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+The Project Gutenberg eBook of Micrographia, by Robert Hooke
+
+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
+www.gutenberg.org. 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.
+
+Title: Micrographia
+       Some Physiological Descriptions of Minute Bodies Made by Magnifying
+         Glasses with Observations and Inquiries Thereupon
+
+Author: Robert Hooke
+
+Release Date: March 29, 2005  [eBook #15491]
+[Most recently updated: May 22, 2021]
+
+Language: English
+
+Character set encoding: UTF-8
+
+Produced by: Robert Shimmin, Keith Edkins, and the Project Gutenberg
+Online Distributed Proofreading Team
+Revised by Richard Tonsing.
+
+*** START OF THE PROJECT GUTENBERG EBOOK MICROGRAPHIA ***
+
+
+
+
+Note: Project Gutenberg also has an HTML version of this
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+
+      The reader of this text file should understand that words or
+      phrases between underscores should be imagined to be set in italics.
+
+
+
+
+       *       *       *       *       *
+
+By the Council of the ROYAL SOCIETY of London
+for Improving of Natural Knowledge.
+
+Ordered, That the Book written by Robert Hooke, M.A. Fellow of this
+Society, Entituled, Micrographia, or some Physiological Descriptions of
+Minute Bodies, made by Magnifying Glasses, with Observations and Inquiries
+thereupon, Be printed by John Martyn, and James Allestry, Printers to
+the said Society.
+
+Novem. 23. 1664.
+
+BROUNCKER. P.R.S.
+
+       *       *       *       *       *
+
+
+
+
+MICROGRAPHIA:
+
+OR SOME
+
+Physiological Descriptions
+
+OF
+
+MINUTE BODIES
+
+MADE BY
+
+MAGNIFYING GLASSES
+
+WITH
+
+OBSERVATIONS and INQUIRIES thereupon.
+
+
+       *       *       *       *       *
+
+By R. HOOKE, Fellow of the ROYAL SOCIETY.
+
+       *       *       *       *       *
+
+
+
+
+  _Non possis oculo quantum contendere Linceus,
+  Non tamen idcirco contemnas Lippus inungi._ Horat. Ep. lib. 1.
+
+
+[Illustration]
+
+       *       *       *       *       *
+
+
+LONDON, Printed by Jo. Martyn, and Ja. Allestry, Printers to the
+ROYAL SOCIETY, and are to be sold at their Shop at the Bell in S.
+Paul’s Church-yard. M DC LX V.
+
+       *       *       *       *       *
+
+
+TO THE
+
+KING.
+
+SIR,
+
+I Do here most humbly lay this _small_ Present at _Your Majesties_ Royal
+feet. And though it comes accompany’d with two _disadvantages_, the
+_meanness_ of the _Author_, and of the _Subject_; yet in both I am
+_incouraged_ by the _greatness_ of your _Mercy_ and your _Knowledge_. By
+the _one_ I am taught, that you can _forgive_ the most _presumptuous
+Offendors_: And by the _other_, that you will not _esteem_ the least work
+of _Nature_, or _Art_, unworthy your _Observation_. Amidst the many
+_felicities_ that have accompani’d _your Majesties_ happy _Restauration_
+and _Government_, it is none of the least considerable that _Philosophy_
+and _Experimental Learning_ have _prosper’d_ under your _Royal Patronage_.
+And as the calm prosperity of your Reign has given us the _leisure_ to
+follow these _Studies_ of _quiet_ and _retirement_, so it is just, that the
+_Fruits_ of them should, by way of _acknowledgement_, be return’d to _your
+Majesty_. There are, Sir, several other of your Subjects, of your _Royal
+Society_, now busie about _Nobler_ matters: The _Improvement_ of
+_Manufactures_ and _Agriculture_, the _Increase_ of _Commerce_, the
+_Advantage_ of _Navigation_: In all which they are _assisted_ by _your
+Majesties Incouragement_ and _Example_. Amidst all those _greater_ Designs,
+I here presume to bring in that which is more _proportionable_ to the
+_smalness_ of my Abilities, and to offer some of the _least_ of all
+_visible things_, to that _Mighty King_, that has _establisht an Empire_
+over the best of all _Invisible things_ of this World, the _Minds_ of Men.
+
+Your Majesties most humble
+and most obedient
+Subject and Servant,
+
+ROBERT HOOKE.
+
+       *       *       *       *       *
+
+TO THE
+
+ROYAL SOCIETY.
+
+After my _Address_ to our _Great Founder_ and _Patron_, I could not but
+think my self oblig’d, in consideration of those _many Ingagements_ you
+have laid upon me, to offer these my _poor Labours_ to this MOST
+ILLUSTRIOUS ASSEMBLY. YOU have been pleas’d formerly to accept of these
+rude _Draughts_. I have since added to them some _Descriptions_, and some
+_Conjectures_ of my own. And therefore, together with YOUR _Acceptance_, I
+must also beg YOUR _pardon_. The Rules YOU have prescrib’d YOUR selves in
+YOUR Philosophical Progress do seem the best that have ever yet been
+practis’d. And particularly that of avoiding _Dogmatizing_, and the
+_espousal_ of any _Hypothesis_ not sufficiently grounded and confirm’d by
+_Experiments_. This way seems the most excellent, and may preserve both
+_Philosophy_ and _Natural History_ from its former _Corruptions_. In saying
+which, I may seem to condemn my own Course in this Treatise; in which there
+may perhaps be some _Expressions_, which may seem more _positive_ then YOUR
+Prescriptions will permit: And though I desire to have them understood only
+as _Conjectures_ and _Quæries_ (which YOUR Method does not altogether
+disallow) yet if even in those I have exceeded, ’tis fit that I should
+declare, that it was not done by YOUR Directions. For it is most
+unreasonable, that YOU should undergo the _imputation_ of the _faults_ of
+my _Conjectures_, seeing YOU can receive so _small advantage_ of reputation
+by the _sleight Observations_ of
+
+YOUR most humble and
+most faithful Servant
+
+ROBERT HOOKE.
+
+       *       *       *       *       *
+
+
+THE
+
+PREFACE.
+
+It is the great prerogative of Mankind above other Creatures, that we are
+not only able to _behold_ the works of Nature, or barely to _sustein_ our
+lives by them, but we have also the power of _considering_, _comparing_,
+_altering_, _assisting_, and _improving_ them to various uses. And as this
+is the peculiar priviledge of humane Nature in general, so is it capable of
+being so far advanced by the helps of Art, and Experience, as to make some
+Men excel others in their Observations, and Deductions, almost as much as
+they do Beasts. By the addition of such _artificial Instruments_ and
+_methods_, there may be, in some manner, a reparation made for the
+mischiefs, and imperfection, mankind has drawn upon it self, by negligence,
+and intemperance, and a wilful and superstitious deserting the Prescripts
+and Rules of Nature, whereby every man, both from a deriv’d corruption,
+innate and born with him, and from his breeding and converse with men, is
+very subject to slip into all sorts of errors.
+
+The only way which now remains for us to recover some degree of those
+former perfections, seems to be, by rectifying the operations of the
+_Sense_, the _Memory_, and _Reason_, since upon the evidence, the
+_strength_, the _integrity_, and the _right correspondence_ of all these,
+all the light, by which our actions are to be guided is to be renewed, and
+all our command over things is to be establisht.
+
+It is therefore most worthy of our consideration, to recollect their
+several defects, that so we may the better understand how to supply them,
+and by what assistances we may _inlarge_ their power, and _secure_ them in
+performing their particular duties.
+
+As for the actions of our _Senses_, we cannot but observe them to be in
+many particulars much outdone by those of other Creatures, and when at
+best, to be far short of the perfection they seem capable of: And these
+infirmities of the Senses arise from a double cause, either from the
+_disproportion of the Object to the Organ_, whereby an infinite number of
+things can never enter into them, or else from _error in the Perception_,
+that many things, which come within their reach, are not received in a
+right manner.
+
+The like frailties are to be found in the _Memory;_ we often let many
+things _slip away_ from us, which deserve to be retain’d, and of those
+which we treasure up, a great part is either _frivolous_ or _false_; and if
+good, and substantial, either in tract of time _obliterated_, or at best so
+_overwhelmed_ and buried under more frothy notions, that when there is need
+of them, they are in vain sought for.
+
+The two main foundations being so deceivable, it is no wonder, that all
+the succeeding works which we build upon them, of arguing, concluding,
+defining, judging, and all the other degrees of Reason, are lyable to the
+same imperfection, being, at best, either vain, or uncertain: So that the
+errors of the _understanding_ are answerable to the two other, being
+defective both in the quantity and goodness of its knowledge; for the
+limits, to which our thoughts are confin’d, are small in respect of the
+vast extent of Nature it self; some parts of it are _too large_ to be
+comprehended, and some _too little_ to be perceived. And from thence it
+must follow, that not having a full sensation of the Object, we must be
+very lame and imperfect in our conceptions about it, and in all the
+proportions which we build upon it; hence, we often take the _shadow_ of
+things for the _substance_, small _appearances_ for good _similitudes_,
+_similitudes_ for _definitions;_ and even many of those, which we think, to
+be the most solid definitions, are rather expressions of our own misguided
+apprehensions then of the true nature of the things themselves.
+
+The effects of these imperfections are manifested in different ways,
+according to the temper and disposition of the several minds of men, some
+they incline to _gross ignorance_ and stupidity, and others to a
+_presumptuous imposing_ on other mens Opinions, and a _confident
+dogmatizing_ on matters, whereof there is no assurance to be given.
+
+Thus all the uncertainty, and mistakes of humane actions, proceed either
+from the narrowness and wandring of our _Senses_, from the slipperiness or
+delusion of our _Memory_, from the confinement or rashness of our
+_Understanding_, so that ’tis no wonder, that our power over natural causes
+and effects is so slowly improv’d, seeing we are not only to contend with
+the obscurity and _difficulty of the things_ whereon we work and think, but
+even the _forces of our own minds_ conspire to betray us.
+
+These being the dangers in the process of humane Reason, the remedies of
+them all can only proceed from the _real_, the _mechanical_, the
+_experimental_ Philosophy, which has this advantage over the Philosophy of
+_discourse_ and _disputation_, that whereas that chiefly aims at the
+subtilty of its Deductions and Conclusions, without much regard to the
+first ground-work, which ought to be well laid on the Sense and Memory; so
+this intends the right ordering of them all, and the making them
+serviceable to each other.
+
+The first thing to be undertaken in this weighty work, is a _watchfulness
+over the failings_ and an _inlargement of the dominion_, of the Senses.
+
+To which end it is requisite, first, That there should be a _scrupulous_
+choice, and a _strict examination_, of the reality, constancy, and
+certainty of the Particulars that we admit: This is the first rise whereon
+truth is to begin, and here the most severe, and most impartial diligence,
+must be imployed; the storing up of all, without any regard to evidence or
+use, will only tend to darkness and confusion. We must not therefore esteem
+the riches of our Philosophical treasure by the _number_ only, but chiefly
+by the _weight_; the most _vulgar_ Instances are not to be neglected, but
+above all, the most _instructive_ are to be entertain’d; the footsteps of
+Nature are to be trac’d, not only in her _ordinary course_, but when she
+seems to be put to her shifts, to make many _doublings_ and _turnings_, and
+to use some kind of art in indeavouring to avoid our discovery.
+
+The next care to be taken, in respect of the Senses, is a supplying of
+their infirmities with _Instruments_, and, as it were, the adding of
+_artificial Organs_ to the _natural_; this in one of them has been of late
+years accomplisht with prodigious benefit to all sorts of useful knowledge,
+by the invention of Optical Glasses. By the means of _Telescopes_, there is
+nothing so _far distant_ but may be represented to our view; and by the
+help of _Microscopes_, there is nothing so _small_, as to escape our
+inquiry; hence there is a new visible World discovered to the
+understanding. By this means the Heavens are open’d, and a vast number of
+new Stars, and new Motions, and new Productions appear in them, to which
+all the antient Astronomers were utterly Strangers. By this the Earth it
+self, which lyes so neer us, under our feet, shews quite a new thing to us,
+and in every _little particle_ of its matter; we now behold almost as great
+a variety of Creatures, as we were able before to reckon up in the whole
+_Universe_ it self.
+
+It seems not improbable, but that by these helps the subtilty of the
+composition of Bodies, the structure of their parts, the various texture of
+their matter, the instruments and manner of their inward motions, and all
+the other possible appearances of things, may come to be more fully
+discovered; all which the antient _Peripateticks_ were content to
+comprehend in two general and (unless further explain’d) useless words of
+_Matter_ and _Form_. From whence there may arise many admirable advantages,
+towards the increase of the _Operative_, and the _Mechanick_ Knowledge, to
+which this Age seems so much inclined, because we may perhaps be inabled to
+discern all the secret workings of Nature, almost in the same manner as we
+do those that are the productions of Art, and are manag’d by Wheels, and
+Engines, and Springs, that were devised by humane Wit.
+
+In this kind I here present to the World my imperfect Indeavours; which
+though they shall prove no other way considerable, yet, I hope, they may be
+in some measure useful to the main Design of a _reformation_ in Philosophy,
+if it be only by shewing, that there it not so much requir’d towards it,
+any strength of _Imagination_, or exactness of _Method_, or depth of
+_Contemplation_ (though the addition of these, where they can be had, must
+needs produce a much more perfect composure) as a sincere _Hand_, and a
+_faithful_ Eye, to examine, and to record, the things themselves as they
+appear.
+
+And I beg my Reader, to let me take the boldness to assure him, that in
+this present condition of knowledge, a man so qualified, as I have
+indeavoured to be, only with resolution, and integrity, and plain
+intentions of imploying his _Senses_ aright, may venture to compare the
+reality and the usefulness of his services, towards the true Philosophy,
+with those of other men, that are of much stronger, and more acute
+_speculations_, that shall not make use of the same method by the Senses.
+
+The truth is, the Science of Nature has been already too long made only a
+work of the _Brain_ and the _Fancy_: It is now high time that it should
+return to the plainness and soundness of _Observations_ on _material_ and
+_obvious_ things. It is said of great Empires, That _the best way to
+preserve them from decay, is to bring them back to the first Principles,
+and Arts, on which they did begin_. The same is undoubtedly true in
+Philosophy, that by wandring far away into _invisible Notions_, has almost
+quite destroy’d it self, and it can never be recovered, or continued, but
+by returning into the same _sensible paths_, in which it did at first
+proceed.
+
+If therefore the Reader expects from me any infallible Deductions, or
+certainty of _Axioms_, I am to say for my self, that those stronger Works
+of Wit and Imagination are above my weak Abilities; or if they had not been
+so, I would not have made use of them in this present Subject before me:
+Whenever he finds that I have ventur’d at any small Conjectures, at the
+causes of the things that I have observed, I beseech him to look upon them
+only as _doubtful Problems_, and _uncertain ghesses_, and not as
+unquestionable Conclusions, or matters of unconfutable Science; I have
+produced nothing here, with intent to bind his understanding to an
+_implicit_ consent; I am so far from that, that I desire him, not
+absolutely to rely upon these Observations of my eyes, if he finds them
+contradicted by the future Ocular Experiments of sober and impartial
+Discoverers.
+
+As for my part, I have obtained my end, if these my small Labours shall be
+thought fit to take up some place in the large stock of _natural
+Observations_, which so many hands are busie in providing. If I have
+contributed the _meanest foundations_ whereon others may raise nobler
+_Superstructures_, I am abundantly satisfied; and all my ambition is, that
+I may serve to the great Philosophers of this Age, as the makers and the
+grinders of my Glasses did to me; that I may prepare and furnish them with
+some _Materials_, which they may afterwards _order_ and _manage_ with
+better skill, and to far greater advantage.
+
+The next remedies in this universal cure of the Mind are to be applied to
+the _Memory_, and they are to consist of such Directions as may inform us,
+what things are best to be _stor’d up_ for our purpose, and which is the
+best way of so _disposing_ them, that they may not only be _kept in
+safety_, but ready and convenient, to be at any time _produc’d_ for use, as
+occasion shall require. But I will not here prevent my self in what I may
+say in another Discourse, wherein I shall make an attempt to propose some
+Considerations of the manner of compiling a Natural and Artificial History,
+and of so ranging and registring its Particulars into Philosophical Tables,
+as may make them most useful for the raising of _Axioms_ and _Theories_.
+
+The last indeed is the most _hazardous_ Enterprize, and yet the most
+_necessary_; and that is, to take such care that the _Judgment_ and the
+_Reason_ of Man (which is the third Faculty to be repair’d and improv’d)
+should receive such assistance, as to avoid the dangers to which it is by
+nature most subject. The Imperfections, which I have already mention’d, to
+which it is lyable, do either belong to the _extent_, or the _goodness_ of
+its knowledge; and here the difficulty is the greater, least that which may
+be thought a _remedy_ for the one should prove _destructive_ to the other,
+least by seeking to inlarge our Knowledge, we should render it weak and
+uncertain; and least by being too scrupulous and exact about every
+Circumstance of it, we should confine and streighten it too much.
+
+In both these the middle wayes are to be taken, nothing is to be_
+omitted_, and yet every thing to pass a _mature deliberation_: No
+_Intelligence_ from Men of all Professions, and quarters of the World, to
+be _slighted_, and yet all to be so _severely examin’d_, that there remain
+no room for doubt or instability; much _rigour_ in admitting, much
+_strictness_ in comparing, and above all, much _slowness_ in debating, and
+_shyness_ in determining, is to be practised. The _Understanding_ is to
+_order_ all the inferiour services of the lower Faculties; but yet it is to
+do this only as a _lawful Master_, and not as a _Tyrant._ It must not
+_incroach_ upon their Offices, nor take upon it self the employments which
+belong to either of them. It must _watch_ the irregularities of the Senses,
+but it must not go before them, or _prevent_ their information. It must
+_examine_, _range_, and _dispose_ of the bank which is laid up in the
+Memory: but it must be sure to make _distinction_ between the _sober_ and
+_well collected heap_, and the _extravagant Ideas_, and _mistaken Images_,
+which there it may sometimes light upon. So many are the _links_, upon
+which the true Philosophy depends, of which, if any one be _loose_, or
+_weak_, the whole _chain_ is in danger of being dissolv’d; it is to _begin_
+with the Hands and Eyes, and to _proceed_ on through the Memory, to be
+_continued_ by the Reason; nor is it to stop there, but to _come about_ to
+the Hands and Eyes again, and so, by a _continual passage round_ from one
+Faculty to another, it is to be maintained in life and strength, as much as
+the body of man is by the _circulation_ of the blood through the several
+parts of the body, the Arms, the Feet, the Lungs, the Heart, and the Head.
+
+If once this method were followed with diligence and attention, there is
+nothing that lyes within the power of human Wit (or which is far more
+effectual) of human Industry, which we might not compass; we might not only
+hope for Inventions to equalize those of _Copernicus_, _Galileo_,
+_Gilbert_, _Harvy_, and of others, whose Names are almost lost, that were
+the Inventors of _Gun-powder_, the _Seamans Compass_, _Printing_,
+_Etching_, _Graving_, _Microscopes_, &c. but multitudes that may far exceed
+them: for even those discoveries seem to have been the products of some
+such method, though but imperfect; What may not be therefore expected from
+it if thoroughly prosecuted? _Talking_ and _contention of Arguments_ would
+soon be turn’d into _labours_; all the fine _dreams_ of Opinions, and
+_universal metaphysical natures_, which the luxury of subtil Brains has
+devis’d, would quickly vanish, and give place to _solid Histories_,
+_Experiments_ and _Works._ And as at first, mankind _fell_ by _tasting_ of
+the forbidden Tree of Knowledge, so we, their Posterity, may be in part
+_restor’d_ by the same way, not only by _beholding_ and _contemplating_,
+but by _tasting_ too those fruits of Natural knowledge, that were never yet
+forbidden.
+
+From hence the World may be assisted with _variety_ of Inventions, _new_
+matter for Sciences may be _collected_, the _old improv’d_, and their
+_rust_ rubb’d away; and as it is by the benefit of Senses that we receive
+all our Skill in the works of Nature, so they also may be wonderfully
+benefited by it, and may be guided to an easier and more exact performance
+of their Offices; ’tis not unlikely, but that we may find out wherein our
+Senses are deficient, and as easily find wayes of repairing them.
+
+The Indeavours of Skilful men have been most conversant about the
+assistance of the Eye, and many noble Productions have followed upon it;
+and from hence we may conclude, that there is a way open’d for advancing
+the operations, not only of all the other Senses, but even of the Eye it
+self; that which has been already done ought not to content us, but rather
+to incourage us to proceed further, and to attempt greater things in the
+same and different wayes.
+
+’Tis not unlikely, but that there may be yet invented several other helps
+for the eye, at much exceeding those already found, as those do the bare
+eye, such as by which we may perhaps be able to discover _living Creatures_
+in the Moon, or other Planets, the _figures_ of the compounding Particles
+of matter, and the particular _Schematisms_ and _Textures_ of Bodies.
