proſper, I ſhould think it worth + my Curioſity to try, what Operation the three differing Kinds of + Salts, I have ſo often mention'd, would have upon the Juice of this + Spice, (expreſs'd at the ſeveral Seaſons of it) as it grows + upon the Tree. Since good Authors inform us, (of what is remarkable) that + theſe whether Fruits, or Rudiments of Fruits, are at firſt <i>White</i>, + afterward <i>Green</i>, and then <i>Reddiſh</i>, before they be + beaten off the Tree, after which being Dry'd before they are put up, they + grow <i>Blackiſh</i> as we ſee them. And one of the recenteſt + <i>Herbariſts</i> informs us, that the Flower grows upon the top of + the Clove it ſelf, conſiſting of four ſmall Leaves, + like a Cherry Bloſſom, but of an excellent <i>Blew</i>. But (<i>Pyrophilus</i>) + to return to our own Obſervations, I ſhall add, that I the + rather chooſe, to mention to you an Example drawn from Roſes, + becauſe that though I am apt to think, as I elſewhere advertiſe, + that ſomething may be gueſs'd at about + <!-- Page 270 --> <span class="pagenum"><a name="LPage_270" + id="LPage_270"></a>[pg 270]</span> ſome of the Qualities of the + Juices of Vegetables, by the Reſemblance or Diſparity that we + meet with in the Changes made of their Colours, by the Operation of the + ſame kinds of Salts; yet that thoſe Conjectures ſhould be + very warily made, may appear among other things, by the Inſtance I + have choſen to give in Roſes. For though, (as I formerly told + you) the Dry'd Leaves, both of the Damask, and of Red ones, give a Red + Tincture to Water ſharpen'd with Acid Salts, yet the one ſort of + Leaves is known to have a Purgative faculty,<a name="LNtA_20" id="LNtA_20_"></a><a + href="#LNt_20"><sup>20</sup></a> and the other are often, and divers ways, + imploy'd for Binding. + </p> + <p> + And I alſo chooſe (<i>Pyrophilus</i>) to ſubjoyn this + twenty ninth Experiment to thoſe that precede it, about the change of + the Colours of Vegetables by Salts, for theſe two reaſons: The + firſt, that you may not eaſily entertain Suſpitions, if in + the Trials of an Experiment of ſome of the Kinds formerly mention'd, + you ſhould meet with an Event ſomewhat differing from what my + Relations may have made you expect. And the ſecond, That you may + hereby be invited to diſcern, that it may not be amiſs to take + notice of the particular Seaſons wherein you gather the Vegetables + which + <!-- Page 271 --> <span class="pagenum"><a name="LPage_271" + id="LPage_271"></a>[pg 271]</span> in Nicer Experiments you make uſe + of. For, it I were not hindred both by haſte and ſome juſtifiable + Conſiderations, I could perhaps add conſiderable Inſtances, + to thoſe lately deliver'd, for the making out of this Obſervation; + but for certain reaſons I ſhall at preſent ſubſtitute + a remarkable paſſage to be met with in that Laborious Herbariſt + Mr. <i>Parkinſon</i>, where treating of the Virtues of the (already + divers times mention'd) Buckthorn Berries, he ſubjoyns the following + account of ſeveral Pigments that are made of them, not only according + to the ſeveral ways of Handling them, but according to the differing + Seaſons of Maturity, at which they are Gather'd; <i>Of theſe + Berries</i>, (ſays he) <i>are made three ſeveral ſorts of + Colours as they ſhall be gather'd, that is, being gather'd while they + are Green, and kept Dry, are call'd Sapberries, which being ſteep'd + into ſome Allom-water, or freſh bruis'd into Allom-water, they + give a reaſonable fair Yellow Colour which Painters uſe for + their Work, and Book-binders to Colour the edges of Books, and Leather-dreſſers + to Colour Leather, as they uſe alſo to make a Green Colour, + call'd Sap-green, taken from the Berries when they are Black, being + bruis'd and put into a Braſs or Copper Kettle or Pan, and there + ſuffer'd to abide three or four</i> + <!-- Page 272 --> <span class="pagenum"><a name="LPage_272" + id="LPage_272"></a>[pg 272]</span> <i>Days, or a little heated upon the + Fire, and ſome beaten Allom put unto them, and afterwards preſs'd + forth, the Juice or Liquor is uſually put in great Bladders tied with + ſtrong thred at the Head and hung up untill it be Dry, which is diſſolv'd + in Water or Wine, but Sack</i> (he affirms) <i>is the beſt to preſerve + the Colour from Starving, (as they call it) that is, from Decaying, and + make it hold freſh the longer. The third Colour (where of none</i> (ſays + he) <i>that I can find have made mention but only</i> Tragus<i>) is a + Purpliſh Colour, which is made of the Berries ſuffer'd to grow + upon the Buſhes untill the middle or end of</i> November, <i>that + they are ready to drop from the Trees.</i> + </p> + <p> + And, I remember (<i>Pyrophilus</i>) that I try'd, with a ſucceſs + that pleas'd me well enough, to make ſuch a kind of Pigment, as + Painters call Sap-green, by a way not unlike that, deliver'd here by our + Author, but I cannot now find any thing relating to that matter among my + looſe Papers. And my Trials were made ſo many years ago, that I + dare not truſt my Memory for Circumſtances, but will rather tell + you, that in a noted Colour-ſhop, I brought them by Queſtions to + confeſs to me, that they made their Sap-green much after the ways by + our <i>Botaniſt</i> here mention'd. And on this occaſion + <!-- Page 273 --> <span class="pagenum"><a name="LPage_273" + id="LPage_273"></a>[pg 273]</span> I ſhall add an Obſervation, + which though it does not ſtrictly belong to this place, may well + enough be mention'd here, namely, that I find by an account given us by + the Learned <i>Cluſius</i>, of <i>Alaternus</i>, that ev'n the Groſſer + Parts of the ſame Plant, are ſome of them one Colour, and ſome + another; For ſpeaking of that Plant, he tells us, that the <i>Portugalls</i> + uſe the Bark to Dye their Nets into a Red Colour, and with the Chips + of the Wood, which are Whitiſh, they Dye a Blackiſh Blew. + </p> + <h3> + <i>EXPERIMENT XXX.</i> + </h3> + <p> + Among the Experiments that tend to ſhew that the change of Colours in + Bodies may proceed from the Vary'd Texture of their Parts, and the conſequent + change of their Diſpoſition to Reflect or Refract the Light, + that ſort of Experiments muſt not be left unmention'd, which is + afforded us by Chymical Digeſtions. For, if <i>Chymiſts</i> will + believe ſeveral famous Writers about what they call the Philoſophers + Stone, they muſt acknowledge that the ſame Matter, ſeald up + Hermetically in a Philoſophical Egg, will by the continuance of Digeſtion, + or if they will have it ſo (for it is not Material in our caſe + which of the two it be) + <!-- Page 274 --> <span class="pagenum"><a name="LPage_274" + id="LPage_274"></a>[pg 274]</span> of Decoction, run through a great + Variety of differing Colours, before it come to that of the Nobleſt + <i>Elixir</i>; whether that be Scarlet, or Purple, or what ever other Kind + of Red. But without building any thing on ſo Obtruſe and Queſtionable + an Operation, (which yet may be pertinently repreſented to thoſe + that believe the thing) we may obſerve, that divers Bodies digeſted + in carefully-clos'd Veſſels, will in tract of time, change their + Colour: As I have elſewhere mention'd my having obſerv'd ev'n in + Rectify'd Spirit of Harts-horn, and as is evident in the Precipitations of + Amalgams of Gold, and Mercury, without Addition, where by the continuance + of a due Heat the Silver-Colour'd Amalgam is reduc'd into a ſhining + Red Powder. Further Inſtances of this Kind you may find here and + there in divers places of my other Eſſays. And indeed it has + been a thing, that has much contributed to deceive many <i>Chymiſts</i>, + that there are more Bodies than one, which by Digeſtion will be + brought to exhibit that Variety and Succeſſion of Colours, which + they imagine to be Peculiar to what they call the <i>True matter of the + Philoſophers</i>. But concerning this, I ſhall referr you to + what you may elſewhere find in the Diſcourſe written + touching the + <!-- Page 275 --> <span class="pagenum"><a name="LPage_275" + id="LPage_275"></a>[pg 275]</span> paſſive Deceptions of <i>Chymiſts</i>, + and more about the Production of Colours by Digeſtion you will meet + with preſently. Wherefore I ſhall now make only this Obſervation + from what has been deliver'd, That in theſe Operations there appears + not any cauſe to attribute the new Colours emergent to the Action of + a new Subſtantial form, nor to any Increaſe or Decrement of + either the Salt, Sulphur, or Mercury of the Matter that acquires new + Colours: For the Veſſels are clos'd, and theſe Principles + according to the <i>Chymiſts</i> are Ingenerable and Incorruptible; + ſo that the Effect ſeems to proceed from hence, that the Heat + agitating and ſhuffling the Corpuſcles of the Body expos'd to + it, does in proceſs of time ſo change its Texture, as that the + Tranſpoſed parts do Modifie the incident Light otherwiſe, + than they did when the Matter appear'd of another Colour. + </p> + <h3> + <i>EXPERIMENT XXXI.</i> + </h3> + <p> + Among the ſeveral changes of Colour, which Bodies acquire or diſcloſe + by Digeſtion, it it very remarkable, that <i>Chymiſts</i> find a + Redneſs rather than any other Colour in moſt of the Tinctures + they Draw, and ev'n in the more Groſs Solutions they + <!-- Page 276 --> <span class="pagenum"><a name="LPage_276" + id="LPage_276"></a>[pg 276]</span> make of almoſt all Concretes, that + abound either with Mineral or Vegetable Sulphur, though the <i>Menſtruum</i> + imploy'd about theſe Solutions or Tinctures be never ſo Limpid + or Colourleſs. + </p> + <p> + This we have obſerv'd in I know not how many Tinctures drawn with + Spirit of Wine from <i>Jalap</i>, <i>Guaicum</i>, and ſeveral other + Vegetables; and not only in the Solutions of <i>Amber</i>, <i>Benzoin</i>, + and divers other Concretes made with the ſame <i>Menſtruum</i>, + but alſo in divers Mineral Tinctures. And, not to urge that familiar + Inſtance of the Ruby of Sulphur, as <i>Chymiſts</i> upon the + ſcore of its Colour, call the Solution of Flowers of Brimſtone, + made with the Spirit of Turpentine, nor to take notice of other more known + Examples of the aptneſs of Chymical Oyls, to produce a Red Colour + with the Sulphur they extract, or diſſolve; not to inſiſt + (I ſay) upon Inſtances of this nature, I ſhall further + repreſent to you, as a thing remarkable, that, both Acid and + Alcalizate Salts, though in moſt other caſes of ſuch + contrary Operations, in reference to Colours, will with many Bodies that + abound with Sulphureous, or with Oyly parts, produce a Red; as is manifeſt + partly in the more Vulgar Inſtances of the Tinctures, or Solutions of + <!-- Page 277 --> <span class="pagenum"><a name="LPage_277" + id="LPage_277"></a>[pg 277]</span> Sulphur made with <i>Lixiviums</i>, + either of Calcin'd Tartar or Pot-aſhes, and other Obvious examples, + partly by this, that the true Glaſs of Antimony extracted with ſome + Acid Spirits, with or without Wine, will yield a Red Tincture, and that I + know an Acid Liquor, which in a moment will turn Oyl of Turpentine into a + deep Red. But among the many Inſtances I could give you of the eaſie + Production of Redneſs by the Operation of Saline Spirit, as well as + of Spirit of Wine; I remember two or three of thoſe I have tried, + which ſeem remarkable enough to deſerve to be mention'd to you + apart. + </p> + <h3> + <i>EXPERIMENT XXXII.</i> + </h3> + <p> + But before we ſet them down, it will not perhaps appear impertinent + to premiſe; + </p> + <p> + That there ſeems to be a manifeſt Diſparity betwixt Red + Liquors, ſo that ſome of them may be ſaid to have a Genuine + Redneſs in compariſon of others, that have a Yellowiſh + Redneſs: For if you take (for example) a good Tincture of <i>Chochineel</i>, + dilute it never ſo much with fair Water, you will not (as far as I + can judge by what I have tried) be able to make it a Yellow Liquor. Inſomuch + that a Single + <!-- Page 278 --> <span class="pagenum"><a name="LPage_278" + id="LPage_278"></a>[pg 278]</span> drop of a rich Solution of <i>Cochineel</i> + in Spirit of Urine, being Diluted with above an Ounce of fair Water, + exhibited no Yellowiſhneſs at all, but a fair (though ſomewhat + faint) Pinck or Carnation; and even when <i>Cochineel</i> was by degrees + Diluted much beyond the newly mention'd Colour, by the way formerly + related to you in the twenty fourth Experiment, I remember not, that there + appear'd in the whole Trial any Yellow. But if you take Balſom of + Sulphur (for Inſtance) though it may appear in a Glaſs, where it + has a good Thickneſs, to be of a deep Red, yet if you ſhake the + Glaſs, or pour a few drops on a ſheet of White Paper, ſpreading + them on it with your Finger, the Balſom that falls back along the + ſides of the Glaſs, and that which ſtains the Paper, will + appear Yellow, not Red. And there are divers Tinctures, ſuch as that + of Amber made with Spirit of Wine, (to name now no more) that will appear + either Yellow or Red, according as the Veſſels that they fill, + are Slender or Broad. + </p> + <h3> + <i>EXPERIMENT XXXIII.</i> + </h3> + <p> + But to proceed to the Experiments I was about to deliver; <i>Firſt</i>; + Oyl or Spirit + <!-- Page 279 --> <span class="pagenum"><a name="LPage_279" + id="LPage_279"></a>[pg 279]</span> of Turpentine, though clear as fair + Water, being Digeſted upon the purely White Sugar of Lead, has, in a + ſhort time, afforded us a high Red Tincture, that ſome Artiſts + are pleas'd to call the Balſom of <i>Saturn</i>, which they very much + (and probably not altogether without cauſe) extoll as an excellent + Medicine in divers Outward affections. + </p> + <h3> + <i>EXPERIMENT XXXIV.</i> + </h3> + <p> + <i>Next</i>, take of common Brimſtone finely powdred five Ounces, of + Sal-Armoniack likewiſe pulveriz'd an equal weight, of beaten + Quick-lime ſix Ounces, mix theſe Powders exquiſitely, and + Diſtill them through a Retort plac'd in Sand by degrees of Fire, + giving at length as intenſe a Heat as you well can in Sand, there + will come over (if you have wrought well) a Volatile Tincture of Sulphur, + which may probably prove an excellent Medicine, and ſhould have been + mention'd among the other Preparations of Sulphur, which we have elſewhere + imparted to you, but that it is very pertinent to our preſent + Subject, The change of Colours. For though none of the Ingredients be Red, + the Diſtill'd Liquor will be ſo: and this Liquor if it + <!-- Page 280 --> <span class="pagenum"><a name="LPage_280" + id="LPage_280"></a>[pg 280]</span> be well Drawn, will upon a little + Agitation of the Vial firſt unſtop'd (eſpecially if it be + held in a Warmer hand) lend forth a copious Fume, not Red, like that of + Nitre, but White; And ſometimes this Liquor may be ſo Drawn, + that I remember, not long ſince, I took pleaſure to obſerve + in a parcel of it, that Ingredients not Red, did not only yield by Diſtillation + a Volatile Spirit that was Red, but though that Liquor did upon the bare + opening of the Bottle it was kept in, drive us away with the plenty and + ſulphureous ſent of a White ſteam which it ſent forth, + yet the Liquor it ſelf being touch'd by our Fingers, did immediately + Dye them Black. + </p> + <h3> + <i>EXPERIMENT XXXV.</i> + </h3> + <p> + The third and <i>laſt</i> Experiment I ſhall now mention to + ſhew, how prone Bodies abounding in Sulphureous parts are to afford a + Red Colour, is one, wherein by the Operation of a Saline Spirit upon a + White or Whitiſh Body, which according to the <i>Chymiſts</i> + ſhould be altogether Sulphureous, a Redneſs may be produc'd, not + (as in the former Experiments) ſlowly, but in the twinkling of an + Eye. We took then of the Eſſential Oyl of Anniſeeds, + <!-- Page 281 --> <span class="pagenum"><a name="LPage_281" + id="LPage_281"></a>[pg 281]</span> which has this Peculiarity, that in + Cold weather it loſes its Fluidity and the greateſt part of its + Tranſparency, and looks like a White or Whitiſh Oyntment, and + near at hand ſeems to conſiſt of a Multitude of little + ſoft Scales: Of this Coagulated Stuff we ſpread a little with a + Knife upon a piece of White Paper, and letting fall on it, and mixing with + it a drop or two of Oyl of Vitriol, immediately (as we fore-ſaw) + there emerg'd together with ſome Heat and Smoak, a Blood-Red Colour, + which therefore was in a trice produc'd by two Bodies, whereof the one had + but a Whitiſh Colour, and the other (if carefully rectify'd) had no + Colour at all. + </p> + <h3> + <i>EXPERIMENT XXXVI.</i> + </h3> + <p> + But on this Occaſion (<i>Pyrophilus</i>) we muſt add once for + all, that in many of the above-recited Experiments, though the changes of + Colour happen'd as we have mention'd them: yet the emergent or produc'd + Colour is oft times very ſubject to Degenerate, both quickly and + much. Notwithſtanding which, ſince the Changes, we have ſet + down, do happen preſently upon the Operation of the Bodies upon each + other, or at the times by us ſpecify'd; + <!-- Page 282 --> <span class="pagenum"><a name="LPage_282" + id="LPage_282"></a>[pg 282]</span> <i>that</i> is ſufficient both to + juſtifie our Veracity, and to ſhew what we Intend; it not being + Eſſential to the Genuineneſs of a Colour to be Durable. For + a fading Leaf, that is ready to Rot, and moulder into Duſt, may have + as true a Yellow, as a Wedge of Gold, which ſo obſtinately reſiſts + both Time and Fire. And the reaſon, why I take occaſion from the + former Experiment to ſubjoyn this general Advertiſement, is, + that I have ſeveral times obſerv'd, that the Mixture reſulting + from the Oyls of Vitriol, and of Anniſeeds, though it acquire a + thicker conſiſtence than either of the Ingredients had, has + quickly loſt its Colour, turning in a very ſhort time into a + dirty Gray, at leaſt in the Superficial parts, where 'tis expos'd to + the Air; which laſt Circumſtance I therefore mention, becauſe + that, though it ſeem probable, that this Degeneration of Colours may + oft times and in divers caſes proceed from the further Action of the + Saline Corpuſcles, and the other Ingredients upon one another, yet in + many caſes much of the Quick change of Colours ſeems aſcribeable + to the Air, as may be made probable by ſeveral reaſons: The firſt + whereof may be fetcht from the newly recited Example of the two Oyls; The + next may be, that we have ſometimes obſerv'd + <!-- Page 283 --> <span class="pagenum"><a name="LPage_283" + id="LPage_283"></a>[pg 283]</span> long Window-Curtains of light Colours, + to have that part of them, which was expos'd to the Air, when the Window + was open, of one Colour, and the lower part, that was ſheltred from + the Air by the Wall, of another Colour: And the third Argument may be + fetch'd from divers Obſervations, both of others, and our own; For of + that Pigment ſo well known in Painters Shops, by the name of <i>Turnſol</i>, + our Induſtrious <i>Parkinſon</i>, in the particular account he + gives of the Plant that bears it, tells us alſo, That <i>the Berries + when they are at their full Maturity, have within them between the outer + Skin and the inward Kirnel or Seed, a certain Juice or Moiſture, + which being rubb'd upon Paper or Cloath, at the first appears of a freſh + and lovely Green Colour, but preſently changeth into a kind of Blewiſh + Purple, upon the Cloath or Paper, and the ſame Cloath afterwards wet + in Water, and wrung forth, will Colour the Water into a Claret Wine + Colour, and theſe</i> (concludes he) <i>are thoſe Raggs of + Cloath, which are uſually call'd</i> Turnſol <i>in the Druggiſts + or Grocers Shops</i><a name="LNtA_21" id="LNtA_21_"></a><a href="#LNt_21"><sup>21</sup></a>. + And to this Obſervation of our <i>Botanist</i> we will add an + Experiment of our own, (made before we met with That) which, though in + many Circumſtances, very + <!-- Page 284 --> <span class="pagenum"><a name="LPage_284" + id="LPage_284"></a>[pg 284]</span> differing, ſerves to prove the + ſame thing; for having taken of the deeply Red Juice of <i>Buckthorn</i> + Berries, which I bought of the Man that uſes to ſell it to the + Apothecaries, to make their Syrrup <i>de Spina Cervina</i>, I let ſome + of it drop upon a piece of White Paper, and having left it there for many + hours, till the Paper was grown dry again, I found what I was inclin'd to + ſuſpect, namely, That this Juice was degenerated from a deep Red + to a dirty kind of Greyiſh Colour, which, in a great part of the + ſtain'd Paper ſeem'd not to have ſo much as an Eye of Red: + Though a little Spirit of Salt or diſſolv'd <i>Alcaly</i> would + turn this unpleaſant Colour (as formerly I told you it would change + the not yet alter'd Juice) into a Red or Green. And to ſatisfie my + ſelf, that this Degeneration of Colour did not proceed from the + Paper, I drop'd ſome of the deep Red or Crimſon Juice upon a + White glaz'd Tile, and ſuffering it to dry on there, I found that + ev'n in that Body, on which it could not Soak, and by which it could not + be Wrought, it nevertheleſs loſt its Colour. And theſe Inſtances + (<i>Pyrophilus</i>) I am the more carefull to mention to you, that you may + not be much Surpris'd or Diſcourag'd, if you ſhould ſometimes + miſs of performing + <!-- Page 285 --> <span class="pagenum"><a name="LPage_285" + id="LPage_285"></a>[pg 285]</span> punctually what I affirm my ſelf + to have done in point of changing Colours; ſince in theſe + Experiments the over-ſight or neglect of ſuch little Circumſtances, + as in many others would not be perhaps conſiderable, may occaſion + the mis-carrying of a Trial. And I was willing alſo to take this occaſion + of Advertiſing you in the repeating of the Experiments mention'd in + this Treatiſe, to make uſe of the Juices of Vegetables, and + other things prepar'd for your Trials, as ſoon as ever they are + ready, leſt one or other of them grow leſs fit, if not quite + unfit by delay; and to eſtimate the Event of the Trials by the + Change, that is produc'd preſently upon the due and ſufficient + Application of Actives to Paſſives, (as they ſpeak) becauſe + in many caſes the effects of ſuch Mixtures may not be laſting, + and the newly produc'd Colour may in a little time degenerate. But, (<i>Pyrophilus</i>) + I forgot to add to the two former Obſervations lately made about + Vegetables, a third of the ſame Import, made in Mineral ſubſtances, + by telling you, That the better to ſatisfie a Friend or two in this + particular, I ſometimes made, according to ſome Conjectures of + mine, this Experiment; That having diſſolv'd good Silver in <i>Aqua-fortis</i>, + and Precipitated it with Spirit of Salt, upon + <!-- Page 286 --> <span class="pagenum"><a name="LPage_286" + id="LPage_286"></a>[pg 286]</span> the firſt Decanting of the Liquor, + the remaining Matter would be purely White; but after it had lain a while + uncover'd, that part of it, that was Contiguous to the Air, would not only + loſe its Whiteneſs, but appear of a very Dark and almoſt + Blackiſh Colour, I ſay that part that was Contiguous to the Air, + becauſe if that were gently taken off, the Subjacent part of the + ſame Maſs would appear very White, till that alſo, having + continu'd a while expos'd to the Air, would likewiſe Degenerate. Now + whether the Air perform theſe things by the means of a Subtile Salt, + which we elſewhere ſhow it not to be deſtitute of, or by a + peircing Moiſture, that is apt eaſily to inſinuate it + ſelf into the Pores of ſome Bodies, and thereby change their + Texture, and ſo their Colour; Or by ſolliciting the Avolation of + certain parts of the Bodies, to which 'tis Contiguous; or by ſome + other way, (which poſſibly I may elſewhere propoſe and + conſider) I have not now the leiſure to diſcourſe. And + for the ſame reaſon, though I could add many other Inſtances, + of what I formerly noted touching the emergency of Redneſs upon the + Digeſtion of many Bodies, inſomuch that I have often ſeen + upon the Borders of <i>France</i> (and probably we may have the like in + <!-- Page 287 --> <span class="pagenum"><a name="LPage_287" + id="LPage_287"></a>[pg 287]</span> <i>England</i>) a ſort of Pears, + which digeſted for ſome time with a little Wine, in a Veſſel + exactly clos'd, will in not many hours appear throughout of a deep Red + Colour, (as alſo that of the Juice, wherein they are Stew'd, becomes) + but ev'n on pure and white Salt of Tartar, pure Spirit of Wine, as clear + as Rock-water, will (as we elſewhere declare) by long Digeſtion + acquire a Redneſs; Though I ſay ſuch Inſtances might + be Multiply'd, and though there be ſome other Obvious changes of + Colours, which happen ſo frequently, that they cannot but be as well + Conſiderable as Notorious; ſuch as is the Blackneſs of almoſt + all Bodies burn'd in the open Air: yet our haſte invites us to reſign + you the Exerciſe of enquiring into the Cauſes of theſe + Changes. And certainly, the reaſon both <i>why</i> the Soots of + ſuch differing Bodies are almoſt all of them all Black, <i>why</i> + ſo much the greater part of Vegetables ſhould be rather Green + than of any other Colour, and particularly (which more directly concerns + this place) <i>why</i> gentle Heats do ſo frequently in Chymical + Operations produce rather a Redneſs than another Colour in digeſted + <i>Menſtruums</i>, not only Sulphureous, as Spirit of Wine, but + Saline, as Spirit of Vinegar, may be very well worth + <!-- Page 288 --> <span class="pagenum"><a name="LPage_288" + id="LPage_288"></a>[pg 288]</span> a ſerious Inquiry; which I ſhall + therefore recommend to <i>Pyrophilus</i> and his Ingenious Friends. + </p> + <h3> + <i>EXPERIMENT XXXVII.</i> + </h3> + <p> + It may ſeem ſomewhat ſtrange, that if you take the Crimſon + Solution of <i>Cochineel</i>, or the Juice of Black Cherries, and of + ſome other Vegetables that afford the like Colour, (which becauſe + many take but for a deep Red, we do with them ſometimes call it + ſo) and let ſome of it fall upon a piece of Paper, a drop or two + of an Acid Spirit, ſuch as Spirit of Salt, or <i>Aqua-fortis</i>, + will immediately turn it into a fair Red. Whereas if you make an Infuſion + of Brazil in fair Water, and drop a little Spirit of Salt or <i>Aqua-fortis</i> + into it, that will deſtroy its Redneſs, and leave the Liquor of + a Yellow, (ſometimes Pale) I might perhaps plauſibly enough + ſay on this occaſion, that if we conſider the caſe a + little more attentively, we may take notice, that the action of the Acid + Spirit ſeems in both caſes, but to weaken the Colour of the + Liquor on which it falls. And ſo though it deſtroy Redneſs + in the Tincture of Brazil, as well as produce Red in the Tincture of <i>Chochineel</i>, + its Operations may be Uniform + <!-- Page 289 --> <span class="pagenum"><a name="LPage_289" + id="LPage_289"></a>[pg 289]</span> enough, ſince as Crimſon + ſeems to be little elſe than a very deep Red, with (perhaps) an + Eye of Blew, ſo ſome kinds of Red ſeem (as I have lately + noted) to be little elſe than heightned Yellow. And conſequently + in ſuch Bodies, the Yellow ſeems to be but a diluted Red. And + accordingly Alcalizate Solutions and Urinous Spirits, which ſeem diſpos'd + to Deepen the Colours of the Juices and Liquors of moſt Vegetables, + will not only reſtore the Solution of <i>Cochineel</i> and the Infuſion + of Brazil to the Crimſon, whence the Spirit of Salt had chang'd them + into a truer Red; but will alſo (as I lately told you) not only + heighthen the Yellow Juice of Madder into Red, but advance the Red Infuſion + of Brazil to a Crimſon. But I know not whether it will not be much + ſafer to derive theſe Changes from vary'd Textures, than certain + kinds of Bodies; and you will perhaps think it worth while, that I ſhould + add on this occaſion, That it may deſerve ſome Speculation, + why, notwithſtanding what we have been obſerving, though Blew + and Purple ſeem to be deeper Colours than Red, and therefore the + Juices of Plants of either of the two former Colours may (congruouſly + enough to what has been juſt now noted) be turn'd Red by + <!-- Page 290 --> <span class="pagenum"><a name="LPage_290" + id="LPage_290"></a>[pg 290]</span> Spirit of Salt or <i>Aqua-fortis</i>, + yet Blew Syrrup of Violets and ſome Purples ſhould both by Oyl + of Tartar and Spirit of Urine be chang'd into Green, which ſeems to + be not a deeper but a more diluted Colour than Blew, if not alſo than + Purple. + </p> + <h3> + <i>EXPERIMENT XXXVIII.</i> + </h3> + <p> + It would much contribute to the Hiſtory of Colours, if <i>Chymiſts</i> + would in their Laboratories take a heedfull notice, and give us a + faithfull account of the Colours obſerv'd in the Steams of Bodies + either Sublim'd or Diſtill'd, and of the Colours of thoſe + Productions of the Fire, that are made up by the Coalition of thoſe + Steams. As (for Inſtance) we obſerve in the Diſtilling of + pure Salt peter, that at a certain ſeaſon of the Operation, the + Body, though it ſeem either Cryſtalline, or White, affords very + Red Fumes: whereas though Vitriol be Green or Blew, the Spirit of it is obſerv'd + to come over in Whitiſh Fumes. The like Colour I have taken notice of + in the Fumes of ſeveral other Concretes of differing Colours, and + Natures, eſpecially when Diſtill'd with ſtrong Fires. And + we elſewhere note, that ev'n Soot, as Black as it is, has fill'd our + Receivers + <!-- Page 291 --> <span class="pagenum"><a name="LPage_291" + id="LPage_291"></a>[pg 291]</span> with ſuch copious White Fumes, + that they ſeem'd to have had their In-ſides waſh'd with + Milk. And no leſs obſervable may be, the Diſtill'd Liqours, + into which ſuch Fumes convene, (for though we will not deny, that by + skill and care a Reddiſh Liqour may be obtain'd from Nitre) yet the + common Spirit of it, in the making ev'n of which ſtore of theſe + Red Fumes are wont to paſs over into the Receiver, appears not to be + at all Red. And beſides, that neither the Spirit of Vitriol, nor that + of Soot is any thing White; And, beſides alſo, that as far as I + have obſerv'd, moſt (for I ſay not all) of the + Empyreumatical Oyls of Woods, and other Concretes, are either of a deep + Red, or of a Colour between Red and Black; beſides this, I ſay, + 'tis very remarkable that notwithſtanding that great Variety of + Colours to be met with in the Herbs, Flowers, and other Bodies wont to be + Diſtill'd in <i>Balneo</i>: yet (as far at leaſt as our common + Diſtillers Experience reacheth) all the Waters and Spirits that firſt + come over by that way of Diſtillation, leave the Colours of their + Concretes behind them, though indeed there be one or two Vegetables not + commonly taken notice of, whoſe Diſtill'd Liqours I elſewhere + obſerve to carry over + <!-- Page 292 --> <span class="pagenum"><a name="LPage_292" + id="LPage_292"></a>[pg 292]</span> the Tincture of the Concrete with them. + And as in Diſtillations, ſo in Sublimations, it were worth while + to take notice of what comes up, in reference to our preſent ſcope, + by purpoſely performing them (as I have in ſome cafes done) in + conveniently ſhap'd Glaſſes, that the Colour of the aſcending + Fumes may be diſcern'd; For it may afford a Naturaliſt good + Information to obſerve the Congruities or the Differences betwixt the + Colours of the aſcending Fumes, and thoſe of the <i>Flowers</i>, + they compoſe by their Convention. For it is evident, that theſe + <i>Flowers</i>, do many of them in point of Colour, much differ, not only + from one another, but oft times from the Concretes that afforded them. + Thus, (not here to repeat what I formerly noted of the Black Soots of very + differingly Colour'd Bodies) though Camphire and Brimſtone afford <i>Flowers</i> + much of their own Colour, ſave that thoſe of Brimſtone are + wont to be a little Paler, than the Lumps that yielded them; yet ev'n of + Red <i>Benzoin</i>, that ſublim'd Subſtance, which <i>Chymiſts</i> + call its <i>Flowers</i>, is wont to be White or Whitiſh. And to omit + other Inſtances, ev'n one and the ſame Black Mineral, Antimony, + may be made to afford <i>Flowers</i>, ſome of them Red, and ſome + Grey, and, which is more ſtrange, + <!-- Page 293 --> <span class="pagenum"><a name="LPage_293" + id="LPage_293"></a>[pg 293]</span> ſome of them purely White. And + 'tis the Preſcription of ſome Glaſs-men by exquiſitely + mingling a convenient proportion of Brimſtone, Sal-Armoniack, and + Quickſilver, and Subliming them, together, to make a Sublimate of an + excellent Blew; and though having caus'd the Experiment to be made, we + found the produc'd Sublimate to be far from being of a lovely Colour, (as + was promis'd) that there and there, it ſeem'd Blewiſh, and at + leaſt was of a Colour differing enough from either of the + Ingredients, which is ſufficient for our preſent purpoſe. + But a much finer Colour is promis'd by ſome of the Empiricks, that + pretend to Secrets, who tell us, that Orpiment, being Sublim'd, will + afford among the Parts of it that fly Upward, ſome little Maſſes, + which, though the Mineral it ſelf be of a good Yellow, will be Red + enough to emulate Rubies, both in Colour and Tranſlucency. And this + Experiment may, for ought I know, ſometimes ſucceed; for I + remember, that having in a ſmall Bolt-head purpoſely ſublim'd + ſome powder'd Orpiment, we could in the Lower part of the Sublimate + diſcern here and there ſome Reddiſh Lines, though much of + the Upper part of the Sublimate conſiſted of a matter, which was + not alone purely + <!-- Page 294 --> <span class="pagenum"><a name="LPage_294" + id="LPage_294"></a>[pg 294]</span> Yellow, but tranſparent almoſt + like a Powder. And we have alſo this way obtain'd a Sublimate, the + Lower part whereof though it conſiſted not of Rubies, yet the + ſmall pieces of it, which were Numerous enough, were of a pleaſant + Reddiſh Colour, and Glitter'd very prettily. But to inſiſt + on ſuch kind of Trials and Obſervations (where the aſcending + Fumes of Bodies differ in Colour from the Bodies themſelves) though + it might indeed Inrich the Hiſtory of Colours, would Robb me of too + much of the little time I have to diſpatch what I have further to + tell you concerning them. + </p> + <h3> + <i>EXPERIMENT XXXIX</i> + </h3> + <p> + Take the dry'd Buds (or Bloſſoms) of the Pomegranate Tree, + (which are commonly call'd in the Shops <i>Balauſtiums</i>) pull off + the Reddiſh Leaves, and by a gentle Ebullition of them in fair Water, + or by a competent Infuſion of them in like Water well heated, extract + a faint Reddiſh Tincture, which if the Liquor be turbid, you may + Clarifie it by Filtrating it Into this, if you pour a little good Spirit + of Urine, or ſome other Spirit abounding in the like ſort of + Volatile Salts, the Mixture will + <!-- Page 295 --> <span class="pagenum"><a name="LPage_295" + id="LPage_295"></a>[pg 295]</span> preſently turn of a dark Greeniſh + Colour, but if inſtead of the fore-mention'd Liquor, you drop into + the ſimple Infuſion a little rectify'd Spirit of Sea-Salt, the + Pale and almoſt Colourleſs Liquor will immediately not only grow + more Tranſparent, but acquire a high Redneſs, like that of Rich + Claret Wine, which ſo ſuddenly acquir'd Colour, may as quickly + be Deſtroy'd and turn'd into a dirty Blewiſh Green, by the affuſion + of a competent quantity of the above-mention'd Spirit of Urine. + </p> + <p class="center"> + <i>Annotation.</i> + </p> + <p> + This Experiment may bring ſome Light to, and receive ſome from a + couple of other Experiments, that I remember I have met with in the + ingenious <i>Gaſſendus</i>'s Animadverſions upon <i>Epicurus</i>'s + Philoſophy, whilſt I was turning over the Leaves of thoſe + Learned Commentaries; (my Eyes being too weak to let me read ſuch + Voluminous Books quite thorough) And I the leſs ſcruple (notwithſtanding + my contrary Cuſtom in this Treatiſe) to ſet down theſe + Experiments of another, becauſe I ſhall a little improve the + latter of them, and becauſe by comparing there with that which I have + laſt recited, we may be aſſiſted to Conjecture + <!-- Page 296 --> <span class="pagenum"><a name="LPage_296" + id="LPage_296"></a>[pg 296]</span> upon what account it is, that Oyl of + Vitriol heightens the Tincture of Red-roſe Leaves, ſince Spirit + of Salt, which is a highly Acid <i>Menſtruum</i>, but otherwiſe + differing enough from Oyl of Vitriol, does the ſame thing. Our + Authors Experiments then, as we made them, are theſe; We took about a + Glaſs-full of luke-warm Water, and in it immerg'd a quantity of the + Leaves of <i>Senna</i>, and preſently upon the Immerſion there + did not appear any Redneſs in the Water, but dropping into it a + little Oyl of Tartar, the Liquor ſoon diſcover'd a Redneſs + to the watchfull Eye, whereas by a little of that Acid Liquor of Vitriol, + which is like the former, undeſervedly called Oyl, ſuch a Colour + would not be extracted from the infuſed <i>Senna</i>. On the other + ſide we took ſome Red-roſe Leaves dry'd, and having ſhaken + them into a Glaſs of fair Water, they imparted to it no Redneſs, + but upon the affuſion of a little Oyl of Vitriol the Water was + immediately turn'd Red, which it would not have been, if inſtead of + Oyl of Vitriol, we had imployed Oyl of Tartar to produce that Colour: That + theſe were <i>Gaſſendus</i> his Experiments, I partly + remember, and was aſſur'd by a Friend, who lately Tranſcribed + them out of <i>Gaſſendus</i> his Book, which I + <!-- Page 297 --> <span class="pagenum"><a name="LPage_297" + id="LPage_297"></a>[pg 297]</span> therefore add, becauſe I have not + now that Book at hand. And the deſign of <i>Gaſſendus</i> + in theſe Experiments our Friend affirms to be, to prove, that of + things not Red a Redneſs may be made only by Mixture, and the Varied + poſition of parts, wherein the Doctrine of that Subtil Philoſopher + doth not a little Authorize, what we have formerly delivered concerning + the Emergency and Change of Colours. But the inſtances, that we have + out of him ſet down, ſeem not to be the moſt Eminent, that + may be produced of this truth: For our next Experiment will ſhew the + production of ſeveral Colours out of Liquors, which have not any of + them any ſuch Colour, nor indeed any diſcernable one at all; and + whereas though our Author tells us, that there was no Redneſs either + in the Water, or the Leaves of <i>Senna</i>, or the Oyl of Tartar; And + though it be true, that the Predominant Colour of the Leaves of <i>Senna</i> + be another than Red, yet we have try'd, that by ſteeping that Plant a + Night even in Cold water, it would afford a very deep Yellow or Reddiſh + Tincture without the help of the Oyl of Tartar, which ſeems to do + little more than aſſiſt the Water to extract more nimbly a + plenty of that Red Tincture, wherewith the Leaves of <i>Senna</i> + <!-- Page 298 --> <span class="pagenum"><a name="LPage_298" + id="LPage_298"></a>[pg 298]</span> do of themſelves abound, and + having taken off the Tincture of <i>Senna</i>, made only with fair Water, + before it grew to be Reddiſh, and Decanted it from the Leaves, we + could not perceive, that by dropping ſome Oyl of Tartar into it, that + Colour was conſiderable, though it were a little heightned into a + Redneſs; which might have been expected, if the particles of the Oyl + did eminently Co-operate, otherwiſe than we have expreſſed, + to the production of this Redneſs. + </p> + <p> + And as for the Experiment with Red-roſe Leaves, the ſame thing + may be alleged, for we found that ſuch Leaves by bare Infuſion + for a Night and Day in fair Water, did afford us a Tincture bordering at + leaſt upon Redneſs, and that Colour being conſpicuous in + the Leaves themſelves, would not by ſome ſeem ſo much + to be produc'd as to be extracted by the affuſion of Oyl of Vitriol. + And the Experiment try'd with the dry'd Leaves of Damask-roſes ſucceeded + but imperfectly, but that is indeed obſervable to our Authors purpoſe, + that Oyl of Tartar will not perform in this Experiment what Oyl of Vitriol + doth; but becauſe this laſt named Liquor is not ſo eaſily + to be had, give me leave to Advertiſe you, that the Experiment will + ſucceed, + <!-- Page 299 --> <span class="pagenum"><a name="LPage_299" + id="LPage_299"></a>[pg 299]</span> if inſtead of it you imploy <i>Aqua-fortis</i>. + And though ſome Trials of our own formerly made, and others eaſily + deducible from what we have already deliver'd, about the different + Families and Operations of Salt, might enable us to preſent you an + Experiment upon Red-roſe Leaves, more accommodated to our Authors + purpoſe, than that which he hath given us; yet our Reverence to + ſo Candid a Philoſopher, invites us rather to improve his + Experiment, than ſubſtitute another in its place. Take therefore + of the Tincture of Red-roſe Leaves, (for with Damask-roſe Leaves + the Experiment ſucceedeth not well) made as before hath been taught + with a little Oyl of Vitriol, and a good quantity of fair Water, pour off + this Liquor into a clear Vial, half fill'd with Limpid water; till the + Water held againſt the Light have acquir'd a competent Redneſs, + without loſing its Tranſparency, into this Tincture drop leiſurely + a little good Spirit of Urine, and ſhaking the Vial, which you muſt + ſtill hold againſt the Light, you ſhall ſee the Red + Liquor immediately turn'd into a fine Greeniſh Blew, which Colour was + not to be found in any of the Bodies, upon whoſe Mixture it emerg'd, + and this Change is the more obſervable, becauſe in many Bodies + <!-- Page 300 --> <span class="pagenum"><a name="LPage_300" + id="LPage_300"></a>[pg 300]</span> the Degenerating of Blew into Red is uſual + enough, but the turning of Red into Blew is very unfrequent. If at every + drop of Spirit of Urine you ſhake the Vial containing the Red + Tincture, you may delightfully obſerve a pretty variety of Colours in + the paſſage of that Tincture from a Red to a Blew, and ſometimes + we have this way hit upon ſuch a Liquor, as being look't upon againſt + and from the Light, did ſeem faintly to emulate the above-mention'd + Tincture of <i>Lignum Nephriticum</i>. And if you make the Tincture of + Red-roſes very high, and without Diluting it with fair Water, pour on + the Spirit of Urine, you may have a Blew ſo deep, as to make the + Liquor Opacous, but being dropt upon White Paper the Colour will ſoon + diſcloſe it ſelf. Alſo having made the Red, and conſequently + the Blew Tincture very Tranſparent, and ſuffer'd it to reſt + in a ſmall open Vial for a Day or two, we found according to our + Conjecture, that not only the Blew but the Red Colour alſo was Vaniſh'd; + the clear Liquor being of a bright Amber Colour, at the bottom of which + ſubſided a Light, but Copious feculency of almoſt the + ſame Colour, which ſeems to be nothing but the Tincted parts of + the Roſe Leaves drawn out by the Acid + <!-- Page 301 --> <span class="pagenum"><a name="LPage_301" + id="LPage_301"></a>[pg 301]</span> Spirits of the Oyl of Vitriol, and + Precipitated by the Volatile Salt of the Spirit of Urine, which makes it + the more probable, that the Redneſs drawn by the Oyl of Vitriol, was + at leaſt as well an extraction of the Tinging parts of the Roſes, + as a production of Redneſs; and laſtly, if you be deſtitute + of Spirit of Urine, you may change the Colour of the Tincture of Roſes + with many other Sulphureous Salts, as a ſtrong Solution of Pot-aſhes, + Oyl of Tartar, &c. which yet are ſeldome ſo free from + Feculency, as the Spirituous parts of Urine becomes by repeated Diſtillation. + </p> + <p class="center"> + <i>Annotation</i>. + </p> + <p> + On this, occaſion, I call to mind, that I found, a way of producing, + though not the ſame kind of Blew, as I have been mentioning, yet a + Colour near of Kin to it, namely, a fair Purple, by imploying a Liquor not + made Red by Art, inſtead of the Tincture of Red-roſes, made with + an Acid Spirit; And my way was only to take Log-wood, (a Wood very well + known to Dyers) having by Infuſion the Powder of it a while in fair + Water made that Liquor Red, I dropt into it a <i>Tantillum</i> of an + Urinous Spirit, as that of Sal-Armoniack, + <!-- Page 302 --> <span class="pagenum"><a name="LPage_302" + id="LPage_302"></a>[pg 302]</span> (and I have done the ſame thing + with an <i>Alcali</i>) by which the Colour was in a moment turn'd into a + Rich, and lovely Purple. But care muſt be had, that you let not fall + into a Spoonfull above two or three Drops, leſt the Colour become + ſo deep, as to make the Liquor too Opacous. And (to anſwer the + other part of <i>Gaſſendus</i> his Experiment) if inſtead + of fair Water, I infus'd the Log-wood in Water made ſomewhat ſowr + by the Acid Spirit of Salt, I ſhould obtain neither a Purple Liquor, + nor a Red, but only a Yellow one. + </p> + <h3> + <i>EXPERIMENT XL.</i> + </h3> + <p> + The Experiment I am now to mention to you, <i>Pyrophilus</i>, is that + which both you, and all the other <i>Virtuoſi</i> that have ſeen + it, have been pleas'd to think very ſtrange; and indeed of all the + Experiments of Colours, I have yet met with, it ſeems to be the fitteſt + to recommend the Doctrine propos'd in this Treatiſe, and to ſhew + that we need not ſuppoſe, that all Colours muſt neceſſarily + be Inherent Qualities, flowing from the Subſtantial Forms of the + Bodies they are ſaid to belong to, ſince by a bare Mechanical + change of Texture in the Minute parts of Bodies; two Colours may in + <!-- Page 303 --> <span class="pagenum"><a name="LPage_303" + id="LPage_303"></a>[pg 303]</span> a moment be Generated quite <i>De novo,</i> + and utterly Deſtroy'd. For there is this difference betwixt the + following Experiment, and moſt of the others deliver'd in theſe + Papers, that in this, the Colour that a Body already had, is not chang'd + into another, but betwixt two Bodies, each of them apart devoid of Colour, + there is in a moment generated a very deep Colour, and which if it were + let alone, would be permanent; and yet by a very ſmall Parcel of a + third Body, that has no Colour of its own, (leſt ſome may + pretend I know not what Antipathy betwixt Colours) this otherwiſe + permanent Colour will be in another trice ſo quite Deſtroy'd, + that there will remain no foot-ſtepts either of it or of any other + Colour in the whole Mixture. + </p> + <p> + The Experiment is very eaſie, and it is thus perform'd: Take good + common Sublimate, and fully ſatiate with it what quantity of Water + you pleaſe, Filtre the Solution carefully through clean and cloſe + Paper, that it may drop down as Clear and Colourleſs as Fountain + water. Then when you'l ſhew the Experiment, put of it about a + Spoonfull into a ſmall Wine-glaſs, or any other convenient Veſſel + made of clear Glaſs, and droping in three or four + <!-- Page 304 --> <span class="pagenum"><a name="LPage_304" + id="LPage_304"></a>[pg 304]</span> drops of good Oyl of Tartar, <i>per + Deliquium</i>; well Filtred that it may likewiſe be without Colour, + theſe two Limpid Liquors will in the twinkling of an Eye turn into an + Opacous mixture of a deep Orange Colour, which by keeping the Glaſs + continually ſhaking in your hand, you muſt preſerve from + ſetling too ſoon to the Bottom; And when the Spectators have a + little beheld this firſt Change, then you muſt preſently + drop in about four or five drops of Oyl of Vitriol, and continuing to + ſhake the Glaſs pretty ſtrongly, that it may the Nimbler + diffuſe it ſelf, the whole Colour, if you have gone Skilfully to + work, will immediately diſappear, and all the Liquor in the Glaſs + will be Clear and Colourleſs as before, without ſo much as a + Sediment at the Bottom. But for the more gracefull Trial of this + Experiment, 'twill not be amiſs to obſerve, Firſt, That + there ſhould not be taken too much of the Solution of Sublimate, nor + too much of the Oyl of Tartar drop'd in, to avoid the neceſſity + of putting in ſo much Oyl of Vitriol as may make an Ebullition, and + perhaps run over the Glaſs. Secondly, That 'tis convenient to keep + the Glaſs always a little ſhaking, both for the better mixing of + the Liquors, and to keep the Yellow Subſtance from Subſiding, + which + <!-- Page 305 --> <span class="pagenum"><a name="LPage_305" + id="LPage_305"></a>[pg 305]</span> elſe it would in a ſhort time + do, though when 'tis ſubſided it will retain its Colour, and alſo + be capable of being depriv'd of it by the Oyl newly mention'd. Thirdly, + That if any Yellow matter ſtick at the ſides of the Glaſs, + 'tis but inclining the Glaſs, till the clarify'd Liquor can waſh + alongſt it, and the Liquor will preſently imbibe it, and deprive + it of its Colour. + </p> + <p> + Many have ſomewhat wondred, how I came to light upon this Experiment, + but the Notions or Conjectures I have about the differing Natures of the + Several Tribes of Salts, having led me to deviſe the Experiment, it + will not be difficult for me to give you the Chymical Reaſon, if I + may ſo ſpeak, of the <i>Phænomenon</i>. Having then obſerv'd, + that <i>Mercury</i> being diſſolv'd in Some <i>Menſtruums</i>, + would yield a dark Yellow Precipitate, and ſuppoſing that, as to + this, common Water, and the Salts that ſtick to the <i>Mercury</i> + would be equivalent to thoſe Acid <i>Menſtruums</i>, which work + upon the <i>Quick-ſilver</i>, upon the account of their Saline + particles, I ſubſtituted a Solution of Sublimate in fair Water, + inſtead of a Solution of <i>Mercury</i> in <i>Aqua-fortis</i>, or + Spirit of <i>Nitre</i>, that ſimple Solution being both clearer and + free from that very offenſive Smell, which accompanies the Solutions + <!-- Page 306 --> <span class="pagenum"><a name="LPage_306" + id="LPage_306"></a>[pg 306]</span> of <i>Mercury</i> made with thoſe + other corroſive Liquors; then I conſider'd, that That, which + makes the Yellow Colour, is indeed but a Precipitate made by the means of + the Oyl of Tartar, which we drop in, and which, as <i>Chymiſts</i> + know, does generally precipitate Metalline Bodies corroded by Acid Salts; + ſo that the Colour in our caſe reſults from the Coalition + of the Mercurial particles with the Saline ones, wherewith they were + formerly aſſociated, and with the Alcalizate particles of the + Salt of Tartar that ſwim up and down in the Oyl. Wherefore conſidering + alſo, that very many of the effects of Lixiviate Liquors, upon the + Solutions of other Bodies, may be deſtroy'd by Acid <i>Menstruums</i>, + as I elſewhere more particularly declare, I concluded, that if I choſe + a very potently Acid Liquor, which by its Inciſive power might undo + the work of the Oyl of Tartar, and diſperſe again thoſe + Particles, which the other had by Precipitation aſſociated, into + ſuch minute Corpuſcles as were before ſingly Inconſpicuous, + they would become Inconſpicuous again, and conſequently leave + the Liquor as Colourleſs as before the Precipitation was made. + </p> + <p> + This, as I ſaid, <i>Pyrophilus</i>, ſeems to be the Chymical reaſon + of this Experiment, that + <!-- Page 307 --> <span class="pagenum"><a name="LPage_307" + id="LPage_307"></a>[pg 307]</span> is ſuch a reaſon, as, ſuppoſing + the truth of thoſe Chymical Notions I have elſewhere I hope + evinc'd, may give ſuch an account of the <i>Phænomena</i> as Chymical + Notions can ſupply us with; but I both here and elſewhere make uſe + of this way of ſpeaking, to intimate that I am ſufficiently + aware of the difference betwixt a Chymical Explication of a <i>Phænomenon</i>, + and one that is truly Philoſophical or Mechanical; as in our preſent + caſe, I tell you ſomething, when I tell you that the Yellowneſs + of the Mercurial Solution and the Oyl of Tartar is produc'd by the + Precipitation occaſion'd by the affuſion of the latter of thoſe + Liquors, and that the deſtruction of the Colour proceeds from the Diſſipation + of that Curdl'd matter, whoſe Texture is deſtroy'd, and which is + diſſolv'd into Minute and Inviſible particles by the + potently Acid <i>Menſtruum</i>, which is the reaſon, why there + remains no Sediment in the Bottom, becauſe the infuſed Oyl takes + it up, and reſolves it into hidden or inviſible Parts, as Water + does Salt or Sugar. But when I have told you all this, I am far from + thinking I have told all that ſuch an Inquiſitive Perſon as + your ſelf would know, for I preſume you would deſire as + well as I to learn (at leaſt) why the Particles of the + <!-- Page 308 --> <span class="pagenum"><a name="LPage_308" + id="LPage_308"></a>[pg 308]</span> <i>Mercury</i>, of the Tartar, and of + the Acid Salts convening together, ſhould make rather an Orange + Colour than a Red, or a Blew, or a Green, for 'tis not enough to ſay + what I related a little before, that divers Mercurial Solutions, though + otherwiſe made, would yield a Yellow precipitate, becauſe the + Queſtion will recurr concerning them; and to give it a ſatisfactory + anſwer, is, I freely acknowledge, more than I dare as yet pretend to. + </p> + <p> + But to confirm my conjecture about the Chymical reaſon of our + Experiment, I may add, that as I have (<i>viz.</i> pag. 34<sup>th</sup>. + of this Treatiſe) elſewhere (on another occaſion) told you, + with Saline Liquors of another kind and nature than Salt of Tartar, + (namely, with Spirit of Urine, and Liquors of kin to that) I can make the + <i>Mercury</i> precipitate out of the firſt ſimple Solution + quite of another Colour than that hitherto mention'd; Nay, if inſtead + of altering the Precipitating liquor, I alter'd the Texture of the + Sublimate in ſuch a way as my Notions about Salt requir'd, I could + produce the ſame <i>Phænomenon</i>. For having purpoſely + Sublim'd together Equal parts (or thereabout) of Sal-Armoniack and + Sublimate, firſt diligently Mix'd, the aſcending Flowers being + diffolv'd in fair Water, + <!-- Page 309 --> <span class="pagenum"><a name="LPage_309" + id="LPage_309"></a>[pg 309]</span> and Filtred, gave a Solution Limpid and + Colourleſs, like that of the other Sublimates, and yet an <i>Akaly</i> + drop'd into this Liquor did not turn it Yellow but White. And upon the + ſame Grounds we may with <i>Quick-ſilver</i>, without the help + of common Sublimate, prepare another ſort of Flowers diſſoluble + in Water without Diſcolouring it, with which I could likewiſe do + what I newly mention'd; to which I ſhall add, (what poſſibly + you'l ſomewhat wonder at) That ſo much does the Colour depend + upon the Texture reſulting from the Convention of the ſeveral + ſorts of Corpuſcles, that though in out Experiment, Oyl of + Vitriol deſtroys the Yellow Colour, yet with <i>Quick-ſilver</i> + and fair Water, by the help of Oyl of Vitriol alone, we may eaſily + make a kind of Precipitate of a fair and permanent Yellow, as you will + e're long (in the forty ſecond Expement of this third Part) be + taught. And I may further add, that I choſe Oyl of Vitriol, not + ſo much for any other or peculiar Quality, as for its being, when + 'tis well rectify'd, (which 'tis ſomewhat hazardous to bring it to + be) not only devoid of Colour and in Smells, but extremely Strong and Inciſive; + For though common and undephlegmated <i>Aqua-fortis</i> will not perform + <!