+
+And as _Glasses_ have highly promoted our _seeing_, so ’tis not
+improbable, but that there may be found many _Mechanical Inventions_ to
+improve our other Senses, of _hearing_, _smelling_, _tasting_, _touching._
+’Tis not impossible to hear a _whisper_ a _furlongs_ distance, it having
+been already done; and perhaps the nature of the thing would not make it
+more impossible, though that furlong should be ten times multiply’d. And
+though some famous Authors have affirm’d it impossible to hear through the
+_thinnest plate_ of _Muscovy-glass_; yet I know a way, by which ’tis easie
+enough to hear one speak through a _wall a yard thick_. It has not been yet
+thoroughly examin’d, how far _Otocousticons_ may be improv’d, nor what
+other wayes there may be of _quickning_ our hearing, or _conveying_ sound
+through _other bodies_ then the _Air_: for that that is not the only
+_medium_, I can assure the Reader, that I have, by the help of a _distended
+wire_, propagated the sound to a very considerable distance in an
+_instant_, or with as seemingly quick a motion as that of light, at least,
+incomparably swifter then that, which at the same time was propagated
+through the Air; and this not only in a straight line, or direct, but in
+one bended in many angles.
+
+Nor are the other three so perfect, but that _diligence_, _attention_, and
+many _mechanical contrivances_, may also highly improve them. For since the
+sense of _smelling_ seems to be made by the _swift passage_ of the _Air_
+(_impregnated_ with the steams and _effluvia_ of several odorous Bodies)
+through the grisly _meanders_ of the Nose whose surfaces are _cover’d_ with
+a very sensible _nerve_, and _moistned_ by a _transudation_ from the
+_processus mamillares_ of the Brain, and some adjoyning _glandules_, and by
+the moist _steam_ of the _Lungs_, with a Liquor convenient for the
+reception of those _effluvia_ and by the adhesion and mixing of those
+steams with that liquor, and thereby affecting the nerve, or perhaps by
+insinuating themselves into the juices of the brain, after the same manner,
+as I have in the following Observations intimated, the parts of Salt to
+pass through the skins of Effs, and Frogs. Since, I say, smelling seems to
+be made by some such way, ’tis not improbable, but that some contrivance,
+for making a great quantity of Air pass quick through the Nose, might as
+much promote the sense of smelling, as the any wayes hindring that passage
+does dull and destroy it. Several tryals I have made, both of hindring and
+promoting this sense, and have succeeded in some according to expectation;
+and indeed to me it seems capable of being improv’d, for the judging of the
+constitutions of many Bodies. Perhaps we may thereby also judge (as other
+Creatures seem to do) what is wholsome, what poyson; and in a word, what
+are the specifick properties of Bodies.
+
+There may be also some other mechanical wayes found out, of sensibly
+perceiving the _effluvia_ of Bodies; several Instances of which, were it
+here proper, I could give of Mineral steams and exhalations; and it seems
+not impossible, but that by some such wayes improved, may be discovered,
+what Minerals lye buried under the Earth, without the trouble to dig for
+them; some things to confirm this Conjecture may be found in _Agricola_,
+and other Writers of Minerals, speaking of the Vegetables that are apt to
+thrive, or pine, in those steams.
+
+Whether also those steams, which seem to issue out of the Earth, and mix
+with the Air (and so to precipitate some _aqueous_ Exhalations, wherewith
+’tis impregnated) may not be by some way detected before they produce the
+effect, seems hard to determine; yet something of this kind I am able to
+discover, by an Instrument I contriv’d to shew all the minute variations in
+the pressure of the Air; by which I constantly find, that before, and
+during the time of rainy weather, the pressure of the Air is less, and in
+_dry weather_, but especially when an _Eastern Wind_ (which having past
+over vast tracts of Land is heavy with Earthy Particles) blows, it is much
+more, though these changes are varied according to very odd Laws.
+
+    The Instrument is this. I prepare a pretty capacious Bolt-head AB, with
+    a small stem about two foot and a half long DC; upon the end of this D
+    I put on a small bended Glass, or brazen _syphon_ DEF (open at D, E and
+    F, but to be closed with cement at F and E, as occasion serves) whose
+    stem F should be about six or eight inches long, but the bore of it not
+    above half an inch diameter, and very even; these I fix very strongly
+    together by the help of very hard Cement, and then fit the whole Glass
+    ABCDEF into a long Board, or Frame, in such manner, that almost half
+    the head AB may lye buried in a concave Hemisphere cut into the Board
+    RS; then I place it so on the Board RS, as is exprest in the first
+    figure of the first Scheme; and fix it very firm and steady in that
+    posture, so as that the weight of the _Mercury_ that is afterwards to
+    be put into it, may not in the least shake or stir it; then drawing a
+    line XY on the Frame RT, so that it may divide the ball into two equal
+    parts, or that it may pass, as ’twere, through the center of the ball.
+    I begin from that, and divide all the rest of the Board towards UT into
+    inches, and the inches between the 25 and the end E (which need not be
+    above two or three and thirty inches distant from the line XY) I
+    subdivide into Decimals; then stopping the end F with soft Cement, or
+    soft Wax, I invert the Frame, placing the head downwards, and the
+    Orifice E upwards; and by it, with a small Funnel, I fill the whole
+    Glass with Quicksilver; then by stopping the small Orifice E with my
+    finger, I oftentimes erect and invert the whole Glass and Frame, and
+    thereby free the Quicksilver and Glass from all the bubbles or parcels
+    of lurking Air; then inverting it as before, I fill it top full with
+    clear and well strain’d Quicksilver, and having made ready a small ball
+    of pretty hard Cement, by heat made very soft, I press it into the hole
+    E, and thereby stop it very fast; and to secure this Cement from flying
+    out afterward, I bind over it a piece of Leather, that is spread over
+    in the inside with Cement, and wound about it while the Cement is hot:
+    Having thus fastned it, I gently erect again the Glass after this
+    manner: I first let the Frame down edge-wayes, till the edge RV touch
+    the Floor, or ly horizontal; and then in that edging posture raise the
+    end RS; this I do, that if there chance to be any Air hidden in the
+    small Pipe E, it may ascend into the Pipe F, and not into the Pipe DC:
+    Having thus erected it, and hung it by the hole Q, or fixt it
+    perpendicularly by any other means, I open the end F, and by a small
+    _Syphon_ I draw out the _Mercury_ so long, till I find the surface of
+    it AB in the head to touch exactly the line XY; at which time I
+    immediately take away the _Syphon_, and if by chance it be run somewhat
+    below the line XY, by pouring in gently a little _Mercury_ at F, I
+    raise it again to its desired height, by this contrivance I make all
+    the sensible rising and falling of the _Mercury_ to be visible in the
+    surface of the _Mercury_ in the Pipe F, and scarce any in the head AB.
+    But because there really is some small change of the upper surface
+    also, I find by several Observations how much it rises in the Ball, and
+    falls in the Pipe F, to make the distance between the two surfaces an
+    inch greater then it was before; and the measure that it falls in the
+    Pipe is the length of the inch by which I am to mark the parts of the
+    Tube F, or the Board on which it lyes, into inches and Decimals: Having
+    thus justned and divided it, I have a large Wheel MNOP, whose outmost
+    limb is divided into two hundred equal parts; this by certain small
+    Pillars is fixt on the Frame RT, in the manner exprest in the Figure.
+    In the middle of this, on the back side, in a convenient frame, is
+    placed a small Cylinder, whose circumference is equal to twice the
+    length of one of those divisions, which I find answer to an inch of
+    ascent, or descent, of _Mercury_: This Cylinder I, is movable on a very
+    small Needle, on the end of which is fixt a very light Index KL, all
+    which are so pois’d on the Axis, or Needle, that no part is heavier
+    then another: Then about this Cylinder is wound a small Clew of Silk,
+    with two small steel Bullets at each end of it GH; one of these, which
+    is somewhat the heavier, ought to be so big, as freely to move to and
+    fro in the Pipe F; by means of which contrivance, every the least
+    variation of the height of the _Mercury_ will be made exceeding visible
+    by the motion to and fro of the small Index KL.
+
+But this is but one way of discovering the _effluvia_ of the Earth mixt
+with the Air; there may be perhaps many others, witness the _Hygroscope_,
+an Instrument whereby the watery steams volatile in the Air are discerned,
+which the Nose it self is not able to find. This I have describ’d in the
+following Tract in the Description of the Beard of a wild Oat. Others
+there are, may be discovered both by the Nose, and by other wayes also.
+Thus the _smoak_ of burning _Wood_ is _smelt_, _seen_, and sufficiently
+_felt_ by the eyes: The _fumes_ of burning _Brimstone_ are _smelt_ and
+discovered also by the destroying the Colours of Bodies, as by the
+_whitening of a red Rose_: And who knows, but that the Industry of man,
+following this method, may find out wayes of improving this sense to as
+great a degree of perfection at it is in any Animal, and perhaps yet
+higher.
+
+’Tis not improbable also, but that our _taste_ may be very much improv’d,
+either by _preparing_ our taste for the Body, as, after eating _bitter_
+things, _Wine_, or other _Vinous liquors_, are more sensibly tasted; or
+else by _preparing_ Bodies for our tast; as the dissolving of Metals with
+acid Liquors, make them tastable, which were before altogether insipid;
+thus _Lead_ becomes _sweeter_ then Sugar, and _Silver_ more _bitter_ then
+Gall, _Copper_ and _Iron_ of most _loathsome_ tasts. And indeed the
+business of this sense being to discover the presence of dissolved Bodies
+in Liquors put on the Tongue, or in general to discover that a fluid body
+has some solid body dissolv’d in it, and what they are; whatever
+contrivance makes this discovery improves this sense. In this kind the
+mixtures of Chymical Liquors afford many Instances; as the sweet Vinegar
+that is impregnated with Lead may be discovered to be so by the affusion of
+a little of an _Alcalizate solution_: The bitter liquor of _Aqua fortis_
+and _Silver_ may be discover’d to be charg’d with that Metal, by laying in
+it some plates of Copper: ’Tis not improbable also, but there may be
+multitudes of other wayes of discovering the parts dissolv’d, or dissoluble
+in liquors; and what is this discovery but a kind of _secundary tasting_.
+
+’Tis not improbable also, but that the sense of _feeling_ may be highly
+improv’d, for that being a sense that judges of the more _gross_ and
+_robust motions_ of the _Particles_ of _Bodies_, seems capable of being
+improv’d and assisted very many wayes. Thus for the distinguishing of
+_Heat_ and _Cold_, the _Weather-glass_ and _Thermometer_, which I have
+describ’d in this following Treatise, do exceedingly perfect it; by each of
+which the least variations of heat or cold, which the most Acute sense is
+not able to distinguish, are manifested. This is oftentimes further
+promoted also by the help of _Burning-glasses_, and the like, which collect
+and unite the radiating heat. Thus the _roughness_ and _smoothness_ of a
+Body is made much more sensible by the help of a _Microscope_, then by the
+most _tender_ and _delicate Hand_. Perhaps, a Physitian might, by several
+other _tangible_ proprieties, discover the constitution of a Body as well
+as by the _Pulse_. I do but instance in these, to shew what possibility
+there may be of many others, and what probability and hopes there were of
+finding them, if this method were followed; for the Offices of the five
+Senses being to detect either the _subtil_ and _curious Motions_ propagated
+through all _pellucid_ or perfectly _homogeneous_ Bodies; Or the more
+_gross_ and _vibrative Pulse_ communicated through the _Air_ and all other
+convenient _mediums_, whether fluid or solid: Or the _effluvia_ of Bodies
+_dissolv’d_ in the _Air_; Or the _particles_ of bodies _dissolv’d_ or
+_dissoluble_ in _Liquors_, or the more _quick_ and _violent shaking motion_
+of _heat_ in all or any of these: whatsoever does any wayes promote any of
+these kinds of _criteria_, does afford a way of improving some one sense.
+And what a multitude of these would a diligent Man meet with in his
+inquiries? And this for the helping and promoting the _sensitive faculty_
+only.
+
+Next, as for the _Memory_, or _retentive faculty_, we may be sufficiently
+instructed from the _written Histories_ of _civil actions_, what great
+assistance may be afforded the Memory, in the committing to writing things
+observable in _natural operations_. If a Physitian be therefore accounted
+the more able in his Faculty, because he has had long experience and
+practice, the remembrance of which, though perhaps very imperfect, does
+regulate all his after actions: What ought to be thought of that man, that
+has not only a perfect _register_ of his own experience, but is grown _old_
+with the experience of many hundreds of years, and many thousands of men.
+
+And though of late, men, beginning to be sensible of this convenience,
+have here and there registred and printed some few _Centuries_, yet for the
+most part they are set down very lamely and imperfectly, and, I fear, many
+times not so truly, they seeming, several of them, to be design’d more for
+_Ostentation_ then _publique use_: For, not to instance, that they do, for
+the most part, omit those Experiences they have made, wherein their
+Patients have miscarried, it is very easie to be perceiv’d, that they do
+all along _hyperbolically extol_ their own Prescriptions, and vilifie those
+of others. Notwithstanding all which, these kinds of Histories are
+generally esteem’d useful, even to the ablest Physitian.
+
+What may not be expected from the _rational_ or _deductive Faculty_ that
+is furnisht with such _Materials_, and those so readily _adapted_, and
+rang’d for use, that in a moment, as ’twere, thousands of Instances,
+serving for the _illustration_, _determination_, or _invention_, of almost
+any inquiry, may be _represented_ even to the sight? How neer the nature of
+_Axioms_ must all those _Propositions_ be which are examin’d before so many
+_Witnesses_? And how difficult will it be for any, though never so subtil
+an error in Philosophy, to _scape_ from being discover’d, after it has
+indur’d the _touch_, and so many other _tryals_?
+
+What kind of mechanical way, and physical invention also is there requir’d
+that might not this way be found out? The _Invention_ of a way to find the
+_Longitude_ of places is easily perform’d, and that to as great
+_perfection_ as is desir’d, or to at great an _accurateness_ as the
+_Latitude_ of places can be found at Sea; and perhaps yet also to a greater
+certainty then that has been hitherto found, as I shall very speedily
+freely manifest to the world. The way of _flying_ in the Air seems
+principally unpracticable, by reason of the _want of strength_ in _humane
+muscles_; if therefore that could be suppli’d, it were, I think, easie to
+make twenty contrivances to perform the office of _Wings_: What Attempts
+also I have made for the supplying that Defect, and my successes therein,
+which, I think, are wholly new, and not inconsiderable, I shall in another
+place relate.
+
+’Tis not unlikely also, but that _Chymists_, if they followed this method,
+might find out their so much sought for _Alkahest_. What an _universal
+Menstruum_, which dissolves all sorts of _Sulphureous Bodies_, I have
+discover’d (which has not been before taken notice of as such) I have shewn
+in the sixteenth Observation.
+
+What a prodigious variety of Inventions in _Anatomy_ has this latter Age
+afforded, even in our own Bodies in the very _Heart_, by which we live, and
+the Brain, which is the seat of our knowledge of other things? witness all
+the excellent Works of _Pecquet_, _Bartholinus_, _Billius_, and many
+others; and at home, of Doctor _Harvy_, Doctor _Ent_, Doctor _Willis_,
+Doctor _Glisson_. In _Celestial Observations_ we have far exceeded all the
+Antients, even the _Chaldeans_ and _Egyptians_ themselves, whose _vast
+Plains_, _high Towers_, and _clear Air_, did not give them so great
+advantages over us, as have over them by our _Glasses_. By the help of
+which, they have been very much outdone by the famous _Galileo_,
+_Hevelius_, _Zulichem_; and our own Countrymen, Mr. _Rook_, Doctor _Wren_,
+and the great Ornament of our Church and Nation, the _Lord Bishop of
+Exeter_. And to say no more in _Aerial Discoveries_, there has been a
+wonderful progress made by the _Noble Engine_ of _the most Illustrious Mr.
+Boyle_, whom it becomes me to mention with all honour, not only as my
+particular Patron, but as the _Patron_ of _Philosophy_ it self; which he
+every day _increases_ by his _Labours_, and _adorns_ by his _Example_.
+
+The good success of all these _great Men_, and many others, and the now
+seemingly great _obviousness_ of most of their and divers other Inventions,
+which from the beginning of the world have been, as ’twere, trod on, and
+yet not minded till these last _inquisitive_ Ages (an Argument that there
+may be yet behind multitudes of the like) puts me in mind to recommend such
+Studies, and the prosecution of them by such methods, to the _Gentlemen_ of
+our Nation, whose _leisure_ makes them fit to _undertake_, and the _plenty_
+of their fortunes _to accomplish_, extraordinary things in this way. And I
+do not only propose this kind of _Experimental Philosophy_ as a matter of
+high _rapture_ and _delight_ of the mind, but even as a _material_ and
+_sensible Pleasure_. So vast it the _variety of Objects_ which will come
+under their Inspections, so many _different wayes_ there are _of handling_
+them, so great is the _satisfaction_ of _finding_ out _new things_, that I
+dare compare the _contentment_ which they will injoy, not only to that of
+_contemplation_, but even to that which most men prefer of _the very Senses
+themselves_.
+
+And if they will please to take any incouragement from so mean and so
+imperfect endeavours as mine, upon my own experience, I can assure them,
+without arrogance, That there has not been any inquiry or Problem in
+_Mechanicks_, that I have hitherto propounded to my self, but by a certain
+method (which I may on some other opportunity explain) I have been able
+presently to examine the possibility of it; and if so, as easily to
+excogitate divers wayes of performing it: And indeed it is possible to do
+as much by _this method_ in _Mechanicks_, as by _Algebra_ can be perform’d
+in _Geometry_. Nor can I at all doubt, but that the same method is as
+applicable to _Physical Enquiries_, and as likely to find and reap thence
+as plentiful a crop of Inventions; and indeed there seems to be no subject
+so barren, but may with this good husbandry be highly improv’d.
+
+Toward the prosecution of this method in _Physical Inquiries_, I have here
+and there _gleaned_ up an _handful_ of Observations, in the collection of
+most of which I made use of _Microscopes_, and some other _Glasses_ and
+_Instruments_ that improve the sense; which way I have herein taken, not
+that there are not multitudes of useful and pleasant Observables, yet
+uncollected, obvious enough without the helps of Art, but only to promote
+the use of Mechanical helps for the Senses, both in the surveying the
+already visible World, and for the discovery of many others hitherto
+unknown, and to make us, with the great Conqueror, to be affected that we
+have not yet overcome one World when there are so many others to be
+discovered, every considerable improvement of _Telescopes_ or _Microscopes_
+producing new Worlds and _Terra-Incognita’s_ to our view.
+
+The Glasses I used were of our English make, but though very good of the
+kind, yet far short of what might be expected, could we once find a way of
+making Glasses Elliptical, or of some more true shape; for though both
+_Microscopes_, and _Telescopes_, as they now are, will magnifie an Object
+about a thousand thousand times bigger then it appears to the naked eye;
+yet the Apertures of the Object glasses are so very small, that very few
+Rays are admitted, and even of those few there are so many false, that the
+Object appears _dark_ and _indistinct_: And indeed these inconveniences are
+such, as seem inseparable from Spherical Glasses, even when most exactly
+made; but the way we have hitherto made use of for that purpose is so
+imperfect, that there may be perhaps ten wrought before one be made
+tolerably good, and most of those ten perhaps every one differing in
+goodness one from another, which is an Argument, that the way hitherto used
+is, at least, very uncertain. So that these Glasses have a double defect;
+the one, that very few of them are exactly true wrought; the other, that
+even of those that are best among them, none will admit a sufficient number
+of Rayes to magnifie the Object beyond a determinate bigness. Against which
+Inconveniences the only Remedies I have hitherto met with are these.
+
+    First, for _Microscopes_ (where the Object we view is near and within
+    our power) the best way of making it appear bright in the Glass, is to
+    cast a great quantity of light on it by means of _convex glasses_, for
+    thereby, though the aperture be very small, yet there will throng in
+    through it such multitudes, that an Object will by this means indure to
+    be magnifi’d as much again as it would be without it. The way for doing
+    which is this. I make choice of some Room that has only one window open
+    to the South, and at about three or four foot distance from this
+    Window, on a Table, I place my _Microscope_, and then so place either a
+    round Globe of Water, or a very deep clear_ plano convex_ Glass (whose
+    convex side is turn’d towards the Window) that there is a great
+    quantity of Rayes collected and thrown upon the Object: Or if the Sun
+    shine, I place a small piece of oyly Paper very near the Object,
+    between that and the light; then with a good large Burning-Glass I so
+    collect and throw the Rayes on the Paper, that there may be a very
+    great quantity of light pass through it to the Object; yet I so
+    proportion that light, that it may not singe or burn the Paper. Instead
+    of which Paper there may be made use of a small piece of Looking-glass
+    plate, one of whose sides is made rough by being rubb’d on a flat Tool
+    with very fine sand, this will, if the heat be leisurely cast on it,
+    indure a much greater degree of heat, and consequently very much
+    augment a convenient light. By all which means the light of the Sun, or
+    of a Window, may be so cast on an Object, as to make it twice as light
+    as it would otherwise be without it, and that without any inconvenience
+    of glaring, which the immediate light of the Sun is very apt to create
+    in most Objects; for by this means the light is so equally diffused,
+    that all parts are alike inlightned; but when the immediate light of
+    the Sun falls on it, the reflexions from some few parts are so vivid,
+    that they drown the appearance of all the other, and are themselves
+    also, by reason of the inequality of light, indistinct, and appear only
+    radiant spots.
+
+    But because the light of the Sun, and also that of a Window, is in a
+    continual variation, and so many Objects cannot be view’d long enough
+    by them to be throughly examin’d; besides that, oftentimes the Weather
+    is so dark and cloudy, that for many dayes together nothing can be
+    view’d: And because also there are many Objects to be met with in the
+    night, which cannot so conveniently be kept perhaps till the day,
+    therefore to procure and cast a sufficient quantity of light on an
+    Object in the night, I thought of, and often used this, Expedient.