-- Page 310 --> <span class="pagenum"><a name="LPage_310" + id="LPage_310"></a>[pg 310]</span> the ſame thing well, yet that + which is made exceeding Strong by being carefully Dephlegm'd, will do it + pretty well, though not ſo well as Oyl of Vitriol which is ſo + Strong, that even without Rectification it may for a need be made uſe + of. I will not here tell you what I have try'd, that I may be able to + deprive at pleaſure the Precipitate that one of the Sulphureous + Liquors had made, by the copious Affuſion of the other: Becauſe + I found, though this Experiment is too tickliſh to let me give a full + account of it in few words, I ſhall therefore tell you, that it is + not only for once, that the other above-mention'd Experiment may be made, + the ſame Numerical parcels of Liquor being ſtill imploy'd in it; + for after I have Clarify'd the Orange Colour'd Liquor, by the addition of + as little of the Oyl of Viriol as will ſuffice to perform the effect, + I can again at pleaſure re-produce the Opacous Colour, by the + dropping in of freſh Oyl of Tartar, and deſtroy it again by the + Re-affuſion of more of the Acid <i>Menſtruum</i>; and yet oftner + if I pleaſe, can I with theſe two contrariant Liquors recall and + diſperſe the Colour, though by reaſon of the addition of + ſo much new Liquor, in reference to the Mercurial particles, the + Colour will at length appear more dilute and faint. + <!-- Page 311 --> <span class="pagenum"><a name="LPage_311" + id="LPage_311"></a>[pg 311]</span> + </p> + <p class="center"> + <i>An improvement of the fortieth Experiment</i>. + </p> + <p> + And, <i>Pyrophilus</i>, to confirm yet further the Notions that led me to + think on the propos'd Experiment, I ſhall acquaint you with another, + which when I had conveniency I have ſometimes added to it, and which + has to the Spectators appear'd little leſs Odd than the firſt; + And though becauſe the Liquor, requiſite to make the Trial + ſucceed well, muſt be on purpoſe prepar'd anew a while + before, becauſe it will not long retain its fitneſs for this + work, I do but ſeldome annex this Experiment to the other, yet I + ſhall tell you how I devis'd it, and how I make it. If you boyl Crude + Antimony in a ſtrong and clear <i>Lixivium</i>, you ſhall ſeparate + a Subſtance from it, which ſome Modern <i>Chymiſts</i> are + pleas'd to call its Sulphur, but how deſervedly I ſhall not here + examine, having elſewhere done it in an Opportune place; wherefore I + ſhall now but need to take notice, that when this ſuppos'd + Sulphur (not now to call it rather a kind of <i>Crocus</i>) is let fall by + the Liquor upon its Refrigeration, it often ſettles in Flakes, or + ſuch like parcels of a Yellow Subſtance, (which being by the + precedent + <!-- Page 312 --> <span class="pagenum"><a name="LPage_312" + id="LPage_312"></a>[pg 312]</span> diſſolution reduc'd into + Minute parts, may peradventure be made to take Fire much more eaſily + than the Groſſer Powder of unprepar'd Antimony would have done.) + Conſidering therefore, that common Sulphur boyl'd in a <i>Lixivium</i> + may be Precipitated out of it by Rheniſh-wine or White-wine, which + are Sowriſh Liquors, and have in them, as I elſewhere ſhew, + an Acid Salt; and having found alſo by Trial, that with other Acid + Liquors I could Precipitate out of Lixiviate Solvents ſome other + Mineral concretions abounding with Sulphureous parts, of which ſort + is crude Antimony, I concluded it to be eaſie to Precipitate the + Antimony diſſolv'd, as was lately mention'd, with the Acid Oyl + of Vitriol; and though common Sulphur yields a White Precipitate, which + the <i>Chymiſts</i> call <i>Lac Sulphuris</i>, yet I ſuppos'd + the Precipitated Antimony would be of a deep Yellow Colour, as well, if + made with Oyl of Vitriol, as if made only by Refrigeration and length of + Time. From this 'twas eaſie to deduce this Experiment, that if you + put into one Glaſs ſome of the freſhly Impregnated and + Filtrated Solution of Antimony, and into another ſome of the + Orange-Colour'd Mixture, (which I formerly ſhew'd you how to make + with a + <!-- Page 313 --> <span class="pagenum"><a name="LPage_313" + id="LPage_313"></a>[pg 313]</span> Mercurial Solution and Oyl of Tartar) a + few drops of Oyl of Vitriol dropp'd into the laſt mention'd Glaſs, + would, as I told you before, turn the Deep Yellow mixture into a Cleer + Liquor; whereas a little of the ſame Oyl dropp'd out of the ſame + Viol into the other Glaſs would preſently (but not without + ſome ill ſent) turn the moderately cleer Solution into a Deep + Yellow Subſtance, But this, as I Said, ſucceeds not well, unleſs + you employ a <i>Lixivium</i> that has but newly diſſolv'd + Antimony, and has not yet let it fall. But yet in Summer time, if your <i>Lixivium</i> + have been duly Impregnated and well Filtred after it is quite cold, it + will for ſome dayes (perhaps much longer than I had occaſion to + try) retain Antimony enough to exhibit, upon the Affuſion of the + Corroſive Oyl, as much of a good Yellow Subſtance as is neceſſary + to ſatisfie the Beholders of the Poſſibility of the + Experiment. + </p> + <p class="center"> + <i>Reflections upon the XL. Experiment Compared with the X. and XX.</i> + </p> + <p> + The Knowledge of the Diſtinction of Salts which we have propos'd, + whereby they are diſcriminated into <i>Acid, Volatile,</i> + <!-- Page 314 --> <span class="pagenum"><a name="LPage_314" + id="LPage_314"></a>[pg 314]</span> or <i>Salfuginous</i> (if I may for Diſtinction + ſake ſo call the Fugitive Salts of Animal Subſtances) and + <i>fix'd</i> or <i>Alcalizate</i>, may poſſibly (by that little + part which we have already deliver'd, of what we could ſay of its + Applicableneſs) appear of ſo much Uſe in Natural Philoſophy + (eſpecially in the Practick part of it) that I doubt not but it will + be no Unwelcome Corollary of the Preceding Experiment, if by the help of + it I teach you to diſtinguiſh, which of thoſe Salts is + Predominant in Chymical Liquors, as well as whether any of them be ſo + or not. For though in our Notes upon the X. and XX. Experiments I have + ſhown you a way by means of the Tincture of <i>Lignum Nephriticum</i>, + or of Syrrup of Violets, to diſcover whether a propounded Salt be + Acid or not, yet you can thereby only find in general that ſuch and + ſuch Salts belong not to the Tribe of Acids, but cannot determine + whether they belong to the Tribe of Urinous Salts (under which for diſtinction + ſake I comprehend all thoſe Volatile Salts of Animal or other + Subſtances that are contrary to Acids) or to that of Alcalies. For as + well the one as the other of theſe Salino-Sulphurous Salts will reſtore + the Cæruleous Colour to the Tincture of <i>Lignum Nephriticum</i>, and + turn that of Syrrup of Violets + <!-- Page 315 --> <span class="pagenum"><a name="LPage_315" + id="LPage_315"></a>[pg 315]</span> into Green. Wherefore this XL. + Experiment does opportunely ſupply the deficiency of thoſe. For + being ſollicitous to find out ſome ready wayes of diſcriminating + the Tribes of Chymical Salts, I found that all thoſe I thought fit to + make Tryal of, would, if they were of a Lixiviate Nature, make with + Sublimate diſſolv'd in Fair Water an <i>Orange Tawny</i> + Precipitate; whereas if they were of an Urinous Nature the Precipitate + would be <i>White</i> and Milky. So that having alwayes by me ſome + Syrrup of Violets and ſome Solution of Sublimate, I can by the help + of the firſt of thoſe Liquors diſcover in a trice, whether + the propounded Salt or Saline Body be of an Acid Nature or no, if it be I + need (you know) inquire no further; but if it be not, I can very eaſily, + and as readily diſtinguiſh between the other two kinds of Salts, + by the White or Orange-Colour that is immediately produc'd, by letting + fall a few Drops or Grains of the Salt to be examin'd, into a ſpoonfull + of the cleer Solution of Sublimate. For Example, it has been ſuppos'd + by ſome eminently Learned, That when Sal Armoniack being mingled with + an Alcaly is forc'd from it by the Fire in cloſe Veſſels, + the Volatile Salt that will thereby be obtain'd (if the Operation be + skilfully perform'd,) + <!-- Page 316 --> <span class="pagenum"><a name="LPage_316" + id="LPage_316"></a>[pg 316]</span> is but a more fine and ſubtile + ſort of Sal Armoniack, which, 'tis preſum'd, this Operation do's + but more exquiſitely purifie, than common Solutions, Filtrations, and + Coagulations. But this Opinion may be eaſily ſhown to be + Erroneous, as by other Arguments, ſo particularly by the lately + deliver'd Method of diſtinguiſhing the Tribes of Salts. For the + Saline Spirit of Sal Armoniack, as it is in many other manifeſt + Qualities very like the Spirit of Urine, ſo like, that it will in a + trice make Syrrup of Violets of a Lovely Green, turn a Solution of good + Verdigreaſe into an Excellent Azure, and make the Solution of a + Sublimate yield a White Precipitate, inſomuch that in moſt (for + I ſay not all of the Experiments) where I Aim onely at producing a + ſudden change of Colour, I ſcruple not to uſe Spirit of Sal + Armoniack when it is at hand, inſtead of Spirit of Urine, as indeed + it ſeems chiefly to conſiſt (beſides the flegm that + helps to make it fluid) of the Volatile Urinous Salt (yet not excluding + that of Soot) that abounds in the Sal Armoniack and is ſet at liberty + from the Sea Salt wherewith it was formerly aſſociated, and + clogg'd, by the Operation of the Alcaly, that divides the Ingredients of + Sal Armoniack, and retains that Sea Salt with it ſelf. What uſe + may be + <!-- Page 317 --> <span class="pagenum"><a name="LPage_317" + id="LPage_317"></a>[pg 317]</span> made of the like way of exploration in + that inquiry which puzzles ſo many Modern Naturaliſts, whether + the Rich Pigment (which we have often had occaſion to mention) + belongs to the Vegetable or Animal Kingdome, you may find in another place + where I give you ſome account of what I try'd about Cocheneel. But I + think it needleſs to exemplifie here our Method by any other Inſtances, + many ſuch being to be met with in divers parts of this Treatiſe; + but I will rather advertiſe you, that, by this way of examining + Chymical Liquors, you may not onely in moſt Caſes conclude <i>Affirmatively</i>, + but in ſome Caſes <i>Negatively</i>. As ſince Spirit of + Wine, and as far as I have try'd, thoſe Chymical Oyles which Artiſts + call Eſſential, did not (when I us'd them as I had us'd the + ſeveral Families of Salts upon that Syrrup) turn Syrrup of Violets + Red or Green, nor the Solution of Sublimate White or Yellow, I inferr'd it + may thence be probably argued, that either they are deſtitute of + Salt, or have ſuch as belongs not to either of the three Grand + families already often mention'd. When I went to examine the Spirit of Oak + or of ſuch like Concretes forced over through a Retort, I found by + this means amongſt others, that (as I elſewhere ſhow) theſe + Chymiſts are + <!-- Page 318 --> <span class="pagenum"><a name="LPage_318" + id="LPage_318"></a>[pg 318]</span> much miſtaken in it, that account + it a ſimple Liquor, and one of their Hypoſtatical Principles: + for not to mention what flegm it may have, I found that with a few drops + of one of this ſort of Spirits mix'd with a good proportion of Syrrup + of Violets, I could change the Colour and make it Purpliſh, by the + affinity of which Colour to Redneſs, I conjectur'd that this Spirit + had ſome Acid Corpuſcles in it, and accordingly I found that as + it would deſtroy the Blewneſs of a Tincture of <i>Lignum + Nephriticum</i>, ſo being put upon Corals it would Corrode them, as + common Spirit of Vinegar, and other Acid Liquors are wont to do. And + farther to examine whether there were not a great part of the Liquor that + was not of an Acid nature, having ſeparated the Sour or Vinegar-like + part from the reſt, which (if I miſtake not) is far the more + Copious, we concluded as we had conjectured, the other or remaining part, + though it had a ſtrong taſte as well as ſmell, to be of a + nature differing from that of either of the three ſorts of Salts + above mention'd, ſince it did as little as Spirit of Wine, and + Chymical Oyls, alter the Colour either of Syrrup of Violets or Solution of + Sublimate, whence we alſo inferr'd that the change that had been made + of that Syrrup into a Purple Colour, was + <!-- Page 319 --> <span class="pagenum"><a name="LPage_319" + id="LPage_319"></a>[pg 319]</span> effected by the Vinegar, that was one + of the two Ingredients of the Liquor, which was wont to paſs for a + Simple or Uncompounded Spirit. And, upon this account, 'twas of the Spirit + of Oak (and the like Concretes) freed from it's Vinegar that I elſewhere + told you, that I had not then obſerv'd it, (and I have repeated the + Tryal but very lately) to deſtroy the Cæruleous Tincture of <i>Lignum + Nephriticum</i>. But this onely, <i>en paſsant</i>; for the Chief + thing I had to add was this, That by the ſame way may be examin'd and + diſcover'd, divers changes that are produc'd in Bodies either by + Nature only, or by Art; either of them being able by changing the Texture + of ſome Concretes I could name, to qualifie them to Operate after a + New manner upon the above mention'd Syrrup, or Solution, or both. And by + this means, to tell you that upon the by, I have been able to diſcover, + that there may be made Bodies, which though they run <i>per Deliquium</i>, + as readily as Salt of Tartar, belong in other reſpects, not to the + family of Alcaliz, much leſs to that of Salfuginous, or that of Acid + Salts. Perhaps too, I may know a way of making a highly operative Saline + Body that ſhall neither change the Colour of Syrrup of Violets, nor + Precipitate the Solution of Sublimate; And, I can + <!-- Page 320 --> <span class="pagenum"><a name="LPage_320" + id="LPage_320"></a>[pg 320]</span> likewiſe if I pleaſe conceal + by what Liquors I perform ſuch changes of Colour, as I have been + mentioning to you, by quite altering the Texture of ſome ordinary + Chymical productions, the Exploration of which is the main uſe of the + fortieth Experiment, which I think teaches not a little, if it teach us to + diſcover the nature of thoſe things (in reference to Salt) that + are obtain'd by the ordinary Chymical Analyſis of mix'd Bodyes, + though perhaps there may be other Bodyes prepar'd by Chymiſtry which + may have the ſame Effects in the change of Colours; and yet be + produc'd not from what Chymiſts call the Reſolution of Bodies, + but from their Compoſition. But the diſcourſing of things + of this nature is more proper for another place. I ſhall now onely + add, what might perhaps have been more ſeaſonably told you + before; That the Reaſon why the way of Exploration of Salts hitherto + deliver'd, ſucceeds in the Solution of Sublimate, depends upon the + particular Texture of that Solution, as well as upon the differing Natures + of the Saline Liquors imploy'd to Precipitate it. For Gold diſſolv'd + in <i>Aqua Regia</i>, whether you Precipitate it with Oyl of Tartar which + is an Alcaly, or with Spirit of Urine + <!-- Erratum: for Urne --> , or Sal Armoniack which belongs to the + family of + <!-- Page 321 --> <span class="pagenum"><a name="LPage_321" + id="LPage_321"></a>[pg 321]</span> Volatile Salts, will either way afford + a Yellow ſubſtance: though with ſuch an Acid Liquor, as, I + ſay not Spirit of Salt, the Body that yields it, being upon the + matter an Ingredient of <i>Aqua Regis</i>, but Oyl of Vitriol it ſelf, + I did not find that I could Precipitate the Metall out of the Solution, or + deſtroy the Colour of it, though the ſame Oyl of Vitriol would + readily Precipitate Silver diſſolv'd in <i>Aqua-fortis</i>. And + if you diſſolve pure Silver in <i>Aqua-fortis</i>, and ſuffer + it to ſhoot into Cryſtals, the cleer Solution of theſe made + in fair Water, will afford a very White Precipitate, whether it be made + with an Alcaly, or an Acid Spirit, as that of Salt, whereas, which may + ſeem ſomewhat ſtrange, with Spirit of Sal Armoniack (that I + us'd was made of Quicklime) I could obtain no ſuch White Precipitate; + that Volatile Spirit, nor (as I remember) that of Urine, ſcarce doing + any more than ſtriking down a very ſmall quantity of Matter, + which was neither White nor Whitiſh, ſo that the remaining + Liquor being ſuffer'd to evaporate till the ſuperfluous Moiſture + was gone, the greateſt part of the Metalline Corpuſcles with the + Saline ones that had imbib'd them, concoagulated into Salt, as is uſual + in ſuch Solutions, wherein the Metall has not been Precipitated. + </p> + <!-- Page 322 --> + <p> + <span class="pagenum"><a name="LPage_322" id="LPage_322"></a>[pg 322]</span> + </p> + <h3> + <i>EXPERIMENT XLI.</i> + </h3> + <p> + Of Kin to the laſt or fortieth Experiment is another which I remember + I have ſometimes ſhewn to <i>Virtuoſi</i> that were pleas'd + not to diſlike it. I took Spirit of Urine made by Fermentation, and + with a due proportion of Copper brought into ſmall parts, I obtain'd + a very lovely Azure Solution, and when I ſaw the Colour was ſuch + as was requiſite, pouring into a clean Glaſs, about a ſpoonfull + of this tincted Liquor, (of which I us'd to keep a Quantity by me,) I + could by ſhaking into it ſome drops of Strong Oyl of Vitriol, + deprive it in a trice of its Deep Colour, and make it look like + Common-water. + </p> + <p class="center"> + <i>Annotation</i>. + </p> + <p> + This Experiment brings into my mind this other, which oftentimes ſuccceds + well enough, though not quite ſo well as the former; Namely, that if + into about a ſmall ſpoonfull of a Solution of good French + Verdigreaſe made in fair Water, I drop't and ſhak'd ſome + ſtrong Spirit of Salt, or rather deflegm'd <i>Aqua Fortis</i>, the + Greenneſs of the Solution would be made in a trice almoſt + <!-- Page 323 --> <span class="pagenum"><a name="LPage_323" + id="LPage_323"></a>[pg 323]</span> totally to diſappear, & the + Liquor held againſt the Light would ſcarce ſeeme other than + Cleer or Limpid, to any but an Attentive Eye, which is therefore + remarkable; becauſe we know that <i>Aqua-fortis</i> corroding Copper, + which is it that gives the Colour to Verdigreaſe, is wont to reduce + it to a Green Blew Solution. But if into the other altogether or almoſt + Colourleſs Liquor I was ſpeaking of, you drop a juſt + quantity either of Oyl of Tartar or Spirit of Urine, you ſhall find + that after the Ebullition is ceas'd, the mixture will diſcloſe a + lively Colour, though ſomewhat differing from that which the Solution + of Verdigreaſe had at firſt. + </p> + <h3> + <i>EXPERIMENT XLII.</i> + </h3> + <p> + That the Colour (<i>Pyrophilus</i>) of a Body may be chang'd by a Liquor + which of it ſelf is of no Colour, provided it be Saline, we have + already manifeſted by a multitude of inſtances. Nor doth it + ſeem ſo ſtrange, becauſe Saline Particles ſwimming + up and down in Liquors, have been by many obſerv'd to be very + operative in the Production and change of Colours. But divers of our + Friends that are not acquainted with Chymical Operations have thought it + very ſtrange that a White Body, and a Dry one + <!-- Page 324 --> <span class="pagenum"><a name="LPage_324" + id="LPage_324"></a>[pg 324]</span> too, ſhould immediately acquire a + rich new Colour upon the bare affuſion of Spring-Water deſtitute + as well of adventitious Salt as of Tincture. And yet (<i>Pyrophilus</i>) + the way of producing ſuch a change of Colours may be eaſily + enough lighted on by thoſe that are converſant in the Solutions + of Mercury. For we have try'd, that though by Evaporating a Solution of + Quick-Silver in <i>Aqua-fortis</i>, and abſtracting the Liquor till + the remaining matter began to be well, but not too ſtrongly dryed, + fair Water pour'd on the remaining <i>Calx</i> made it but ſomewhat + Yellowiſh; yet when we took good Quick-Silver, and three or four + times its weight of Oyl of Vitriol, in caſe we in a Glaſs Retort + plac'd in Sand drew off the Saline <i>Menſtruum</i> from the + Metalline Liquor, till there remain'd a dry <i>Calx</i> at the bottome, + though this Precipitate were a Snow White Body, yet upon pouring on it a + large quantity of fair Water, we did almoſt in a moment perceive it + to paſs from a Milky Colour to one of the lovelieſt Light + Yellows that ever we had beheld. Nor is the Turbith Mineral, that Chymiſts + extol for its power to Salivate, and for other vertues, of a Colour much + inferiour to this, though it be often made with a differing proportion of + the Ingredients, + <!-- Page 325 --> <span class="pagenum"><a name="LPage_325" + id="LPage_325"></a>[pg 325]</span> a more troubleſome way. For <i>Beguinus</i>,<a + name="LNtA_22" id="LNtA_22_"></a><a href="#LNt_22"><sup>22</sup></a> who + calls it <i>Mercurius præcipitatus optimus</i>, takes to one part of + Quick-Silver, but two of Liquor, and that is Rectifi'd Oyl of Sulphur, + which is (in <i>England</i> at leaſt) far more ſcarce and dear + than Oyl of Vitriol; he alſo requires a previous Digeſtion, two + or three Cohobations, and frequent Ablutions with hot Diſtill'd + Water, with other preſcriptions, which though they may conduce to the + Goodneſs of the Medicine, which is that he aims at, are troubleſome, + and, our Tryals have inform'd you unnecceſſary to the <i>obtaining + the Lemmon Colour</i> which he regards not. But though we have very rarely + ſeen either in Painters Shops, or elſewhere a finer Yellow than + that which we have divers times this way produc'd (which is the more conſiderable, + becauſe durable and pleaſant Yellows are very hard to be met + with, as may appear by the great uſe which Painters are for its + Colours ſake fain to make of that pernicious and heavy Mineral, + Orpiment) yet I fear our Yellow is too coſtly, to be like to be + imploy'd by Painters, unleſs about Choice pieces of Work, nor do I + know how well it will agree with every Pigment, eſpecially, wich + Oyl'd Colours. And whether this + <!-- Page 326 --> <span class="pagenum"><a name="LPage_326" + id="LPage_326"></a>[pg 326]</span> Experiment, though it have ſeem'd + ſomewhat ſtrange to moſt we have ſhown it to, be + really of another Nature than thoſe wherein Saline Liquors are + imploy'd, may, as we formerly alſo hinted, be ſo plauſibly + doubted, that whether the Water pour'd on the <i>Calx</i>, do barely by + imbibing ſome of its Saline parts alter its Colour by altering its + Texture, or whether by diſſolving the Concoagulated Salts, it + does become a Saline <i>Menſtruum</i>, and, as ſuch, work upon + the Mercury, I freely leave to you (<i>Pyrophilus</i>) to conſider. + And that I may give you ſome Aſſiſtance in your + Enquiry, I will not only tell you, that I have ſeveral times with + fair Water waſh'd from this <i>Calx</i>, good ſtore of ſtrongly + taſted Corpuſcles, which by the abſtraction of the <i>Menſtruum</i>, + I could reduce into Salt; but I will alſo ſubjoyn an Experiment, + which I devis'd, to ſhew among other things, how much a real and + permanent Colour may be as it were drawn forth by a Liquor that has + neither Colour, nor ſo much as Saline or other Active parts, provided + it can but bring the parts of the Body it imbibes to convene into cluſters + diſpos'd after the manner requiſite to the exhibiting of the + emergent Colour. The Experiment was this. + </p> + <!-- Page 327 --> + <p> + <span class="pagenum"><a name="LPage_327" id="LPage_327"></a>[pg 327]</span> + </p> + <h3> + <i>EXPERIMENT XLIII.</i> + </h3> + <p> + We took good common Vitriol, and having beaten it to Powder, and put it + into a Crucible, we kept it melted in a gentle heat, till by the + Evaporation of ſome parts, and the ſhuffling of the reſt, + it had quite loſt its former Colour, what remain'd we took out, and + found it to be a friable <i>Calx</i>, of a dirty Gray. On this we pour'd + fair Water, which it did not Colour Green or Blew, but only ſeem'd to + make a muddy mixture with it, then ſtopping the Vial wherein the + Ingredients were put, we let it ſtand in a quiet place for ſome + dayes, and after many hours the water having diſſolv'd a good + part of the imperfectly calcin'd Body, the Vitriolate Corpuſcles + ſwiming to and fro in the Liquor, had time by their opportune Occurſions + to conſtitute many little Maſſes of Vitriol, which gave the + water they impregnated a fair Vitriolate Colour; and this Liquor being + pour'd off, the remaining dirty Powder did in proceſs of time + communicate the like Colour, but not ſo deep, to a ſecond parcel + of cleer Water that we pour'd on it. But this Experiment <i>Pyrophilus</i> + is, (to give you that hint by the way) of too Luciferous a Nature to be + fit to be + <!-- Page 328 --> <span class="pagenum"><a name="LPage_328" + id="LPage_328"></a>[pg 328]</span> fully proſecuted, now that I am in + haſte, and willing to diſpatch what remains. And we have already + ſaid of it, as much as is requiſite to our preſent purpoſe. + </p> + <h3> + <i>EXPERIMENT XLIV.</i> + </h3> + <p> + It may (<i>Pyrophilus</i>) ſomewhat contribute towards the ſhewing + how much ſome Colours depend upon the leſs or greater mixture, + and (as it were,) Contemperation of the Light with ſhades, to obſerve, + how that ſometimes the number of Particles, of the ſame Colour, + receiv'd into the Pores of a Liquor, or ſwiming up and down in it, do + ſeem much to vary the Colour of it. I could here preſent you + with particular inſtances to ſhow, how in many (if not moſt) + conſiſtent Bodyes, if the Colour be not a Light one, as White, + Yellow, or the like, the cloſeneſs of parts in the Pigments + makes it look Blackiſh, though when it is diſplay'd and laid on + thinly, it will perhaps appear to be either Blew, or Green, or Red. But + the Colours of conſiſtent Pigments, not being thoſe which + the Preamble of this Experiment has lead you to expect Examples in, I + ſhall take the inſtances I am now to give you, rather from + Liquors than Dry Bodyes. If then you put a little fair Water into a + <!-- Page 329 --> <span class="pagenum"><a name="LPage_329" + id="LPage_329"></a>[pg 329]</span> cleer and ſlender Vial, (or rather + into one of thoſe pipes of Glaſs, which we ſhall by and by + mention;) and let fall into it a few drops of a ſtrong Decoction or + Infuſion of <i>Cochineel</i>, or (for want of that) of <i>Brazil</i>; + you may ſee the tincted drops deſcend like little Clouds into + the Liquor; through which, if, by ſhaking the Vial, you diffuſe + them, they will turn the water either of a Pinck Colour, or like that + which is wont to be made by the waſhing of raw fleſh in fair + Water; by dropping a little more of the Decoction, you may heighten the + Colour into a fine Red, almoſt like that which ennobles Rubies; by + continuing the affuſion, you may bring the Liquor to a kind of a Crimſon, + and afterwards to a Dark and Opacous Redneſs, ſomewhat like that + of Clotted Blood. And in the paſſage of the Liquor from one of + theſe Colours to the other, you may obſerve, if you conſider + it attentively, divers other leſs noted Colours belonging to Red, to + which it is not eaſie to give Names; eſpecially conſidering + how much the proportion of the Decoction to the fair Water, and the ſtrength + of that Decoction, together with that of the trajected Light and other + Circumſtances, may vary the Phænomena of this Experiment. For the + convenienter making whereof, we uſe + <!-- Page 330 --> <span class="pagenum"><a name="LPage_330" + id="LPage_330"></a>[pg 330]</span> inſtead of a Vial, any ſlender + Pipe of Glaſs of about a foot or more in length, and about the + thickneſs of a mans little finger; For, if leaving one end of this + Pipe open, you Seal up the other Hermetically, (or at leaſt ſtop + it exquiſitely with a Cork well fitted to it, and over-laid with hard + Sealing Wax melted, and rubb'd upon it;) you ſhall have a Glaſs, + wherein may be obſerv'd the Variations of the Colours of Liquors much + better than in large Vials, and wherein Experiments of this Nature may be + well made with very ſmall quantities of Liquor. And if you pleaſe, + you may in this Pipe produce variety of Colours in the various parts of + the Liquor, and keep them ſwimming upon one another unmix'd for a + good while. And ſome have marveil'd to ſee, what variety of + Colours we have ſometimes (but I confeſs rather by chance than + skill) produc'd in thoſe Glaſſes, by the bare infuſion + of Brazil, variouſly diluted with fair Water, and alter'd by the Infuſion + of ſeveral Chymical Spirits and other Saline Liquors devoid themſelves + of Colour, and when the whole Liquor is reduc'd to an Uniform degree of + Colour, I have taken pleaſure to make that very Liquor ſeem to + be of Colours gradually differing, by filling with it Glaſſes of + a Conical figure, (whether the Glaſs have + <!-- Page 331 --> <span class="pagenum"><a name="LPage_331" + id="LPage_331"></a>[pg 331]</span> its baſis in the ordinary poſition, + or turn'd upwards.) And yet you need not Glaſſes of an + extraordinary ſhape to ſee an inſtance of what the vari'd + mixture of Light and Shadow can do in the diverſifying of the Colour. + For if you take but a large round Vial, with a ſomewhat long and + ſlender Neck, and filling it with our Red Infuſion of Brazil, + hold it againſt the Light, you will diſcern a notable Diſparity + betwixt the Colour of that part of the Liquor which is in the Body of the + Vial, and that which is more pervious to the Light in the Neck. Nay, I + remember, that I once had a Glaſs and a Blew Liquor (conſiſting + chiefly (or only, if my memory deceive me not,) of a certain Solution of + Verdigreaſe) ſo fitted for my purpoſe, that though in other + Glaſſes the Experiment would not ſucceed, yet when that + particular Glaſs was fill'd with that Solution, in the Body of the + Vial it appear'd of a Lovely Blew, and in the neck, (where the Light did + more dilute the Colour,) of a manifeſt Green; and though I ſuſpected + there might be ſome latent Yellowneſs in the ſubſtance + of the neck of the Glaſs, which might with the Blew compoſe that + Green, yet was I not ſatisfi'd my ſelf with my Conjecture, but + the thing ſeem'd odd to me, as well as to divers curious + <!-- Page 332 --> <span class="pagenum"><a name="LPage_332" + id="LPage_332"></a>[pg 332]</span> perſons to whom it was ſhown. + And I lately had a Broad piece of Glaſs, which being look'd on againſt + the Light ſeem'd clear enough, and held from the Light appear'd very + lightly diſcolour'd, and yet it was a piece knock'd off from a great + lump of Glaſs, to which if we rejoyn'd it, where it had been broken + off, the whole Maſs was as green as Graſs. And I have ſeveral + times us'd Bottles and ſtopples that were both made (as thoſe, I + had them from aſſur'd me) of the very ſame Metall, and yet + whilſt the bottle appear'd but inclining towards a Green, the Stopple + (by reaſon of its great thickneſs) was of ſo deep a Colour + that you would hardly believe they could poſſibly be made of the + ſame materials. But to ſatisfie ſome Ingenious Men, on + another occaſion, I provided my ſelf of a flat Glaſs (which + I yet have by me,) with which if I look againſt the Light with the + Broad ſide obverted to the Eye, it appeares like a good ordinary + window Glaſs; but if I turn the Edge of it to my Eye, and place my + Eye in a convenient poſture in reference to the Light, it may contend + for deepneſs of Colour with an Emerald. And this Greeneſs puts + me in mind of a certain thickiſh, but not conſiſtent + Pigment I have ſometimes made, and can ſhow you when you pleaſe, + <!-- Page 333 --> <span class="pagenum"><a name="LPage_333" + id="LPage_333"></a>[pg 333]</span> which being dropp'd on a piece of White + Paper appears, where any quantity of it is fallen, of a ſomewhat Crimſon + Colour, but being with ones finger ſpread thinly on the Paper does + preſently exhibit a fair Green, which ſeems to proceed only from + its diſcloſing its Colour upon the Extenuation of its Depth into + Superficies, if the change be not ſomewhat help'd by the Colours + degenerating upon one or other of the Accounts formerly mention'd. Let me + add, that having made divers Tryals with that Blew ſubſtance, + which in Painters ſhops is call'd <i>Litmaſe</i>, we have ſometimes + taken Pleaſure to obſerve, that being diſſolv'd in a + due proportion of fair Water, the Solution either oppos'd to the Light, or + dropp'd upon White paper, did appear of a deep Colour betwixt Crimſon + and Purple; and yet that being ſpread very thin on the Paper and + ſuffer'd to dry on there, the Paper was wont to appear Stain'd of a + Fine Blew. And to ſatisfie my ſelfe, that the diverſity + came not from the Paper, which one might ſuſpect capable of + inbibing the Liquor, and altering the Colour, I made the Tryal upon a flat + piece of purely White Glaſs'd Earth, (which I ſometimes make uſe + of about Experiments of Colours) with an Event not unlike the former. + </p> + <!-- Page 334 --> + <p> + <span class="pagenum"><a name="LPage_334" id="LPage_334"></a>[pg 334]</span> + </p> + <p> + And now I ſpeak of <i>Litmaſs</i>, I will add, that having this + very day taken a piece of it, that I had kept by me theſe ſeveral + years, to make Tryals about Colours, and having let fall a few drops of + the ſtrong Infuſion of it in fair water, into a fine Cryſtal + Glaſs, ſhap'd like an inverted Cone, and almoſt full of + fair Water, I had now (as formerly) the pleaſure to ſee, and to + ſhow others, how theſe few tincted drops variouſly diſperſing + themſelves through the Limpid Water, exhibited divers Colours, or + varieties of Purple and Crimſon. And when the Corpuſcles of the + Pigment ſeem'd to have equally diffus'd themſelves through the + whole Liquor, I then by putting two or three drops of Spirit of Salt, firſt + made an odd change in the Colour of the Liquor, as well as a viſible + commotion among its ſmall parts, and in a ſhort time chang'd it + wholly into a very Glorious Yellow, like that of a Topaz. After which if I + let fall a few drops of the ſtrong and heavy Solution of Pot-aſhes, + whoſe weight would quickly carry it to the ſharp bottome of the + Glaſs, there would ſoon appear four very pleaſant and diſtinct + Colours; Namely, a Bright, but Dilute Colour at the picked bottome of the + Glaſs; a Purple, a little higher; a deep and glorious Crimſon, + (which Crimſon + <!-- Page 335 --> <span class="pagenum"><a name="LPage_335" + id="LPage_335"></a>[pg 335]</span> ſeem'd to terminate the operation + of the Salt upward) in the confines betwixt the Purple and the Yellow; and + an Excellent Yellow, the ſame that before enobled the whole Liquor, + reaching from thence to the top of the Glaſs. And if I pleas'd to + pour very gently a little Spirit of Sal Armoniack, upon the upper part of + this Yellow, there would alſo be a Purple or a Crimſon, or both, + generated there, ſo that the unalter'd part of the Yellow Liquor + appear'd intercepted betwixt the two Neighbouring Colours. + </p> + <p> + My ſcope in this 3<sup>d</sup>. Experiment (<i>Pyrophilus</i>) is + manifold, as firſt to invite you to be wary in judging of the Colour + of Liquors in ſuch Glaſſes as are therein recommended to + you, and conſequently as much, if not more, when you imploy other Glaſſes. + Secondly, That you may not think it ſtrange, that I often content my + ſelf to rub upon a piece of White paper, the Juice of Bodies I would + examine, ſince not onely I could not eaſily procure a ſufficient + Quantity of the juices of divers of them; but in ſeveral Caſes + the Tryals of the quantities of ſuch Juices in Glaſſes + would make us more lyable to miſtakes, than the way that in thoſe + caſes I have made uſe of. Thirdly, I hope you will by theſe + and divers other + <!-- Page 336 --> <span class="pagenum"><a name="LPage_336" + id="LPage_336"></a>[pg 336]</span> particulars deliver'd in this Treatiſe, + be eaſily induc'd to think that I may have ſet down many + Phænomena very faithfully, and juſt as they appear'd to me, and yet + by reaſon of ſome unheeded circumſtance in the conditions + of the matter, and in the degree of Light, or the manner of trying the + Experiment, you may find ſome things to vary from the Relations I + make of them. Laſtly, I deſign'd to give you an opportunity to + free your ſelf from the amazement which poſſeſſes + moſt Men, at the Tricks of thoſe Mountebancks that are commonly + call'd Water-drinkers. For though not only the vulgar, but ev'n many perſons + that are far above that Rank, have ſo much admir'd to ſee, a man + after having drunk a great deal of fair water, to ſpurt it out again + in the form of Claret Wine, Sack, and Milk, that they have ſuſpected + the intervening of Magick, or ſome forbidden means to effect what + they conceived above the power of Art; yet having once by chance had occaſion + to oblige a Wanderer that made profeſſion of that and other + Jugling Tricks, I was eaſily confirm'd by his Ingenious confeſſion + to me, That this ſo much Admir'd Art, indeed conſiſted + rather in a few Tricks, than in any great Skill, in altering the Nature + and Colours of things. And I am eaſy + <!-- Page 337 --> <span class="pagenum"><a name="LPage_337" + id="LPage_337"></a>[pg 337]</span> to be perſwaded; that there may be + a great deal of Truth in a little Pamphlet Printed divers years ago in + Engliſh, wherein the Author undertakes to diſcover, and that (if + I miſtake not) by the confeſſion of ſome of the + Complices themſelves, That a famous Water-drinker then much Admir'd + in <i>England</i>, perform'd his pretended Tranſmutations of Liquors + by the help of two or three inconſiderable preparations and mixtures + of not unobvious Liquors, and chiefly of an Infuſion of Brazil variouſly + diluted and made Pale or Yellowiſh, (and otherwiſe alter'd) with + Vinegar, the reſt of their work being perform'd by the ſhape of + the Glaſſes, by Craft and Legerdemane. And for my part, that + which I marvel at in this buſineſs, is, the Drinkers being able + to take down ſo much Water, and ſpout it out with that violence; + though Cuſtome and a Vomit ſeaſonably taken before hand, + may in ſome of them much facilitate the work. But as for the changes + made in the Liquors, they were but few and ſlight in compariſon + of thoſe, that the being converſant in Chymical Experiments, and + dextrous in applying them to the Tranſmuting of Colours, may eaſily + enough enable a man to make, as ev'n what has been newly deliver'd in + this, and the foregoing Experiment; eſpecially if we add + <!-- Page 338 --> <span class="pagenum"><a name="LPage_338" + id="LPage_338"></a>[pg 338]</span> to it the things contained in the XX, + the XXXIX and the XL. Experiments, may perhaps have already perſwaded + You. + </p> + <h3> + <i>EXPERIMENT XLV.</i> + </h3> + <p> + You may I preſume (<i>Pyrophilus</i>) have taken notice, that in this + whole Treatiſe, I purpoſely decline (as far as I well can) the + mentioning of Elaborate Chymical Experiments, for fear of frighting you by + their tediouſneſs and difficulty; but yet in confirmation of + what I have been newly telling you about the poſſibility of + Varying the Colours of Liquors, better than the Water-drinkers are wont to + do, I ſhall add, that <i>Helmont</i> uſed to make a preparation + of Steel, which a very Ingenious Chymiſt, his Sons Friend, whom you + know, ſometimes employes for a ſuccedaneum to the Spaw-waters, + by Diluting this <i>Eſsentia Martis Liquida</i> (as he calls it) with + a due proportion of Water. Now that for which I mention to you this + preparation, (which as he communicated to me, I know he will not refuſe + to <i>Pyrophilus</i>) is this, that though the Liquor (as I can ſhew + you when you pleaſe) be almoſt of the Colour of a German (not an + Oriental) Amethyſt, and conſequently remote enough from Green, + <!-- Page 339 --> <span class="pagenum"><a name="LPage_339" + id="LPage_339"></a>[pg 339]</span> yet a very few drops being let fall + into a Large proportion of good Rheniſh, or (in want of that) White + Wine (which yet do's not quite ſo well) immediately turn'd the Liquor + into a lovely Green, as I have not without delight ſhown ſeveral + curious Perſons. By which <i>Phænomenon</i> you may learn, among + other things, how requiſite it is in Experiments about the changes of + Colours heedfully to mind the Circumſtances of them; for Water will + not, as I have purpoſely try'd, concurr to the production of any + ſuch Green, nor did it give that Colour to moderate Spirit of Wine, + wherein I purpoſely diſſolv'd it, and Wine it ſelf is + a Liquor that few would ſuſpect of being able to work ſuddenly + any ſuch change in a Metalline preparation of this Nature; and to + ſatisfie my ſelf that this new Colour proceeds rather from the + peculiar Texture of the Wine, than from any greater Acidity, that Rheniſh + or White-wine (for that may not abſurdly be ſuſpected) has + in compariſon of Water; I purpoſely ſharpen'd the Solution + of this Eſſence in fair Water, with a good quantity of Spirit of + Salt, notwithſtanding which, the mixture acquir'd no Greenneſs. + And to vary the Experiment a little, I try'd, that if into a Glaſs of + Rheniſh Wine made Green by this Eſſence, + <!-- Page 340 --> <span class="pagenum"><a name="LPage_340" + id="LPage_340"></a>[pg 340]</span> I dropp'd an Alcalizate Solution, or + Urinous Spirit, the Wine would preſently grow Turbid, and of an odd + Dirty Colour; But if inſtead of diſſolving the Eſſence + in Wine, I diſſolv'd it in fair Water ſharpen'd perhaps + with a little Spirit of Salt, then either the Urinous Spirit of Sal + Armoniack, or the ſolution of the fix'd Salt of Pot-aſhes would + immediately turn it of a Yellowiſh Colour, the fix'd or Urinous Salt + Precipitating the Vitriolate ſubſtance contain'd in the Eſſence. + But here I muſt not forget to take notice of a circumſtance that + deſerves to be compar'd with ſome part of the foregoing + Experiment, for whereas our Eſſence imparts a Greenneſs to + Wine, but not to Water, the Induſtrious <i>Olaus Wormius</i><a + name="LNtA_23" id="LNtA_23_"></a><a href="#LNt_23"><sup>23</sup></a> in his + late <i>Musæum</i> tells us of a rare kind of Turn-Sole which he calls <i>Bezetta + Rubra</i> given him by an Apothecary that knew not how it was made, whoſe + lovely Redneſs would be eaſily communicated to Water, if it were + immers'd in it; but ſcarce to Wine, and not at all to Spirit of Wine, + in which laſt circumſtance it agrees with what I lately told you + of our Eſſence, notwithſtanding their diſagreement in + other particulars. + </p> + <!-- Page 341 --> + <p> + <span class="pagenum"><a name="LPage_341" id="LPage_341"></a>[pg 341]</span> + </p> + <h3> + <i>EXPERIMENT XLVI.</i> + </h3> + <p> + We have often taken notice, as of a remarkable thing, that Metalls as they + appear to the Eye, before they come to be farther alter'd by other Bodyes, + do exhibit Colours very different from thoſe which the Fire and the + <i>Menſtruum</i>, either apart, or both together, do produce in them; + eſpecially conſidering that theſe Metalline Bodyes are + after all theſe diſguiſes reducible not only to their + former Metalline Conſiſtence and other more radical properties, + but to their Colour too, as if Nature had given divers Metalls to each of + them a double Colour, an <i>External</i>, and an <i>Internal</i>; But + though upon a more attentive Conſideration of this difference of + Colours, it ſeem'd probable to me, that divers (for I ſay not + all) of thoſe Colours which we have juſt now call'd <i>Internal</i>, + are rather produc'd by the Coalition of Metalline Particles with thoſe + of the Salts, or other Bodyes employ'd to work on them, than by the bare + alteration of the parts of the Metalls themſelves: and though + therefore we may call the obvious Colours, Natural or Common, & the + others Adventitious, yet becauſe ſuch changes of Colours, from + whatſoever cauſe they be reſolv'd to + <!-- Page 342 --> <span class="pagenum"><a name="LPage_342" + id="LPage_342"></a>[pg 342]</span> proceed may be properly enough taken in + to illuſtrate our preſent Subject, we ſhall not ſcruple + to take notice of ſome of them, eſpecially becauſe there + are among them ſuch as are produc'd without the intervention of + Saline <i>Menſtruums</i>. Of the Adventitious Colours of Metalline + Bodies the Chief ſorts ſeem to be theſe three. The firſt, + ſuch Colours as are produc'd without other Additaments by the Action + of the fire upon Metalls. The next ſuch as emerge from the Coalition + of Metalline Particles with thoſe of ſome <i>Menstruum</i> + imploy'd to Corrode a Metall or Precipitate it; And the laſt, The + Colours afforded by Metalline Bodyes either Colliquated with, or otherwiſe + Penetrating into, other Bodies, eſpecially fuſible ones. But theſe + (<i>Pyrophilus,</i>) are only as I told you, the <i>Chief</i> ſorts + of the adventitious Colours of Metalls, for there may others belong to + them, of which I ſhall hereafter have occaſion to take notice of + ſome, and of which alſo there poſſibly may be others + that I never took notice of. + </p> + <p> + And to begin with the firſt ſort of Colours, 'tis well enough + known to Chymiſts, that Tin being Calcin'd by fire alone is wont to + afford a White <i>Calx</i>, and Lead Calcin'd by fire alone affords that + moſt Common Red-Powder we call <i>Minium:</i> Copper alſo + <!-- Page 343 --> <span class="pagenum"><a name="LPage_343" + id="LPage_343"></a>[pg 343]</span> Calcin'd <i>per ſe</i>, by a long + or violent fire, is wont to yield (as far as I have had occaſion to + take notice of it) a very Dark or Blackiſh Powder; That Iron likewiſe + may by the Action of Reverberated flames be turn'd into a Colour almoſt + like that of Saffron, may be eaſily deduc'd from the Preparation of + that Powder, which by reaſon of its Colour and of the Metall 'tis + made of is by Chymiſts call'd, <i>Crocus Martis per ſe</i>. And + that <i>Mercury</i> made by the ſtreſs of Fire, may be turn'd + into a Red Powder, which Chymiſts call Precipitate <i>per ſe</i>, + I elſewhere more particularly declare. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + It is not unworthy the Admoniſhing you, (<i>Pyrophilus</i>,) and it + agrees very well with our Conjectures about the dependence of the change + of a Body's Colour upon that of its Texture, that the ſame Metall may + by the ſucceſſive operation of the fire receive divers + Adventitious Colours, as is evident in Lead, which before it come to + ſo deep a Colour as that of <i>Minium</i>, may paſs through + divers others. + </p> + <!-- Page 344 --> + <p> + <span class="pagenum"><a name="LPage_344" id="LPage_344"></a>[pg 344]</span> + </p> + <p class="center"> + <i>Annotation II</i>. + </p> + <p> + Not only the <i>Calces</i>, but the Glaſſes of Metalls, + Vitrify'd <i>per ſe</i>, may be of Colours differing from the Natural + or Obvious Colour of the Metall; as I have obſerv'd in the Glaſs + of Lead, made by long expoſing Crude Lead to a violent fire, and what + I have obſerv'd about the Glaſs or Slagg of Copper, (of which I + can ſhow you ſome of an odd kind of Texture,) may be elſewhere + more conveniently related. I have likewiſe ſeen a piece of very + Dark Glaſs, which an Ingenious Artificer that ſhow'd it me profeſs'd + himſelf to have made of Silver alone by an extreme <i>Violence</i> + (which ſeems to be no more than is needfull) of the fire. + </p> + <p class="center"> + <i>Annotation III</i>. + </p> + <p> + Minerals alſo by the Action of the Fire may be brought to afford + Colours very differing from their own, as I not long ſince noted to + you about the variouſly Colour'd Flowers of Antimony, to which we may + add the Whitiſh Grey-Colour of its <i>Calx</i>, and the Yellow or + Reddiſh Colour of the Glaſs, where into that <i>Calx</i> may be + flux'd. + </p> + <p> + And I remember, that I elſewhere told + <!-- Page 345 --> <span class="pagenum"><a name="LPage_345" + id="LPage_345"></a>[pg 345]</span> you, that Vitriol Calcin'd with a very + gentle heat, and afterwards with higher and higher degrees of it, may be + made to paſs through ſeveral Colours before it deſcends to + a Dark Purpliſh Colour, whereto a ſtrong fire is wont at length + to reduce it. But to inſiſt on the Colours produc'd by the + Operation of fire upon ſeveral Minerals would take up farr more time + than I have now to ſpare. + </p> + <h3> + <i>EXPERIMENT XLVII.</i> + </h3> + <p> + The Adventitious Colours produc'd upon Metalls, or rather with them, by + Saline Liquors, are many of them ſo well known to Chymiſts, that + I would not here mention them, but that beſides a not un-needed Teſtimony, + I can add ſomething of my own, to what I ſhall repeat about + them, and divers Experiments which are familiar to Chymiſts, are as + yet unknown to the greateſt part of Ingenious Men. + </p> + <p> + That Gold diſſolv'd in <i>Aqua Regia</i> ennobles the <i>Menſtruum</i> + with its own Colour, is a thing that you cannot (<i>Pyrophilus</i>,) but + have often ſeen. The Solutions of Mercury in <i>Aqua-fortis</i> are + not generally taken notice of, to give any notable Tincture to the <i>Menſtruum</i>; + but ſometimes when the + <!-- Page 346 --> <span class="pagenum"><a name="LPage_346" + id="LPage_346"></a>[pg 346]</span> Liquor firſt falls upon the Quick + Silver, I have obſerv'd a very remarkable, though not durable, + Greenneſs, or Blewneſs to be produc'd, which is a <i>Phænomenon</i> + not unfit for you to conſider, though I have not now the leiſure + to diſcourſe upon it. Tin Corroded by <i>Aqua-fortis</i> till + the <i>Menstruum</i> will work no farther on it, becomes exceeding White, + but as we elſewhere note, does very eaſily of it ſelf + acquire the conſiſtence, not of a Metalline <i>Calx</i>, but of + a Coagulated matter, which we have obſerv'd with pleaſure to + look ſo like, either to curdled Milk, or curdled Whites of Eggs, that + a perſon unacquainted with ſuch Solutions may eaſily be miſtaken + in it. But when I purpoſely prepar'd a <i>Menſtruum</i> that + would diſſolve it as <i>Aqua-fortis</i> diſſolves + Silver, and not barely Corrode it, and quickly let it fall again, I + remember not that I took notice of any particular Colour in the Solution, + as if the more Whitiſh Metalls did not much Tinge their <i>Menſtruums</i>, + though the conſpicuouſly Colour'd Metalls as Gold, and Copper, + do. For Lead diſſolv'd in Spirit of Vinegar or <i>Aqua-fortis</i> + gives a Solution cleer enough, and if the <i>Menſtruum</i> be abſtracted + appears either Diaphanous or White. Of the Colour of Iron we have elſewhere + ſaid ſomething: And 'tis worth + <!-- Page 347 --> <span class="pagenum"><a name="LPage_347" + id="LPage_347"></a>[pg 347]</span> noting, that though if that Metall be + diſſolv'd in oyl of Vitriol diluted with water, it affords a + Salt or Magiſtery ſo like in colour, as well as ſome other + Qualities, to other green Vitriol, that Chymiſts do not improperly + call it <i>Vitriolum Martis</i>; yet I have purpoſely try'd, that, by + changing the <i>Menſtruum</i>, and pouring upon the filings of Steel, + inſtead of oyl of Vitriol, <i>Aqua Fortis</i>, (whereof as I + remember, I us'd 4 parts to one of the Metall) I obtain'd not a Green, but + a Saffron Colour Solution; or rather a thick Liquor of a deep but yellowiſh + Red. Common Silver, ſuch as is to be met with in Coines, being diſſolv'd + in <i>Aqua fortis</i>, yields a Solution tincted like that of Copper, + which is not to be wondred at, becauſe in the coining of Silver, they + are wont (as we elſewhere particularly inform you) to give it an + Allay of Copper, and that which is ſold in ſhops for refined + ſilver, is not (ſo far as we have tryed) ſo perfectly free + from that ignobler Metall, but that a Solution of It in <i>Aqua fortis</i>, + will give a Venereal Tincture to the <i>Menſtruum</i>. But we could + not obſerve upon the ſolution of ſome Silver, which was + perfectly refin'd, (ſuch as ſome that we have, from which 8 or + 10 times its weight of Lead has been blown off) that the <i>Menſtruum</i> + <!-- Page 348 --> <span class="pagenum"><a name="LPage_348" + id="LPage_348"></a>[pg 348]</span> though held againſt the Light in a + Cryſtal Vial did manifeſtly diſcloſe any Tincture, + only it ſeem'd ſometimes not to be quite deſtitute of a + little, but very faint Blewiſhneſs. + </p> + <p> + But here I muſt take notice, that of all the Metalls, there is not + any which doth ſo eaſily and conſtantly diſcloſe + its unobvious colour as Copper doth. For not only in acid <i>Menſtruums</i> + as <i>Aqua Fortis</i> and Spirit of Vinegar, it gives a Blewiſh green + ſolution, but if it be almoſt any way corroded, it <i>appears of + one of thoſe</i> two colours, as may be obſerv'd in Verdigreeſe + made ſeveral wayes, in that odd preparation of <i>Venus</i>, which we + elſewhere teach you to make with Sublimate, and in the common + Vitriols of <i>Venus</i> deliver'd by Chymiſts; and ſo conſtant + is the diſpoſition of Copper, notwithſtanding the diſguiſe + Artiſts put upon it, to diſcloſe the colour we have been + mentioning, that we have by forcing it up with <i>Sal Armoniack</i> + obtain'd a Sublimate of a Blewiſh Colour. Nay a famous Spagyriſt + affirms, that the very Mercury of it is green, but till he teach us an + intelligible way of making ſuch a Mercury, we muſt content ourſelves + to inform you, that we have had a Cupreous Body, that was Præcipitated out + of a diſtill'd Liquor, that ſeem'd to be the + <!-- Page 349 --> <span class="pagenum"><a name="LPage_349" + id="LPage_349"></a>[pg 349]</span> the Sulphur of <i>Venus</i>, and ſeem'd + even when flaming, of a Greeniſh Colour. And indeed Copper is a + Metall ſo eaſily wrought upon by Liquors of ſeveral kinds, + that I ſhould tell you, I know not any Mineral, that will concurr to + the production of ſuch a variety of Colours as Copper diſſol'd + in ſeveral <i>Menſtruums</i>, as Spirit of Vinegar, <i>Aqua + fortis</i>, <i>Aqua Regis</i>, Spirit of Nitre, of Urine, of Soot, Oyls of + ſeveral kinds, and I know not how many other Liquors, if the variety + of ſomewhat differing colours (that Copper will be made to aſſume, + as it is wrought upon by ſeveral Liquors) were not comprehended + within the Limits of Greeniſh Blew, or Blewiſh Green. + </p> + <p> + And yet I muſt advertiſe you (<i>Pyrophilus</i>) that being deſirous + to try if I could not make with crude Copper a Green Solution without the + Blewiſhneſs that is wont to accompany its Vulgar Solutions, I + bethought my ſelf of uſing two <i>Menſtruums</i>, which I + had not known imploy'd to work on this Metall, and which I had certain Reaſons + to make Tryal of, as I ſucceſsfully did. The one of theſe + Liquors (if I much miſremember not) was Spirit of Sugar diſtill'd + in a Retort, which muſt be warily done, (if you will avoid breaking + your + <!