+
+    I procur’d me a small Pedestal, such as is describ’d in the fifth
+    Figure of the first _Scheme_ on the small Pillar AB, of which were two
+    movable Armes CD, which by means of the Screws EF, I could fix in any
+    part of the Pillar; on the undermost of these I plac’d a pretty large
+    Globe of Glass G, fill’d with exceeding clear Brine, stopt, inverted,
+    and fixt in the manner visible in the Figure; out of the side of which
+    Arm proceeded another Arm H, with many joynts; to the end of which was
+    fastned a deep plain _Convex glass_ I, which by means of this Arm could
+    be moved to and fro, and fixt in any posture. On the upper Arm was
+    placed a small Lamp K, which could be so mov’d upon the end of the Arm,
+    as to be set in a fit posture to give light through the Ball: By means
+    of this Instrument duly plac’d, as is exprest in the Figure, with the
+    small flame of a Lamp may be cast as great and convenient a light on
+    the Object as it will well indure; and being always constant, and to be
+    had at any time, I found most proper for drawing the representations of
+    those small Objects I had occasion to observe.
+
+    None of all which ways (though much beyond any other hitherto made use
+    of by any I know) do afford a sufficient help, but after a certain
+    degree of magnifying, they leave us again in the lurch. Hence it were
+    very desirable, that some way were thought of for making the
+    Object-glass of such a Figure as would conveniently bear a large
+    Aperture.
+
+As for _Telescopes_, the only improvement they seem capable of, is the
+increasing of their length; for the Object being remote, there is no
+thought of giving it a greater light then it has; and therefore to augment
+the Aperture, the Glass must be ground of a very large sphere; for, by
+that means, the longer the Glass be, the bigger aperture will it bear, if
+the Glasses be of an equal goodness in their kind. Therefore a six will
+indure a much larger Aperture then a three foot Glass, and a sixty foot
+Glass will proportionably bear a greater Aperture then a thirty, and will
+as much excel it also as a six foot does a three foot, as I have
+experimentally observ’d in one of that length made by Mr. _Richard Reives_
+here at _London_, which will bear an Aperture above three inches over, and
+yet make the Object proportionably big and distinct; whereas there are very
+few thirty foot Glasses that will indure an Aperture of more then two
+inches over. So that for _Telescopes_, supposing we had a very ready way of
+making their Object Glasses of exactly spherical Surfaces, we might, by
+increasing the length of the Glass, magnifie the Object to any assignable
+bigness. And for performing both these, I cannot imagine any way more
+easie, and more exact, then by this following Engine, by means of which,
+any Glasses, of what length soever, may be speedily made. It seems the most
+easie, because with one and the same Tool may be with care ground an Object
+Glass, of any length or breadth requisite, and that with very little or no
+trouble in fitting the Engine, and without much skill in the Grinder. It
+seems to be the most exact, for to the very last stroke the Glass does
+regulate and rectifie the Tool to its exact Figure; and the longer or more
+the Tool and Glass are wrought together, the more exact will both of them
+be of the desir’d Figure. Further, the motions of the Glass and Tool do so
+cross each other, that there is not one point of eithers Surface, but has
+thousands of cross motions thwarting it, so that there can be no kind of
+Rings or Gutters made either in the Tool or Glass.
+
+    The contrivance of the Engine is, only to make the ends of two large
+    _Mandrils_ so to move, that the Centers of them may be at any
+    convenient distance asunder, and that the _Axis_ of the _Mandrils_
+    lying both in the same plain produc’d, may meet each other in any
+    assignable Angle; both which requisites may be very well perform’d by
+    the Engine describ’d in the third Figure of the first _Scheme_: where
+    AB signifies the Beam of a Lath fixt perpendicularly or Horizontally,
+    CD the two Poppet heads, fixt at about two foot distance, EF an Iron
+    _Mandril_, whose tapering neck F runs in an adapted tapering brass
+    Collar; the other end E runs on the point of a Screw G; in a convenient
+    place of this is fastned H a pully Wheel, and into the end of it, that
+    comes through the Poppet head C, is screwed a Ring of a hollow
+    _Cylinder_ K, or some other conveniently shap’d Tool, of what wideness
+    shall be thought most proper for the cize of Glasses, about which it is
+    to be imploy’d: As, for Object glasses, between twelve foot and an
+    hundred foot long, the Ring may be about six inches over, or indeed
+    somewhat more for those longer Glasses. It would be convenient also, and
+    not very chargeable, to have four or five several Tools; as one for all
+    Glasses between an inch and a foot, one for all Glasses between a foot
+    and ten foot long, another for all between ten and an hundred, a fourth
+    for all between a hundred and a thousand foot long; and if Curiosity
+    shall ever proceed so far, one for all lengths between a thousand and
+    ten thousand foot long; for indeed the principle is such, that
+    supposing the _Mandrils_ well made, and of a good length, and supposing
+    great care be used in working and polishing them, I see no reason, but
+    that a Glass of a thousand, nay of ten thousand foot long, may be as
+    well made as one of ten; for the reason is the same, supposing the
+    _Mandrils_ and Tools be made sufficiently strong, so that they cannot
+    bend; and supposing the Glass, out of which they are wrought, be
+    capable of so great a regularity in its parts as to refraction: this
+    hollow _Cylinder_ K is to contain the Sand, and by being drove round
+    very quick to and fro by means of a small Wheel, which may be mov’d
+    with ones foot, serves to grind the Glass: The other _Mandril_ is
+    shap’d like this, but it has an even neck instead of a taper one, and
+    runs in a Collar, that by the help of a Screw and a joynt made like M
+    in the Figure, it can be still adjustned to the wearing or wasting
+    neck: into the end of this _Mandril_ is screwed a Chock N on which with
+    Cement or Glew is fastned the piece of Glass Q that is to be form’d;
+    the middle of which Glass is to be plac’d just on the edge of the Ring,
+    and the Lath OP is to be set and fixt (by means of certain pieces and
+    screws, the manner whereof will be sufficiently evidenc’d by the Figure)
+    in such an Angle as is requisite to the forming of such a Sphere as the
+    Glass is design’d to be of; the geometrical ground of which being
+    sufficiently plain, though not heeded before, I shall, for brevities
+    sake, pass over. This last _Mandril_ to be made (by means of the
+    former, or some other Wheel) to run round very swift also, by which two
+    cross motions the Glass cannot chuse (if care be us’d) but be wrought
+    into a most exactly spherical Surface.
+
+But because we are certain, from the _Laws of refraction_ (which I I have
+experimentally found to be so, by an Instrument I shall presently describe)
+that _the lines of the angles of Incidence are proportionate to the lines
+of the angles of Refraction_, therefore if Glasses could be made of those
+kind of Figures, or some other, such as the most incomparable _Des Cartes_
+has invented, and demonstrated in his Philosophical and Mathematical Works,
+we might hope for a much greater perfection of Opticks then can be
+rationally expected from spherical ones; for though, _cæteris paribus_, we
+find, that the larger the _Telescope_ Object Glasses are, and the shorter
+those of the _Microscope_, the better they magnifie, yet both of them,
+beside such determinate dimensions, are by certain inconveniences rendred
+unuseful; for it will be exceeding _difficult_ to make and _manage_ a Tube
+above an _hundred foot long_, and it will be as difficult to _inlighten_ an
+Object less then an hundred part of an inch distant from the Object Glass.
+
+I have not as yet made any attempts of that kind, though I know two or
+three wayes, which, as far as I have yet considered, seem very probable,
+and may invite me to make a tryal as soon as I have an opportunity, of
+which I may hereafter perhaps acquaint the world. In the Interim, I shall
+describe the Instrument I even now mention’d, by which the _refraction_ of
+all kinds of Liquors may be most exactly measur’d, thereby to give the
+curious an opportunity of making what further tryals of that kind they
+shall think requisite to any of their intended tryals; and to let them see
+that the laws of Refraction are not only notional.
+
+    The Instrument consisted of five Rulers, or long pieces placed
+    together, after the manner exprest in the second Figure of the first
+    _Scheme_, where AB denotes a straight piece of wood about six foot and
+    two inches long, about three inches over, and an inch and half thick,
+    on the back side of which was hung a small plummet by a line stretcht
+    from top to bottom, by which this piece was set exactly upright, and so
+    very firmly fixt; in the middle of this was made a hole or center, into
+    which one end of a hollow cylindrical brass Box CC, fashion’d as I
+    shall by and by describe, was plac’d, and could very easily and truly
+    be mov’d to and fro; the other end of this Box being put into, and
+    moving in, a hole made in a small arm DD; into this box was fastned the
+    long Ruler EF, about three foot and three or four inches long, and at
+    three foot from the above mention’d Centers PP was a hole E, cut
+    through, and cross’d with two small threads, and at the end of it was
+    fixt a small sight G, and on the back side of it was fixt a small Arm
+    H, with a Screw to fix it in any place on the Ruler LM; this Ruler LM
+    was mov’d on the Center B (which was exactly three foot distance from
+    the middle Center P) and a line drawn through the middle of it LM, was
+    divided by a Line of cords into some sixty degrees, and each degree was
+    subdivided into minutes, so that putting the cross of the threads in E
+    upon any part of this divided line, I presently knew what Angle the two
+    Rules AB and EF made with each other, and by turning the Screw in H, I
+    could fix them in any position. The other Ruler also RS was made much
+    after the same manner, only it was not fixt to the hollow cylindrical
+    Box, but, by means of two small brass Armes or Ears, it mov’d on the
+    Centers of it; this also, by means of the cross threads in the hole S,
+    and by a Screw in K, could be fastned on any division of another line
+    of cords of the same radius drawn on NO. And so by that means, the
+    Angle made by the two Rulers, AB and RS, was also known. The Brass box
+    CC in the middle was shap’d very much like the Figure X, that is, it
+    was a cylindrical Box stopp’d close at either end, off of which a part
+    both of the sides and bottomes was cut out, so that the Box, when the
+    Pipe and that was joyned to it, would contain the Water when fill’d
+    half full, and would likewise, without running over, indure to be
+    inclin’d to an Angle, equal to that of the greatest refraction of
+    Water, and no more, without running over. The Ruler EF was fixt very
+    fast to the Pipe V, so that the Pipe V directed the length of the Ruler
+    EF, and the Box and Ruler were mov’d on the Pin TT, so as to make any
+    desirable Angle with the Ruler AB. The bottom of this Pipe V was stop’d
+    with a small piece of exactly plain Glass, which was plac’d exactly
+    perpendicular to the Line of direction, or _Axis_ of the Ruler EF. The
+    Pins also TT were drill’d with small holes through the _Axis_, and
+    through those holes was stretcht and fastned a small Wire. There was
+    likewise a small Pipe of Tin loosly put on upon the end of V, and
+    reaching down to the sight G; the use of which was only to keep any
+    false Rayes of light from passing through the bottom of V, and only
+    admitting such to pass as pierced through the sight G: All things being
+    placed together in the manner describ’d in the Figure; that is, the
+    Ruler AB being fixt perpendicular, I fill’d the Box CC with Water, or
+    any other Liquor, whose refraction I intended to try, till the Wire
+    passing through the middle of it were just covered: then I moved and
+    fixt the Ruler FE at any assignable Angle, and placed the flame of a
+    Candle just against the sight G; and looking through the sight I, I
+    moved the Ruler RS to and fro, till I perceived the light passing
+    through G to be covered, as ’twere, or divided by the dark Wire passing
+    through PP: then turning the Screw in K, I fixt it in that posture: And
+    through the hole S, I observed what degree and part of it was cut by
+    the cross threads in S. And this gave me the Angle of Inclination, APS
+    answering to the Angle of Refraction BPE: for the surface of the Liquor
+    in the Box will be alwayes horizontal, and consequently AB will be a
+    perpendicular to it; the Angle therefore APS will measure, or be the
+    Angle of Inclination in the Liquor; next EPB must be the Angle of
+    Refraction, for the Ray that passes through the sight G, passes also
+    perpendicularly through the Glass _Diaphragme_ at F, and consequently
+    also perpendicularly through the lower surface of the Liquor contiguous
+    to the Glass, and therefore suffers no refraction till it meet with the
+    horizontal surface of the Liquor in CC, which is determined by the two
+    Angles.
+
+By means of this Instrument I can with _little trouble_, and a very small
+quantity of any _Liquor_, examine, most accurately, the _refraction_ of it
+not only for one inclination, but for all; and thereby am inabled to make
+very accurate Tables; several of which I have also experimentally made, and
+find, that _Oyl of Turpentine_ has a much greater Refraction then _Spirit
+of Wine_, though it be _lighter_; and that _Spirit of Wine_ has a greater
+Refraction then _Water_, though it be lighter also; but that _salt Water_
+also has a greater Refraction then _fresh_, though it be _heavier_: but
+_Alum water_ has a less refraction then common _Water_, though heavier
+also. So that it seems, as to the _refraction_ made in a Liquor, the
+_specifick gravity_ is of no efficacy. By this I have also found that look
+what _proportion _the _Sine_ of the Angle of _one Inclination_ has to the
+_Sine_ of the Angle of _Refraction_, correspondent to it, the same
+_proportion_ have all the _Sines_ of other Inclinations to the _Sines_ of
+their appropriate Refractions.
+
+    My way for measuring how much a Glass magnifies an Object, plac’d at a
+    convenient distance from my eye, is this. Having rectifi’d the
+    _Microscope_, to see the desir’d Object through it very distinctly, at
+    the same time that I look upon the Object through the Glass with one
+    eye, I look upon other Objects at the same distance with my other bare
+    eye; by which means I am able, by the help of a _Ruler_ divided into
+    inches and small parts, and laid on the _Pedestal_ of the _Microscope_,
+    to cast, as it were, the magnifi’d appearance of the Object upon the
+    Ruler, and thereby exactly to measure the Diameter it appears of
+    through the Glass, which being compar’d with the Diameter it appears of
+    to the naked eye, will easily afford the quantity of its magnifying.
+
+    The _Microscope_, which for the most part I made use of, was shap’d
+    much like that in the sixth Figure of the first _Scheme_, the Tube
+    being for the most part not above six or seven inches long, though, by
+    reason it had four Drawers, it could very much be lengthened, as
+    occasion required; this was contriv’d with three Glasses; a small
+    Object Glass at A, a thinner Eye Glass about B, and a very deep one
+    about C: this I made use of only when I had occasion to see much of an
+    Object at once; the middle Glass conveying a very great company of
+    radiating Pencils, which would go another way, and throwing them upon
+    the deep Eye Glass. But when ever I had occasion to examine the small
+    parts of a Body more accurately, I took out the middle Glass, and only
+    made use of one Eye Glass with the Object Glass, for always the fewer
+    the Refractions are, the more bright and clear the Object appears. And
+    therefore ’tis not to be doubted, but could we make a_ Microscope _to
+    have one only refraction, it would, _cæteris paribus_, far excel any
+    other that had a greater number. And hence it is, that if you take a
+    very clear piece of a broken _Venice_ Glass, and in a Lamp draw it out
+    into very small hairs or threads, then holding the ends of these
+    threads in the flame, till they melt and run into a small round Globul,
+    or drop, which will hang at the end of the thread; and if further you
+    stick several of these upon the end of a stick with a little sealing
+    Wax, so as that the threads stand upwards, and then on a Whetstone
+    first grind off a good part of them, and afterward on a smooth Metal
+    plate, with a little Tripoly, rub them till they come to be very
+    smooth; if one of these be fixt with a little soft Wax against a small
+    needle hole, prick’d through a thin Plate of Brass, Lead, Pewter, or
+    any other Metal, and an Object, plac’d very near, be look’d at through
+    it, it will both magnifie and make some Objects more distinct then any
+    of the great _Microscopes_. But because these, though exceeding easily
+    made, are yet very troublesome to be us’d, because of their smalness,
+    and the nearness of the Object; therefore to prevent both these, and
+    yet have only two Refractions, I provided me a Tube of Brass, shap’d
+    much like that in the fourth Figure of the first _Scheme_; into the
+    smaller end of this I fixt with Wax a good _plano convex_ Object Glass,
+    with the convex side towards the Object, and into the bigger end I fixt
+    also with wax a pretty large plano _Convex_ Glass, with the _convex_
+    side towards my eye, then by means of the small hole by the side, I
+    fill’d the intermediate space between these two Glasses with very clear
+    Water, and with a Screw stopp’d it in; then putting on a Cell for the
+    Eye, I could perceive an Object more bright then I could when the
+    intermediate space was only fill’d with Air, but this, for other
+    inconveniences, I made but little use of.
+
+    My way for fixing both the Glass and Object to the Pedestal most
+    conveniently was thus: Upon one side of a round Pedestal AB, in the
+    sixth Figure of the first _Scheme_, was fixt a small Pillar CC, on this
+    was fitted a small Iron Arm D, which could be mov’d up and down, and
+    fixt in any part of the Pillar, by means of a small Screw E; on the end
+    of this Arm was a small Ball fitted into a kind of socket F, made in
+    the side of the Brass Ring G, through which the small end of the Tube
+    was screw’d; by means of which contrivance I could place and fix the
+    Tube in what posture I desir’d (which for many Observations was
+    exceeding necessary) and adjusten it most exactly to any Object.
+
+    For placing the Object, I made this contrivance; upon the end of a
+    small brass Link or Staple HH, I so fastned a round Plate II, that it
+    might be turn’d round upon its Center K, and going pretty stiff, would
+    stand fixt in any posture it was set; on the side of this was fixt a
+    small Pillar P, about three quarters of an inch high, and through the
+    top of this was thrust a small Iron pin M, whose top just stood over
+    the Center of the Plate; on this top I fixt a small Object, and by
+    means of these contrivances I was able to turn it into all kind of
+    positions, both to my Eye and the Light; for by moving round the small
+    Plate on its center, could move it one way, and by turning the Pin M, I
+    could move it another way, and this without stirring the Glass at all,
+    or at least but very little; the Plate likewise I could move to and fro
+    to any part of the Pedestal (which in many cases was very convenient)
+    and fix it also in any Position, by means of a Nut N, which was screw’d
+    on upon the lower part of the Pillar CC. All the other Contrivances are
+    obvious enough from the draught, and will need no description.
+
+Now though this were the Instrument I made most use of, yet I have made
+several other Tryals with other kinds of Microscopes, which both for
+_matter_ and _form_ were very different from common spherical Glasses. I
+have made a _Microscope_ with one piece of Glass, both whose surfaces were
+_plains_. I have made another only with a _plano concave_, without any kind
+of reflection, divers also by means of _reflection_. I have made others of
+_Waters_, _Gums_, _Resins_, _Salts_, _Arsenick_, _Oyls_, and with divers
+other _mixtures of watery_ and _oyly Liquors_. And indeed the subject is
+capable of a great variety; but I find generally none more useful then that
+which is made with _two Glasses_, such as I have already describ’d.
+
+What the things are I observ’d, the following descriptions will manifest;
+in brief, they were either _exceeding small Bodies_, or _exceeding small
+Pores_, or _exceeding small Motions_, some of each of which the Reader will
+find in the following Notes, and such, as I presume, (many of them at
+least) will be _new_, and perhaps not less _strange_: Some _specimen_ of
+each of which Heads the Reader will find in the subsequent delineations,
+and indeed of some more then I was willing there should be; which was
+occasioned by my first Intentions to print a much greater number then I
+have since found time to compleat. Of such therefore as I had, I selected
+only some few of every Head, which for some particulars seem’d most
+observable, rejecting the rest as superfluous to the present Design.
+
+What each of the delineated Subjects are, the following descriptions
+annext to each will inform, of which I shall here, only once for all, add,
+That in divers of them the Gravers have pretty well follow’d my directions
+and draughts; and that in making of them, I indeavoured (as far as I was
+able) first to discover the true appearance, and next to make a plain
+representation of it. This I mention the rather, because of these kind of
+Objects there is much more difficulty to discover the true shape, then of
+those visible to the naked eye, the same Object seeming quite differing, in
+one position to the Light, from what it really is, and may be discover’d in
+another. And therefore I never began to make any draught before by many
+examinations in several lights, and in several positions to those lights, I
+had discover’d the true form. For it is exceeding difficult in some
+Objects, to distinguish between a _prominency_ and a _depression_, between
+a _shadow_ and a _black stain_, or a _reflection_ and a _whiteness in the
+colour_. Besides, the transparency of most Objects renders them yet much
+more difficult then if they were _opacous_. The Eyes of a Fly in one kind
+of light appear almost like a Lattice, drill’d through with abundance of
+small holes; which probably may be the Reason, why the Ingenious _Dr.
+Power_ seems to suppose them such. In the Sunshine they look like a Surface
+cover’d with golden Nails; in another posture, like a Surface cover’d with
+Pyramids; in another with Cones; and in other postures of quite other
+shapes; but that which exhibits the best, is the Light collected on the
+Object, by those means I have already describ’d.