-- Page 350 --> <span class="pagenum"><a name="LPage_350" + id="LPage_350"></a>[pg 350]</span> glaſſes) and the other, Oyl + or Spirit of Turpentine, which affords a fine Green Solution that is uſeful + to me on ſeveral occaſions. And yet to ſhew that the + adventitious colour may reſult, as well from the true and permanent + Copper it ſelf, as the Salts wherewith 'tis corroded, I ſhall + add, that if you take a piece of good <i>Dantzick</i> Copperis, or any + other Vitriol wherein <i>Venus</i> is prædominant, and having moiſtened + it in your Mouth, or with fair water, rubb it upon a whetted knife, or any + other bright piece of Steel or Iron, it will (as we have formerly told + you) preſent'y ſtain the Steel with a Reddiſh colour, like + that of Copper, the reaſon of which, we muſt not now ſtay + to inquire. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + I preſume you may have taken notice (<i>Pyrophilus</i>) that I have + borrowed ſome of the Inſtances mention'd in this 47<sup>th</sup> + Experiment, from the Laboratories of Chymiſts, and becauſe in + ſome (though very few) other paſſages of this Eſſay, + I have likewiſe made uſe of Experiments mention'd alſo by + ſome Spagyrical Writers, I think it not amiſs to repreſent + to you on this Occaſion once for all, ſome things beſides + <!-- Page 351 --> <span class="pagenum"><a name="LPage_351" + id="LPage_351"></a>[pg 351]</span> those which I intimated in the præamble + of this preſent Experiment; For beſides, that 'tis very + allowable for a Writer to repeat an Experiment which he invented not, in + caſe he improve it; And beſides that many Experiments familiar + to Chymiſts are unknown to the generality of Learned Men, who either + never read Chymical proceſſes, or never underſtood their + meaning, or never durſt believe them; beſides theſe things, + I ſay, I ſhall repreſent, That, as to the few Experiments I + have borrowed from the Chymiſts, if they be very Vulgar, 'twould + perhaps be difficult to aſcribe each of them its own Author, and 'tis + more than the generality of Chymiſts themſelves can do: and if + they be not of very known and familiar practiſe among them, unleſs + the Authors wherein I found them had given me cauſe to believe, themſelves + had try'd them, I know not why I might not ſet them down, as a part + of the <i>Phænomena</i> of Colours which I preſent you; Many things + unanimouſly enough deliver'd as matters of fact by (I know not how + many Chymical Writers) being not to be rely'd on, upon the ſingle + Authority of ſuch Authors: For Inſtance, as ſome Spagyriſts + deliver (perhaps amongſt ſeveral deceitful proceſſes) + that <i>Saccarum Saturni</i> + <!-- Page 352 --> <span class="pagenum"><a name="LPage_352" + id="LPage_352"></a>[pg 352]</span> with Spirit of Turpentine will afford a + Balſom, ſo <i>Beguinus</i> and many more tell us, that the + ſame Concrete (<i>Saccarum Saturni</i>) will yield an incomparably + fragrant Spirit, and a pretty Quantity of two ſeveral Oyles, and yet + ſince many have complain'd, as well as I have done, that they could + find no ſuch odoriferous, but rather an ill-ſented Liquor, and + ſcarce any oyl in their Diſtillation of that ſweet Vitriol, + a wary perſon would as little build any thing on what they ſay + of the former Experiment, as upon what they averr of the later, and + therefore I ſcrupled not to mention this Red Balſom of which I + have not ſeen any, (but what I made) among my other experiments about + redneſs. + </p> + <p class="center"> + <i>Annot. II.</i> + </p> + <p> + We have ſometimes had the Curioſity to try what Colours + Minerals, as Tinglaſs, Antimony, Spelter, &c. would yield in + ſeveral <i>Menſtruums</i>, nor have we forborn to try the + Colours of ſtones, of which that famous one, (which <i>Helmont</i> + calls <i>Paracelſus's Ludus</i>) though it be digg'd out of the Earth + and ſeem a true ſtone, has afforded in <i>Menſtruums</i> + capable to diſſolve ſo ſolid a ſtone, ſometimes + a Yellowiſh, + <!-- Page 353 --> <span class="pagenum"><a name="LPage_353" + id="LPage_353"></a>[pg 353]</span> ſometimes a Red ſolution of + both which I can ſhow you. But though I have from Minerals obtain'd + with ſeveral <i>Menſtruums</i> very differing Colours, and + ſome ſuch as perhaps you would be ſurpriz'd to ſee + drawn from ſuch Bodies: yet I muſt now paſs by the + particulars, being deſirous to put an End to this Treatiſe, + before I put an end to your Patience and my own. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + And yet before I paſs to the next Experiment, I muſt put you in + mind, that the Colours of Metals may in many caſes be further alter'd + by imploying, either præcipitating Salts, or other convenient Subſtances + to act upon their Solutions. Of this you may remember, that I have given + you ſeveral Inſtances already, to which may be added ſuch + as theſe, That if Quickſilver be diſſolv'd in <i>Aqua + fortis</i>, and Præcipitated out of the Solution, either with water + impregnated with Sea ſalt, or with the ſpirit of that Concrete, + it falls to the Bottom in the form of a white powder, whereas if it be + Præcipitated with an Alcaly, it will afford a Yellowiſh or tawny + powder, and if there be no Præcipitation made, and the <i>Menſtruum</i> + be drawn off with a convenient + <!-- Page 354 --> <span class="pagenum"><a name="LPage_354" + id="LPage_354"></a>[pg 354]</span> fire, the corroded Mercury will remain + in the bottom, in the form of a ſubſtance that may be made to + appear of differing Colours by differing degrees of Heat; As I remember + that lately having purpoſely abſtracted <i>Aqua fortis</i> from + ſome Quickſilver that we had diſſolv'd in it, ſo + that there remain'd a white <i>Calx</i>, expoſing that to ſeveral + degrees of Fire, and afterwards to a naked one, we obtain'd ſome new + Colours, and at length the greateſt part of the <i>Calx</i> lying at + the Bottome of the Vial, and being brought partly to a Deep Yellow, and + partly to a Red Colour, the reſt appear'd elevated to the upper part + and neck of the Vial, ſome in the form of a Reddiſh, and ſome + of an Aſh-Colour Sublimate. But of the differing Colours which by + differing wayes and working of Quick Silver with Fire, and Saline Bodies, + may be produc'd in Precipitates, I may elſewhere have occaſion + to take further notice. I alſo told you not long ſince, that if + you corrode Quick-ſilver with Oyl of Vitriol inſtead of <i>Aqua-fortis</i>, + and abſtract the <i>Menſtruum</i>, there will remain a White <i>Calx</i> + which by the Affuſion of Fair Water preſently turns into a + Lemmon Colour. And ev'n the <i>Succedaneum</i> to a <i>Menſtruum</i> + may ſometimes ſerve the turn to change the Colours of a Metal. + The lovely + <!-- Page 355 --> <span class="pagenum"><a name="LPage_355" + id="LPage_355"></a>[pg 355]</span> Red which Painters call Vermillion, is + made of Mercury, which is of the Colour of Silver, and of Brimſtone + which is of Kin to that of Gold, Sublim'd up together in a certain + proportion, as is vulgarly known to Spagyriſts. + </p> + <h3> + <i>EXPERIMENT XLVIII.</i> + </h3> + <p> + The third chief ſort of the Adventitious Colours of Metals, is, that + which is produc'd by aſſociating them (eſpecially when + Calcin'd) with other fuſible Bodies, and Principally Venice, and + other fine Glaſs devoid of Colour. + </p> + <p> + I have formerly given you an Example, whereby it may appear, that a Metal + may impart to Glaſs a Colour much differing from its own, when I told + you, how with Silver, I had given Glaſs a lovely Golden Colour. And I + ſhall now add, that I have Learn'd from one of the Chief Artificers + that ſells Painted Glaſs, that thoſe of his Trade Colour it + Yellow with a preparation of the <i>Calx</i> of Silver. Though having + lately had occaſion among other Tryals to mingle a few grains of + Shell-ſilver (ſuch as is imploy'd with the Penſil and Pen) + with a convenient proportion of powder'd Cryſtal Glaſs, having + kept them two or three + <!-- Page 356 --> <span class="pagenum"><a name="LPage_356" + id="LPage_356"></a>[pg 356]</span> hours in fuſion, I was ſurpriz'd + to find the Colliquated Maſs to appear upon breaking the Crucible of + a lovely Saphirine Blew, which made me ſuſpect my Servant might + have brought me a wrong Crucible, but he conſtantly affirm'd it to be + the ſame wherein the Silver was put, and conſiderable Circumſtances + countenanc'd his Aſſertion, ſo that till I have opportunity + to make farther Tryal, I cannot but ſuſpect, either that Silver + which is not (which is not very probable) brought to a perfect Fuſion + and Colliquation with Glaſs, may impart to it other Colours than when + Neal'd upon it, or elſe (which is leſs unlikely) that though + Silver Beaters uſually chuſe the fineſt Coyn they can get, + as that which is moſt extenſive under the Hammer, yet the + Silver-leaves of which this Shel-ſilver was made, might retain ſo + much Copper as to enable it to give the predominant tincture to the Glaſs. + </p> + <p> + For, I muſt proceed to tell you (<i>Pyrophilus</i>) as another inſtance + of the Adventitious Colours of Metals, that which is ſomething ſtrange, + Namely, That though Copper Calcin'd <i>per ſe</i> affords but a Dark + and baſely Colour'd <i>Calx</i>, yet the Glaſsmen do with it, as + themſelves inform me, Tinge their Glaſs green. And I remember, + that when once we took ſome crude Copper, + <!-- Page 357 --> <span class="pagenum"><a name="LPage_357" + id="LPage_357"></a>[pg 357]</span> and by frequent Ignition quenching it + in Water had reduc'd it to a Dark and Ill-colour'd Powder, and afterward + kept it in Fuſion in about a 100. times its weight of fine Glaſs, + we had, though not a Green, yet a Blew colour'd Maſs, which would + perhaps have been Green, if we had hit right upon the Proportion of the + Materials, and the Degree of Fire, and the Time wherein it ought to be + kept in Fuſion, ſo plentifully does that Metal abound in a + Venerial Tincture, as Artiſts call it, and in ſo many wayes does + it diſcloſe that Richneſs. But though Copper do as we have + ſaid give ſomewhat near the like Colour to Glaſs, which it + does to <i>Aqua-fortis</i>, yet it ſeems worth inquiry, whether thoſe + new Colours which Mineral Bodies diſcloſe in melted Glaſs, + proceed from the Coalition of the Corpuſcles of the Mineral with the + Particles of the Glaſs as ſuch, or from the Action (excited or + actuated by fire) of the Alcalizate Salt (which is a main Ingredient of + Glaſs,) upon the Mineral Body, or from the concurrence of both theſe + Cauſes, or elſe from any other. But to return to that which we + were ſaying, we may obſerve that <i>Putty</i> made by calcining + together a proportion of Tin and Lead, as it is it ſelf a White <i>Calx</i>, + ſo does it turn the <i>Pitta di Cryſtallo</i> (as the + <!-- Page 358 --> <span class="pagenum"><a name="LPage_358" + id="LPage_358"></a>[pg 358]</span> Glaſsmen call the matter of the + Purer ſort of Glaſs, wherewith it is Colliquated into a White Maſs, + which if it be opacous enough is employ'd, as we elſewhere declare, + for White Amel. But of the Colours which the other Metals may be made to + produce in Colourleſs Glaſs, and other Vitrifiable Bodies, that + have native Colours of their own, I muſt leave you to inform your + ſelf upon Tryal, or at leaſt muſt forbear to do it till + another time, conſidering how many Annotations are to follow, upon + what has in this and the two former Experiments been ſaid already. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + When the Materials of Glaſs being melted with Calcin'd Tin, have + compos'd a Maſs Undiaphanous and White, this White Amel is as it were + the Baſis of all thoſe fine Concretes that Goldſmiths and + ſeveral Artificers imploy in the curious Art of Enamelling. For this + White and Fuſible ſubſtance will receive into it ſelf, + without ſpoyling them, the Colours of divers other Mineral ſubſtances, + which like it will indure the fire. + </p> + <!-- Page 359 --> + <p> + <span class="pagenum"><a name="LPage_359" id="LPage_359"></a>[pg 359]</span> + </p> + <p class="center"> + <i>Annotation II.</i> + </p> + <p> + So that as by the preſent (XLVIII.) Experiment it appears, that + divers Minerals will impart to fuſible Maſſes, Colours + differing from their own; ſo by the making and compounding of Amels, + it may appear, that divers Bodies will both retain their Colour in the + fire, and impart the <i>ſame</i> to ſome others wherewith they + were vitrifi'd, and in ſuch Tryals as that mention'd in the 17. + Experiment, where I told you, that ev'n in Amels a Blew and Yellow will + compound a Green. 'Tis pretty to behold, not only that ſome Colours + are of ſo fix'd a Nature, as to be capable of mixture without + receiving any detriment by the fire, that do's ſo eaſily deſtroy + or ſpoyl thoſe of other Bodies; but Mineral Pigments may be + mingled by fire little leſs regularly and ſucceſsfully, + than in ordinary Dyeing Fatts, the vulgar Colours are wont to be mingled + by the help of Water. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + 'Tis not only Metalline, but other Mineral Bodies, that may be imploy'd, + to give Tinctures unto Glaſs (and 'tis worth noting + <!-- Page 360 --> <span class="pagenum"><a name="LPage_360" + id="LPage_360"></a>[pg 360]</span> how ſmall a quantity of ſome + Mineral ſubſtances, will Tinge a Comparatively vaſt + proportion of Glaſs, and we have ſometimes attempted to Colour + Glaſs, ev'n with Pretious Stones, and had cauſe to think the + Experiment not caſt away. And 'tis known by them that have look'd + into the Art of Glaſs, that the Artificers uſe to tinge their + Glaſs Blew, with that Dark Mineral <i>Zaffora</i>, (ſome of my + Tryals on which I elſewhere acquaint you) which ſome would have + to be a Mineral Earth, others a Stone, and others neither the one, nor the + other, but which is confeſſedly of a Dark, but not a Blew + Colour, though it be not agreed of what particular Colour it is. 'Tis + likewiſe though a familiar yet a remarkable practiſe among thoſe + that Deal in the making of Glaſs, to imploy (as ſome of themſelves + have inform'd me) what they call Manganeſs, and ſome Authors + call <i>Magneſia</i> (of which I make particular mention in another + Treatiſe) to exhibit in Glaſs not only other Colours than its + own, (which is ſo like in Darkneſs or blackiſhneſs to + the Load ſtone, that 'tis given by Mineraliſts, for one of the + Reaſons of its Latine Name) but Colours differing from one another. + For though they uſe it, (which is ſomewhat ſtrange) to + Clarifye their Glaſs, and free + <!-- Page 361 --> <span class="pagenum"><a name="LPage_361" + id="LPage_361"></a>[pg 361]</span> it from that Blewiſh Greeniſh + Colour, which elſe it would too often be ſubject to, yet they alſo + imploy it in certain proportions, to tinge their Glaſs both with a + Red colour, and with a Purpliſh or Murry, and putting in a greater + Quantity, they alſo make with it that deep obſcure Glaſs + which is wont to paſs for Black, which agrees very well with, and may + ſerve to confirm what we noted near the beginning of the 44<sup>th</sup> + Experiment, of the ſeeming Blackneſs of thoſe Bodies that + are overcharg'd with the Corpuſcles of ſuch Colours, as Red, or + Blew, or Green, &c. And as by ſeveral Metals and other Minerals + we can give various Colours to Glaſs, ſo on the other ſide, + by the differing Colours that Mineral Oars, or other Mineral Powders being + melted with Glaſs diſcloſe in it, a good Conjecture may be + oftentimes made of the Metall or known Mineral, that the Oar propos'd, + either holds, or is moſt of kin to. And this eaſie way of + examining Oars, may be in ſome caſes of good uſe, and is + not ill deliver'd by <i>Glauber</i>, to whom I ſhall at preſent + refer you, for a more particular account of it: unleſs your Curioſity + command alſo what I have obſerv'd about theſe matters; only + I muſt here advertiſe you, that great circumſpection is + <!-- Page 362 --> <span class="pagenum"><a name="LPage_362" + id="LPage_362"></a>[pg 362]</span> requiſite to keep this way from + proving fallacious, upon the account of the variations of Colour that may + be produc'd by the differing proportions that may be us'd betwixt the Oar + and the Glaſs, by the Richneſs or Poorneſs of the Oar it + ſelf, by the Degree of Fire, and (eſpecially) by the Length of + Time, during which the matter is kept in fuſion; as you will eaſily + gather from what you will quickly meet with in the following Annotation + upon this preſent 48<sup>th</sup> Experiment. + </p> + <p class="center"> + <i>Annotation IV.</i> + </p> + <p> + There is another way and differing enough from thoſe already + mention'd, by which Metalls may be brought to exhibit adventitious + Colours: For by This, the Metall do's not ſo much impart a Colour to + another Body, as receive a Colour from it, or rather both Bodies do by the + new Texture reſulting from their miſtion produce a new Colour. I + will not inſiſt to this purpoſe upon the Examples afforded + us by yellow Orpiment, and common Sea Salt, from which, ſublim'd + together, Chymiſts unanimouſly affirm their White or Cryſtalline + Arſenick to be made: But 'tis not unworthy our noting, That though + Yellow + <!-- Page 363 --> <span class="pagenum"><a name="LPage_363" + id="LPage_363"></a>[pg 363]</span> Orpiment be acknowledg'd to be the + Copiouſeſt by far of the two Ingredients of Arſenick, yet + this laſt nam'd Body being duely added to the higheſt Colour'd + Metall Copper, when 'tis in fuſion, gives it a whiteneſs both + within and without. Thus <i>Lapis Calaminaris</i> changes and improves the + Colour of Copper by turning it into Braſs. And I have ſometimes + by the help of Zinck duely mix'd after a certain manner, given Copper one + of the Richeſt Golden Colours that ever I have ſeen the Beſt + true Gold Ennobled with. But pray have a care that ſuch Hints fall + not into any hands that may mis-imploy them. + </p> + <p class="center"> + <i>Annotation V.</i> + </p> + <p> + Upon the Knowledge of the differing wayes of making Minerals and Metalls + produce their adventitious Colours in Bodies capable of Vitrification, + depends the pretty Art of making what Chymiſts by a Barbarous Word + are pleas'd to call <i>Amanſes</i>, that is counterfeit, or + factitious Gemms, as Emeralds, Rubies, Saphires, Topazes, and the like. + For in the making of theſe, though pure Sand or Calcin'd Cryſtal + give the Body, yet 'tis for the moſt part ſome Metalline or + Mineral <i>Calx</i>, mingled in a + <!-- Page 364 --> <span class="pagenum"><a name="LPage_364" + id="LPage_364"></a>[pg 364]</span> small proportion that gives the Colour. + But though I have many years ſince taken delight, to divert my ſelf + with this pleaſing Art, and have ſeen very pretty Productions of + it, yet beſides that I fear I have now forgot moſt of the little + Skill I had in it, this is no place to entertain you with what would + rather take up an intire Diſcourſe, than be comprehended in an + Annotation; wherefore the few things which I ſhall here take notice + of to you, are only what belong to the preſent Argument, Namely, + </p> + <p> + Firſt, That I have often obſerv'd that Calcin'd Lead Colliquated + with fine White Sand or Cryſtal, reduc'd by ignitions and ſubſequent + extinctions in Water to a ſubtile Powder, will of it ſelf be + brought by a due Decoction to give a cleer Maſs Colour'd like a <i>German</i> + Amethyſt. For though this glaſs of Lead, is look'd upon by them + that know no better way of making <i>Amanſes</i>, as the grand Work + of them all, yet which is an inconvenience that much blemiſhes this + way, the Calcin'd Lead it ſelf does not only afford matter to the <i>Amanſes</i>, + but has alſo as well as other Metals a Colour of its own, which as I + was ſaying, I have often found to be like that of <i>German</i> (as + many call them) not Eaſtern Amethyſts. + </p> + <p> + Secondly, That nevertheleſs this Colour + <!-- Page 365 --> <span class="pagenum"><a name="LPage_365" + id="LPage_365"></a>[pg 365]</span> may be eaſily over-powr'd by thoſe + of divers other Mineral Pigments (if I may ſo call them) ſo that + with a glaſs of Lead, you may Emulate (for Inſtance) the freſh + and lovely Greenneſs of an Emerald, though in divers caſes the + Colour which the Lead it ſelf upon Vitrification tends to, may + vitiate that of the Pigment, which you would introduce into the Maſs. + </p> + <p> + Thirdly, That ſo much ev'n theſe Colours depend upon Texture, + that in the Glaſs of Lead it ſelf made of about three parts of + <i>Lytharge</i> or <i>Minium</i> Colliquated with one of very finely + Powder'd Cryſtal or Sand, we have taken pleaſure to make the + mixture paſs through differing Colours, as we kept it more or leſs + in the Fuſion. For it was not uſually till after a pretty long + Decoction that the Maſs attain'd to the Amethyſtin Colour. + </p> + <p> + Fourthly and laſtly, That the degrees of Coction and other Circumſtances + may ſo vary the Colour produc'd in the ſame maſs, that in a + Crucible that was not great I have had fragments of the ſame Maſs, + in ſome of which perhaps not ſo big as a Hazel-Nut, you may diſcern + four diſtinct Colours. + </p> + <!-- Page 366 --> + <p> + <span class="pagenum"><a name="LPage_366" id="LPage_366"></a>[pg 366]</span> + </p> + <p class="center"> + <i>Annotation VI.</i> + </p> + <p> + You may remember (<i>Pyrophilus</i>) that when I mention'd the three + ſorts of adventitious Colours of Metals, I mention'd them but as the + chief, not the only. For there may be other wayes, which though they do + not in ſo ſtrict a ſenſe belong to the adventitious + Colours of Metals, may not inconveniently be reduc'd to them. And of theſe + I ſhall name now a couple, without denying that there may be more. + </p> + <p> + The firſt may be drawn from the practiſe of thoſe that Dye + Scarlet. For the famouſeſt Maſter in that Art, either in <i>England</i> + or <i>Holland</i>, has confeſs'd to me, that neither others, nor he + can ſtrike that lovely Colour which is now wont to be call'd the <i>Bow-Dye</i>, + without their Materials be Boyl'd in Veſſels, either made of, or + lin'd with a particular Metall. But of what I have known attempted in this + kind, I muſt not as yet for fear of prejudicing or diſpleaſing + others give you any particular Account.<a name="LNtA_24" id="LNtA_24_"></a><a + href="#LNt_24"><sup>24</sup></a> + </p> + <p> + The other way (<i>Pyrophilus</i>) of making Metals afford unobvious + Colours, is by imbuing divers Bodies with Solutions of them made in their + proper <i>Menſtruum's</i>, As (for + <!-- Page 367 --> <span class="pagenum"><a name="LPage_367" + id="LPage_367"></a>[pg 367]</span> Inſtance) though Copper + plentifully diſſolv'd in <i>Aqua fortis</i>, will imbue ſeveral + Bodies with the Colour of the Solution; Yet Some other Metalls will not + (as I elſewhere tell you) and have often try'd. Gold diſſolv'd + in <i>Aqua Regia</i>, will, (which is not commonly known) Dye the Nails + and Skin, and Hafts of Knives, and other things made of Ivory, not with a + Golden, but a Purple Colour, which though it manifeſt it ſelf + but ſlowly, is very durable, and ſcarce ever to be waſh'd + out. And if I miſremember not, I have already told you in this Treatiſe, + that the purer Cryſtals of fine Silver made with <i>Aqua fortis</i>, + though they appear White, will preſently Dye the Skin and Nails, with + a Black, or at leaſt a very Dark Colour, which Water will not waſh + off, as it will ordinary Ink from the ſame parts. And divers other + Bodies may the Same way be Dy'd, ſome of a Black, and others of a + Blackiſh Colour. + </p> + <p> + And as Metalline, ſo likewiſe Mineral Solutions may produce + Colours differing enough from thoſe of the Liquors themſelves. I + ſhall not fetch an Example of this, from what we daily ſee + happen in the powdring of Beef, which by the Brine imploy'd about it (eſpecially + if the fleſh be + <!-- Page 368 --> <span class="pagenum"><a name="LPage_368" + id="LPage_368"></a>[pg 368]</span> over ſalted) do's oftentimes + appear at our Tables of a Green, and ſometimes of a Reddiſh + Colour, (deep enough) nor ſhall I inſiſt on the practiſe + of ſome that deal in Salt Petre, who, (as I ſuſpected, and + as themſelves acknowledg'd to me) do, with the mixture of a certain + proportion of that; and common Salt, give a fine Redneſs, not only to + Neats Tongues, but which is more pretty as well as difficult, to ſuch + fleſh, as would otherwiſe be purely White; Theſe Examples, + I ſay, I ſhall decline inſiſting on, as chuſing + rather to tell you, that I have ſeveral times try'd, that a Solution + of the Sulphur of Vitriol, or ev'n of common Sulphur, though the Liquor + appear'd clear enough, would immediately tinge a piece of new Coin, or + other clean Silver, ſometimes with a Golden, ſometimes with a + deeper, and more Reddiſh colour, according to the ſtrength of + the Solution, and the quantity of it, that chanc'd to adhere to the + Metall; which may take off your wonder that the water of the hot Spring at + <i>Bath</i>, abounding with diſſolv'd Subſtances of a very + Sulphureous Nature, ſhould for a while, as it were gild, the new or + clean pieces of Silver coyn, that are for a due time immers'd in it. And + to theſe may be added thoſe formerly mention'd Examples + <!-- Page 369 --> <span class="pagenum"><a name="LPage_369" + id="LPage_369"></a>[pg 369]</span> of the adventitious Colours of Mineral + Bodies; which brings into my mind, that, ev'n Vegetable Liquors, whether + by degeneration, or by altering the Texture of the Body that imbibes them, + may ſtain other Bodies with Colours differing enough, from their own, + of which very good Herbariſts have afforded us a notable Example, by + affirming that the Juice of <i>Alcanna</i> being green (in which ſtate + I could never here procure it) do's yet Dye the Skin and Nails of a Laſting + Red. But I ſee this Treatiſe is like to prove too bulky without + the addition of further Inſtances of this Nature. + </p> + <h3> + <i>EXPERIMENT XLIX.</i> + </h3> + <p> + Meeting the other day, <i>Pyrophilus</i>, in an <i>Italian</i> book, that + treats of other matters, with a way of preparing what the Author calls a + <i>Lacca</i> of Vegetables, by which the <i>Italians</i> mean a kind of + Extract fit for Painting, like that rich <i>Lacca</i> in Engliſh + commonly call'd <i>Lake</i>, which is imploy'd by Painters as a glorious + Red. And finding the Experiment not to be inconſiderable, and very + defectively ſet down, it will not be amiſs to acquaint you with + what ſome Tryals have inform'd us, in reference to this + <!-- Page 370 --> <span class="pagenum"><a name="LPage_370" + id="LPage_370"></a>[pg 370]</span> Experiment, which both by our Italian + Author, and by divers of his Countrymen, is look'd upon as no trifling + Secret. + </p> + <p> + Take then the root call'd in Latin <i>Curcuma</i>, and in Engliſh + Turmerick, (which I made uſe of, becauſe it was then at hand, + and is among Vegetables fit for that purpoſe one of the moſt eaſieſt + to be had) and when it is beaten, put what Quantity of it you pleaſe + into fair Water, adding to every pound of Water about a ſpoonfull or + better of as ſtrong a <i>Lixivium</i> or Solution of Potaſhes as + you can well make, clarifying it by Filtration before you put it to the + Decocting water. Let theſe things boyl, or rather ſimper over a + ſoft Fire in a clean glaz'd Earthen Veſſel, till you find + by the Immerſion of a ſheet of White Paper (or by ſome + other way of Tryal) that the Liquor is ſufficiently impregnated with + the Golden Tincture of the Turmerick, then take the Decoction off the + Fire, and Filter or Strain it that it may be clean, and leiſurely + dropping into it a ſtrong Solution of Roch Allum, you ſhall find + the Decoction as it were curdl'd, and the tincted part of it either to + emerge, to ſubſide, or to ſwim up and down, like little + Yellow flakes; and if you pour this mixture into a Tunnel lin'd with Cap + Paper, the Liquor that Filtred formerly + <!-- Page 371 --> <span class="pagenum"><a name="LPage_371" + id="LPage_371"></a>[pg 371]</span> ſo Yellow, will now paſs + clean thorow the Filtre, leaving its tincted, and as it were curdled parts + in the Filtre, upon which fair Water muſt be ſo often pour'd, + till you have Dulcifi'd the matter therein contain'd, the ſign of + which Dulcification is (you know) when the Water that has paſs'd + through it, comes from it as taſteleſs as it was pour'd on it. + And if without Filtration you would gather together the flakes of this + Vegetable Lake, you muſt pour a great Quantity of fair Water upon the + Decoction after the affuſion of the Alluminous Solution, and you + ſhall find the Liquor to grow clearer, and the Lake to ſettle + together at the bottom, or emerge to the top of the Water, though ſometimes + having not pour'd out a ſufficient Quantity of fair Water, we have obſerv'd + the Lake partly to ſubſide, and partly to emerge, leaving all + the middle of the Liquor clear. But to make this Lake fit for uſe, it + muſt by repeated affuſions of freſh Water, be Dulcifi'd + from the adhering Salts, as well as that ſeparated by Filtration, and + be ſpread and ſuffer'd to dry leiſurely upon pieces of + Cloth, with Brown Paper, or Chalk, or Bricks under + <!-- Page 372 --> <span class="pagenum"><a name="LPage_372" + id="LPage_372"></a>[pg 372]</span> them to imbibe the Moiſture<a + name="LNtA_25" id="LNtA_25_"></a><a href="#LNt_25"><sup>25</sup></a>. + </p> + <p class="center"> + <i>Annotation I.</i> + </p> + <p> + Whereas it is preſum'd that the Magiſtery of Vegetables obtain'd + this way conſiſts but of the more Soluble and Coloured parts of + the Plants that afford it, I muſt take the liberty to Queſtion + the ſuppoſition. And for my ſo doing, I ſhall give you + this account. + </p> + <p> + According to the Notions (ſuch as they were) that I had concerning + Salts; Allom, though to ſenſe a Homogeneous Body, ought not to + be reckon'd among true Salts, but to be it ſelf look'd upon as a kind + of Magiſtery, in regard that as Native Vitriol (for ſuch I have + had) contains both a Saline ſubſtance and a Metall, whether + Copper, or Iron, corroded by it, and aſſociated with it; ſo + Allom which may be of ſo near a kin to Vitriol, that in ſome + places of <i>England</i> (as we are aſſur'd by good Authority + the ſame ſtone will + <!-- Page 373 --> <span class="pagenum"><a name="LPage_373" + id="LPage_373"></a>[pg 373]</span> ſometimes afford both) ſeems + manifeſtly to contain a peculiar kind of Acid Spirit, generated in + the Bowels of the Earth, and ſome kind of ſtony matter diſſolv'd + by it. And though in making our ordinary Allom, the Workmen uſe the Aſhes + of a Sea Weed (vulgarly call'd Kelp) and Urine: yet thoſe that ſhould + know, inform us, that, here in <i>England</i>, there is beſides the + factitious Allom, Allom made by Nature Without the help of thoſe + Additaments. Now (<i>Pyrophilus</i>) when I conſider'd this compoſition + of Allom, and that Alcalizate Salts are wont to Præcipitate what acid + Salts have diſſolv'd, I could not but be prone to ſuſpect + that the Curdled Matter, which is call'd the Magiſtery of Vegetables, + may have in it no inconſiderable proportion of a ſtony ſubſtance + Præcipitated out of the Allom by the <i>Lixivium</i>, wherein the + Vegetable had been decocted, and to ſhew you, that there is no neceſſity, + that all the curdl'd ſubſtance muſt belong to the + Vegetable, I ſhall add, that I took a ſtrong Solution of Allom, + and having Filtred it, by pouring in a convenient Quantity of a ſtrong + Solution of Potaſhes, I preſently, as I expected, turn'd the + mixture into a kind of white Curds, which being put to Filtre, the Paper + retain'd a ſtony + <!-- Page 374 --> <span class="pagenum"><a name="LPage_374" + id="LPage_374"></a>[pg 374]</span> <i>Calx</i>, copious enough, very + White, and which ſeem'd to be of a Mineral Nature, both by ſome + other ſignes, and this, that little Bits of it being put upon a live + Coal, which was Gently Blown whilſt they were on it, they did neither + melt nor fly away, and you may keep a Quantity of this White ſubſtance + for a good while, (nay for ought I can gueſs for a very long one) in + a red hot Crucible without loſing or ſpoiling it; nor did hot + Water wherein I purpoſely kept another parcel of ſuch <i>Calx</i>, + ſeem to do any more than waſh away the looſer adhering + Salts from the ſtony ſubſtance, which therefore ſeem'd + unlikely to be ſeparable by ablutions (though reiterated) from the + Præcipitated parts of the Vegetable, whoſe Lake is intended. And to + ſhew you, that there is likewiſe in Allom a Body, with which the + fix'd Salt of the Alcalizate Solution will concoagulate into a Saline Subſtance + differing from either of them, I ſhall add, that I have taken pleaſure + to recover out of the ſlowly exhal'd Liquor, that paſs'd through + the filtre, and left the foremention'd <i>Calx</i> behind, a Body that at + leaſt ſeem'd a Salt very pretty to look on, as being very White, + and conſiſting of an innumerable company of exceeding ſlender, + and ſhining Particles, which + <!-- Page 375 --> <span class="pagenum"><a name="LPage_375" + id="LPage_375"></a>[pg 375]</span> would in part eaſily melt at the + flame of a Candle, and in part flye away with ſome little noiſe. + But of this ſubſtance, and its odd Qualities more perhaps elſewhere; + for now I ſhall only take notice to you, that I have likewiſe + with Urinous Salts, ſuch as the Spirit of Sal Armoniack, as well as + with the Spirit of Urine it ſelf, Nay, (if I much miſtake not) + ev'n with Stale Urine undiſtil'd, eaſily Precipitated ſuch + a White <i>Calx</i> as I was formerly ſpeaking of, out of a Limpid + Solution of Allom, ſo that there is need of Circumſpection in + judging of the Natures of Liquors by Precipitations wherein Allom + intervenes, elſe we may ſometimes miſtakingly imagine that + to be Precipitated out of a Liquor by Allom, which is rather Precipitated + out of Allom by the Liquor: And this puts me in mind to tell you, that + 'tis not unpleaſant to behold how quickly the Solution of Allom (or + injected lumps of Allom) do's occaſion the ſevering of the + colour'd parts of the Decoction from the Liquor that ſeem'd to have + ſo perfectly imbib'd them. + </p> + <!-- Page 376 --> + <p> + <span class="pagenum"><a name="LPage_376" id="LPage_376"></a>[pg 376]</span> + </p> + <p class="center"> + <i>Annot. II.</i> + </p> + <p> + The above mention'd way of making Lakes we have tryed not only with + Turmerick, but alſo with Madder, which yielded us a Red Lake; and + with Rue, which afforded us an extract, of (almoſt if not altogether) + the ſame Colour with that of the leaves. + </p> + <p> + But in regard that 'tis Principally the Alcalizate Salt of the Pot-aſhes, + which enables the water to Extract ſo powerfully the Tincture of the + Decocted Vegetables, I fear that our Author may be miſtaken by ſuppoſing + that the Decoction will alwayes be of the very ſame Colour with the + Vegetable it is made off. For Lixiviate Salts, to which Pot-aſhes + eminently belong, though by peircing and opening the Bodies of Vegetables, + they prepare and diſpoſe them to part readily with their + Tincture, yet ſome Tinctures they do not only draw out, but likewiſe + alter them, as may be eaſily made appear by many of the Experiments + already ſet down in this Treatiſe, and though Allom being of an + Acid Nature, its Solutions may in ſome Caſes deſtroy the + Adventitious Colours produc'd by the Alcaly, and reſtore the former: + yet + <!-- Page 377 --> <span class="pagenum"><a name="LPage_377" + id="LPage_377"></a>[pg 377]</span> beſides that Allom is not, as I + have lately ſhown, a meer Acid Salt, but a mixt Body, and beſides, + that its operations are languid in compariſon of the activity of + Salts freed by Diſtillation, or by Incineration and Diſſolution, + from the moſt of their Earthy parts, we have ſeen already + Examples, that in divers Caſes an Acid Salt will not reſtore a + Vegetable ſubſtance to the Colour of which an Alcalizate one had + depriv'd it, but makes it aſſume a third very differing from + both, as we formerly told you, that if Syrrup of Violets were by an Alcaly + turn'd Green, (which Colour, as I have try'd, may be the ſame way + produc'd in the Violet-leaves themſelves without any Relation to a + Syrrup) an Acid Salt would not make it Blew again, but Red. And though I + have by this way of making Lakes, made Magiſteries (for ſuch + they ſeem to be) of Brazil, and as I remember of Cochinele it ſelf, + and of other things, Red, Yellow or Green which Lakes were enobled with a + Rich Colour, and others had no bad one; yet in ſome the colour of the + Lake ſeem'd rather inferiour than otherwiſe to that of the + Plant, and in others it ſeem'd both very differing, and much worſe; + but Writing this in a time and place where I cannot provide my ſelf + of Flowres and other Vegetables to proſecute + <!-- Page 378 --> <span class="pagenum"><a name="LPage_378" + id="LPage_378"></a>[pg 378]</span> ſuch Tryals in a competent variety + of Subjects, I am content not to be poſitive in delivering a judgment + of this way of Lakes, till Experience, or You, <i>Pyrophilus</i>, ſhall + have afforded me a fuller and more particular Information. + </p> + <p class="center"> + <i>Annotation III.</i> + </p> + <p> + And on this occaſion (<i>Pyrophilus</i>) I muſt here (having + forgot to do it ſooner) advertiſe you once for all, that having + written ſeveral of the foregoing Experiments, not only in haſte + but at ſeaſons of the year, and in places wherein I could not + furniſh my ſelf with ſuch Inſtruments, and ſuch a + variety of Materials, as the deſign of giving you an Introduction + into the Hiſtory of Colours requir'd, it can ſcarce be otherwiſe + but that divers of the Experiments, that I have ſet down, may afford + you ſome matter of new Tryals, if you think fit to ſupply the + deficiencies of ſome of them (eſpecially the freſhly + mention'd about Lakes, and thoſe that concern Emphatical Colours) + which deficiencies for want of being befriended with accommodations I + could better diſcern than avoid. + </p> + <!-- Page 379 --> + <p> + <span class="pagenum"><a name="LPage_379" id="LPage_379"></a>[pg 379]</span> + </p> + <p class="center"> + <i>Annotation IV.</i> + </p> + <p> + The uſe of Allom is very great as well as familiar in the Dyers + Trade, and I have not been ill pleas'd with the uſe I have been able + to make of it in preparing other pigments than thoſe they imploy with + Vegetable Juices. But the Lucriferous practiſes of Dyers and other + Tradeſmen, I do, for Reaſons that you may know when you pleaſe, + purpoſely forbear in this Eſſay, though not ſtrictly + from pointing at, yet from making it a part of my preſent work + explicitly and circumſtantially to deliver, eſpecially ſince + I now find (though late and not without ſome Bluſhes at my + prolixity) that what I intended but for a ſhort Eſſay, is + already ſwell'd into almoſt a Volume. + </p> + <h3> + <i>EXPERIMENT L.</i> + </h3> + <p> + Yet here, <i>Pyrophilus</i>, I muſt take leave to inſert an + Experiment, though perhaps you'l think its coming in here an Intruſion, + For I confeſs its more proper place would have been among thoſe + Experiments, that were brought as proofs and applications of our Notions + concerning the differences of + <!-- Page 380 --> <span class="pagenum"><a name="LPage_380" + id="LPage_380"></a>[pg 380]</span> Salts; but not having remembred to inſert + it in its fitteſt place, I had rather take notice of it in this, than + leave it quite unmention'd: partly becauſe it doth ſomewhat + differ from the reſt of our Experiments about Colours, in the way + whereby 'tis made; and partly becauſe the grounds upon which I + devis'd it, may hint to you ſomewhat of the Method I uſe in Deſigning + and Varying Experiments about Colours, and upon this account I ſhall + inform you, not only What I did, but Why I did it. + </p> + <p> + I conſider'd then that the work of the former Experiments was either + to change the Colour of a Body into another, or quite to deſtroy it, + without giving it a ſucceſſor, but I had a mind to give you + alſo a way, whereby to turn a Body endued with one Colour into two + Bodies, of Colours, as well as conſiſtencies, very diſtinct + from each other, and that by the help of a Body that had it ſelf no + Colour at all. In order to this, I remembred, that finding the Acidity of + Spirit of Vinegar to be wholly deſtroy'd by its working upon <i>Minium</i> + (or calcin'd Lead) whereby the Saline particles of the <i>Menſtruum</i> + have their Taſte and Nature quite alter'd, I had, among other + Conjectures I had built upon that change, rightly concluded, that the + Solution of Lead + <!-- Page 381 --> <span class="pagenum"><a name="LPage_381" + id="LPage_381"></a>[pg 381]</span> in Spirit of Vinegar would alter the + Colour of the Juices and Infuſions of Several Plants, much after the + like manner that I had found Oyl of Tartar to do; and accordingly I was + quickly ſatisfied upon Tryal, that the Infuſion of Roſe-leaves + would by a ſmall quantity of this Solution well mingl'd with it, be + immediately turn'd into a ſomewhat ſad Green. + </p> + <p> + And further, I had often found, that Oyl of Vitriol, though a potently + Acid <i>Menſtruum</i>, will yet Præcipitate many Bodies, both Mineral + and others, diſſolv'd not onely in <i>Aqua fortis</i> (as ſome + Chymiſts have obſerv'd) but particularly in Spirit of Vinegar, + and I have further found, that the <i>Calces</i> or Powders Præcipitated + by this Liquor were uſually fair and White. + </p> + <p> + Laying theſe things together, 'twas not difficult to conclude, that + if upon a good Tincture of Red Roſe-leaves made with fair Water, I + dropp'd a pretty quantity of a ſtrong and ſweet Solution of <i>Minium</i>, + the Liquor would be turn'd into the like muddy Green Subſtance, as I + have formerly intimated to You, that Oyl of Tartar would reduce it to, and + that if then I added a convenient quantity of good Oyl of Vitriol, this laſt + nam'd Liquor would have two diſtinct operations upon the Mixture, the + one, that + <!-- Page 382 --> <span class="pagenum"><a name="LPage_382" + id="LPage_382"></a>[pg 382]</span> it would Præcipitate that reſolv'd + Lead in the form of a White Powder; the other, that it would Clarifie the + muddy Mixture, and both reſtore, and exceedingly heighten the Redneſs + of the Infuſion of Roſes, which was the moſt copious + Ingredient of the Green compoſition, and accordingly trying the + Experiment in a Wine glaſs ſharp at the bottom (like an inverted + Cone) that the ſubſiding Powder might ſeem to take up the + more room, and be the more conſpicuous, I found that when I had + ſhaken the Green Mixture, that the colour'd Liquor might be the more + equally diſperſed, a few drops of the rectifi'd Oyl of Vitriol + did preſently turn the opacous Liquor into one that was cleer and + Red, almoſt like a Rubie, and threw down good ſtore of a Powder, + which when 'twas ſettl'd, would have appear'd very White, if ſome + interſpers'd Particles of the red Liquor had not a little Allay'd the + Purity, though not blemiſh'd the Beauty of the Colour. And to ſhew + you, <i>Pyrophilus</i>, that theſe Effects do not flow from the Oyl + of Vitriol, as it is ſuch, but as it is a ſtrongly Acid <i>Menſtruum</i>, + that has the property both to Præcipitate Lead, as well as ſome other + Concretes out of Spirit of Vinegar, and to heighten the Colour of Red Roſe-leaves, + I add, that I + <!-- Page 383 --> <span class="pagenum"><a name="LPage_383" + id="LPage_383"></a>[pg 383]</span> have done the ſame thing, though + perhaps not quite ſo well with Spirit of Salt, and that I could not + do it with <i>Aqua-fortis</i>, becauſe though that potent <i>Menſtruum</i> + does as well as the others heighthen the Redneſs of Roſes, yet + it would not like them Precipitate Lead out of Spirit of Vinegar, but + would rather have diſſolv'd it, if it had not found it diſſolv'd + already. + </p> + <p> + And as by this way we have produc'd a Red Liquor, and a White Precipitate + out of a Dirty Green magiſtery of Roſe-leaves, ſo by the + ſame Method, you may produce a fair Yellow, and ſometimes a Red + Liquor, and the like Precipitate, out of an Infuſion of a curious + Purple Colour. For you may call to mind, that in the Annotation upon the + 39<sup>th</sup>. Experiment I intimated to you, that I had with a few + drops of an Alcaly turn'd the Infuſion of Logg-wood into a lovely + Purple. Now if inſtead of this Alcaly I ſubſtituted a very + Strong and well Filtrated Solution of <i>Minium</i>, made with Spirit of + Vinegar, and put about half as much of this Liquor as there was of the + Infuſion of Logg-wood, (that the mixture might afford a pretty deal + of Precipitate,) the affuſion of a convenient proportion of Spirit of + Salt, would (if the Liquors were well and nimbly ſtirr'd together) + preſently + <!-- Page 384 --> <span class="pagenum"><a name="LPage_384" + id="LPage_384"></a>[pg 384]</span> ſtrike down a Precipitate like + that formerly mention'd, and turn the Liquor that ſwam above it, for + the moſt part into a lovely Yellow. + </p> + <p> + But for the advancing of this Experiment a little further, I conſider'd, + that in caſe I firſt turn'd a ſpoonfull of the infuſion + of Logg-wood Purple, by a convenient proportion of the Solution of <i>Minium</i>, + the Affuſion of Spirit of Sal Armnoniack, would Precipitate the Corpuſcles + of Lead conceal'd in the Solution of <i>Minium</i>, and yet not deſtroy + the Purple colour of the Liquor; whereupon I thus proceeded; I took about + a ſpoonfull of the <i>freſh</i> Tincture of Logg-wood, (for I + found that if it were <i>ſtale</i> the Experiment would not alwayes + ſucceed,) and having put to it a convenient proportion of the + Solution of <i>Minium</i> to turn it into a deep and almoſt opacous + Purple, I then drop'd in as much Spirit of Sal Armoniack, as I gueſs'd + would Precipitate about half or more (but not all) of the Lead, and + immediately ſtirring the mixture well together, I mingled the + Precipitated parts with the others, ſo that they fell to the bottom, + partly in the form of a Powder, and partly in the form of a Curdled Subſtance, + that (by reaſon of the Predominancy of the Ting'd Corpuſcles + over + <!-- Page 385 --> <span class="pagenum"><a name="LPage_385" + id="LPage_385"></a>[pg 385]</span> the White) retain'd as well as the + Supernatant Liquor; a Blewiſh Purple colour ſufficiently Deep, + and then inſtantly (but yet Warily,) pouring on a pretty Quantity of + Spirit of Salt, the matter firſt Precipitated, was, by the above + ſpecified figure of the bottome of the Glaſs preſerv'd from + being reach'd by the Spirituous Salt; which haſtily Precipitated upon + it a new Bed (if I may ſo call it) of White Powder, being the + remaining Corpuſcles of the Lead, that the Urinous Spirit had not + ſtruck down: So that there appear'd in the Glaſs three diſtinct + and very differingly colour'd Subſtances; a Purple or Violet-colour'd + Precipitate at the bottom, a White and Carnation (ſometimes a Variouſly + colour'd) Precipitate over That, and at the Top of all a Tranſparent + Liquor of a lovely Yellow, or Red. + </p> + <p> + Thus you ſee, <i>Pyrophilus</i>, that though to ſome I may have + ſeem'd to have lighted on this (50<sup>th</sup>.) Experiment by + chance, and though others may imagine, that to have excogitated it, muſt + have proceeded from ſome extraordinary inſight into the nature + of Colours, yet indeed, the deviſing of it need not be look'd upon as + any great matter, eſpecially to one that is a little vers'd in the + notions, I have in theſe, and other Papers + <!-- Page 386 --> <span class="pagenum"><a name="LPage_386" + id="LPage_386"></a>[pg 386]</span> hinted concerning the differences of + Salts. And perhaps I might add upon more than conjecture, that theſe + very notions and ſome particulars ſcatteringly deliver'd in this + Treatiſe, being skilfully put together, may ſuggeſt divers + matters (at leaſt,) about Colours, that will not be altogether Deſpicable. + But thoſe hinted, <i>Pyrophilus</i>, I muſt now leave ſuch + as You to proſecute, having already ſpent farr more time than I + intended to allow my ſelf in acquainting You with particular + Experiments and Obſervations concerning the changes of Colour, to + which I might have added many more, but that I hope I may have preſented + You with a competent number to make out in ſome meaſure what I + have at the beginning of this Eſſay either propos'd as my Deſign + in this Tract, or deliver'd as my Conjectures concerning theſe + matters. And it not being my preſent Deſigne, as I have more + than once Declar'd, to deliver any Poſitive Hypotheſis or ſolemn + Theory of Colours, but only to furniſh You with ſome Experiments + towards the framing of ſuch a Theory; I ſhall add nothing to + what I have ſaid already, but a requeſt that you would not be + forward to think I have been miſtaken in any thing I have deliver'd + as matter of Fact concerning the changes of Colours, in caſe you + <!-- Page 387 --> <span class="pagenum"><a name="LPage_387" + id="LPage_387"></a>[pg 387]</span> ſhould not every time you trye it, + find it exactly to ſucceed. For beſides the Contingencies to + which we have elſewhere ſhewn ſome other Experiments to be + obnoxious, the omiſſion or variation of a ſeemingly unconſiderable + circumſtance, may hinder the ſucceſs of an Experiment, + wherein no other fault has been committed. Of which truth I ſhall + only give you that ſingle and almoſt obvious, but yet illuſtrious + inſtance of the Art of Dying Scarlets, for though you ſhould + ſee every Ingredient that is us'd about it, though I ſhould + particularly inform You of the weight of each, and though you ſhould + be preſent at the kindling of the fire, and at the increaſing + and remitting of it, when ever the degree of Heat is to be alter'd, and + though (in a word) you ſhould ſee every thing done ſo + particularly that you would ſcarce harbour the leaſt doubt of + your comprehending the whole Art: Yet if I ſhould not diſcloſe + to You, that the Veſſels, that immediately contain the Tinging + Ingredients, are to be made of or to be lin'd with Tin, You would never be + able by all that I could tell you elſe (at-leaſt, if the Famouſeſt + and Candideſt Artificers do not ſtrangely delude themſelves) + to bring your Tincture of + <!-- Page 388 --> <span class="pagenum"><a name="LPage_388" + id="LPage_388"></a>[pg 388]</span> Chochinele to Dye a perfect Scarlet. So + much depends upon the very Veſſel, wherein the Tinging matters + are boyl'd, and ſo great an Influence may an unheeded Circumſtance + have on the Succeſs of Experiments concerning Colours. + </p> + <hr /> + <h3> + <i>FINIS.</i> + </h3> + <hr /> + <!-- Page 389 --> + <p> + <span class="pagenum"><a name="LPage_389" id="LPage_389"></a>[pg 389]</span> + </p> + <h2> + <span style="font-size:50%;">A SHORT</span><br /> <span + style="font-size:125%;">ACCOUNT</span><br /> <span style="font-size:50%;">OF + SOME</span><br /> <span style="font-size:100%;">OBSERVATIONS</span><br /> + <span style="font-size:75%;">Made by Mr. <i>BOYLE</i></span><br /> <span + style="font-size:50%;">About a <i>Diamond</i> that <i>Shines</i> in the + Dark.</span> + </h2> + <p class="center"> + Firſt encloſed in a Letter written to<br /> a Friend, + </p> + <p class="center"> + And now together with it annexed to the Foregoing<br /> Treatiſe, upon + the ſcore of the<br /> Affinity Betwixt + </p> + <h2> + <span style="font-size:75%;"><i>Light</i> and <i>Colours</i>.</span> + </h2> + <hr /> + <div class="figcenter" style="width:25%;"> + <img width="100%" src="images/429.png" alt="Decorative tiles" /> + </div> + <hr /> + <h3> + <i>LONDON,</i> + </h3> + <h4> + Printed for <i>Henry Herringman</i>. 1664 + </h4> + <!-- Page 390 blank --> + <!-- Page 391 --> + <p> + <span class="pagenum"><a name="LPage_391" id="LPage_391"></a>[pg 391]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/431a.png" alt="Decorative rule" /> + </div> + <h2> + <span style="font-size:75%; letter-spacing:6px">A COPY</span><br /> <span + style="font-size:50%;">OF THE</span><br /> <span + style="font-size:100%; letter-spacing:10px">LETTER</span> + </h2> + <p class="center"> + That Mr. <i>Boyle</i> wrote to Sir <i>Robert Morray</i>,<br /> to accompany + the <i>Obſervations</i> touching<br /> the <i>Shining Diamond</i>. + </p> + <p> + <i>SIR,</i> + </p> + <p> + <img width="100" height="100" src="images/431b.png" + alt="Illuminated T in Though" /> Hough Sir <i>Robert Morray</i> and Monſieur + <i>Zulichem</i> be Perſons that have deſerv'd ſo well of + the Commonwealth of Learning, that I ſhould think my ſelf + unworthy to be look'd upon as a Member of it, if I declin'd to Obey them, + or to Serve them; yet I ſhould not without Reluctancy ſend you + the Notes, you deſire for him, if I did not hope that you will tranſmit + together with them, ſome Account why they are not leſs unworthy + of his peruſal; which, that you may do; I muſt inform you, how + <!-- Page 392 --> <span class="pagenum"><a name="LPage_392" + id="LPage_392"></a>[pg 392]</span> the writing of them was Occaſion'd, + which in ſhort was thus. As I was juſt going out of Town, + hearing that an Ingenious Gentleman of my Acquaintance, lately return'd + from <i>Italy</i>, had a Diamond, that being rubb'd, would ſhine in + the Dark, and that he was not far off, I ſnatch'd time from my Occaſions + to make him a Viſit, but finding him ready to go abroad, and having + in vain try'd to make the Stone yield any Light in the Day time, I + borrow'd it of him for that Night, upon condition to reſtore it him + within a Day or two at furtheſt, at <i>Greſham</i> College, + where we appointed to attend the meeting of the Society, that was then to + be at that place. And hereupon I haſted that Evening out of Town, and + finding after Supper that the Stone which in the Day time would afford no + diſcernable Light, was really Conſpicuous in the Dark, I was + ſo taken with the Novelty, and ſo deſirous to make ſome + uſe of an opportunity that was like to laſt ſo little a + while, that though at that time I had no body to aſſiſt me + but a Foot-Boy, yet ſitting up late, I made a ſhift that Night + to try a pretty number of ſuch of the things that then came into my + thoughts, as were not in that place and time unpracticable. And the next + Day being otherwiſe imploy'd, + <!