+
+And this was undertaken in prosecution of the Design which the _ROYAL
+SOCIETY_ has propos’d to it self. For the Members of the Assembly having
+before their eys so many _fatal_ Instances of the errors and falshoods, in
+which the greatest part of mankind has so long wandred, because they rely’d
+upon the strength of humane Reason alone, have begun anew to correct all
+_Hypotheses_ by sense, as Seamen do their _dead Reckonings_ by _Cœlestial
+Observations_; and to this purpose it has been their principal indeavour to
+_enlarge & strengthen_ the _Senses_ by _Medicine_, and by such _outward
+Instruments_ as are proper for their particular works. By this means they
+find some reason to suspect, that those effects of Bodies, which have been
+commonly attributed to _Qualities_, and those confess’d to be _occult_, are
+perform’d by the small _Machines_ of Nature, which are not to be discern’d
+without these helps, seeming the meer products of _Motion_, _Figure_, and
+_Magnitude_; and that the _Natural Textures_, which some call the _Plastick
+faculty_, may be made in _Looms_, which a greater perfection of Opticks may
+make discernable by these Glasses; so as now they are no more puzzled about
+them, then the vulgar are to conceive, how _Tapestry_ or _flowred Stuffs_
+are woven. And the ends of all these Inquiries they intend to be the
+_Pleasure_ of Contemplative minds, but above all, the _ease and dispatch_
+of the labours of mens hands. They do indeed neglect no opportunity to
+bring all the _rare_ things of Remote Countries within the compass of their
+knowledge and practice. But they still acknowledg their _most useful_
+Informations to arise from _common_ things, and from _diversifying_ their
+most _ordinary_ operations upon them. They do not wholly reject Experiments
+of meer _light_ and _theory_; but they principally aim at such, whose
+Applications will _improve and facilitate_ the present way of _Manual
+Arts_. And though some men, who are perhaps taken up about less honourable
+Employments, are pleas’d to censure their proceedings, yet they can shew
+more _fruits_ of their first three years, wherein they have assembled, then
+any other _Society_ in _Europe_ can for a much larger space of time. ’Tis
+true, such undertakings as theirs do commonly meet with small
+incouragement, because men are generally rather taken with the _plausible_
+and _discursive_, then the _real_ and the solid part of Philosophy; yet by
+the good fortune of their institution, in an Age of all others the most
+_inquisitive_, they have been assisted by the _contribution_ and _presence_
+of very many of the chief _Nobility_ and _Gentry_, and others who are some
+of the _most considerable_ in their several Professions. But that that yet
+farther convinces me of the _Real esteem_ that the more _serious_ part of
+men have of this _Society_, is, that several _Merchants_, men who act in
+earnest (whose Object is _meum & tuum_, that great _Rudder_ of humane
+affairs) have adventur’d considerable sums of _Money_, to put in practice
+what some of our Members have contrived, and have continued _stedfast_ in
+their good opinions of such Indeavours, when not one of a hundred of the
+vulgar have believed their undertakings feasable. And it is also fit to be
+added, that they have one advantage peculiar to themselves, that very many
+of their number are _men of Converse and Traffick_; which is a good Omen,
+that their attempts will bring Philosophy from _words_ to _action_, seeing
+the men of Business have had so great a share in their first foundation.
+
+And of this kind I ought not to conceal one particular _Generosity_, which
+more nearly concerns my self. It is the _munificence_ of _Sir John Cutler_,
+in endowing a Lecture for the promotion of _Mechanick Arts_, to be governed
+and directed by This _Society._This _Bounty_ I mention for the
+_Honourableness_ of the thing it self, and for the expectation which I have
+of the _efficacy_ of the _Example_; for it cannot now be objected to them,
+that their Designs will be esteemed _frivolous_ and _vain_, when they have
+such a _real Testimony_ of the _Approbation_ of a _Man_ that is such an
+_eminent Ornament_ of this renowned City, and one, who, by the _Variety_,
+and the _happy Success_, of his negotiations, has given evident proofs,
+that he is not easie to be deceiv’d. This Gentleman has well observ’d, that
+the _Arts_ of life have been too long _imprison’d_ in the dark shops of
+Mechanicks themselves, & there _hindred from growth_, either by ignorance,
+or self-interest: and he has bravely _freed_ them from these
+_inconveniences_: He hath not only obliged _Tradesmen_, but _Trade_ it
+self: He has done a work that is worthy of _London_, and has taught the
+chief City of Commerce in the world the right way how Commerce is to be
+improv’d. We have already seen many other great signs of Liberality and a
+large mind, from the same hand: For by his _diligence_ about the
+_Corporation for the Poor_; by his honorable _Subscriptions_ for the
+rebuilding of St. Paul’s; by his chearful _Disbursment_ for the replanting
+of _Ireland_, and by many other such _publick works_, he has shewn by what
+means he indeavours to _establish_ his Memory; and now by this last gift he
+has done that, which became one of the _wisest Citizens_ of our Nation to
+accomplish, seeing one of the _wisest of our Statesmen, the Lord Verulam_,
+first propounded it.
+
+But to return to my Subject, from a digression, which, I hope, my Reader
+will pardon me, seeing the Example is so rare that I can make no more such
+digressions. If these my first Labours shall be any wayes useful to
+inquiring men, I must attribute the incouragement and promotion of them to
+a very _Reverend_ and _Learned Person_, of whom this ought in justice to be
+said, _That there is scarce any one Invention, which this Nation has
+produc’d in our Age, but it has some way or other been set forward by his
+assistance_. My Reader, I believe, will quickly ghess, that it is _Dr.
+Wilkins_ that I mean. He is indeed a man born for the _good_ of _mankind_,
+and for the _honour_ of his _Country_. In the _sweetness_ of whose
+_behaviour_, in the _calmness_ of his _mind_, in the _unbounded goodness_
+of his _heart_, we have an evident Instance, what the true and the
+_primitive unpassionate Religion_ was, before it was _sowred_ by particular
+_Factions._ In a word, his _Zeal_ has been so _constant_ and _effectual_ in
+advancing all good and profitable _Arts, that_ as one of the Antient
+_Romans_ said of _Scipio_, _That he thanked God that he was a _Roman_;
+because whereever _Scipio_ had been born, there had been the seat of the
+Empire of the world_: So may I thank God, that _Dr. Wilkins_ was an
+_Englishman_, for whereever he had lived, there had been the chief Seat of
+_generous Knowledge_ and _true Philosophy_. To the truth of this, there are
+so many worthy men living that will subscribe, that I am confident, what I
+have here said, will not be looked upon, by any ingenious Reader, as a
+_Panegyrick_, but only as a _real testimony_.
+
+By the Advice of this _Excellent man_ I first set upon this Enterprise,
+yet still came to it with much _Reluctancy_, because I was to follow the
+footsteps of so eminent a Person as _Dr. Wren_, who was the first that
+attempted any thing of this nature; whose original draughts do now make one
+of the Ornaments of that great Collection of Rarities in the _Kings
+Closet_. This _Honor_, which his first beginnings of this kind have
+receiv’d, to be admitted into the most famous place of the world, did not
+so much _incourage_, as the _hazard_ of coming after _Dr. Wren_ did
+_affright_ me; for of him I must affirm, that, since the time of
+_Archimedes_, there scarce ever met in one man, in so great a perfection,
+such a _Mechanical Hand_, and so _Philosophical_ a _Mind_.
+
+But at last, being assured both by _Dr. Wilkins_, and _Dr. Wren_ himself,
+that he had given over his intentions of prosecuting it, and not finding
+that there was any else design’d the pursuing of it, I set upon this
+undertaking, and was not a little incourag’d to proceed in it, by the
+Honour the _Royal Society_ was pleas’d to favour me with, in approving of
+those draughts (which from time to time as I had an opportunity of
+describing) I presented to them. And particularly by the Incitements of
+divers of those Noble and excellent Persons of it, which were my more
+especial Friends, who were not less urgent with me for the publishing, then
+for the prosecution of them.
+
+After I had almost compleated these Pictures and Observations (having had
+divers of them engraven, and was ready to send them to the Press) I was
+inform’d, that the Ingenious Physitian _Dr. Henry Power_ had made several
+_Microscopical_ Observations, which had I not afterwards, upon our
+interchangably viewing each others Papers, found that they were for the
+most part differing from mine, either in the Subject it self, or in the
+particulars taken notice of; and that his design was only to print
+Observations without Pictures, I had even then _suppressed_ what I had so
+far proceeded in. But being further _excited_ by several of my Friends, in
+compliance with their opinions, that it would not be unacceptable to
+several inquisitive Men, and hoping also, that I should thereby discover
+something New to the World, I have at length cast in my Mite, into the vast
+Treasury of _A Philosophical History_. And it is my _hope_, as well as
+_belief_, that these my _Labours_ will be no more comparable to the
+_Productions_ of many other _Natural Philosophers_, who are now every where
+busie about _greater_ things; then my _little Objects_ are to be compar’d
+to the greater and more beautiful _Works of Nature_, A Flea, a Mite, a
+Gnat, to an Horse, an Elephant, or a Lyon.
+
+
+       *       *       *       *       *
+
+
+MICROGRAPHIA,
+
+OR SOME
+
+Physiological Descriptions
+
+OF
+
+MINUTE BODIES,
+
+MADE BY
+
+MAGNIFYING GLASSES;
+
+WITH
+
+OBSERVATIONS and INQUIRIES thereupon.
+
+       *       *       *       *       *
+
+
+Observ. I. _Of the Point of a sharp small Needle._
+
+As in _Geometry_, the most natural way of beginning is from a Mathematical
+_point_; so is the same method in Observations and _Natural history_ the
+most genuine, simple, and instructive. We must first endevour to make
+_letters_, and draw _single_ strokes true, before we venture to write whole
+_Sentences_, or to draw large _Pictures_. And in _Physical_ Enquiries, we
+must endevour to follow Nature in the more _plain_ and _easie_ ways she
+treads in the most _simple_ and _uncompounded bodies_, to trace her steps,
+and be acquainted with her manner of walking there, before we venture our
+selves into the multitude of _meanders_ she has in _bodies of a more
+complicated_ nature; lest, being unable to distinguish and judge of our
+way, we quickly lose both _Nature_ our Guide, and _our selves_ too, and are
+left to wander in the _labyrinth_ of groundless opinions; wanting both
+_judgment_, that _light_, and _experience_, that _clew_, which should
+direct our proceedings.
+
+We will begin these our Inquiries therefore with the Observations of Bodies
+of the most _simple nature_ first, and so gradually proceed to those of a
+more _compounded_ one. In prosecution of which method, we shall begin with
+a _Physical point_; of which kind the _Point of a Needle_ is commonly
+reckon’d for one; and is indeed, for the most part, made so sharp, that the
+naked eye cannot distinguish any parts of it: It very easily pierces, and
+makes its way through all kind of bodies softer then it self: But if view’d
+with a very good _Microscope_, we may find that the _top_ of a Needle
+(though as to the sense very _sharp_) appears a _broad_, _blunt_, and very
+_irregular_ end; not resembling a Cone, as is imagin’d, but onely a piece
+of a tapering body, with a great part of the top remov’d, or deficient. The
+Points of Pins are yet more blunt, and the Points of the most curious
+Mathematical Instruments do very seldome arrive at so great a sharpness;
+how much therefore can be built upon demonstrations made onely by the
+productions of the Ruler and Compasses, he will be better able to consider
+that shall but view those _points_ and _lines_ with a _Microscope_.
+
+Now though this point be commonly accounted the sharpest (whence when we
+would express the sharpness of a point the most _superlatively_, we say, As
+sharp as a Needle) yet the _Microscope_ can afford us hundreds of Instances
+of Points many thousand times sharper: such as those of the _hairs_, and
+_bristles_, and _claws_ of multitudes of _Insects_; the _thorns_, or
+_crooks_, or _hairs_ of _leaves_, and other small vegetables; nay, the ends
+of the _stiriæ_ or small _parallelipipeds_ of _Amianthus_, and _alumen
+plumosum_; of many of which, though the Points are so sharp as not to be
+visible, though view’d with a _Microscope_ (which magnifies the Object, in
+bulk, above a million of times) yet I doubt not, but were we able
+_practically_ to make _Microscopes_ according to the _theory_ of them, we
+might find hills, and dales, and pores, and a sufficient bredth, or
+expansion, to give all those parts elbow-room, even in the blunt top of the
+very Point of any of these so very sharp bodies. For certainly the
+_quantity_ or extension of any body may be _Divisible in infinitum_, though
+perhaps not the _matter_.
+
+But to proceed: The Image we have here exhibited in the first
+Figure[1], was the top of a small and very sharp Needle, whose point
+_aa_ nevertheless appear’d through the _Microscope_ above a quarter
+of an inch broad, not round nor flat, but _irregular_ and _uneven_;
+so that it seem’d to have been big enough to have afforded a hundred
+armed Mites room enough to be rang’d by each other without endangering
+the breaking one anothers necks, by being thrust off on either side.
+The surface of which, though appearing to the naked eye very smooth,
+could not nevertheless hide a multitude of holes and scratches and
+ruggednesses from being discover’d by the _Microscope_ to invest it,
+several of which inequalities (as A, B, C, seem’d _holes_ made by some
+small specks of _Rust_; and D some _adventitious body_, that stuck very
+close to it) were _casual_. All the rest that roughen the surface,
+were onely so many marks of the rudeness and bungling of _Art_. So
+unaccurate is it, in all its productions, even in those which seem most
+neat, that if examin’d with an organ more acute then that by which
+they were made, the more we see of their _shape_, the less appearance
+will there be of their _beauty_: whereas in the works of _Nature_,
+the deepest Discoveries shew us the greatest Excellencies. An evident
+Argument, that he that was the Author of all these things, was no other
+then _Omnipotent_; being able to include as great a variety of parts
+and contrivances in the yet smallest Discernable Point, as in those
+vaster bodies (which comparatively are called also Points) such as the
+_Earth_, _Sun_, or _Planets_. Nor need it seem strange that the Earth
+it self may be by an _Analogie_ call’d a Physical Point: For as its
+body, though now so near us as to fill our eys and fancies with a sense
+of the vastness of it, may by a little Distance, and some convenient
+_Diminishing_ Glasses, be made vanish into a scarce visible Speck, or
+Point (as I have often try’d on the _Moon_, and (when not too bright)
+on the _Sun_ it self.) So, could a Mechanical contrivance succesfully
+answer our _Theory_, we might see the least spot as big as the Earth
+it self; and Discover, as _Des Cartes_[2] also conjectures, as great a
+variety of bodies in the _Moon_, or _Planets_, as in the _Earth_.
+
+But leaving these Discoveries to future Industries, we shall proceed to add
+one Observation more of a _point_ commonly so call’d, that is, the mark of
+a _full stop_, or _period_. And for this purpose I observed many both
+_printed_ ones and _written_; and among multitudes I found _few_ of them
+more _round_ or _regular_ then this which I have delineated in the third
+figure of the second Scheme, but _very many_ abundantly _more disfigur’d_;
+and for the most part if they seem’d equally round to the eye, I found
+those points that had been made by a _Copper-plate_, and Roll-press, to be
+as misshapen as those which had been made with _Types_, the most curious
+and smothly _engraven strokes_ and _points_, looking but as so many
+_furrows_ and _holes_, and their _printed impressions_, but like _smutty
+daubings_ on a matt or uneven floor with a blunt extinguisht brand or
+stick’s end. And as for _points_ made with a _pen_ they were much _more
+ragged_ and _deformed_. Nay, having view’d certain pieces of exceeding
+curious writing of the kind (one of which in the bredth of a _two-pence_
+compris’d _the Lords prayer, the Apostles Creed, the ten Commandments, and
+about half a dozen verses besides of the Bible_, whose _lines_ were _so
+small_ and _near together_, that I was unable to _number_ them with my
+_naked eye_,) a very ordinary _Microscope_, I had then about me, inabled me
+to see that what the Writer of it had asserted was _true_, but withall
+discover’d of what pitifull _bungling scribbles_ and _scrawls_ it was
+compos’d, _Arabian_ and _China characters_ being almost as well shap’d, yet
+thus much I must say for the Man, that it was for the most part _legible_
+enough, though in some places there wanted a good _fantsy_ well _preposest_
+to help one through. If this manner _of small writing_ were made _easie_
+and _practicable_ (and I think I know such a one, but have never yet made
+tryal of it, whereby one might be inabled to write _a great deale_ with
+_much ease_, and _accurately_ enough in a very _little roome_) it might be
+of very good use to convey _secret Intelligence_ without any danger of
+_Discovery_ or _mistrusting_. But to come again to the point. The
+_Irregularities_ of it are caused by three or four _coadjutors_, one of
+which is, the _uneven surface_ of the _paper_, which at best appears no
+smother then a very course piece of _shag’d cloth_, next the _irregularity
+of the Type_ or _Ingraving_, and a third is the _rough Daubing_ of the
+_Printing-Ink_ that lies upon the instrument that makes the impression, to
+all which, add the _variation_ made by the Different _lights_ and
+_shadows_, and you may have sufficient reason to ghess that a _point_ may
+appear much more _ugly_ then _this_, which I have here presented, which
+though it appear’d through the _Microscope_ _gray_, like a great splatch of
+_London_ dirt, about three inches over; yet to the _naked eye_ it was
+_black_ and no bigger then that in the midst of the Circle A. And could I
+have found Room in this Plate to have inserted an O you should have seen
+that the _letters_ were not more distinct then the _points_ of Distinction,
+nor a _drawn circle_ more exactly _so_, then we have now shown a _point_ to
+be a _point_.
+
+       *       *       *       *       *
+
+
+Observ. II. _Of the Edge of a Razor._
+
+The sharpest _Edge_ hath the same kind of affinity to the sharpest _Point_
+in Physicks, as a _line_ hath to a _point_ in Mathematicks; and therefore
+the Treaty concerning this, may very properly be annexed to the former. A
+Razor doth appear to be a Body of a very neat and curious aspect, till more
+closely viewed by the _Microscope_, and there we may observe its very Edge
+to be of all kind of shapes, except what it should be. For examining that
+of a very sharp one, I could not find that any part of it had any thing of
+sharpness in it; but it appeared a rough surface of a very considerable
+bredth from side to side, the narrowest part not seeming thinner then the
+back of a pretty thick Knife. Nor is’t likely that it should appear any
+otherwise, since as we just now shew’d that a _point_ appear’d a _circle_,
+’tis rational a _line_ should be a _parallelogram_.
+
+Now for the drawing this second Figure[3] (which represents a part of the
+Edge about half a quarter of an inch long of a Razor well set) I so plac’d
+it between the Object-glass & the light, that there appear’d a reflection
+from the very Edge, represented by the white line abcdef. In which you may
+perceive it to be somewhat sharper then elsewhere about d, to be indented
+or pitted about b, to be broader and thicker about c, and unequal and
+rugged about e, and pretty even between ab and ef. Nor was that part of the
+Edge ghik so smooth as one would imagine so smooth bodies as a Hone and Oyl
+should leave it; for besides those multitudes of scratches, which appear to
+have raz’d the surface ghik, and to cross each other every way which are
+not half of them exprest in the Figure, there were several great and deep
+scratches, or furrows, such as gh and ik, which made the surface yet more
+rugged, caus’d perhaps by some small Dust casually falling on the Hone, or
+some harder or more flinty part of the Hone it self. The other part of the
+Razor ll, which is polish’d on a grinding-stone, appear’d much rougher then
+the other, looking almost like a plow’d field, with many parallels, ridges,
+and furrows, and a cloddy, as ’twere, or an uneven surface: nor shall we
+wonder at the roughnesses of those surfaces, since even in the most curious
+wrought Glasses for _Microscopes_, and other Optical uses, I have, when the
+Sun has shone well on them, discover’d their surface to be variously raz’d
+or scratched, and to consist of an infinite of small broken surfaces, which
+reflect the light of very various and differing colours. And indeed it
+seems impossible by Art to cut the surface of any hard and brittle body
+smooth, since _Putte_, or even the most curious _Powder_ that can be made
+use of, to polish such a body, must consist of little hard rough particles,
+and each of them must cut its way, and consequently leave some kind of
+gutter or furrow behind it. And though Nature does seem to do it very
+readily in all kinds of fluid bodies, yet perhaps future observators may
+discover even these also rugged; it being very probable, as I elsewhere
+shew, that fluid bodies are made up of small solid particles variously and
+strongly mov’d, and may find reason to think there is scarce a surface _in
+rerum naturâ_ perfectly smooth. The black spot mn, I ghess to be some small
+speck of rust, for that I have oft observ’d to be the manner of the working
+of Corrosive Juyces. To conclude, this Edge and piece of a Razor, if it had
+been really such as it appear’d through the _Microscope_, would scarcely
+have serv’d to cleave wood, much less to have cut off the hair of beards,
+unless it were after the manner that _Lucian_ merrily relates _Charon_ to
+have made use of, when with a Carpenters Axe he chop’d off the beard of a
+sage Philosopher, whose gravity he very cautiously fear’d would indanger
+the oversetting of his Wherry.
+
+       *       *       *       *       *
+
+
+Observ. III. _Of fine Lawn, or Linnen Cloth._
+
+This is another product of Art, A piece of the finest Lawn I was able to
+get, so curious that the threads were scarce discernable by the naked eye,
+and yet through an ordinary _Microscope_ you may perceive[4] what a goodly
+piece of _coarse Matting_ it is; what proportionable cords each of its
+threads are, being not unlike, both in shape and size, the bigger and
+coarser kind of _single Rope-yarn_, wherewith they usually make _Cables_.
+That which makes the Lawn so transparent, is by the _Microscope_, nay by
+the naked eye, if attentively viewed, plainly enough evidenced to be the
+multitude of square holes which are left between the threads, appearing to
+have much more hole in respect of the intercurrent parts then is for the
+most part left in a _lattice-window_, which it does a little resemble,
+onely the crossing parts are round and not flat.