-- Page 393 --> <span class="pagenum"><a name="LPage_393" + id="LPage_393"></a>[pg 393]</span> I was fain to make uſe of a drowſie + part of the Night to ſet down haſtily in Writing what I had obſerv'd, + and without having the time in the Morning, to ſtay the tranſcribing + of it, I order'd the Obſervations to be brought after me to <i>Greſham</i> + College, where you may remember, that they were together with the Stone it + ſelf ſhown to the Royal Society, by which they had the good + Fortune not to be diſlik'd, though ſeveral things were through + haſt omitted, ſome of which you will find in the Margin of the + incloſed Paper. The ſubſtance of this ſhort Narrative + I hope you will let Monſieur <i>Zulichem</i> know, that he may be + kept from expecting any thing of finiſh'd in the Obſervations, + and be diſpos'd to excuſe the want of it. But ſuch as they + are, I hope they will prove (without a Clinch) Luciferous Experiments, by + ſetting the Speculations of the Curious on work, in a diligent + Inquiry after the Nature of Light, towards the diſcovery of which, + perhaps they have not yet met with ſo conſiderable an + Experiment, ſince here we ſee Light produc'd in a dead and + opacous Body, and that not as in rotten Wood, or in Fiſhes, or as in + the <i>Bolonian</i> Stone, by a Natural Corruption, or by a + <!-- Page 394 --> <span class="pagenum"><a name="LPage_394" + id="LPage_394"></a>[pg 394]</span> Violent Deſtruction of the Texture + of the Body, but by ſo ſlight a Mechanical operation upon its + Texture, as we ſeem to know what it is, and as is immediately + perform'd, and that ſeveral wayes without at all prejudicing the + Body, or making any ſenſible alterations in its Manifeſt + Qualities. And I am the more willing to expoſe my haſty Tryals + to Monſieur <i>Zulichem</i>, and to You, becauſe, he being upon + the Conſideration of Dioptricks, ſo odd a <i>Phœnomemon</i> + relateing to the Subject, as probably he treats of, Light will, I hope, + excite a perſon to conſider it, that is wont to conſider + things he treats of very well. And for you Sir, I hope you will both + recrute and perfect the Obſervations you receive, For you know that I + cannot add to them, having a good while ſince reſtor'd to Mr. <i>Clayton</i> + the Stone, which though it be now in the hands of a Prince that ſo + highly deſerves, by underſtanding them, the greateſt Curioſities; + yet he vouchſafes you that acceſs to him as keeps me from + doubting, you may eaſily obtain leave to make further Tryals with it, + of ſuch a Monarch as ours, that is not more inquiſitive himſelf, + than a favourer of them that are ſo. I doubt not but theſe Notes + will put you in mind of the Motion you made to the Society, to impoſe + upon + <!-- Page 395 --> <span class="pagenum"><a name="LPage_395" + id="LPage_395"></a>[pg 395]</span> me the Task of bringing in, what I had + on other occaſions obſerv'd concerning ſhining Bodies. But + though I deny not, that I ſometimes made obſervations about the + <i>Bolonian</i> Stone, and try'd ſome Experiments about ſome + other ſhining Bodies; Yet the ſame Reaſons that reduc'd me + then to be unwilling to receive ev'n their commands, muſt now be my + Apology for not anſwering your Expectations, Namely the abſtruſe + nature of Light, and my being already over-burden'd, and but too much kept + imploy'd by the Urgency of the Preſs, as well as by more concerning + and diſtracting Occaſions. But yet I will tell you ſome + part of what I have met with in reference to the Stone, of which I ſend + you an account. Becauſe I find on the one ſide, that a great + many think it no Rarity upon a miſtaken perſwaſion, that + not only there are ſtore of Carbuncles, of which this is one; but + that all Diamonds and other Gliſtering Jewels ſhine in the Dark. + Whereas on the other ſide there are very Learn'd Men, who (plauſibly + enough) deny that there are any Carbuncles or ſhining Stones at all. + </p> + <p> + And certainly, thoſe Judicious men have much more to ſay for + themſelves, than the others commonly Plead, and therefore did deſervedly + look upon Mr. <i>Clayton</i>'s Diamond + <!-- Page 396 --> <span class="pagenum"><a name="LPage_396" + id="LPage_396"></a>[pg 396]</span> as a great Rarity. For not only <i>Boetius + de Boot</i>, who is judg'd the beſt Author on this Subject, aſcribes + no ſuch Virtue to Diamonds, but begins what he delivers of + Carbuncles, with this paſſage.<a name="LNtA_26" id="LNtA_26_"></a><a + href="#LNt_26"><sup>26</sup></a> <i>Magna fama est Carbunculi. Is vulgo + putatur in tenebris Carbonis inſtar lucere; fortaſſis quia + Pyropus ſeu Anthrax appellatus a veteribus fuit. Verum hactenus nemo + nunquam verè aſſerere auſus fuit, ſe gemmam noctu + lucentem vidiſſe. Garcias ab Horto proregis Indiæ Medicus, + refert ſe allocutum fuiſſe, qui ſe vidiſſe + affirmarent. Sed iis fidem non habuit.</i> And a later Author, the + Diligent and Judicious <i>Johannes de Laet</i> in his Chapter of + Carbuncles and of Rubies, has this paſſage. <i>Quia autem + Carbunculi, Pyropi & Anthraces a veteribus nominantur, vulgo creditum + fuit, Carbonis instar in tenebris lucere, quod tamen nullâ gemmâ hastenus + deprehenſum, licet à quibuſdam temerè jactetur.</i> And the + recenteſt Writer I have met with on this Subject, <i>Olaus Wormius</i>, + in his Account of his well furniſh'd <i>Musæum</i>, do's, where he + treats of Rubies, concurr with the former Writers by theſe Words.<a + name="LNtA_27" id="LNtA_27_"></a><a href="#LNt_27"><sup>27</sup></a> <i>Sunt + qui Rubinum veterum Carbunculum eſſe existimant, ſed deeſt + una illa nota, quod + <!-- Page 397 --> <span class="pagenum"><a name="LPage_397" + id="LPage_397"></a>[pg 397]</span> in tenebris inſtar Anthracis non + luceat: Aſt talem Carbunculum in rerum naturâ non inveniri major pars + Authoram exiſtimant. Licet unum aut alterum in India apud Magnates + quoſdam reperiri ſcribant, cum tamen ex aliorum relatione id + habeant ſaltem, ſed ipſi non viderint.</i> In confirmation + of which I ſhall only add, that hearing of a Rubie, ſo very + Vivid, that the Jewellers themſelves have ſeveral times begg'd + leave of the fair Lady to whom it belong'd, that they might try their + choiceſt Rubies by comparing them with That, I had the Opportunity by + the Favour of this Lady and her Huſband, (both which I have the + Honour to be acquainted with) to make a Trial of this famous Rubie in the + Night, and in a Room well Darkn'd, but not only could not diſcern any + thing of Light, by looking on the Stone before any thing had been done to + it, but could not by all my Rubbing bring it to afford the leaſt + Glimmering of Light. + </p> + <p> + But, Sir, though I be very backward to admit ſtrange things for + truths, yet I am not very forward to reject them as impoſſibilities, + and therefore I would not diſcourage any from making further Inquiry, + whether or no there be Really in <i>Rerum natura</i>, any ſuch thing + as a true Carbuncle or Stone that without Rubbing will ſhine + <!-- Page 398 --> <span class="pagenum"><a name="LPage_398" + id="LPage_398"></a>[pg 398]</span> in the Dark. For if ſuch a thing + can be found, it may afford no ſmall Aſſiſtance to the + Curious in the Inveſtigation of Light, beſides the Nobleneſs + and Rarity of the thing it ſelfe. And though <i>Vartomannus</i> was + not an Eye witneſs of what he relates, that the King of <i>Pegu</i>, + one of the Chief Kings of the <i>East-Indies</i>, had a true Carbuncle of + that Bigneſs and Splendour, that it ſhin'd very Gloriouſly + in the Dark, and though <i>Garcias ab Horto</i>, the <i>Indian</i> + Vice-Roys Phyſician, ſpeaks of another Carbuncle, only upon the + Report of one, that he Diſcours'd with, who affirmed himſelf to + have ſeen it; yet as we are not ſure that theſe Men that + gave themſelves out to be Eye-witneſſes ſpeak true, + yet they may have done ſo for ought we know to the contrary. And I + could preſent you with a much conſiderabler Teſtimony to + the ſame purpoſe, if I had the permiſſion of a Perſon + concern'd, without whoſe leave I muſt not do it. I might tell + you that <i>Marcus Paulus Venetus</i><a name="LNtA_28" id="LNtA_28_"></a><a + href="#LNt_28"><sup>28</sup></a> (whoſe ſuppos'd Fables, divers + of our later Travellours and Navigatours have ſince found to be + truths) ſpeaking of the King of <i>Zeilan</i> that then was, tells + us, that he was ſaid to have the beſt Rubie in the World, a Palm + long and as + <!-- Page 399 --> <span class="pagenum"><a name="LPage_399" + id="LPage_399"></a>[pg 399]</span> big as a mans Arm, without ſpot, + ſhining like a Fire, and he ſubjoyns, that the Great <i>Cham</i>, + under whom <i>Paulus</i> was a conſiderable Officer, ſent and + offer'd the value of a City for it; But the King anſwer'd, he would + not give it for the treaſure of the World, nor part with it, having + been his Anceſtours. And I could add, that in the Relation made by + two <i>Ruſſian</i> Coſſacks of their Journey into <i>Catay</i><a + name="LNtA_29" id="LNtA_29_"></a><a href="#LNt_29"><sup>29</sup></a>, written + to their Emperour, they mention'd their having been told by the people of + thoſe parts, that their King had a Stone, which Lights as the Sun + both Day and Night, call'd in their Language <i>Sarra</i>, which thoſe + Coſſacks interpret a Ruby. But theſe Relations are too + uncertain for me to build any thing upon, and therefore I ſhall + proceed to tell you, that there came hither about two years ſince out + of <i>America</i>, the Governour of one of the Principal Colonies there, + an Ancient <i>Virtuoſo</i>, and one that has the Honour to be a + member of the Royal Society; this Gentleman finding ſome of the chief + Affairs of his Country committed to another and me, made me divers Viſits, + and in one of them when I enquir'd what Rare Stones they had in thoſe + parts of the <i>Indies</i> he belong'd to, he told me, that the <i>Indians</i> + had a Tradition + <!-- Page 400 --> <span class="pagenum"><a name="LPage_400" + id="LPage_400"></a>[pg 400]</span> that in a certain hardly acceſſible + Hill, a pretty way up in the Country, there was a Stone which in the Night + time ſhin'd very vividly, and to a great diſtance, and he aſſur'd + me, that though he thought it not fit to venture himſelf ſo far + among thoſe Savages, yet he purpoſely ſent thither a bold + <i>Engliſhman</i>, with ſome Natives to be his guides, and that + this Meſſenger brought him back word, that at a diſtance + from the Hillock he had plainly perceiv'd ſuch a ſhining Subſtance + as the <i>Indians</i> Tradition mention'd, and being ſtimulated by + Curioſity, had ſlighted thoſe Superſtitious Fears of + the Inhabitants, and with much ado by reaſon of the Difficulty of the + way, had made a ſhift to clamber up to that part of the Hill, where, + by a very heedful Obſervation, he ſuppos'd himſelf to have + ſeen the Light: but whether 'twere that he had miſtaken the + place, or for ſome other Reaſon, he could not find it there, + though when he was return'd to his former Station, he did agen ſee + the Light ſhining in the ſame place where it ſhone before. + A further Account of this Light I expect from the Gentleman that gave me + this, who lately ſent me the news of his being landed in that + Country. And though I reſerve to my ſelf a full Liberty of + Believing no more + <!-- Page 401 --> <span class="pagenum"><a name="LPage_401" + id="LPage_401"></a>[pg 401]</span> than I ſee cauſe; yet I do + the leſs ſcruple to relate this, becauſe a good part of it + agrees well enough with another Story that I ſhall in the next place + have occaſion to ſubjoyn, in order whereunto I ſhall tell + you, that though the Learned Authors I formerly mention'd, tell us, that + no Writer has affirm'd his having himſelf ſeen a real Carbuncle, + yet, conſidering the Light of Mr. <i>Claytons</i> Diamond, it + recall'd into my mind, that ſome years before, when I was Inquiſitive + about Stones, I had met with an old <i>Italian</i> Book highly extoll'd to + me by very competent Judges, and that though the Book were very ſcarce, + I had purchas'd it at a dear Rate, for the ſake of a few conſiderable + paſſages I met with in it, and particularly one, which being + very remarkable in it ſelf, and pertinent to our preſent + Argument, I ſhall put it for you, though not word for word, which I + fear I have forgot to do, yet as to the Senſe, into <i>Engliſh</i>. + </p> + <p> + <i>Having promis'd</i> (Says our Author)<a name="LNtA_30" id="LNtA_30_"></a><a + href="#LNt_30"><sup>30</sup></a> <i>to ſay ſomething of that moſt + precious ſort of Jewels,</i> Carbuncles, <i>becauſe they are + very rarely to be met with, we ſhall briefly deliver what we know of + them. In</i> Clement <i>the ſeventh's time, I happen'd to ſee + one of</i> + <!-- Page 402 --> <span class="pagenum"><a name="LPage_402" + id="LPage_402"></a>[pg 402]</span> <i>them at a certain</i> Raguſian + <i>Merchants, nam'd</i> Beigoio di Bona, <i>This was a Carbuncle white, of + that kind of whiteneſs which we ſaid was to be found in thoſe + Rubies of which we made mention a little above,</i> (where he had ſaid + that thoſe Rubies had a kind of Livid Whiteneſs or Paleneſs + like that of a Calcidonian) <i>but it had in it a Luſtre ſo pleaſing + and ſo marveilous, that it ſhin'd in the Dark, but not as much + as colour'd Carbuncles, though it be true, that in an exceeding Dark place + I ſaw it ſhine in the manner of fire almoſt gone out. But + as for colour'd Carbuncles, it has not been my Fortune to have ſeen + any, wherefore I will onely ſet down what I Learn'd about them Diſcourſing + in my Youth with a</i> Roman <i>Gentleman of antient Experience in matters + of Jewels, who told me, That one</i> Jacopo Cola <i>being by Night in a + Vineyard of his, and eſpying ſomething in the midſt of it, + that ſhin'd like a little</i> glowing Coal, at the foot of a Vine, + went near towards the place where he thought himſelf to have ſeen + that fire, but not finding it, he ſaid, that being return'd to the + ſame place, whence he had firſt deſcry'd it, and perceiving + there the ſame ſplendor as before, he mark'd it ſo + heedfully, that he came at length to it, where he took up a very little + Stone, which he carry'd away with Tranſports and Joy. And the next + <!-- Page 403 --> <span class="pagenum"><a name="LPage_403" + id="LPage_403"></a>[pg 403]</span> day carrying it about to ſhow it + divers of his Friends, whilſt he was relating after what manner he + found it, there caſually interven'd a <i>Venetian</i> Embaſſadour, + exceedingly expert in Jewels, who preſently knowing it to be a + Carbuncle, did craftily before he and the ſaid <i>Jacopo</i> parted (ſo + that there was no Body preſent that underſtood the Worth of + ſo Precious a Gemm) purchaſe it for the Value of 10. Crowns, and + the next day left <i>Rome</i> to ſhun the being neceſſitated + to reſtore it, and (as he affirm'd) it was known within ſome + while after that the ſaid <i>Venetian</i> Gentleman did in <i>Conſtantinople</i> + ſell that Carbuncle to the then Grand Seignior, newly come to the + Empire, for a hundred thouſand Crowns. <i>And this is what I can + ſay</i> concerning <i>Carbuncles</i>, and this is not a little at leaſt + as to the firſt part of this account, where our <i>Cellini</i> + affirms himſelf to have ſeen a Real Carbuncle with his own Eyes, + eſpecially ſince this Author appears wary in what he delivers, + and is inclin'd rather to leſſen, than increaſe the wonder + of it. And his Teſtimony is the more conſiderable, becauſe + though he were born a Subject neither to the Pope nor the then King of <i>France</i> + (that Royal <i>Virtuoſo</i> <i>Francis</i> the firſt) yet both + the one and the other of thoſe Princes imploy'd him much + <!-- Page 404 --> <span class="pagenum"><a name="LPage_404" + id="LPage_404"></a>[pg 404]</span> about making of their Nobleſt + Jewels. What is now reported concerning a Shining Subſtance to be + ſeen in one of the Iſlands about <i>Scotland</i>, were very + improper for me to mention to Sr. <i>Robert Morray</i>, to whom the firſt + Information was Originally brought, and from whom I expect a farther (for + I ſcarce dare expect a convincing) account of it. But I muſt not + omit that ſome <i>Virtuoſo</i> queſtioning me the other day + at <i>White-Hall</i> about Mr. <i>Claytons</i> Diamond, and meeting amongſt + them an Ingenious <i>Dutch</i> Gentleman, whoſe Father was long Embaſſador + for the Netherlands in <i>England</i>, I Learn'd of him, that, he is + acquainted with a perſon, whoſe Name he told (but I do not well + remember it) who was Admiral of the <i>Dutch</i> in the <i>Eaſt-Indies</i>, + and who aſſur'd this Gentleman <i>Monſieur Boreel</i>, that + at his return from thence he brought back with him into <i>Holland</i> a + Stone, which though it look'd but like a Pale Dull Diamond, ſuch as + he ſaw Mr. <i>Claytons</i> to be, yet was it a Real Carbuncle, and + did without rubbing ſhine ſo much, that when the Admiral had + occaſion to open a Cheſt which he kept under Deck in a Dark + place, where 'twas forbidden to bring Candles for fear of Miſchances, + as ſoon as he open'd the Trunck, the Stone + <!-- Page 405 --> <span class="pagenum"><a name="LPage_405" + id="LPage_405"></a>[pg 405]</span> would by its Native Light, ſhine + ſo as to Illuſtrate a great part of it, and this Gentleman + having very civilly and readily granted me the requeſt I made him, to + Write to the Admiral, who is yet alive in <i>Holland</i>, (and probably + may ſtill have the Jewel by him,) for a particular account of this + Stone, I hope ere long to receive it, which will be the more welcome to + me, not onely becauſe ſo unlikely a thing needs a cleer + evidence, but becauſe I have had ſome ſuſpition of + that (ſuppoſing the truth of the thing) what may be a ſhining + Stone in a very hot Countrey as the <i>Eaſt-Indies</i>, may perhaps + ceaſe to be ſo (at leaſt in certain ſeaſons,) in + one as cold as <i>Holland</i>. For I obſerv'd in the Diamond I ſend + you an account of, that not onely rubbing but a very moderate degree of + warmth, though excited by other wayes, would make it ſhine a little. + And 'tis not impoſſible that there may be Stones as much more + ſuſceptible than that, of the Alterations requiſite to make + a Diamond ſhine, as that appeares to be more ſuſceptible of + them, than ordinary Diamonds. And I confeſs to you, that this is not + the only odd ſuſpition (for they are not ſo much as + conjectures) that what I try'd upon this Diamond ſuggeſted to + me. For not here to entertain you with the + <!-- Page 406 --> <span class="pagenum"><a name="LPage_406" + id="LPage_406"></a>[pg 406]</span> changes I think may be effected ev'n in + harder ſorts of Stones, by wayes not vulgar, nor very promiſing, + becauſe I may elſewhere have occaſion to ſpeak of + them, and this Letter is but too Prolix already, that which I ſhall + now acknowledge to you is, That I began to doubt whether there may not in + ſome Caſes be ſome Truth in what is ſaid of the right + Turquois, that it often changes Colour as the wearer is Sick or Well, and + manifeſtly loſes its ſplendor at his Death. For when I + found that ev'n the warmth of an Affriction that laſted not above a + quarter of a minute, Nay, that of my Body, (whoſe Conſtitution + you know is none of the hotteſt) would make a manifeſt change in + the ſolideſt of Stones a Diamond, it ſeem'd not impoſſible, + that certain warm and Saline ſteams iſſuing from the Body + of a living man, may by their plenty or paucity, or by their peculiar + Nature, or by the total abſence of them, diverſifie the Colour, + and the ſplendor of ſo ſoft a Stone as the Turquois. And + though I admir'd to ſee, that I know not how many Men otherwiſe + Learn'd, ſhould confidently aſcribe to Jewels ſuch Virtues + as ſeem no way competible to Inanimate Agents, if to any Corporeal + ones at all, yet as to what is affirm'd concerning the Turquois's + <!-- Page 407 --> <span class="pagenum"><a name="LPage_407" + id="LPage_407"></a>[pg 407]</span> changing Colour, I know not well how to + reject the Affirmation of ſo Learned (and which in this caſe is + much more conſiderable) ſo Judicious a Lapidary as <i>Boetius de + Boot</i><a name="LNtA_31" id="LNtA_31_"></a><a href="#LNt_31"><sup>31</sup></a>, + who upon his own particular and repeated Experience delivers ſo + memorable + <!-- Page 408 --> <span class="pagenum"><a name="LPage_408" + id="LPage_408"></a>[pg 408]</span> a Narrative of the Turquois's changing + Colour, that I cannot but think it worth your Peruſal, eſpecially + ſince a much later and very Experienc'd Author, <i>Olaus Wormius</i>,<a + name="LNtA_32" id="LNtA_32_"></a><a href="#LNt_32"><sup>32</sup></a> where he + treats of that Stone, Confirms it with this Teſtimony. <i>Imprimis + memorandum exemplum quod Anſhelmus Boetius de ſeipſo + refert, tam mutati Coloris, quam à caſu preſervationis. Cui + & ipſe haud diſſimile adferre poſsum, niſi ex + Anſhelmo petitum quis putaret.</i> I remember that I ſaw two or + three years ſince a <i>Turcois</i> (worn in a Ring) wherein there + were ſome ſmall ſpots, which the <i>Virtuoſo</i> whoſe + it was aſur'd me he had obſerv'd to grow ſometimes greater + ſometimes leſs, and to be ſometimes in one part of the + Stone, ſometimes in another. And I having encourag'd to make Pictures + from time to time of the Stone, and of the Situation of the cloudy parts, + thatſo their Motion may be more indiſputable, and better obſerv'd, + he came to me about the midle of this very week, and aſſur'd me + that he had, as I wiſh'd, made from time to time Schemes or Pictures + of the differing parts of the Stone, whereby the ſeveral Removes and + motions of the above mentioned Clouds are very manifeſt, though the + cauſe ſeem'd to him very occult: theſe Pictures + <!-- Page 409 --> <span class="pagenum"><a name="LPage_409" + id="LPage_409"></a>[pg 409]</span> he has promis'd to ſhow me, and is + very ready to put the Stone it ſelf into my hands. But the ring + having been the other day caſually broken upon his finger, unleſs + it can be taken out, and ſet again without any conſiderable + heat, he is loath to have it medled with, for fear its peculiarity ſhould + be thereby deſtroy'd. And poſſibly his apprehenſion + would have been ſtrengthen'd, if I had had opportunity to tell him + what is related by the Learned <i>Wormius</i><a name="LNtA_33" id="LNtA_33_"></a><a + href="#LNt_33"><sup>33</sup></a> of an acquaintance of his, that had a <i>Nephritick</i> + ſtone, of whoſe eminent Virtues he had often Experience ev'n in + himſelf, and for that cauſe wore it ſtill about his Wriſt; + and yet going upon a time into a Bath of fair Water only, wherein certain + Herbs had been boyl'd, the Stone by being wetted with this decoction, was + depriv'd of all his Virtue, whence <i>Wormius</i> takes Occaſion to + advertiſe the ſick, to lay by ſuch ſtones whenſoever + they make uſe of a Bath. And we might expect to find <i>Turcos</i> + likewiſe, eaſily to be wrought upon in point of Colour, if that + were true, which the curious <i>Antonio Neri</i>, in his ingenious <i>Arte + Vetraria</i><a name="LNtA_34" id="LNtA_34_"></a><a href="#LNt_34"><sup>34</sup></a> + teaches of it, namely, That <i>Turcois's diſcolour'd</i> and grown + white, will regain and acquire + <!-- Page 410 --> <span class="pagenum"><a name="LPage_410" + id="LPage_410"></a>[pg 410]</span> an excellent Colour, if you but keep + them two or three days at moſt cover'd with Oyl of ſweet Almonds + kept in a temperate heat by warm aſhes, I ſay if it were true, + becauſe I doubt whether it be ſo, and have not as yet had + opportunity to ſatisfie my ſelf by Tryals, becauſe I find + by the confeſſion of the moſt Skilfull Perſons among + whom I have laid out for <i>Turcoiſes</i>, that the true ones are + great rarities, though others be not at all ſo. And therefore I + ſhall now only mind you of one thing that you know as well as I, + namely, that the rare Stone which is called <i>Oculus Mundi</i>, if it be + good in its Kind, will have ſo great a change made in its Texture by + being barely left a while in the Languideſt of Liquors, common + Waters, that from Opacous it will become Tranſparent, and acquire a + Luſtre of which it will again be depriv'd, without uſing any + other Art or Violence, by leaving it a while in the Air. And before + experience had ſatisfy'd us of the truth of this, it ſeem'd as + unlikely that common Water or Air, ſhould work ſuch great + changes in that Gemm, as it now ſeems that the Effluviums of a human + Body ſhould effect leſſer changes in a <i>Turcois</i>, eſpecially + if more ſuſceptible of them, than other Stones of the ſame + kind. But both my Watch and my Eyes tell me that + <!-- Page 411 --> <span class="pagenum"><a name="LPage_411" + id="LPage_411"></a>[pg 411]</span> 'tis now high time to think of going to + ſleep, matters of this Nature, will be better, as well as more eaſily, + clear'd by Conference, than Writing. And therefore ſince I think you + know me too well to make it needfull for me to diſclame Credulity, + notwithſtanding my having entertain'd you with all theſe + Extravagancies; for you know well, how wide a difference I am wont to put + betwixt things that barely <i>may be</i>, and things that <i>are</i>, and + between thoſe Relations that are but not unworthy to be inquir'd + into, and thoſe that are not worthy to be actually believ'd; without + making Apologies for my Ravings, I ſhall readily comply with the drowſineſs + that calls upon me to releaſe You, and the rather, becauſe Monſieur + <i>Zulichem</i> being concern'd in your deſire to know the few things + I have obſerved about the ſhining Stone. To entertain thoſe + with Suſpicions that are accuſtomed not to acquieſce but in + Demonſtrations, were a thing that cannot be look'd upon as other than + very improper by, + </p> + <p class="i16"> + SIR, + </p> + <p class="center"> + <i>Your most Affectionate</i><br /> and<br /> <i>most Faithfull Servant,</i> + </p> + <p class="center"> + RO. BOYLE. + </p> + <!-- Page 412 blank --> + <!-- Page 413 --> + <p> + <span class="pagenum"><a name="LPage_413" id="LPage_413"></a>[pg 413]</span> + </p> + <div class="figcenter" style="width:50%;"> + <img width="100%" src="images/453.png" alt="Decorative rule" /> + </div> + <h2> + OBSERVATIONS + </h2> + <p> + Made this 27<sup>th</sup>.<a name="LNtA_35" id="LNtA_35_"></a><a + href="#LNt_35"><sup>35</sup></a> of <i>October</i> 1663. about Mr. <i>Clayton</i>'s + Diamond.<a name="LNtA_36" id="LNtA_36_"></a><a href="#LNt_36"><sup>36</sup></a> + </p> + <p> + Being look'd on in the Day time, though in a Bed, whoſe Curtains were + carefully drawn, I could not diſcern it to Shine at all, though well + Rubb'd, but about a little after Sun-ſet, whilſt the Twilight + yet laſted, Nay, this Morning<a name="LNtA_37" id="LNtA_37_"></a><a + href="#LNt_37"><sup>37</sup></a> a pretty while after Sun-riſing, (but + before I had been abroad in the more freely inlightned Air of the Chamber) + I could upon a light Affriction eaſily perceive the Stone to Shine. + </p> + <!-- Page 414 --> + <p> + <span class="pagenum"><a name="LPage_414" id="LPage_414"></a>[pg 414]</span> + </p> + <p> + Secondly, The Candles being removed, I could not in a Dark place diſcern + the Stone to have any Light, when I looked on it, without having Rubb'd or + otherwiſe prepar'd it. + </p> + <p> + Thirdly, By two white Pibbles though hard Rubb'd one againſt another, + nor by the long and vehement Affriction of Rock Cryſtal againſt + a piece of Red cloath, nor yet by Rubbing two Diamonds ſet in Ring, + as I had Rubb'd this Stone, I could produce any ſenſible degree + of Light. + </p> + <p> + Fourthly, I found this Diamond hard enough, not only to enable me to write + readily with it upon Glaſs, but to Grave on Rock Cryſtal it + ſelf. + </p> + <p> + Fifthly, I found this to have like other Diamonds, an Electrical faculty.