+
+These threads that compose this fine contexture, though they are as small
+as those that constitute the finer sorts of Silks, have notwithstanding
+nothing of their glossie, pleasant, and lively reflection. Nay, I have been
+informed both by the Inventor himself, and several other eye-witnesses,
+that though the flax, out of which it is made, has been (by a singular art,
+of that excellent Person, and Noble Virtuoso, M. _Charls Howard_, brother
+to the _Duke of Norfolk_) so curiously dress’d and prepar’d, as to appear
+both to the eye and the touch, full as _fine_ and as _glossie_, and to
+receive all kinds of colours, as well as Sleave-Silk; yet when this Silken
+Flax is twisted into threads, it quite loseth its former luster, and
+becomes as plain and base a thread to look on, as one of the same bigness,
+made of common Flax.
+
+The reason of which odd _Phenomenon_ seems no other then this; that though
+the curiously drest Flax has its parts so exceedingly small, as to
+equallize, if not to be much smaller then the clew of the Silk-worm,
+especially in thinness, yet the differences between the figures of the
+constituting filaments are so great, and their substances so various, that
+whereas those of the _Silk_ are _small_, _round_, _hard_, _transparent_,
+and to their bigness proportionably _stiff_, so as each filament preserves
+its proper _Figure_, and consequently its vivid _reflection_ intire, though
+twisted into a thread, if not too hard; those of Flax are _flat_, _limber_,
+_softer_, and _less transparent_, and in twisting into a thread they joyn,
+and lie so close together, as to lose their own, and destroy each others
+particular reflections. There seems therefore three Particulars very
+requisite to make the so drest Flax appear Silk also when spun into
+threads. First, that the substance of it should be made more _clear_ and
+_transparent_, Flax retaining in it a kind of opacating brown, or yellow;
+and the parts of the whitest kind I have yet observ’d with the _Microscope_
+appearing white, like flaw’d Horn or Glass, rather then clear, like clear
+Horn or Glass. Next that, the filaments should each of them be _rounded_,
+if that could be done, which yet is not so very necessary, if the first be
+perform’d, and this third, which is, that each of the small filaments be
+_stifned_; for though they be square, or flat, provided they be
+_transparent_ and stiff, much the same appearances must necessarily follow.
+Now, though I have not yet made trial, yet I doubt not, but that both these
+proprieties may be also induc’d upon the Flax, and perhaps too by one and
+the same Expedient, which some trials may quickly inform any ingenious
+attempter of, who from the use and profit of such an Invention, may find
+sufficient argument to be prompted to such Inquiries. As for the _tenacity_
+of the substance of Flax, out of which the thread is made, it seems much
+inferiour to that of Silk, the one being a _vegetable_, the other an
+_animal_ substance. And whether it proceed from the better concoction, or
+the more homogeneous constitution of _animal_ substances above those of
+_vegetables_, I do not here determine; yet since I generally find, that
+_vegetable_ substances do not equalize the _tenacity_ of _animal_, nor
+these the _tenacity_ of some purified _mineral_ substances; I am very apt
+to think, that the _tenacity_ of bodies does not proceed from the _hamous_,
+or _hooked_ particles, as the _Epicureans_ and some modern _Philosophers_
+have imagin’d; but from the more exact _congruity_ of the constituent
+parts, which are contiguous to each other, and so bulky, as not to be
+easily separated, or shatter’d, by any small pulls or concussion of heat.
+
+       *       *       *       *       *
+
+
+Observ. IV. _Of fine waled Silk, or Taffety._
+
+This[5] is the appearance of a piece of very fine Taffety-riband in the
+bigger magnifying Glass, which you see exhibits it like a very convenient
+substance to make Bed-matts, or Door-matts of, or to serve for Beehives,
+Corn-scuttles, Chairs, or Corn-tubs, it being not unlike that kind of work,
+wherewith in many parts in _England_, they make such Utensils of Straw, a
+little wreathed, and bound together with thongs of Brambles. For in this
+Contexture, each little filament, fiber, or clew of the Silk-worm, seem’d
+about the bigness of an ordinary Straw, as appears by the little irregular
+pieces, ab, cd, and ef; The _Warp_, or the thread that ran crossing the
+Riband, appear’d like a single Rope of an Inch Diameter; but the _Woof_, or
+the thread that ran the length of the Riband, appear’d not half so big.
+Each Inch of six-peny-broad Riband appearing no less then a piece of
+Matting Inch and half thick, and twelve foot square, a few yards of this,
+would be enough to floor the long Gallery of the _Loure_ at _Paris_. But to
+return to our piece of Riband: It affords us a not unpleasant object,
+appearing like a bundle, or wreath, of very clear and transparent
+_Cylinders_, if the Silk be white, and curiously ting’d; if it be colour’d,
+each of those small horney _Cylinders_ affording in some place or other of
+them, as vivid a reflection, as if it had been sent from a _Cylinder_ of
+Glass or Horn. Insomuch, that the reflections of Red, appear’d as if
+coming from so many _Granates_, or _Rubies_. The loveliness of the colours
+of Silks above those of hairy Stuffs, or Linnen, consisting, as I
+else-where intimate, chiefly in the transparency, and vivid reflections
+from the _Concave_, or inner surface of the _transparent Cylinder_, as are
+also the colours of Precious Stones; for most of the reflections from each
+of these _Cylinders_, come from the _Concave_ surface of the air, which is
+as ’twere the foil that incompasses the _Cylinder_. The colours with which
+each of these _Cylinders_ are ting’d, seem partly to be superficial, and
+sticking to the out-sides of them; and partly, to be imbib’d, or sunck into
+the substance of them: for Silk, seeming to be little else then a dried
+thread of Glew, may be suppos’d to be very easily relaxt, and softened, by
+being steeped in warm, nay in cold, if penetrant, juyces or liquors. And
+thereby those tinctures, though they tinge perhaps but a small part of the
+substance, yet being so highly impregnated with the colour, as to be almost
+black with it, may leave an impression strong enough to exhibite the
+desir’d colour. A pretty kinde of artificial Stuff I have seen, looking
+almost like transparent Parchment, Horn, or Ising-glass, and perhaps some
+such thing it may be made of, which being transparent, and of a glutinous
+nature, and easily mollified by keeping in water, as I found upon trial,
+had imbib’d, and did remain ting’d with a great variety of very vivid
+colours, and to the naked eye, it look’d very like the substance of the
+Silk. And I have often thought, that probably there might be a way found
+out, to make an artificial glutinous composition, much resembling, if not
+full as good, nay better, then that Excrement, or whatever other substance
+it be out of which, the Silk-worm wire-draws his clew. If such a
+composition were found, it were certainly an easie matter to find very
+quick ways of drawing it out into small wires for use. I need not mention
+the use of such an Invention, nor the benefit that is likely to accrue to
+the finder, they being sufficiently obvious. This hint therefore, may, I
+hope, give some Ingenious inquisitive Person an occasion of making some
+trials, which if successfull, I have my aim, and I suppose he will have no
+occasion to be displeas’d.
+
+       *       *       *       *       *
+
+
+Observ. V. _Of watered Silks, or Stuffs._
+
+There are but few _Artificial_ things that are worth observing with a
+_Microscope_, and therefore I shall speak but briefly concerning them. For
+the Productions of art are such rude mis-shapen things, that when view’d
+with a _Microscope_, is little else observable, but their deformity. The
+most curious Carvings appearing no better then those rude _Russian_ Images
+we find mention’d in _Purchas_, where three notches at the end of a Stick,
+stood for a face. And the most smooth and burnish’d surfaces appear most
+rough and unpolisht: So that my first Reason why I shall add but a few
+observations of them, is, their mis-shapen form; and the next, is their
+uselessness. For why should we trouble our selves in the examination of
+that form or shape (which is all we are able to reach with a _Microscope_)
+which we know was design’d for no higher a use, then what we were able to
+view with our naked eye? Why should we endeavour to discover mysteries in
+that which has no such thing in it? And like _Rabbins_ find out
+_Caballisms_, and _ænigmâs_ in the Figure, and placing of Letters, where no
+such thing lies hid: whereas in _natural_ forms there are some so small,
+and so curious, and their design’d business so far remov’d beyond the reach
+of our sight, that the more we magnify the object, the more excellencies
+and mysteries do appear; And the more we discover the imperfections of our
+senses; and the Omnipotency and Infinite perfections of the great Creatour.
+I shall therefore onely add one or two Observations more _artificial_
+things, and then come to the Treaty concerning such matters as are the
+Productions of a more curious Workman. One of these, shall be that of a
+piece of water’d Silk, represented in the second Figure of the third
+_Scheme_,[6] as it appear’d through the least magnifying Glass. _AB_
+signifying the long way of the Stuff, and _CD_ the broad way. This Stuff,
+if the right side of it be looked upon, appears to the naked eye, all over
+so waved, undulated, or grain’d, with a curious, though irregular variety
+of brighter and darker parts, that it adds no small gracefulness to the
+Gloss of it. It is so known a propriety, that it needs but little
+explication, but it is observable, which perhaps everyone has not
+considered, that those parts which appear the darker part of the wave, in
+one position to the light, in another appears the lighter, and the
+contrary; and by this means the undulations become transient, and in a
+continual change, according as the position of the parts in respect of the
+incident beams of light is varied. The reason of which odd _phænomena_, to
+one that has but diligently examin’d it even with his naked eye, will be
+obvious enough. But he that observes it with a _Microscope_, may more
+easily perceive what this _Proteus_ is, and how it comes to change its
+shape. He may very easily perceive, that it proceeds onely from the variety
+of the _Reflections_ of light, which is caus’d by the various _shape of the
+Particles_, or little protuberant parts of the thread that compose the
+surface; and that those parts of the waves that appear the brighter, throw
+towards the eye a multitude of small reflections of light, whereas the
+darker scarce afford any. The reason of which reflection, the _Microscope_
+plainly discovers, as appears by the Figure. In which you may perceive,
+that the brighter parts of the surface consist of an abundance of large and
+strong reflections, denoted by a, a, a, a, a, &c. for the surfaces of those
+threads that run the _long way_, are by the Mechanical process of watering,
+_creas’d_ or _angled_ in another kind of posture then they were by the
+weaving: for by the weaving they are onely _bent round_ the warping
+threads; but by the watering, they are _bent with an angle, or elbow_, that
+is in stead of lying, or being bent _round_ the threads, as in the third
+Figure, a, a, a, a, a, are about b, b, b (b, b, b representing the ends, as
+’twere, of the cross threads, they are bent about) they are creas’d on the
+top of those threads, with an _angle_, as in the fourth Figure, and that
+with all imaginable variety; so that, whereas before they reflected the
+light onely from one point of the round surface, as about c, c, c, they now
+when water’d, reflect the beams from more then half the whole surface, as
+de, de, de, and in other postures they return no reflections at all from
+those surfaces. Hence in one posture they compose the brighter parts of the
+waves, in another the darker. And these reflections are also varied,
+according as the particular parts are variously bent. The reason of which
+creasing we shall next examine; and here we must fetch our information from
+the Mechanism or manner of proceeding in this operation; which, as I have
+been inform’d, is no other then this.
+
+They double all the Stuff that is to be water’d, that is, they crease it
+just through the middle of it, the whole length of the piece, leaving the
+right side of the Stuff inward, and placing the two edges, or silvages just
+upon one another, and, as near as they can, place the wale so in the
+doubling of it, that the wale of the one side may lie very near parallel,
+or even with the wale of the other; for the nearer that posture they lie,
+the greater will the watering appear; and the more obliquely, or across to
+each other they lie, the smaller are the waves. Their way for folding it
+for a great wale is thus: they take a Pin, and begin at one side of the
+piece in any wale, and so moving it towards the other side, thereby direct
+their hands to the opposite ends of the wale, and then, as near as they
+can, place the two opposite ends of the same wale together, and so double,
+or fold the whole piece, repeating this enquiry with a Pin at every yard or
+two’s distance through the whole length; then they sprinkle it with water,
+and fold it the long-ways, placing between every fold a piece of Pastboard,
+by which means all the wrong side of the water’d Stuff becomes flat, and
+with little wales, and the wales on the other side become the more
+protuberant; whence the creasings or angular bendings of the wales become
+the more perspicuous. Having folded it in this manner, they place it with
+an interjacent Pastboard into an hot Press, where it is kept very violently
+prest, till it be dry and stiff; by which means, the wales of either
+contiguous sides leave their own impressions upon each other, as is very
+manifest by the second Figure, where ’tis obvious enough, that the wale of
+the piece ABCD runs parallel between the pricked lines ef, ef, ef, and as
+manifest to discern the impressions upon these wales, left by those that
+were prest upon them, which lying not exactly parallel with them, but a
+little athwart them, as is denoted by the lines of, oooo, gh, gh, gh,
+between which the other wales did lie parallel; they are so variously, and
+irregularly creas’d that being put into that shape when wet, and kept so
+till they be drie, they so let each others threads, that the Moldings
+remain almost as long as the Stuff lasts.
+
+Hence it may appear to any one that attentively considers the Figure, why
+the parts of the wale a, a, a, a, a, a, should appear bright; and why the
+parts b, b, b, b, b, b, b, should appear shadowed, or dark; why some, as d,
+d, d, d, d, d, should appear partly light, and partly dark: the varieties
+of which reflections and shadows are the only cause of the appearance of
+watering in Silks, or any other kind of Stuffs.
+
+From the variety of reflection, may also be deduc’d the cause why a small
+breez or gale of wind ruffling the surface of a smooth water, makes it
+appear black; as also, on the other side, why the smoothing or burnishing
+the surface of whitened Silver makes it look black; and multitudes of other
+phænomena might hereby be solv’d, which are too many to be here insisted
+on.
+
+       *       *       *       *       *
+
+
+Observ. VI. _Of Small Glass Canes._
+
+That I might be satisfi’d, whether it were not possible to make an
+_Artificial_ pore as _small_ as any _Natural_ I had yet found, I made
+several attempts with small _glass pipes_, melted in the flame of a Lamp,
+and then very _suddenly_ drawn out into a great length. And, by _that
+means_, without much difficulty, I was able to draw some almost as small as
+a _Cobweb_, which yet, with the _Microscope_, I could plainly perceive[7]
+to be _perforated_, both by looking on the _ends_ of it, and by looking on
+it _against the light_ which was much the _easier way_ to determine whether
+it were solid or perforated; for, taking a small pipe of glass, and closing
+one end of it, then filling it _half full_ of water, and holding it
+_against the light_, I could, by this means, very easily find what was the
+_differing aspect_ of a _solid_ and a _perforated_ piece of glass; and so
+easily distinguish, without seeing either end, whether any _Cylinder_ of
+glass I look’d on, were a _solid stick_, or a _hollow cane_. And by this
+means, I could also presently judge of any small _filament_ of glass,
+whether it were _hollow_ or _not_, which would have been exceeding tedious
+to examine by looking on the end. And many such like ways I was fain to
+make use of, in the examining of divers other particulars related in this
+Book, which would have been no easie task to have determined meerly by the
+more common way of looking on, or viewing the Object. For, if we consider
+first, the very _faint light_ wherewith the object is enlightened, whence
+many particles appear _opacous_, which when more enlightned, appear very
+_transparent_, so that I was fain to _determine_ its _transparency_ by one
+glass, and its _texture_ by another. Next, the _unmanageableness_ of most
+_Objects_, by reason of their _smalness_, 3. The _difficulty of finding_
+the desired point, and of _placing_ it so, as to reflect the _light
+conveniently_ for the Inquiry. Lastly, ones being able to view it but with
+_one eye_ at once, they will appear no small _obstructions_, nor are they
+easily _remov’d_ without many _contrivances_. But to proceed, I could not
+find that water, or some _deeply ting’d_ liquors would in small ones rise
+so high as one would expect; and the _highest_ I have found it yet rise in
+any of the pipes I have try’d, was to 21 _inches_ above the level of the
+water in the vessel: for though I found that in the small pipes it would
+_nimbly enter_ at first, and run about 6 or 7 _inches_ upwards; yet I found
+it then to move upwards _so slow_, that I have not yet had the _patience_
+to observe it above that height of 21 _inches_ (and that was in a pretty
+_large Pipe_, in comparison of those I formerly mentioned; for I could
+observe the _progress_ of a _very deep ting’d liquor_ in it with my _naked
+eye_, without much trouble; whereas many of the _other pipes_ were so _very
+small_, that unless in a _convenient posture_ to the light, I could not
+perceive _them_:) But ’tis very probable, that a greater _patience_ and
+_assiduity_ may discover the liquors to _rise_, at least to remain
+_suspended_, at heights that I should be loath now even to _ghess_ at, if
+at least there be any _proportion_ kept between the height of the ascending
+liquor, and the _bigness of the holes_ of the pipes.
+
+_AN ATTEMPT FOR THE EXPLICATION OF THIS EXPERIMENT._
+
+My Conjecture, _That the unequal height of the surfaces of the water,
+proceeded from the greater pressure made upon the water by the Air without
+the Pipes_ ABC, _then by that within them_[8]; I shall endeavour to confirm
+from the truth of the two following _Propositions_:
+
+The first of which is, _That an unequal pressure of the incumbent Air, will
+cause an unequal height in the water’s Surfaces_.
+
+And the second is, _That in this experiment there is such an unequal
+pressure_.
+
+That the first is true, the following _Experiment_ will evince. For if you
+take any Vessel so contrived, as that you can at pleasure either _increase_
+or _diminish_ the _pressure_ of the Air upon this or that part of the
+_Superficies_ of the _water_, the _equality_ of the height of those parts
+will presently be _lost_; and that part of the _Superficies_ that sustains
+the _greater pressure_, will be _inferior_ to that which undergoes the
+_less_. A fit Vessel for this purpose, will be an inverted Glass _Syphon_,
+such an one as is described in the _Sixth Figure_. For if into it you put
+Water enough to fill it as high as _AB_, and gently blow in at _D_, you
+shall _depress_ the Superficies _B_, and thereby _raise_ the opposite
+Superficies _A_ to a _considerable height_, and by gently _sucking_ you may
+produce clean _contrary_ effects.
+
+Next, That there is such an _unequal pressure_, I shall prove from this,
+_That there is a much greater incongruity of Air to Glass, and some other
+Bodies, then there is of Water to the same_.
+
+By _Congruity, I mean a property of a fluid Body, whereby any part of it is
+readily united with any other part, either of itself, or of any other
+Similar, fluid, or solid body: And by Incongruity a property of a fluid, by
+which it is hindred from uniting with any dissimilar, fluid, or solid
+Body._
+
+This last property, any one that hath been observingly conversant about
+fluid Bodies, cannot be ignorant of. For (not now to mention several
+_Chymical Spirits_ and _Oyls_, which will _very hardly_, if at _all_, be
+brought to _mix_ with one another; insomuch that there may be found some 8
+or 9, or more, several distinct Liquors, which _swimming_ one upon another,
+will not presently _mix_) we need seek no further for Examples of this kind
+in _fluids_, then to observe the _drops of rain_ falling through the _air_
+and the _bubbles of air_ which are by any means conveyed under the surface
+of the _water_; or a drop of common _Sallet-Oyl_ swimming upon water. In
+all which, and many more examples of this kind that might be enumerated,
+the _incongruity_ of two _fluids_ is easily discernable. And as for the
+_Congruity_ or _Incongruity_ of Liquids, with several kinds of _firm_
+Bodies, they have long since been taken notice of, and called by the Names
+of _Driness_ and _Moisture_ (though these two names are not comprehensive
+enough, being commonly used to signifie only the adhering or not adhering
+of _water_ to some other _solid Bodies_) of this kind we may observe that
+_water_ will more readily _wet some woods_ then _others_; and that _water_,
+let fall upon a _Feather_, the whiter side of a _Colwort_, and some other
+leaves, or upon almost any _dusty_, _unctuous_, or _resinous_ superficies,
+will not _at all adhere_ to them, but easily _tumble off_ from them, like a
+solid _Bowl_; whereas, if dropt upon _Linnen_, _Paper_, _Clay_, _green
+Wood_, &c. it will not be taken off, without leaving some part of it behind
+_adhering_ to them. So _Quick-silver_, which will very _hardly_ be brought
+to _stick_ to any _vegetable body_, will _readily adhere_ to, and _mingle_
+with, several clean _metalline bodies_.
+
+And that we may the better finde what the _cause_ of _Congruity_ and
+_Incongruity_ in bodies is, it will be requisite to consider, First, what
+is the _cause_ of _fluidness_; And this, _I conceive_, to be nothing else
+but a certain _pulse_ or _shake_ of _heat_; for Heat being nothing else but
+a very _brisk_ and _vehement agitation_ of the parts of a body (as I have
+elswhere made _probable_) the parts of a body are thereby made so _loose_
+from one another, that they easily _move any way_, and become _fluid_. That
+I may explain this a little by a gross Similitude, let us suppose a dish of
+sand set upon some body that is very much _agitated_, and shaken with some
+_quick_ and _strong vibrating motion_, as on a _Milstone_ turn’d round upon
+the under stone very violently whilst it is empty; or on a very stiff
+_Drum_-head, which is vehemently or very nimbly beaten with the Drumsticks.
+By this means, the sand in the dish, which before lay like a _dull_ and
+unactive body, becomes a perfect _fluid_; and ye can no sooner make a
+_hole_ in it with your finger, but it is immediately _filled up again_, and
+the upper surface of it _levell’d_. Nor can you _bury_ a _light body_, as a
+piece of Cork under it, but it presently _emerges_ or _swims_ as ’twere on
+the top; nor can you lay a _heavier_ on the top of it, as a piece of Lead,
+but it is immediately _buried_ in Sand, and (as ’twere) sinks to the
+bottom. Nor can you make a _hole_ in the side of the Dish, but the sand
+shall _run out_ of it to a _level_, not an _obvious property_ of a fluid
+body, as such, but this dos _imitate_; and all this meerly caused by the
+vehement _agitation_ of the conteining vessel; for by this means, _each_
+sand becomes to have a _vibrative_ or _dancing_ motion, so as no other
+heavier body can _rest_ on it, unless _sustein’d_ by some other on either
+side: Nor will it suffer any Body to be _beneath_ it, unless it be a
+_heavier_ then it self. Another Instance of the strange _loosening_ nature
+of a violent jarring Motion, or a strong and nimble vibrative one, we may
+have from a piece of _iron_ grated on very strongly with a _file_: for if
+into that a pin _screw’d_ so firm and hard, that though it has a convenient
+head to it, yet it can by no means be _unscrew’d_ by the fingers; if, I
+say, you attempt to unscrew this whilst _grated on by the file_, it will be
+found to undoe and turn very _easily_. The first of these Examples
+manifests, how a body actually _divided_ into small parts, becomes a
+_fluid_. And the latter manifests by what means the agitation of heat so
+easily _loosens_ and _unties_ the parts of _solid_ and _firm_ bodies. Nor
+need we suppose heat to be any thing else, besides such a motion; for
+supposing we could _Mechanically_ produce such a one _quick_ and _strong_
+enough, we need not spend _fuel_ to _melt_ a body. Now, that I do not speak
+this altogether groundless, I must refer the Reader to the Observations I
+have made upon the shining sparks of Steel, for there he shall find that
+_the same_ effects are produced upon small chips or parcels of Steel by the
+_flame_, and by _a quick and violent motion_; and if the body of _steel_
+may be thus melted (as I there shew it may) I think we have little reason
+to doubt that almost _any other_ may not also. Every Smith can inform one
+how quickly both his _File_ and the _Iron_ grows _hot_ with _filing_, and
+if you _rub_ almost any two _hard_ bodies together, they will do the same:
+And we know, that a sufficient degree of heat causes _fluidity_, in some
+bodies much sooner, and in others later; that is, the parts of the body of
+some are so _loose_ from one another, and so _unapt to cohere_, and so
+_minute_ and _little_, that a very _small_ degree of agitation keeps them
+always in the _state of fluidity_. Of this kind, I suppose, the _Æther_,
+that is the _medium_ or _fluid_ body, in which all other bodies do as it
+were swim and move; and particularly, the _Air_, which seems nothing else
+but a kind of _tincture_ or _solution_ of terrestrial and aqueous particles
+_dissolv’d_ into it, and agitated by it, just as the _tincture_ of
+_Cocheneel_ is nothing but some finer _dissoluble_ parts of that Concrete
+lick’d up or _dissolv’d_ by the _fluid_ water. And from this Notion of it,
+we may easily give a more Intelligible reason how the Air becomes so
+capable of _Rarefaction_ and _Condensation_. For, as in _tinctures_, one
+grain of some _strongly tinging_ substance may _sensibly_ colour some
+_hundred thousand_ grains of _appropriated_ Liquors, so as every _drop_ of
+it has its proportionate share, and be sensibly ting’d, as I have try’d
+both with _Logwood_ and _Cocheneel_: And as some few grains of _Salt_ is
+able to infect as great a quantity, as may be found by _præcipitations_,
+though not so easily by the _sight_ or _taste_; so the _Air_, which seems
+to be but as ’twere a _tincture_ or _saline substance, dissolv’d and
+agitated by the fluid and agil Æther_, may disperse and _expand_ it self
+into a _vast space_, if it have room enough, and infect, as it were, every
+part of that space. But, as on the other side, if there be but some _few
+grains_ of the liquor, it may _extract all_ the colour of the tinging
+substance, and may _dissolve_ all the Salt, and thereby become _much more
+impregnated_ with those substances, so may _all_ the air that sufficed in a
+_rarify’d state_ to fill some _hundred thousand_ spaces of Æther, be
+compris’d in only _one_, but in a position proportionable _dense_. And
+though we have not yet found out such _strainers_ for Tinctures and Salts
+as we have for the Air, being yet unable to _separate_ them from their
+dissolving liquors by any kind of _filtre_, without _præcipitation_, as we
+are able to _separate_ the Air from the Æther by _Glass_, and several other
+bodies. And though we are yet unable and ignorant of the ways of
+_præcipitating_ Air out of the Æther as we can Tinctures, and Salts out of
+several _dissolvents_; yet neither of these seeming _impossible_ from the
+nature of the things, nor so _improbable_ but that some happy future
+industry may find out ways to effect them; nay, further, since we find that
+Nature _does really perform_ (though by what means we are not certain) both
+these actions, namely, by _præcipitating_ the Air in Rain and Dews, and by
+supplying the Streams and Rivers of the World with fresh water, _strain’d_
+through secret subterraneous Caverns: And since, that in very many other
+_proprieties_ they do so exactly _seem_ of the _same nature_; till further
+observations or tryals do inform us of the _contrary_, we may _safely
+enough conclude_ them of the _same kind_. For it seldom happens that any
+two natures have so many properties _coincident_ or the _same_, as I have
+observ’d Solutions and Air to have, and to be _different_ in the rest. And
+therefore I think it neither _impossible_, _irrational_, nay nor
+_difficult_ to be able to _predict_ what is _likely_ to happen in other
+particulars also, besides those which _Observation_ or _Experiment_ have
+declared thus or thus; especially, if the _circumstances_ that do often
+very much conduce to the variation of the effects be duly _weigh’d_ and
+_consider’d_. And indeed, were there not a _probability_ of this, our
+_inquiries_ would be _endless_, our _tryals vain_, and our greatest
+_inventions_ would be nothing but the meer _products_ of _chance_, and not
+of _Reason_; and, like _Mariners_ in an Ocean, destitute both of a
+_Compass_ and the sight of the _Celestial guides_, we might indeed, _by
+chance_, Steer _directly_ towards our desired Port, but ’tis _a thousand to
+one_ but we _miss_ our aim. But to proceed, we may hence also give a plain
+reason, how the Air comes to be _darkned_ by _clouds_, &c. which are
+nothing but a kind of _precipitation_, and how those _precipitations_ fall
+down in _Showrs_. Hence also could I very easily, and I think truly, deduce
+the cause of the curious _sixangular figures_ of Snow, and the appearances
+of _Haloes, &c._ and the sudden _thickning_ of the Sky with Clouds, and the
+_vanishing_ and _disappearing_ of those Clouds again; for all these things
+may be very easily _imitated_ in a _glass of liquor_, with some slight
+_Chymical preparations_ as I have often try’d, and may somewhere else more
+largely relate, but have not now time to set them down. But to proceed,
+there are other bodies that consist of particles more _Gross_, and of a
+more _apt_ figure for _cohesion_, and this requires _somewhat greater_
+agitation; such, I suppose ☿, _fermented vinous_ _Spirits_, several
+_Chymical Oils_, which are much of kin to those Spirits, &c. Others yet
+require a _greater_, as _water_, and so others _much greater_, for almost
+infinite degrees: For, I suppose there are very _few_ bodies in the world
+that may not be made _aliquatenus_ fluid, by _some_ or _other_ degree of
+agitation or heat.
+
+Having therefore in short set down my Notion of a Fluid body, I come in the
+next place to consider what _Congruity_ is; and this, as I said before,
+being a _Relative property_ of a fluid, whereby it may be said to be _like_
+or _unlike_ to this or that other body, whereby it _does_ or _does not mix_
+with this or that body. We will again have recourse to our former
+Experiment, though but a rude one; and here if we mix in the dish _several
+kinds_ of sands, some of _bigger_, others of _less_ and finer bulks, we
+shall find that by the agitation _the fine sand_ will _eject_ and _throw
+out_ of it self all those _bigger_ bulks of small _stones_ and the like,
+and those will _be gathered_ together all into _one_ place; and if there be
+_other_ bodies in it of other natures, those also will be _separated_ into
+a place by themselves, and _united_ or _tumbled_ up together. And though
+this do not come up to the _highest property_ of _Congruity_, which is a
+_Cohæsion_ of the parts of the fluid together, or a kind of _attraction_
+and _tenacity_, yet this does as ’twere _shadow_ it out, and somewhat
+resemble it; for just after the same manner, I suppose the _pulse_ of heat
+to _agitate_ the small parcels of matter, and those that are of a _like
+bigness_, and _figure_, and _matter_, will _hold_, or _dance_ together, and
+those which are of a _differing_ kind will be _thrust_ or _shov’d_ out from
+between them; for particles that are _similar_, will, like so many _equal
+musical strings equally stretcht_, vibrate together in a kind of _Harmony_
+or _unison_; whereas others that are _dissimilar_, upon what account
+soever, unless the disproportion be otherwise counter-ballanc’d, will, like
+so many _strings out of tune_ to those unisons, though they have the same
+agitating _pulse_, yet make quite _differing_ kinds of _vibrations_ and
+_repercussions_, so that though they may be both mov’d, yet are their
+_vibrations_ so _different_, and so _untun’d_, as ’twere to each other,
+that they _cross_ and _jar_ against each other, and consequently, _cannot
+agree_ together, but _fly back_ from each other to their similar particles.
+Now, to give you an instance how the _disproportion_ of some bodies in one
+respect, may be _counter-ballanc’d_ by a _contrary disproportion_ of the
+same body in another respect, whence we find that the subtil _vinous
+spirit_ is _congruous_, or does readily _mix_ with _water_, which in many
+properties is of a very _differing nature_, we may consider that a _unison_
+may be made either by two _strings_ of the same _bigness_, _length_, and
+_tension_, or by two strings of the same _bigness_, but of _differing
+length_, and a _contrary differing tension_, or _3ly._ by two strings of
+_unequal length_ and _bigness_, and of a _differing tension_, or of _equal
+length_, and _differing bigness_ and _tension_, and several other such
+varieties. To which _three properties_ in _strings_, will correspond _three
+proprieties_ also in _sand_, or the _particles_ of bodies, their _Matter_
+or _Substance_, their _Figure_ or _Shape_, and their _Body_ or _Bulk_. And
+from the _varieties_ of these _three_, may arise _infinite varieties_ in
+fluid bodies, though all agitated by the _same pulse_ or _vibrative_
+motion. And there may be as many ways of making Harmonies and Discords with
+these, as there may be with _musical strings_. Having therefore seen what
+is the cause of Congruity or Incongruity, those relative properties of
+fluids, we may, from what has been said, very easily collect, what is the
+_reason_ of those Relative proprieties also between _fluid bodies_ and
+_solid_; for since all bodies consist of _particles_ of such a _Substance_,
+_Figure_, and _Bulk_; but in some they are _united_ together more _firmly_
+then to be _loosened_ from each other by every _vibrative_ motion (though I
+imagine that there is no body in the world, but that some degree of
+agitation may, as I hinted before, agitate and loosen the particles so as
+to make them fluid) those _cohering_ particles may _vibrate_ in the same
+manner almost as those that are _loose_ and become _unisons_ or _discords_,
+as I may so speak, to them. Now that the _parts_ of all _bodies_, though
+never so _solid_, do yet _vibrate_, I think we need go no further for
+proof, then that _all_ bodies have some _degrees_ of _heat_ in them, and
+that there has not been yet found any thing _perfectly cold_: Nor can I
+believe indeed that there is any such thing in Nature, as a body whose
+particles are at _rest_, or _lazy_ and _unactive_ in the great _Theatre_ of
+the _World_, it being quite _contrary_ to the grand _Oeconomy_ of the
+Universe. We see therefore what is the reason of the _sympathy_ or uniting
+of some bodies together, and of the _antipathy_ or flight of others from
+each other: For _Congruity_ seems nothing else but a _Sympathy_, and
+_Incongruity_ an _Antipathy_ of bodies, hence _similar_ bodies once
+_united_ will not _easily part_, and _dissimilar_ bodies once _disjoyn’d_
+will not _easily unite_ again; from hence may be very easily deduc’d the
+reason of the _suspension_ of _water_ and _Quick-silver_ above their usual
+_station_, as I shall more at large anon shew.
+
+These properties therefore (alwayes the concomitants of fluid bodies)
+produce these following visible _Effects_:
+
+First, They _unite_ the parts of a fluid to its _similar_ Solid, or keep
+them _separate_ from its _dissimilar_. Hence _Quick-silver_ will (as we
+noted before) _stick_ to _Gold_, _Silver_, _Tin_, _Lead_, &c. and _unite_
+with them: but _roul_ off from _Wood_, _Stone_, _Glass_, &c. if never so
+little scituated out of its _horizontal level_; and _water_ that will _wet
+salt_ and _dissolve_ it, will _slip_ off from _Tallow_, or the like,
+without at all _adhering_; as it may likewise be observed to do upon a
+_dusty_ superficies. And next they cause the parts of _homogeneal fluid_
+bodies readily to _adhere_ together and _mix_, and of _heterogeneal_, to be
+exceeding _averse_ thereunto. Hence we find, that _two_ small _drops_ of
+_water_, on any superficies they can roul on, will, if they chance to touch
+each other, _readily unite_ and _mix_ into one 3d _drop_: The like may be
+observed with two small _Bowls_ of _Quick-silver_ upon a Table or Glass,
+provided their surfaces be not _dusty_; and with two drops of _Oyl_ upon
+fair water, _&c._ And further, _water_ put unto _wine_, _salt water_,
+_vinegar_, _spirit_ of _wine_, or the like, does immediately (especially if
+they be shaken together) _disperse_ it self all over them. Hence, on the
+contrary, we also find, that _Oyl of Tartar_ poured upon _Quick-silver_,
+and _Spirit of Wine_ on that _Oyl_, and _Oyl of Turpentine_ on that
+_Spirit_, and _Air_ upon that _Oyl_, though they be stopt closely up into a
+Bottle, and _shaken_ never so much, they will by no means long suffer any
+of their bigger parts to be _united_ or included within any of the other
+Liquors (by which recited Liquors, may be plainly enough represented the
+four _Peripatetical Elements_, and the more subtil _Æther_ above all.) From
+this property ’tis, that a drop of _water_ does not mingle with, or vanish
+into _Air_, but is _driven_ (by that Fluid equally protruding it on every
+side) and forc’t into as little a space as it can possibly be contained in,
+namely, into a _Round Globule_. So likewise a little _Air_ blown under the
+_water_, is _united_ or thrust into a _Bubble_ by the ambient water. And a
+parcel of _Quick-silver_ enclosed with _Air_, _Water_, or almost any other
+_Liquor_, is _formed_ into a _round Ball_.
+
+Now the cause why all these included Fluids, newly mentioned, or as many
+others as are wholly included within a heterogeneous fluid, are not
+_exactly_ of a _Spherical Figure_ (seeing that if caused by these
+Principles only, it could be of no other) must proceed from some other kind
+of _pressure_ against the two opposite flatted sides. This _adventitious_
+or _accidental pressure_ may proceed from _divers causes_, and accordingly
+must _diversifie_ the Figure of the included heterogeneous fluid: For
+seeing that a body may be included either with a fluid only, or only with a
+solid, or partly with a fluid, and partly with a solid, or partly with one
+fluid, and partly with another; there will be found a very great variety of
+the terminating _surfaces_, much differing from a _Spherical_, according to
+the various resistance or pressure that belongs to each of these
+encompassing bodies.
+
+Which Properties may in general be deduced from two heads, _viz._ _Motion_,
+and _Rest_. For, either this Globular Figure is altered by a _natural
+Motion_, such as is _Gravity_, or a _violent_, such as is any _accidental
+motion_ of the fluids, as we see in the _wind_ ruffling up the water, and
+the _purlings_ of _Streams_, and _foaming_ of _Catarracts_, and the like.
+Or thirdly, By the _Rest_, _Firmness_ and _Stability_ of the ambient
+_Solid_. For if the including _Solid_ be of an _angular_ or any other
+_irregular_ Form, the included _fluid_ will be near of the _like_, as a
+Pint-_Pot_ full of _water_, or a _Bladder_ full of _Air_. And next, if the
+including or included fluid have a greater _gravity_ one than another, then
+will the _globular_ Form be deprest into an _Elliptico-spherical_: As if,
+for example, we suppose the Circle _ABCD_, in the _fourth Figure_, to
+represent a _drop of water_, _Quick-silver_, or the like, included with the
+_Air_ or the like, which supposing there were no _gravity_ at all in either
+of the _fluids_, or that the _contained_ and _containing_ were of the _same
+weight_, would be _equally comprest_ into an exactly _spherical_ body (the
+ambient fluid _forcing equally_ against every side of it.) But supposing
+either a greater _gravity_ in the included, by reason whereof the parts of
+it being _prest_ from _A_ towards _B_, and thereby the whole put into
+_motion_, and that _motion_ being _hindred_ by the _resistance_ of the
+_subjacent_ parts of the ambient, the _globular_ Figure _ADBC_ will be
+_deprest_ into the _Elliptico-spherical_, _EGFH_. For the side _A_ is
+_detruded_ to _E_ by the _Gravity_, and _B_ to _F_ by the _resistance_ of
+the subjacent medium: and therefore _C_ must necessarily be thrust to _G_;
+and _D_ to _H_. Or else, supposing a greater _gravity_ in the _ambient_, by
+whose more then ordinary _pressure_ against the under side of the included
+globule; _B_ will be forced to _F_, and by its _resistance_ of the motion
+_upwards_, the side _A_ will be _deprest_ to _E_, and therefore _C_ being
+thrust to _G_ and _D_ to _H_; the _globular_ Figure by this means also will
+be made an _Elliptico-spherical_. Next if a fluid be included _partly_ with
+one, and _partly_ with another fluid, it will be found to be shaped
+_diversly_, according to the proportion of the _gravity_ and _incongruity_
+of the 3 _fluids_ one to another: As in the _second Figure_, let the upper
+_MMM_ be _Air_, the middle _LMNO_ be common _Oyl_, the lower _OOO_ be
+_Water_, the _Oyl_ will be form’d, not into a _spherical_ Figure, such as
+is represented by the _pricked Line_, but into such a Figure as LMNO, whose
+side LMN will be of a flatter _Elliptical_ Figure, by reason of the great
+disproportion between the _Gravity_ of _Oyl_ and _Air_, and the side LOM of
+a rounder, because of the smaller difference between the weight of _Oyl_
+and _Water_. Lastly, The _globular_ Figure will be changed, if the
+_ambient_ be partly _fluid_ and partly _solid_. And here the termination of
+the incompassed _fluid_ towards the incompassing is shap’d according to the
+proportion of the congruity or incongruity of the _fluids_ to the _solids_,
+and of the gravity and incongruity of the _fluids_ one to another. As
+suppose the subjacent _medium_ that hinders an included fluids descent, be
+a _solid_, as let KI, in the _fourth Figure_, represent the smooth
+superficies of a _Table_; EGFH, a parcel of _running Mercury_; the side GFH
+will be more flatted, according to the proportion of the incongruity of the
+_Mercury_ and _Air_ to the _Wood_, and of the _gravity_ of _Mercury_ and
+_Air_ one to another; The side GEH will likewise be a little more deprest
+by reason the subjacent parts are now at rest, which were before in motion.
+
+Or further in the _third figure_, let AILD represent an including _solid_
+medium of a cylindrical shape (as suppose a small _Glass Jar_) Let FGEMM
+represent a contain’d _fluid_, as water; this towards the bottom and sides,
+is figured according to the concavity of the _Glass_: But its upper
+_Surface_, (which by reason of its gravity, (not considering at all the Air
+above it, and so neither the congruity or incongruity of either of them to
+the Glass) should be terminated by part of a _Sphere_ whose diameter should
+be the same with that of the earth, which to our sense would appear a
+straight _Line_, as FGE, Or which by reason of its having a greater
+congruity to Glass than Air has, (not considering its Gravity) would be
+thrust into a _concave Sphere_, as CHB, whose diameter would be the same
+with that of the concavity of the Vessel:) Its upper Surface, I say, by
+reason of its having a greater gravity then the Air, and having likewise a
+greater congruity to Glass then the Air has, is terminated, by a _concave
+Elliptico-spherical Figure_, as CKB. For by its congruity it easily
+conforms it self, and adheres to the Glass, and constitutes as it were one
+containing body with it, and therefore should thrust the contained Air on
+that side it touches it, into a _spherical_ Figure, as BHC, but the motion
+of Gravity depressing a little the Corners B and C, reduces it into the
+aforesaid Figure CKB. Now that it is the greater congruity of one of the
+two _contiguous fluids_, then of the other, to the containing _solid_, that
+causes the separating surfaces to be thus or thus figured: And that it is
+not because this or that figurated surface is more proper, natural, or
+peculiar to one of these fluid bodies, then to the other, will appear from
+this; that the same _fluids_ will by being put into differing _solids_,
+change their _surfaces_. For the same water, which in a Glass or wooden
+Vessel will have a concave surface upwards, and will rise higher in a
+smaller then a greater Pipe, the same water, I say, in the same Pipes
+greased over or oyled, will produce quite contrary effects; for it will
+have a _protuberant_ and _convex_ surface upwards, and will not rise so
+high in small, as in bigger Pipes: Nay, in the very same solid Vessel, you
+may make the very same two contiguous _Liquids_ to alter their Surfaces;
+for taking a small Wine-glass, or such like Vessel, and pouring water
+gently into it, you shall perceive the _surface_ of the water all the way
+_concave_, till it rise even with the top, when you shall find it (if you
+gently and carefully pour in more) to grow very _protuberant_ and _convex_;
+the reason of which is plain, for that the _solid_ sides of the containing
+body are no longer extended, to which the water does more readily adhere
+then the air; but it is henceforth to be included with air, which would
+reduce it into a _hemisphere_, but by reason of its _gravity_, it is
+flatted into an _Oval_. _Quicksilver_ also which to _Glass_ is more
+incongruous then _Air_ (and thereby being put into a _Glass-pipe_, will not
+adhere to it, but by the more _congruous air_ will be forced to have a very
+_protuberant_ surface, and to rise higher in a greater then a lesser Pipe)
+this _Quicksilver_ to clean _Metal_, especially to _Gold_, _Silver_, _Tin_,
+_Lead_, &c. _Iron_ excepted, is more _congruous_ then _Air_, and will not
+only stick to it, but have a _concave_ Surface like _water_, and rise
+higher in a less, then in a greater Pipe.