<a + name="LNtA_38" id="LNtA_38_"></a><a href="#LNt_38"><sup>38</sup></a> + </p> + <p> + Sixthly, Being rubb'd upon my Cloaths, as is uſual for the exciting + of Amber, Wax, and other Electrical Bodies, it did in the Dark manifeſtly + ſhine like Rotten Wood, or the Scales of Whitings, or other putrified + Fiſh. + </p> + <p> + Seventhly, But this Conſpicuouſneſs was Fainter than that + of the Scales, and Slabber (if I may ſo call it) of Whitings, and + much Fainter than the Light of a Glow-worm, by + <!-- Page 415 --> <span class="pagenum"><a name="LPage_415" + id="LPage_415"></a>[pg 415]</span> which I have been ſometimes able + to Read a ſhort Word, whereas after an ordinary Affriction of this + Diamond I was not able to diſcern diſtinctly by the Light of it + any of the neareſt Bodies: And this Glimmering alſo did very + manifeſtly and conſiderably Decay preſently upon the ceaſing + of the Affriction, though the Stone continued Viſible ſome while + after. + </p> + <p> + Eighthly, But if it were Rubb'd upon a convenient Body for a pretty while, + and Briskly enough, I found the Light would be for ſome moments much + more conſiderable, almoſt like the Light of a Glow-worm, inſomuch + after I ceaſed Rubbing, I could with the Chaf'd ſtone exhibit a + little Luminous Circle, like that, but not ſo bright as that which + Children make by moving a ſtick Fir'd at the end, and in this caſe + it would continue Viſible about ſeven or eight times as long as + I had been in Rubbing it. + </p> + <p> + Ninthly, I found that holding it a while near<a name="LNtA_39" id="LNtA_39_"></a><a + href="#LNt_39"><sup>39</sup></a> the Flame of a Candle, (from which yet I + was carefull to avert my Eyes) and + <!-- Page 416 --> <span class="pagenum"><a name="LPage_416" + id="LPage_416"></a>[pg 416]</span> being immediately remov'd into the + Dark, it diſcloſed ſome faint Glimmering, but inferiour to + that, it was wont to acquire by Rubbing. And afterward holding it near a + Fire that had but little Flame, I found the Stone to be rather leſs + than more excited, than it had been by the Candle. + </p> + <p> + Tenthly, I likewiſe indeavour'd to make it Shine, by holding it a + pretty while in a very Dark place, over a thick piece of Iron, that was + well Heated, but not to that Degree as to be Viſibly ſo. And + though at length I found, that by this way alſo, the Stone acquired + ſome Glimmering, yet it was leſs than by either of the other + ways above mention'd. + </p> + <p> + Eleventhly, I alſo brought it to ſome kind of Glimmering Light, + by taking it into Bed with me, and holding it a good while upon a warm + part of my Naked Body. + </p> + <p> + Twelfthly, To ſatisfie my ſelf, whether the Motion introduc'd + into the Stone did generate the Light upon the account of its producing + Heat there, I held it near the Flame of a Candle, till it was qualify'd to + ſhine pretty well in the Dark, and then immediately I apply'd a + ſlender Hair to try whether it would attract it, but found not that + it did ſo; though if it were made to + <!-- Page 417 --> <span class="pagenum"><a name="LPage_417" + id="LPage_417"></a>[pg 417]</span> ſhine by Rubbing, it was as I + formerly noted Electrical. And for further Confirmation, though I once + purpoſedly kept it ſo near the hot Iron I juſt now + mention'd, as to make it ſenſibly Warm, yet it ſhin'd more + Dimly than it had done by Affriction or the Flame of a Candle, though by + both thoſe ways it had not acquir'd any warmth that was ſenſible. + </p> + <p> + Thirteenthly, Having purpoſely rubb'd it upon ſeveral Bodies + differing as to Colour, and as to Texture, there ſeem'd to be ſome + little Diſparity in the excitation (if I may ſo call it) of + Light. Upon White and Red Cloths it ſeem'd to ſucceed beſt, + eſpecially in compariſon of Black ones. + </p> + <p> + Fourteenthly, But to try what it would do rubb'd upon Bodies more hard, + and leſs apt to yield Heat upon a light Affriction, than Cloath, I + firſt rubb'd it upon a white wooden Box, by which it was excited, and + afterwards upon a piece of purely Glazed Earth, which ſeem'd during + the Attrition to make it Shine better than any of the other Bodies had + done, without excepting the White ones, which I add, leſt the Effect + ſhould be wholly aſcrib'd to the diſpoſition White + Bodies are wont to have to Reflect much Light. + </p> + <!-- Page 418 --> + <p> + <span class="pagenum"><a name="LPage_418" id="LPage_418"></a>[pg 418]</span> + </p> + <p> + Fifteenthly, Having well excited the Stone, I nimbly plung'd it under + Water<a name="LNtA_40" id="LNtA_40_"></a><a href="#LNt_40"><sup>40</sup></a>, + that I had provided for that purpoſe, and perceiv'd it to Shine whilſt + it was beneath the Surface of that Liquor, and this I did divers times. + But when I indeavour'd to produce a Light by rubbing it upon the lately + mentioned Cover of the Box, the Stone and it being both held beneath the + Surface of the Water, I did not well ſatisfie my ſelf in the + Event of the Trial; But this I found, if I took the Stone out, and Rubb'd + it upon a piece of Cloath, it would not as elſe it was wont to do, + preſently acquire a Luminouſneſs, but needed to be rubb'd + manifeſtly much longer before the deſired Effect was found. + </p> + <p> + Sixteenthly, I alſo try'd ſeveral times, that by covering it + with my + <!-- Page 419 --> <span class="pagenum"><a name="LPage_419" + id="LPage_419"></a>[pg 419]</span> warm Spittle (having no warm Water at + hand) it did not loſe his Light.<a name="LNtA_41" id="LNtA_41_"></a><a + href="#LNt_41"><sup>41</sup></a> + </p> + <p> + Seventeenthly, Finding that by Rubbing the Stone with the Flat ſide + downwards, I did by reaſon of the Opacity of the Ring; and the ſudden + Decay of Light upon the ceaſing of the Attrition, probably loſe + the ſight of the Stones greateſt Vividneſs; and ſuppoſing + that the Commotion made in one part of the ſtone will be eaſily + propagated all over, I ſometimes held the piece of Cloath upon which + I rubb'd it, ſo, that one ſide of the Stone was expoſed to + my Eye, whilſt I was rubbing the other, whereby it appear'd more + Vivid than formerly, and to make Luminous Tracts by its Motions too and + fro. And ſometimes holding the Stone upwards, I rubb'd its Broad + ſide with a fine ſmooth piece of Tranſparent Horn, by which + means the Light through that Diaphanous Subſtance, did whilſt I + was actually rubbing the Stone, appear ſo Brisk that ſometimes + and in ſome places it ſeem'd to have little Sparks of fire. + </p> + <p> + Eighteenthly, I took alſo a piece of flat Blew Glaſs, and having + rubb'd the Diamond well upon a Cloath, and nimbly clapt the Glaſs + upon it, to try whether in caſe the Light could peirce it, it would + by + <!-- Page 420 --> <span class="pagenum"><a name="LPage_420" + id="LPage_420"></a>[pg 420]</span> appearing Green, or of ſome other + Colour than Blew, aſſiſt me to gueſs whether it ſelf + were ſincere or no. But finding the Glaſs impervious to ſo + faint a Light, I then thought it fit to try whether that hard Bodies would + not by Attrition increaſe the Diamonds Light ſo as to become + penetrable thereby, and accordingly when I rubb'd the Glaſs briskly + upon the Stone, I found the Light to be Conſpicuous enough, and + ſomewhat Dy'd in its paſſage, but found it not eaſie + to give a Name to the Colour it exhibited. + </p> + <p> + Laſtly, To comply with the Suſpition I had upon the whole + Matter, that the chief manifeſt Change wrought in the Stone, was by + Compreſſion of its parts, rather than Incaleſcence, I took + a piece of white Tile well Glaz'd, and if I preſs'd the Stone hard + againſt it, it ſeem'd though I did not rub it to and fro, to + ſhine at the Sides: And however it did both very manifeſtly and + vigorouſly Shine, if whilſt I ſo preſs'd it, I mov'd + it any way upon the Surface of the Tile, though I did not make it draw a + Line of above a quarter of an Inch long, or thereabouts. And though I made + it not move to and fro, but only from one end of the ſhort Line to + the other, without any return or Lateral motion. Nay, after it had been + <!-- Page 421 --> <span class="pagenum"><a name="LPage_421" + id="LPage_421"></a>[pg 421]</span> often rubb'd, and ſuffer'd to loſe + its Light again, not only it ſeem'd more eaſie to be excited + than at the beginning of the Night; but if I did preſs hard upon it + with my Finger, at the very inſtant that I drew it briskly off, it + would diſcloſe a very Vivid but exceeding ſhort Liv'd + Splendour, not to call it a little Coruſcation.<a name="LNtA_42" + id="LNtA_42_"></a><a href="#LNt_42"><sup>42</sup></a> So that a <i>Carteſian</i> + would ſcarce ſcruple to think he had found in this Stone no + ſlight Confirmation of his Ingenious Maſters <i>Hypotheſis</i>, + touching the Generation of Light in Sublunary Bodies, not ſenſibly + Hot. + </p> + <!-- Page 422 --> + <p> + <span class="pagenum"><a name="LPage_422" id="LPage_422"></a>[pg 422]</span> + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/462.png" alt="Decorative rule" /> + </div> + <h2> + A Poſtſcript. + </h2> + <h3> + Annexed ſome Hours after the<br /> Obſervations were Written. + </h3> + <p> + <i>So many particulars taken notice of in one Night, may make this Stone + appear a kind of Prodigie, and the rather, becauſe having try'd as I + formerly noted, not only a fine Artificial Cryſtal, and ſome alſo + that is Natural, but a Ruby and two Diamonds, I did not find that any of + theſe diſclos'd the like Glimmering of + <!-- Page 423 --> <span class="pagenum"><a name="LPage_423" + id="LPage_423"></a>[pg 423]</span> Light;<a name="LNtA_43" id="LNtA_43_"></a><a + href="#LNt_43"><sup>43</sup></a> yet after all, perceiving by the Hardneſs, + and the Teſtimony of a Skilfull Goldſmith, that this was rather + a Natural than Artificial Stone; for fear leſt there might be ſome + difference in the way of Setting, or in the ſhape of the Diamonds I + made uſe of, neither of which was like this, a flat Table-ſtone, + I thought fit to make a farther Trial of my own Diamonds, by ſuch a + brisk and aſſiduous Affriction as might make amends for the Diſadvantages + above-mention'd, in caſe they were the cauſe of the unſucceſsfulneſs + of the former Attempts: And accordingly I found, that by this way I could + eaſily bring a Diamond I wore on my Finger to diſcloſe a + Light, that was ſenſible enough, and continued ſo though I + cover'd it with Spittle, and us'd ſome other trials about it. And + this will much leſſen the wonder of all the formerly mention'd + Obſervations, by ſhewing that the properties that are ſo + ſtrange are not peculiar to one Diamond, but may be found in others + alſo, and perhaps in divers other hard and</i> Diaphanous <i>Stones. + Yet I hope that what this Diſcovery takes away from the Wonder of theſe + Obſervations, it will add to the Inſtructiveneſs of them, + by affording pregnants Hints, towards the Inveſtigation of the Nature + of Light.</i> + </p> + <h3> + FINIS. + </h3> + <hr /> + <h2> + Notes. + </h2> + <p class="note"> + <a name="LNt_1" id="LNt_1_"></a><a href="#LNtA_1">1</a> L. Annæ Senecæ Natur. + Queſt. l. 6. c. 5. + </p> + <p class="note"> + <a name="LNt_2" id="LNt_2_"></a><a href="#LNtA_2">2</a> He that deſires + more inſtances of this kind and matter, that according to this + doctrine may much help the Theory of colours, and particularly the force + both of Sulphureous and volatile, is likewiſe of Alcalizate and Acid + Salts, and in what particulars, Colours likely depend not in the cauſation + from any Salt at all, may beg his information from M. Boyle who hath + ſome while ſince honoured me with the ſight of his papers + concerning this ſubject, containing many excellent experiments, made + by him for the Elucidation of this doctrine, &c Dr. R. Sharrock in his + ingenious and uſefull Hiſtory of the Propagation and Improvement + of Vegetables, publiſhed in the yeare 1660. + </p> + <p class="note"> + <a name="LNt_3" id="LNt_3_"></a><a href="#LNtA_3">3</a> <i>See the Diſcourſe + of the Nature of Whiteneſs and Blackneſs.</i> + </p> + <p class="note"> + <a name="LNt_4" id="LNt_4_"></a><a href="#LNtA_4">4</a> Since for his eminent + Qualities and Loyalty Grac'd, by his Majeſty, with the Honour of + Knighthood. + </p> + <p class="note"> + <a name="LNt_5" id="LNt_5_"></a><a href="#LNtA_5">5</a> Exercitat. 325 Parag. + 4 + </p> + <p class="note"> + <a name="LNt_6" id="LNt_6_"></a><a href="#LNtA_6">6</a> <i>Album quippe & + agrum, hoc quidem aſperum eſſe dicit, hoc vero læve. de Senſu + & Senſib. 3. 3.</i> + </p> + <p class="note"> + <a name="LNt_7" id="LNt_7_"></a><a href="#LNtA_7">7</a> Epist. 2. pag. 45. + </p> + <p class="note"> + <a name="LNt_8" id="LNt_8_"></a><a href="#LNtA_8">8</a> Gent. Septen. Hiſtor. + lib. 4 cap. 13. + </p> + <p class="note"> + <a name="LNt_9" id="LNt_9_"></a><a href="#LNtA_9">9</a> Hiſt. Anatom. + Cent. 3. Hiſt. 44. + </p> + <p class="note"> + <a name="LNt_10" id="LNt_10_"></a><a href="#LNtA_10">10</a> Olearius Voyage + de Moſco. et de Perſe <i>liv</i>. 3. + </p> + <p class="note"> + <a name="LNt_11" id="LNt_11_"></a><a href="#LNtA_11">11</a> <i>Piſo</i> + Nat. & Med. Hiſt. <i>Braſil. lib</i> 1. in fine. + </p> + <p class="note"> + <a name="LNt_12" id="LNt_12_"></a><a href="#LNtA_12">12</a> <i>Purchas</i> + Pilgrim. Second part, Seventh Book 3. Chap. Sect 5. + </p> + <p class="note"> + <a name="LNt_13" id="LNt_13_"></a><a href="#LNtA_13">13</a> <i>Purchas</i>. + Ibid. + </p> + <p class="note"> + <a name="LNt_14" id="LNt_14_"></a><a href="#LNtA_14">14</a> <i>Purchas</i> + Ibid. in fin + </p> + <p class="note"> + <a name="LNt_15" id="LNt_15_"></a><a href="#LNtA_15">15</a> See <i>Scaliger</i> + Exercit. 325. Sect. 9. + </p> + <p class="note"> + <a name="LNt_16" id="LNt_16_"></a><a href="#LNtA_16">16</a> <i>Nicolaus + Monardes</i> lib <i>ſimplic. ex India allatis</i>, cap. 27. + </p> + <p class="note"> + <a name="LNt_17" id="LNt_17_"></a><a href="#LNtA_17">17</a> Kircher. Art. + Mag. lucis & umbræ, <i>lib. 1. part. 3.</i> + </p> + <p class="note"> + <a name="LNt_18" id="LNt_18_"></a><a href="#LNtA_18">18</a> <i>Herbariſts</i> + are wont to call this Plant <i>Cyanus vulgaris minor</i>. + </p> + <p class="note"> + <a name="LNt_19" id="LNt_19_"></a><a href="#LNtA_19">19</a> Paracelſus + de Mineral. tract. 1. pag. m. 243 + </p> + <p class="note"> + <a name="LNt_20" id="LNt_20_"></a><a href="#LNtA_20">20</a> See <i>Parkinſon</i> + Th. Boran. Trib. 9. cap. 26. + </p> + <p class="note"> + <a name="LNt_21" id="LNt_21_"></a><a href="#LNtA_21">21</a> <i>Parkinſon</i>, + Thea. Bot. Trib. 4 cap. 12. + </p> + <p class="note"> + <a name="LNt_22" id="LNt_22_"></a><a href="#LNtA_22">22</a> <i>Beguinus</i>, + Tyr. Chy. Lib. 2º. Cap. 13º. + </p> + <p class="note"> + <a name="LNt_23" id="LNt_23_"></a><a href="#LNtA_23">23</a> Libr. 2<sup>do</sup> + Cap. 34. + </p> + <p class="note"> + <a name="LNt_24" id="LNt_24_"></a><a href="#LNtA_24">24</a> See the latter + end of the fiftieth Experiment. + </p> + <p class="note"> + <a name="LNt_25" id="LNt_25_"></a><a href="#LNtA_25">25</a> <i>The Curious + Reader that deſires further Information concerning Lakes, may Reſort + to the 7th Book of</i> Neri's <i>Art of Glaſs, Engliſhed (6 or 7 + years ſince the Writing of this 49th Experiment) and Illuſtrated + with Learned Obſervations, by the Inquiſitive and experienc'd + Dr.</i> Charles Merret. + </p> + <p class="note"> + <a name="LNt_26" id="LNt_26_"></a><a href="#LNtA_26">26</a> Boetius de Boot. + Gem. & Lapid. Hiſtor. Lib. 3. Cap. 8. + </p> + <p class="note"> + <a name="LNt_27" id="LNt_27_"></a><a href="#LNtA_27">27</a> Musæi Wormiani. + Cap. 17. + </p> + <p class="note"> + <a name="LNt_28" id="LNt_28_"></a><a href="#LNtA_28">28</a> <i>Purchas</i>'s + Pilgrim. lib. 1. cap. 4. pag. 104. + </p> + <p class="note"> + <a name="LNt_29" id="LNt_29_"></a><a href="#LNtA_29">29</a> In the year 1619. + </p> + <p class="note"> + <a name="LNt_30" id="LNt_30_"></a><a href="#LNtA_30">30</a> Benvonuto Cellini + <i>nell Arte del</i> Gioiellare, <i>Lib.</i> 1. <i>pag.</i> 10. + </p> + <p class="note"> + <a name="LNt_31" id="LNt_31_"></a><a href="#LNtA_31">31</a> The Narrative in + the Authors own words, is this. <i>Ego</i> (ſayes he) <i>ſanctè + affirmare poſſum me unam aureo Annulo incluſam perpetuo geſtare, + cujus facultatem (ſi gemmæ eſt) nunquam ſatis admirari + potui. Geſtaverat enim ante Triginta annos Hiſpanus quidam non + procula puternis ædibus habitans. Is cum vitâ functus eſſet, + & ipſius ſuſpellex (ut moris apud nos eſt) venum + expoſita eſſet, inter cætera etiam Turcois exponebatur. + Verum nemo (licet complures eo concurriſſent, ut eam propter + Coloris Elegantiam, quam vivo Domino habuerat emerent) ſibi emptam + voluit, priſtinum enim nitorem & Colorem prorſus amiſerat, + ut potius Malachites, quam Turcois videretur. Aderat tum temporis gemmæ + habendæ deſiderio etiam parens & frater meus, qui antea sæpius + gratiam & elegantiam ipſius viderant, mirabundi eam nunc tam eſſe + deformem, Emit eam nihilominus pater, ſatiſque vili pretio, qua + omnibus contemptui erat, ac preſentes non eam eſſe quam Hiſpanus + geſtarat, arbitrarentur. Domum reverſus Pater, qui tam turpem + Gemmam geſtare ſibi indecorum putabat, eam mihi dono dat, + inquiens; Quandoquidem, fili mi, vulgi fama eſt, Turcoidem, ut + facultates ſuas exercere poſſit, dono dari debere tibi eam + devoveo, ego acceptam Gemmam ſculptori trado, at gentilitia mea inſignia + illi, quamadmodum fieri ſolet, in Jaſpide Chalcedono, aliiſque + Ignobilioribus Gemmis, inſculperat. Turpe enim exiſtimabam, hujuſmodi + Gemmâ ornatus gratia, dum gratiam nullam haberet, uti. Paret Sculptor + redditque Gemmam, quam geſto pro annulo Signatorio. Vix per menſem + geſtaram, redit illi priſtinus color, ſed non ita nitens + propter Sculpturam, ac inæqualem ſuperficiem. Miramur omnes gemmam, + atque id præcipuè quod color indies pulchrior fieret. Id quià obſervabam, + nunquam fere eam à manu depoſui, ita ut nunc adhuc candem geſtem.</i> + </p> + <p class="note"> + <a name="LNt_32" id="LNt_32_"></a><a href="#LNtA_32">32</a> <i>Olaus Wormius, + in Musæ. 18º pag. 186.</i> + </p> + <p class="note"> + <a name="LNt_33" id="LNt_33_"></a><a href="#LNtA_33">33</a> <i>Musæ. Worm.</i> + pag. 99. + </p> + <p class="note"> + <a name="LNt_34" id="LNt_34_"></a><a href="#LNtA_34">34</a> Arte Vetraria, + lib. 7 cap. 102. + </p> + <p class="note"> + <a name="LNt_35" id="LNt_35_"></a><a href="#LNtA_35">35</a> Theſe were + brought in and Read before the Royal Society, (the Day following) <i>Oct.</i> + 28. 1663. + </p> + <p class="note"> + <a name="LNt_36" id="LNt_36_"></a><a href="#LNtA_36">36</a> <i>The Stone it + ſelf being to be ſhown to the Royal Society, when the Obſervations + were deliver'd, I was willing (being in haſte) to omit the Deſcription + of it, which is in ſhort, That it was a Flat or Table Diamond, of + about a third part of an Inch in length, and ſomewhat leſs in + breadth, that it was a Dull Stone, and of a very bad Water, having in the + Day time very little of the Vividneſs of ev'n ordinary Diamonds, and + being Blemiſhed with a whitiſh Cloud about the middle of it, + which covered near a third part of the Stone.</i> + </p> + <p class="note"> + <a name="LNt_37" id="LNt_37_"></a><a href="#LNtA_37">37</a> <i>Haſt made + me forget to take notice that I went abroad the ſame Morning, the Sun + ſhining forth clear enough, to look upon the Diamond though a</i> + Microſcope, <i>that I might try whether by that Magnifying Glaſs + any thing of peculiar could be diſcern'd in the Texture of the Stone, + and eſpecially of the whitiſh Cloud that poſſeſt + a good part of it. But for all my attention I could not diſcover any + peculiarity worth mentioning.</i> + </p> + <p class="note"> + <a name="LNt_38" id="LNt_38_"></a><a href="#LNtA_38">38</a> V. <i>For it drew + light Bodies like Amber, Jet, and other Concretes that are noted to do + ſo; But its attractive power ſeem'd inferiour to theirs.</i> + </p> + <p class="note"> + <a name="LNt_39" id="LNt_39_"></a><a href="#LNtA_39">39</a> IX. <i>We durſt + not hold it in the Flame of a Candle, no more than put it into a naked + Fire; For fear too Violent a Heat (which has been obſerv'd to ſpoil + many other precious Stones) ſhould vitiate and impair a Jewel, that + was but borrow'd, and was ſuppos'd to be the only one of its Kind.</i> + </p> + <p class="note"> + <a name="LNt_40" id="LNt_40_"></a><a href="#LNtA_40">40</a> XV. <i>We likewiſe + Plung'd it as ſoon as we had excited it, under Liquors of ſeveral + ſorts, as Spirit of Wine, Oyl both Chymical and expreſs'd, an + Acid Spirit, and as I remember an Alcalizate Solution, and found not any + of thoſe various Liquors to deſtroy its Shining property.</i> + </p> + <p class="note"> + <a name="LNt_41" id="LNt_41_"></a><a href="#LNtA_41">41</a> XVI. <i>Having + found by this Obſervation, that a warm Liquor would not extinguiſh + Light in the Diamond, I thought fit to try, whether by reaſon of its + warmth it would not excite it, and divers times I found, that if it were + kept therein, till the Water had leiſure to communicate ſome of + its Heat to it, it would often ſhine as ſoon as it was taken + out, and probably we ſhould have ſeen it Shine more, whilſt + it was in the Water, if ſome degree of Opacity which heated Water is + wont to acquire, upon the ſcore of the Numerous little Bubbles + generated in it, had not kept us from diſcerning the Luſtre of + the Stone.</i> + </p> + <p class="note"> + <a name="LNt_42" id="LNt_42_"></a><a href="#LNtA_42">42</a> <i>I after + bethought my ſelf of imploying a way, which produc'd the deſir'd + Effect both ſooner and better. For holding betwixt my Fingers a Steel + Bodkin, near the Lower part of it, I preſs'd the point hard againſt + the Surface of the Diamond, and much more if I ſtruck the point againſt + it, the Coruſcation would be extremely ſuddain, and very Vivid, + though very Vaniſhing too, and this way which commonly much ſurpris'd + and pleas'd the Spectators, ſeem'd far more proper than the other, to + ſhow that preſſure alone, if forcible enough, though it + were ſo ſuddain, and ſhort, that it could not well be + ſuppos'd to give the Stone any thing near a ſenſible degree + of Warmth, as may be ſuſpected of Rubbing, yet 'tis ſufficient + to generate a very Vivid Light.</i> + </p> + <p class="note"> + <a name="LNt_43" id="LNt_43_"></a><a href="#LNtA_43">43</a> We afterwards, + try'd precious Stones, as Diamonds, Rubies, Saphires, and Emeralls, &c. + but found not any of them to Shine except ſome Diamonds, and of theſe + we were not upon ſo little practice, able to fore-tell before hand, + which would be brought to Shine, and which would not; For ſeveral + very good Diamonds, either would not Shine at all, or much leſs than + others that were farr inferiour to them. And yet thoſe Ingenious Men + are miſtaken, that think a Diamond muſt be foul and cloudy, as + Mr. <i>Claytons</i> was, to be fit for Shining; for as we could bring + ſome ſuch to afford a Glimmering Light, ſo with ſome + clear and excellent Diamonds, we could do the like. But none of thoſe + many that we try'd of all Kinds, were equal to the Diamond on which the Obſervations + were made, not only conſidering the degree of Light it afforded, but + the eaſineſs wherewith it was excited, and the Comparatively + great duration of its Shining. + </p> + <div class="figcenter" style="width:80%;"> + <img width="100%" src="images/039a.png" alt="Decorative rule" /> + </div> + <p> + <b>Transcriber's notes.</b> + </p> + <p> + The Errata of the printed book have all been corrected. They were as + follows: + </p> + <p> + Pag. <a href="#LPage_142">142</a>. l. 20. Theſe words, <i>And to + manifeſt</i>, with the reſt of what is by a miſtake further + printed in this fourth Experiment, belongeth, and is to be referred to the + end of the ſecond Eperiment, p.<a href="#LPage_137">137</a>. pag. <a + href="#LPage_145">145</a>. l. 1. leg. <i>matter</i>. <a href="#LPage_146">146</a>. + l. 4. leg. <i>Bolts-head</i>. pag <a href="#LPage_161">161</a>. in the + marginal note l. 2. dele <i>de</i> ib. l. 3. lege lib 1. p <a + href="#LPage_163">163</a>. l. ult. inſert <i>where</i> between the + words <i>places</i> and <i>the</i>. p. <a href="#LPage_164">164</a> l. 1. + dele <i>that</i>. ibid, l. 8. leg <i>Epidermis</i>. ibid. l. 19 leg. 300. + for 200. p. <a href="#LPage_169">169</a>. l. 22. leg. <i>into it</i>. p. + <a href="#LPage_170">170</a>. l. 23. & 24. leg. <i>Some Solutions + hereafter to be mentioned</i>, for <i>the Solutions of Potaſhes</i>, + and other <i>Lixiviate Salts</i>. p. <a href="#LPage_171">171</a>. l. 6. + inſert <i>part of</i> between the words <i>moſt</i> and <i>diſſolved</i> + p. <a href="#LPage_176">176</a>. l. ult. inſert the participle <i>it</i> + between the words <i>Judged</i> and <i>not</i> p. <a href="#LPage_234">234</a>. + l. 4. leg. <i>Woud-wax</i> or <i>Wood-wax</i>. p. <a href="#LPage_320">320</a> + l. 29. leg. <i>urine</i> for <i>urne</i>. + </p> + <p> + In addition I have corrected the following original typos: + </p> + <p> + The preface: I devis'd tbem -> I devis'd them<br /> The preface: make + Expements -> make Experiments<br /> The Publisher to the reader: made of + Eperiments -> made of Experiments<br /> I. Ch. III.6 divers Expements -> + divers Experiments<br /> I. Ch. III.13 epecially with some sorts -> + especially with some sorts<br /> II. Ch. II.8 Slightet Texture -> Slightest + Texture<br /> II. Exp. I two Colonrs -> two Colours<br /> II. Exp. XIII were + the change of Colour ... is attempted -> where the change (etc.)<br /> III. + Exp. XII avoiding of Ambignity -> avoiding of Ambiguity<br /> III. Exp. + XXIX Juice of this Sipce -> Juice of this Spice<br /> III. Exp. XL forty + second Expement -> forty second Experiment<br /> III. Exp. XLIV keep them + swimning -> keep them swimming<br /> III. Exp. XLVI it seem'd propable to + me -> it seem'd probable to me<br /> III. Exp. XLVII where not comprehended + -> were not comprehended<br /> III. Exp. XLVIII frequent Igintion -> + frequent Ignition<br /> III. Exp. L I could tell yon -> I could tell you<br /> + A Copy of the Letter: nemo unqnam vere asserere -> nemo nunquam vere + asserere<br /> (ib.): what is reladed -> what is related<br /> Observations: + carefulsy drawn -> carefully drawn + </p> + <p> + - and emended<br /> Phœnomenon/a to Phænomenon/a 10 times and<br /> Cœruleous + etc. -> Cæruleous 20 times + </p> + +<div style='display:block;margin-top:4em'>*** END OF THE PROJECT GUTENBERG EBOOK EXPERIMENTS AND CONSIDERATIONS TOUCHING COLOURS ***</div> +<div style='display:block;margin:1em 0;'>This file should be named 14504-h.htm or 14504-h.zip</div> +<div style='display:block;margin:1em 0;'>This and all associated files of various formats will be found in https://www.gutenberg.org/1/4/5/0/14504/</div> +<div style='display:block; margin:1em 0'> +Updated editions will replace the previous one—the old editions will +be renamed. +</div> + +<div style='display:block; margin:1em 0'> +Creating the works from print editions not protected by U.S. copyright +law means that no one owns a United States copyright in these works, +so the Foundation (and you!) can copy and distribute it in the United +States without permission and without paying copyright +royalties. 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