+
+In all these Examples it is evident, that there is an _extraordinary_ and
+_adventitious force_, by which the _globular_ Figure of the contained
+_heterogeneous_ fluid is altered; neither can it be imagined, how it should
+otherwise be of any other Figure then _Globular_: For being by the
+_heterogeneous_ fluid equally _protruded_ every way, whatsoever part is
+_protuberant_, will be thereby _deprest_. From this cause it is, that in
+its effects it does very much resemble a _round Spring_ (such as a _Hoop_.)
+For as in a _round Spring_ there is required an additional _pressure_
+against two opposite sides, to reduce it into an _Oval_ Form, or to force
+it in between the sides of a _Hole_, whose _Diameter_ is less then that of
+the _Spring_, there must be a considerable force or _protrusion_ against
+_the concave_ or inner side of the _Spring_; So to alter this _spherical_
+constitution of an included fluid body, there is required more pressure
+against opposite sides to reduce it into an _Oval_; and, to press it into
+an _Hole_ less in _Diameter_ then it self, it requires a greater
+_protrusion_ against all the other sides, What degrees of force are
+requisite to reduce them into longer and longer _Ovals_, or to press them
+into less and less _holes_, I have not yet experimentally calculated; but
+thus much by experiment I find in general, that there is alwayes required a
+greater pressure to close them into longer _Ovals_, or protrude them into
+smaller _holes_. The necessity and reason of this, were it requisite, I
+could easily explain: but being not so necessary, and requiring more room
+and time then I have for it at present, I shall here omit it; and proceed
+to shew, that this may be presently found true, if Experiment be made with
+a _round Spring_ (the way of making which trials is _obvious_ enough.) And
+with the fluid bodies of _Mercury_, _Air_, _&c._ the way of trying which,
+will be somewhat more difficult; and therefore I shall in brief describe
+it. He therefore that would try with _Air_, must first be provided of a
+_Glass-pipe_, made of the shape of that in the _fifth Figure_, whereof the
+side AB, represents a straight _Tube_ of about three foot long, C,
+represents another part of it, which consists of a _round Bubble_; so
+ordered, that there is left a _passage_ or _hole_ at the top, into which
+may be fastened with _cement_ several _small Pipes_ of determinate
+_cylindrical_ cavities: as let the _hollow_ of
+
+  F.       ¼
+  G.       ⅙
+  H.       ⅛
+  I.  be   ¹⁄₁₂   of an inch.
+  K.       ¹⁄₁₆
+  L.       ¹⁄₂₄
+  M.       ¹⁄₃₂
+  &c.——
+There may be added as many more, as the Experimenter shall think fit, with
+holes continually decreasing by known quantities, so far as his senses are
+able to help him; I say, so far, because there may be made _Pipes_ so small
+that it will be impossible to perceive the _perforation_ with ones naked
+eye, though by the help of a _Microscope_, it may easily enough be
+perceived: Nay, I have made a _Pipe_ perforated from end to end, so small,
+that with my naked eye I could very hardly see the body of it, insomuch
+that I have been able to knit it up into a knot without breaking: And more
+accurately examining one with my _Microscope_, I found it not so big as a
+sixteenth part of one of the smaller hairs of my head which was of the
+smaller and finer sort of hair, so that sixteen of these _Pipes_ bound
+faggot-wise together, would but have equalized one single hair; how small
+therefore must its _perforation_ be? It appearing to me through the
+_Microscope_ to be a proportionably _thick-sided Pipe_.
+
+To proceed then, for the trial of the Experiment, the Experimenter must
+place the _Tube_ AB, perpendicular, and fill the _Pipe_ F (cemented into
+the hole E) with water, but leave the _bubble_ C full of _Air_, and then
+gently pouring in water into the Pipe AB, he must observe diligently how
+high the water will rise in it before it protrude the _bubble_ of Air C,
+through the narrow passage of F, and denote exactly the height of the
+_Cylinder_ of water, then cementing in a second Pipe as G, and filling it
+with water; he may proceed as with the former, denoting likewise the height
+of the _Cylinder_ of water, able to protrude the _bubble_ C through the
+passage of G, the like may he do with the next _Pipe_, and the next, &c. as
+far as he is able: then comparing the several heights of the _Cylinders_,
+with the several _holes_ through which each _Cylinder_ did force the _air_
+(having due regard to the _Cylinders_ of water in the small _Tubes_) it
+will be very easie to determine, what force is requisite to press the _Air_
+into such and such _a hole_, or (to apply it to our present experiment) how
+much of the pressure of the _Air_ is taken off by its ingress into smaller
+and smaller _holes_. From the application of which to the entring of the
+_Air_ into the bigger _hole_ of the _Vessel_, and into the smaller _hole_
+of the _Pipe_, we shall clearly find, that there is a greater pressure of
+the air upon the water in the _Vessel_ or greater _pipe_, then there is
+upon that in the lesser _pipe_: For since the pressure of the _air_ every
+way is found to be equal, that is, as much as is able to press up and
+sustain a _Cylinder_ of _Quicksilver_ of two foot and a half high, or
+thereabouts; And since of this pressure so many more degrees are required
+to force the _Air_ into a smaller then into a greater _hole_ that is full
+of a more congruous fluid. And lastly, since those degrees that are
+requisite to press it in, are thereby taken off from the _Air_ within, and
+the _Air_ within left with so many degrees of pressure less then the _Air_
+without; it will follow, that the _Air_ in the less _Tube_ or _pipe_, will
+have less pressure against the superficies of the _water_ therein, then the
+_Air_ in the bigger: which was the minor Proposition to be proved.
+
+The Conclusion therefore will necessarily follow, _viz._ That _this
+unequal pressure of the Air caused by its ingress into unequal holes,
+is a cause sufficient to produce this effect, without the help of any
+other concurrent_; and therefore is probably the principal (if not the
+only) cause of these _Phænomena_.
+
+This therefore being thus explained, there will be divers _Phænomena_
+explicable thereby, as, the rising of _Liquors_ in a _Filtre_, the rising
+of _Spirit of Wine_, _Oyl_, _melted Tallow_, &c. in the _Week_ of a _Lamp_,
+(though made of small _Wire_, _Threeds_ of _Asbestus_, _Strings_ of
+_Glass_, or the like) the rising of _Liquors_ in a _Spunge_, piece of
+_Bread_, _Sand_, &c. perhaps also the ascending of the _Sap_ in _Trees_ and
+_Plants_, through their small, and some of them _imperceptible pores_, (of
+which I have said more, on another occasion) at least the passing of it out
+of the earth into their roots. And indeed upon the consideration of this
+Principle, multitudes of other uses of it occurr’d to me, which I have not
+yet so well examined and digested as to propound for _Axioms_, but only as
+_Queries_ and _Conjectures_ which may serve as _hints_ toward some further
+_discoveries_.
+
+As first, Upon the consideration of the _congruity_ and _incongruity_ of
+Bodies, as to _touch_, I found also the like _congruity_ and _incongruity_
+(if I may so speak) as to the _Transmitting_ of the _Rates_ of Light: For
+as in this regard, _water_ (not now to mention other Liquors) seems nearer
+of affinity to _Glass_ then _Air_, and _Air_ then _Quicksilver_: whence an
+_oblique Ray_ out of _Glass_, will pass into _water_ with very little
+_refraction_ from the _perpendicular_, but none out of _Glass_ into _Air_,
+excepting a _direct_, will pass without a very great refraction from the
+perpendicular, nay any oblique Ray under thirty degrees, will not be
+admitted into the Air at all. And _Quicksilver_ will neither admit oblique
+or direct, but reflects all; seeming, as to the transmitting of the Raies
+of Light, to be of a quite differing constitution, from that of _Air_,
+_Water_, _Glass_, &c. and to resemble most those opacous and strong
+reflecting bodies of Metals: So also as to the property of cohesion or
+congruity, Water seems to keep the same order, being more congruous to
+Glass then Air, and Air then Quicksilver.
+
+A Second thing (which was hinted to me, by the consideration of the
+included fluids globular form, caused by the protrusion of the ambient
+heterogeneous fluid) was, whether the _Phænomena_ of gravity might not by
+this means be explained, by supposing the _Globe_ of Earth, Water, and Air
+to be included with a _fluid_, heterogeneous to all and each of them, so
+subtil, as not only to be every where _interspersed_ through the _Air_, (or
+rather the _air_ through it) but to _pervade_ the bodies of _Glass_, and
+even the _closest Metals_, by which means it may endeavour to _detrude_ all
+earthly bodies as far from it as it can; and partly thereby, and partly by
+other of its properties may move them towards the Center of the Earth. Now
+that there is some such fluid, I could produce many Experiments and
+Reasons, that do seem to prove it: But because it would ask some time and
+room to set them down and explain them, and to consider and answer all the
+Objections (many whereof I foresee) that may be alledged against it; I
+shall at present proceed to other _Queries_, contenting my self to have
+here only given a hint of what I may say more elswhere.
+
+A Third _Query_ then was, Whether the _heterogeneity_ of the _ambient
+fluid_ may not be accounted a _secondary cause_ of the _roundness_ or
+_globular form_ of the _greater bodies_ of the world, such as are those of
+the _Sun_, _Stars_, and _Planets_, the _substance_ of each of which seems
+altogether _heterogeneous_ to the _circumambient fluid æther_? And of this
+I shall say more in the Observation of the Moon.
+
+A Fourth was, Whether the _globular form_ of the _smaller parcels_ of
+matter here upon the _Earth_, as that of _Fruits_, _Pebbles_, or _Flints_,
+&c. (which seem to have been a _Liquor_ at first) may not be caused by the
+_heterogeneous ambient fluid_. For thus we see that melted _Glass_ will be
+naturally formed into a _round Figure_; so likewise any small Parcel of any
+_fusible body_, if it be perfectly enclosed by the _Air_, will be driven
+into a _globular_ Form; and, when cold, will be found a _solid Ball_. This
+is plainly enough manifested to us by their way of making _shot_ with the
+_drops of Lead_; which being a very pretty curiosity, and known but to a
+very few, and having the liberty of publishing it granted me, by that
+_Eminent Virtuoso_ Sir _Robert Moray_, who brought in this Account of it to
+the _Royal Society_, I have here transcribed and inserted.
+
+To make small shot of different sizes; Communicated by his Highness _P.R._
+
+_Take Lead out of the Pig what quantity you please, melt it down, stir and
+clear it with an iron Ladle, gathering together the blackish parts that
+swim at top like scum, and when you see the colour of the clear Lead to be
+greenish, but no sooner, strew upon it _Auripigmentum_ powdered according
+to the quantity of Lead, about as much as will lye upon a half Crown piece
+will serve for eighteen or twenty pound weight of some sorts of Lead;
+others will require more, or less. After the _Auripigmentum_ is put in,
+stir the Lead well, and the _Auripigmentum_ will flame: when the flame is
+over, take out some of the Lead in a Ladle having a lip or notch in the
+brim for convenient pouring out of the Lead, and being well warmed amongst
+the melted Lead, and with a stick make some single drops of Lead trickle
+out of the Ladle into water in a Glass, which if they fall to be round and
+without tails, there is _Auripigmentum_ enough put in, and the temper of
+the heat is right, otherwise put in more. Then lay two bars of Iron (or
+some more proper Iron-tool made on purpose) upon a Pail of water, and place
+upon them a round Plate of Copper, of the size and figure of an ordinary
+large Pewter or Silver Trencher, the hollow whereof is to be about three
+inches over, the bottom lower then the brims about half an inch, pierced
+with thirty, forty, or more small holes; the smaller the holes are, the
+smaller the shot will be; and the brim is to be thicker then the bottom, to
+conserve the heat the better._
+
+_The bottom of the Trencher being some four inches distant from the water
+in the Pail, lay upon it some burning Coles, to keep the Lead melted upon
+it. Then with the hot Ladle take Lead off the Pot where it stands melted,
+and pour it softly upon the burning Coles over the bottom of the Trencher,
+and it will immediately run through the holes into the water in small round
+drops. Thus pour on new Lead still as fast as it runs through the Trencher
+till all be done; blowing now and then the Coles with hand-Bellows, when
+the Lead in the Trencher cools so as to stop from running._
+
+_Whilst one pours on the Lead, another must, with another Ladle, thrusted
+four or five inches under water in the Pail, catch from time to time some
+of the shot, as it drops down, to see the size of it, and whether there be
+any faults in it. The greatest care is to keep the Lead upon the Trencher
+in the right degree of heat; if it be too cool, it will not run through the
+Trencher, though it stand melted upon it; and this is to be helped by
+blowing the Coals a little, or pouring on new Lead that is hotter: but the
+cooler the Lead, the larger the Shot; and the hotter, the smaller; when it
+is too hot, the drops will crack and fly; then you must stop pouring on new
+Lead, and let it cool; and so long as you observe the right temper of the
+heat, the Lead will constantly drop into very round Shot, without so much
+as one with a tail in many pounds._
+
+_When all is done, take your Shot out of the Pail of water, and put it in a
+Frying-pan over the fire to dry them, which must be done warily, still
+shaking them that they melt not; and when they are dry you may separate the
+small from the great, in Pearl Sives made of Copper or Lattin let into one
+another, into as many sizes at you please. But if you would have your Shot
+larger then the Trencher makes them, you may do it with a Stick, making
+them trickle out of the Ladle, as hath been said._
+
+_If the Trencher be but toucht a very little when the Lead stops from going
+through it, and be not too cool, it will drop again, but it is better not
+to touch it at all. At the melting of the Lead take care that there be no
+kind of Oyl, Grease, or the like, upon the Pots, or Ladles, or Trencher._
+
+_The Chief cause of this Globular Figure of the Shot, seems to be the
+_Auripigmentum_; for, as soon as it is put in among the melted Lead, it
+loses its shining brightness, contracting instantly a grayish film or skin
+upon it, when you scum it to make it clean with the Ladle. So that when the
+Air comes at the falling drop of the melted Lead, that skin constricts them
+every where equally: but upon what account, and whether this be the true
+cause, is left to further disquisition._
+
+Much after this same manner, when the Air is exceeding cold through which
+it passes; do we find the drops of Rain, falling from the Clouds, congealed
+into round Hail-stones by the freezing Ambient.
+
+To which may be added this other known Experiment, That if you gently let
+fall a drop of _water_ upon small _sand_ or _dust_, you shall find, as it
+were, an artificial _round stone_ quickly generated. I cannot upon this
+occasion omit the mentioning of the strange kind of _Grain_, which I have
+observed in a _stone_ brought from _Kettering_ in _Northamptonshire_, and
+therefore called by Masons _Kettering-Stone_, of which see the Description.
+Which brings into my mind what I long since observed in the fiery Sparks
+that are struck out of a Steel. For having a great desire to see what was
+left behind, after the Spark was gone out, I purposely struck fire over a
+very white piece of Paper, and observing diligently where some conspicuous
+sparks went out, I found a very little black spot no bigger then the point
+of a Pin, which through a _Microscope_ appeared to be a perfectly round
+Ball, looking much like a polisht ball of Steel, insomuch that I was able
+to see the Image of the window reflected from it. I cannot here stay
+(having done it more fully in another place) to examine the particular
+Reasons of it, but shall only hint, that I imagine it to be some small
+parcel of the Steel, which by the violence of the motion of the stroke
+(most of which seems to be imprest upon those small parcels) is made so
+glowing hot, that it is melted into a _Vitrum_, which by the ambient Air is
+thrust into the form of a Ball.
+
+A Fifth thing which I thought worth Examination was, Whether the motion of
+all kind of Springs, might not be reduced to the Principle whereby the
+included _heterogeneous fluid_ seems to be moved; or to that whereby two
+Solids, as Marbles, or the like, are thrust and kept together by the
+_ambient fluid_.
+
+A Sixth thing was, Whether the Rising and Ebullition of the Water out of
+Springs and Fountains (which lie much higher from the Center of the Earth
+then the Superficies of the Sea, from whence it seems to be derived) may
+not be explicated by the rising of Water in a smaller Pipe: For the
+Sea-water being strained through the Pores or Crannies of the Earth, is, as
+it were, included in little Pipes, where the pressure of the Air has not so
+great a power to resist its rising: But examining this way, and finding in
+it several difficulties almost irremovable, I thought upon a way that would
+much more naturally and conceivably explain it, which was by this following
+Experiment: I took a Glass-Tube, of the form of that described in the sixth
+Figure, and chusing two _heterogeneous fluids_, such as Water and Oyl, I
+poured in as much Water as filled up the Pipes as high as AB, then putting
+in some Oyl into the Tube AC, I deprest the superficies A of the Water to
+F, and B I raised to G, which was not so high perpendicularly as the
+superficies of the Oyl F, by the space FI, wherefore the proportion of the
+gravity of these two Liquors was as GH to FE.
+
+This Experiment I tried with several other Liquors, and particularly with
+fresh Water and Salt (which I made by dissolving Salt in warm Water) which
+two though they are nothing heterogeneous, yet before they would perfectly
+mix one with another, I made trial of the Experiment: Nay, letting the Tube
+wherein I tried the Experiment remain for many dayes, I observed them not
+to mix; but the superficies of the fresh was rather more then less elevated
+above that of the Salt. Now the proportion of the gravity of Sea-water, to
+that of River-water, according to _Stevinus_ and _Varenius_, and as I have
+since found pretty true by making trial my self, is as 46. to 45. that is,
+46. Ounces of the salt Water will take up no more room then 45. of the
+fresh. Or reciprocally 45 pints of salt-water weigh as much as 46 of fresh.
+
+But I found the proportion of Brine to fresh Water to be near 13 to 12:
+Supposing therefore GHM to represent the Sea, and FI the height of the
+Mountain above the Superficies of the Sea, FM a Cavern in the Earth,
+beginning at the bottom of the Sea, and terminated at the top of the
+Mountain, LM the Sand at the bottom, through which the Water is as it were
+strained, so as that the fresher parts are only permitted to transude, and
+the saline kept back; if therefore the proportion of G M to FM be as 45 to
+46, then may the Cylinder of Salt-water GM make the Cylinder of Fresh-water
+to rise as high as E, and to run over at N. I cannot here stand to examine
+or confute their Opinion, who make the depth of the Sea, below its
+Superficies, to be no more perpendicularly measured then the height of the
+Mountains above it: ’Tis enough for me to say, there is no one of those
+that have asserted it, have experimentally known the perpendicular of
+either; nor shall I here determine, whether there may not be many other
+causes of the separation of the fresh water from the salt, as perhaps some
+parts of the Earth through which it is to pass, may contain a Salt, that
+mixing and uniting with the Sea-salt, may precipitate it; much after the
+same manner as the _Alcalizate_ and _Acid Salts_ mix and precipitate each
+other in the preparation of _Tartarum Vitriolatum._ I know not also whether
+the exceeding cold (that must necessarily be) at the bottom of the Water,
+may not help towards this separation, for we find, that warm Water is able
+to dissolve and contain more Salt, then the same cold; insomuch that Brines
+strongly impregnated by heat, if let cool, do suffer much of their Salt to
+subside and crystallize about the bottom and sides. I know not also whether
+the exceeding pressure of the parts of the Water one against another, may
+not keep the Salt from descending to the very bottom, as finding little or
+no room to insert it self between those parts, protruded so violently
+together, or else squeeze it upwards into the superiour parts of the Sea,
+where it may more easily obtain room for it self, amongst the parts of the
+Water, by reason that there is more heat and less pressure. To this Opinion
+I was somewhat the more induced by the relations I have met with in
+_Geographical Writers_, of drawing fresh Water from the bottom of the Sea,
+which is salt above. I cannot now stand to examine, whether this natural
+perpetual motion may not artificially be imitated: Nor can I stand to
+answer the Objections which may be made against this my Supposition: As,
+First, How it comes to pass, that there are sometimes salt Springs much
+higher then the Superficies of the Water? And, Secondly, Why Springs do not
+run faster and slower, according to the varying height made of the Cylinder
+of Sea-water, by the ebbing and flowing of the Sea?
+
+As to the First, In short, I say, the fresh Water may receive again a
+saline Tincture near the Superficies of the Earth, by passing through some
+salt _Mines_, or else many of the saline parts of the Sea may be kept back,
+though not all.
+
+And as to the Second, The same _Spring_ may be fed and supplyed by divers
+_Caverns_, coming from very far distant parts of the _Sea_, so as that it
+may in one place be _high_, in another _low water_; and so by that means
+the _Spring_ may be equally supply’d at all times. Or else the _Cavern_ may
+be so straight and narrow, that the water not having so ready and free
+passage through it, cannot upon so short and quick mutations of pressure,
+be able to produce any sensible effect at such a distance. Besides that, to
+confirm this _hypothesis_, there are many _Examples_ found in _Natural
+Historians_, of _Springs_ that do ebb and flow like the Sea: As
+particularly, those recorded by the Learned _Camden_, and after him by
+_Speed_, to be found in this _Island_: One of which, they relate to be on
+the Top of a Mountain, by the small Village _Kilken_ in _Flintshire_,
+_Maris æmulus qui statis temporibus suas evomit & resorbet Aquas_; Which at
+certain times riseth and falleth after the manner of the Sea. A Second in
+_Caermardenshire_, near _Caermarden_, at a place called _Cantred Bichan_;
+_Qui (ut scribit Giraldus) naturali die bis undis deficiens, & toties
+exuberans, marinas imitatur instabilitates_; That twice in four and twenty
+hours ebbing and flowing; resembleth the unstable motions of the Sea. The
+_Phænomena_ of which two may be easily made out, by supposing the _Cavern_,
+by which they are fed, to arise from the bottom of the next Sea. A Third,
+is a Well upon the River _Ogmore_ in _Glamorganshire_, and near unto
+_Newton_, of which _Camden_ relates himself to be certified, by a Letter
+from a Learned Friend of his that observed it, _Fons abest hinc, &c._ The
+Letter is a little too long to be inserted, but the substance is this; That
+this Well ebbs and flows quite contrary to the flowing and ebbing of the
+Sea in those parts: for ’tis almost empty at Full Sea, but full at Low
+water. This may happen from the Channel by which it is supplied, which may
+come from the bottom of a Sea very remote from those parts, and where the
+Tides are much differing from those of the approximate shores. A Fourth,
+lies in _Westmorland_, near the River _Leder_; _Qui instar Euripi sæpius in
+die reciprocantibus undis fluit & refluit_, which ebbs and flows many times
+a day. This may proceed from its being supplyed from many Channels, coming
+from several parts of the Sea, lying sufficiently distant asunder to have
+the times of High water differing enough one from the other; so as that
+whensoever it shall be High water over any of those places, where these
+Channels begin, it shall likewise be so in the Well; but this is but a
+supposition.
+
+A Seventh _Query_ was, Whether the _dissolution_ or mixing of several
+bodies, whether fluid or solid, with saline or other Liquors, might not
+partly be attributed to this Principle of the congruity of those bodies and
+their dissolvents? As of Salt in Water, Metals in several _Menstruums_,
+Unctuous Gums in Oyls, the mixing of Wine and Water, &c. And whether
+_precipitation_ be not partly made from the same Principle of Incongruity?
+I say _partly_, because there are in some Dissolutions, some other Causes
+concurrent.
+
+I shall lastly make a much more seemingly strange and unlikely _Query_; and
+that is, Whether this Principle, well examined and explained, may not be
+found a _coefficient_ in the most considerable Operations of Nature? As in
+those of _Heat_, and _Light_, and consequently of _Rarefaction_ and
+_Condensation_, _Hardness_, and _Fluidness_, _Perspicuity_ and
+_Opacousness_, _Refractions_ and _Colours. &c._ Nay, I know not whether
+there may be many things done in Nature, in which this may not (be said to)
+have a Finger? This I have in some other passages of this Treatise further
+enquired into and shewn, that as well _Light_ as _Heat_ may be caused by
+_corrosion_, which is applicable to _congruity_, and consequently all the
+rest will be but _subsequents_: In the mean time I would not willingly be
+guilty of that _Error_, which the thrice Noble and Learned _Verulam_ justly
+takes notice of, as such, and calls _Philosophiæ Genus Empiricum, quod in
+paucorum Experimentorum Angustiis & Obscuritate fundatum est_. For I
+neither conclude from one single Experiment, nor are the Experiments I make
+use of all made upon one Subject: Nor wrest I any Experiment to make it
+_quadrare_ with any preconceiv’d Notion. But on the contrary, I endeavour
+to be conversant in divers kinds of Experiments, and all and every one of
+those Trials, I make the Standards or Touchstones, by which I try all my
+former Notions, whether they hold out in weight, and measure, and touch,
+&c. For as that Body is no other then a Counterfeit Gold, which wants any
+one of the Proprieties of Gold, (such as are the Malleableness, Weight,
+Colour, Fixtness in the Fire, Indissolubleness in _Aqua fortis_, and the
+like) though it has all the other; so will all those Notions be found to be
+false and deceitful, that will not undergo all the Trials and Tests made of
+them by Experiments. And therefore such as will not come up to the desired
+_Apex_ of Perfection, I rather wholly reject and take new, then by piecing
+and patching, endeavour to retain the old, as knowing such things at best
+to be but lame and imperfect. And this course I learned from Nature; whom
+we find neglectful of the old Body, and suffering its Decaies and
+Infirmities to remain without repair, and altogether sollicitous and
+careful of perpetuating the _Species_ by new _Individuals_. And it is
+certainly the most likely way to erect a glorious Structure and Temple to
+_Nature_, such as she will be found (by any _zealous Votary_) to reside in;
+to begin to build a new upon a sure Foundation of Experiments.
+
+But to digress no further from the consideration of the _Phænomena_, more
+immediately explicable by this Experiment, we shall proceed to shew, That,
+as to the rising of Water in a _Filtre_, the reason of it will be manifest
+to him, that does take notice, that a _Filtre_ is constituted of a great
+number of small long solid bodies, which lie so close together, that the
+Air in its getting in between them, doth lose of its pressure that it has
+against the _Fluid_ without them, by which means the Water or Liquor not
+finding so strong a resistance between them as is able to counter-ballance
+the pressure on its superficies without, is raised upward, till it meet
+with a pressure of the Air which is able to hinder it. And as to the Rising
+of Oyl, melted Tallow, Spirit of Wine, &c. in the Week of a Candle or Lamp,
+it is evident, that it differs in nothing from the former, save only in
+this, that in a _Filtre_ the Liquor descends and runs away by another part;
+and in the Week the Liquor is dispersed and carried away by the Flame;
+something there is ascribable to the Heat, for that it may rarifie the more
+volatil and spirituous parts of those combustible Liquors, and so being
+made lighter then the Air, it may be protruded upwards by that more
+ponderous fluid body in the Form of Vapours; but this can be ascribed to
+the ascension of but a very little, and most likely of that only which
+ascends without the Week. As for the Rising of it in a Spunge, Bread,
+Cotton, &c. above the superficies of the subjacent Liquor, what has been
+said about the _Filtre_ (if considered) will easily suggest a reason,
+considering that all these bodies abound with small holes or pores.
+
+From this same Principle also (_viz. the unequal pressure of the Air
+against the unequal superficies of the water_) proceeds the cause of the
+accession or incursion of any floating body against the sides of the
+containing Vessel; or the _appropinquation_ of two floating bodies, as
+_Bubbles_, _Corks_, _Sticks_, _Straws_, &c. one towards another. As for
+instance, Take a Glass jar, such as AB in the seventh _Figure_, and filling
+it pretty near the top with water, throw into it a small round piece of
+Cork, as C, and plunge it all over in water, that it be wet, so as that the
+water may rise up by the sides of it, then placing it any where upon the
+superficies, about an inch, or one inch and a quarter from any side, and
+you shall perceive it by degrees to make _perpendicularly_ toward the
+nearest part of the side, and the nearer it approaches, the faster to be
+moved, the reason of which _Phænomenon_ will be found no other then this,
+that the Air has a greater pressure against the middle of the
+_superficies_, then it has against those parts that approach nearer, and
+are _contiguous_ to the sides. Now that the pressure is greater, may (as I
+shewed before in the explication of the third _Figure_) be evinced from the
+flatting of the water in the middle, which arises from the gravity of the
+under _fluid_: for since, as I shewed before, if there were no gravity in
+the under _fluid_, or that it were equal to that of the upper, the
+terminating Surface would be _Spherical_, and since it is the additional
+pressure of the gravity of water that makes it so flat, it follows, that
+the pressure upon the middle must be greater then towards the sides. Hence
+the Ball having a stronger pressure against that side of it which respects
+the middle of the _superficies_, then against that which respects the
+_approximate_ side, must necessarily move towards that part, from whence it
+finds least resistance, and so be _accelerated_, as the resistance
+decrease. Hence the more the water is raised under that part of its way it
+is passing above the middle, the faster it is moved: And therefore you will
+find it to move faster in E then in D, and in D then in C. Neither could I
+find the floating substance to be moved at all, until it were placed upon
+some part of the _Superficies_ that was sensibly elevated above the height
+of the middle part. Now that this may be the true cause, you may try with a
+blown Bladder, and an exactly round Ball upon a very smooth side of some
+pliable body, as _Horn_ or _Quicksilver._ For if the Ball be placed under a
+part of the Bladder which is upon one side of the middle of its pressure,
+and you press strongly against the Bladder, you shall find the Ball moved
+from the middle towards the sides.
+
+Having therefore shewn the reason of the motion of any float towards the
+sides, the reason of the incursion of any two floating bodies will easily
+appear: For the rising of the water against the sides of either of them, is
+an Argument sufficient, to shew the pressure of the Air to be there less,
+then it is further from it, where it is not so much elevated; and therefore
+the reason of the motion of the other toward it, will be the same as
+towards the side of the Glass, only here from the same reason, they are
+mutually moved toward each other, whereas the side of the Glass in the
+former remains fixt. If also you gently fill the Jar so full with water,
+that the water is _protuberant_ above the sides, the same piece of Cork
+that before did hasten towards the sides, does now fly from it as fast
+towards the middle of the Superficies; the reason of which will be found no
+other then this, that the pressure of the Air is stronger against the sides
+of the Superficies G and H, then against the middle I; for since, as I
+shewed before, the Principle of congruity would make the terminating
+Surface Spherical, and that the flatting of the Surface in the middle is
+from the abatement of the waters pressure outwards, by the contrary
+indeavour of its gravity; it follows that the pressure in the middle must
+be less then on the sides; and therefore the consecution will be the same
+as in the former. It is very odd to one that considers not the reason of
+it, to see two floating bodies of wood to approach each other, as though
+they were indued with some magnetical vigour; which brings into my mind
+what I formerly tried with a piece of Cork or such like body, which I so
+ordered, that by putting a little stick into the same water, one part of
+the said Cork would approach and make toward the stick, whereas another
+would discede and fly away, nay it would have a kind of verticity, so as
+that if the _Æquator_ (as I may so speak) of the Cork were placed towards
+the stick, if let alone, it would instantly turn its appropriate Pole
+toward it, and then run a-tilt at it: and this was done only by taking a
+dry Cork, and wetting one side of it with one small stroak; for by this
+means gently putting it upon the water, it would depress the superficies on
+every side of it that was dry, and therefore the greatest pressure of the
+Air, being near those sides, caused it either to chase away, or else to fly
+off from any other floating body, whereas that side only, against which the
+water ascended, was thereby able to attract.
+
+It remains only, that I should determine how high the Water or other Liquor
+may by this means be raised in a smaller Pipe above the Superficies of that
+without it, and at what height it may be sustained: But to determine this,
+will be exceeding difficult, unless I could certainly know how much of the
+Airs pressure is taken off by the smalness of such and such a Pipe, and
+whether it may be wholly taken off, that is, whether there can be a hole or
+pore so small, into which Air could not at all enter, though water might
+with its whole force, for were there such, ’tis manifest, that the water
+might rise in it to some five or six and thirty English Foot high. I know
+not whether the capillary Pipes in the bodies of small Trees, which we call
+their _Microscopical pores_, may not be such; and whether the congruity of
+the sides of the Pore may not yet draw the juyce even higher then the Air
+was able by its bare pressure to raise it: For, Congruity is a principle
+that not only unites and holds a body joyned to it, but, which is more,
+attracts and draws a body that is very near it, and holds it above its
+usual height.
+
+And this is obvious even in a drop of water suspended under any Similar or
+Congruous body: For, besides the ambient pressure that helps to keep it
+sustein’d, there is the Congruity of the bodies that are contiguous. This
+is yet more evident in Tenacious and Glutinous bodies; such as Gummous
+Liquors, Syrups, Pitch, and Rosin melted, &c. Tar, Turpentine, Balsom,
+Birdlime, &c. for there it is evident, that the Parts of the tenacious
+body, as I may so call it, do stick and adhere so closely together, that
+though drawn out into long and very slender Cylinders, yet they will not
+easily relinquish one another; and this, though the bodies be _aliquatenus_
+fluid, and in motion by one another, which, to such as consider a fluid
+body only as its parts are in a confused irregular motion, without taking
+in also the congruity of the parts one among another, and incongruity to
+some other bodies, does appear not a little strange. So that besides the
+incongruity of the ambient fluid to it, we are to consider also the
+congruity of the parts of the contein’d fluid one with another.
+
+And this Congruity (that I may here a little further explain it) is both a
+Tenacious and an Attractive power; for the Congruity, in the Vibrative
+motions, may be the cause of all kind of attraction, not only Electrical,
+but Magnetical also, and therefore it may be also of Tenacity and
+Glutinousness. For, from a perfect congruity of the motions of two distant
+bodies, the intermediate fluid particles are separated and droven away from
+between them, and thereby those congruous bodies are, by the incompassing
+mediums, compell’d and forced neerer together; wherefore that
+attractiveness must needs be stronger, when, by an immediate contact, they
+are forc’d to be exactly the same: As I shew more at large in my _Theory_
+of the _Magnet_. And this hints to me the reason of the suspension of the
+_Mercury_ many inches, nay many feet, above the usual station of 30 inches.
+For the parts of _Quick-Silver_, being so very similar and congruous to
+each other, if once united, will not easily suffer a divulsion: And the
+parts of water, that were any wayes _heterogeneous_, being by _exantlation_
+or rarefaction exhausted, the remaining parts being also very similar, will
+not easily part neither. And the parts of the Glass being solid, are more
+difficultly disjoyn’d; and the water, being somewhat similar to both, is,
+as it were, a medium to unite both the _Glass_ and the _Mercury_ together.
+So that all three being united, and not very dissimilar, by means of this
+contact, if care be taken that the Tube in erecting be not shogged, the
+_Quicksilver_ will remain suspended, notwithstanding its contrary indeavour
+of Gravity, a great height above its ordinary Station; but if this
+immediate Contact be removed, either by a meer separation of them one from
+another by the force of a shog, whereby the other becomes imbodied between
+them, and licks up from the surface some agil parts, and so hurling them
+makes them air, or else by some small heterogeneous agil part of the Water,
+or Air, or Quicksilver, which appears like a bubble, and by its jumbling to
+and fro there is made way for the _heterogeneous Æther_ to obtrude it self
+between the Glass and either of the other Fluids, the Gravity of _Mercury
+precipitates_ it downward with very great violence; and if the Vessel that
+holds the restagnating _Mercury_ be convenient, the _Mercury_ will for a
+time _vibrate_ to and fro with very large _reciprocations_, and at last
+will remain kept up by the pressure of the external Air at the height of
+neer thirty inches. And whereas it may be objected, that it cannot be, that
+the meer imbodying of the _Æther_ between these bodies can be the cause,
+since the _Æther_ having a free passage alwayes, both through the Pores of
+the Glass, and through those of the Fluids, there is no reason why it
+should not make a separation at all times whilst it remains suspended, as
+when it is violently disjoyned by a shog. To this I answer, That though
+the _Æther_ passes between the Particles, that is, through the Pores of
+bodies, so as that any chasm or separation being made, it has infinite
+passages to admit its entry into it, yet such is the tenacity or attractive
+virtue of Congruity, that till it be overcome by the meer strength of
+Gravity, or by a shog assisting that Conatus of Gravity, or by an agil
+Particle, that is like a leaver agitated by the _Æther_; and thereby the
+parts of the congruous substances are separated so far asunder, that the
+strength of congruity is so far weakened, as not to be able to reunite
+them, the parts to be taken hold of being removed out of the attractive
+Sphere, as I may so speak, of the congruity; such, I say, is the tenacity
+of congruity, that it retains and holds the almost contiguous Particles of
+the Fluid, and suffers them not to be separated, till by meer force that
+attractive or retentive faculty be overcome: But the separation being once
+made beyond the Sphere of the attractive activity of congruity, that virtue
+becomes of no effect at all, but the _Mercury_ freely falls downwards till
+it meet with a resistance from the pressure of the _ambient_ Air, able to
+resist its gravity, and keep it forced up in the Pipe to the height of
+about thirty inches.
+
+Thus have I gently raised a Steel _pendulum_ by a Loadstone to a great
+Angle, till by the shaking of my hand I have chanced to make a separation
+between them, which is no sooner made, but as if the Loadstone had retained
+no attractive virtue, the _Pendulum_ moves freely from it towards the other
+side. So vast a difference is there between the attractive virtue of the
+_Magnet_ when it acts upon a contiguous and upon a disjoyned body: and much
+more must there be between the attractive virtues of congruity upon a
+contiguous and disjoyned body; and in truth the attractive virtue is so
+little upon a body disjoyned, that though I have with a _Microscope_
+observed very diligently, whether there were any extraordinary
+_protuberance_ on the side of a drop of water that was exceeding neer to
+the end of a green stick, but did not touch it, I could not perceive the
+least; though I found, that as soon as ever it toucht it the whole drop
+would presently unite it self with it; so that it seems an absolute contact
+is requisite to the exercising of the tenacious faculty of congruity.
+
+       *       *       *       *       *
+
+
+Observ. VII. _Of some _Phænomena_ of Glass drops._
+
+These _Glass Drops_ are small parcels of coarse green Glass taken out of
+the Pots that contain the _Metal_ (as they call it) in fusion, upon the end
+of an Iron Pipe; and being exceeding hot, and thereby of a kind of sluggish
+fluid Consistence, are suffered to drop from thence into a Bucket of cold
+Water, and in it to lye till they be grown sensibly cold.
+
+Some of these I broke in the open air, by snapping off a little of the
+small stem with my fingers, others by crushing it with a small pair of
+Plyers; which I had no sooner done, then the whole bulk of the drop flew
+violently, with a very brisk noise, into multitudes of small pieces, some
+of which were as small as dust, though in some there were remaining pieces
+pretty large, without any flaw at all, and others very much flaw’d, which
+by rubbing between ones fingers was easily reduced to dust; these dispersed
+every way so violently, that some of them pierced my skin. I could not find,
+either with my naked Eye, or a _Microscope_, that any of the broken pieces
+were of a regular figure, nor any one like another, but for the most part
+those that flaw’d off in large pieces were prettily branched.
+
+The ends of others of these drops I nipt off whilst all the bodies and ends
+of them lay buried under the water, which, like the former, flew all to
+pieces with as brisk a noise, and as strong a motion.
+
+Others of these I tried to break, by grinding away the blunt end, and
+though I took a seemingly good one, and had ground away neer two thirds of
+the Ball, yet would it not fly to pieces, but now and then some small rings
+of it would snap and fly off, not without a brisk noise and quick motion,
+leaving the Surface of the drop whence it flew very prettily branched or
+creased, which was easily discoverable by the _Microscope_. This drop,
+after I had thus ground it, without at all impairing the remnant that was
+not ground away, I caused to fly immediately all into sand upon the nipping
+off the very tip of its slender end.
+
+Another of these drops I began to grind away at the smaller end, but had
+not worn away on the stone above a quarter of an inch before the whole drop
+flew with a brisk crack into sand or small dust; nor would it have held so
+long, had there not been a little flaw in the piece that I ground away, as
+I afterwards found.
+
+Several others of these drops I covered over with a thin but very tuff skin
+of _Icthyocolla_, which being very tough and very transparent, was the most
+convenient substance for these tryals that I could imagine, having dipt, I
+say, several of these drops in this transparent Glue whilst hot, and
+suffering them to hang by a string tied about the end of them till they
+were cold, and the skin pretty tough; then wrapping all the body of the
+drop (leaving out only the very tip) in fine supple Kids-leather very
+closely, I nipped off the small top, and found, as I expected, that
+notwithstanding this skin of Glue, and the close wrapping up in Leather,
+upon the breaking of the top, the drop gave a crack like the rest, and gave
+my hand a pretty brisk impulse: but yet the skin and leather was so strong
+as to keep the parts from flying out of their former posture; and, the skin
+being transparent, I found that the drop retained exactly its former figure
+and polish, but was grown perfectly opacous and all over flaw’d, all those
+flaws lying in the manner of rings, from the bottom or blunt end, to the
+very top or small point. And by several examinations with a _Microscope_,
+of several thus broken, I found the flaws, both within the body of the
+drop, and on the outward surface, to lye much in this order.
+
+Let AB in the Figure X of the fourth Scheme represent the drop cased over
+with _Icthyocolla_ or _Isinglass_, (by being ordered as is before
+prescribed) crazed or flawed into pieces, but by the skin or case kept in
+its former figure, and each of its flawed parts preserved exactly in its
+due posture; the outward appearance of it somewhat plainly to the naked
+eye, but much more conspicuous if viewed with a small lens appeared much
+after this shape. That is, the blunt end B for a pretty breadth, namely, as
+far as the Ring CCC seemed irregularly flawed with divers clefts, which all
+seemed to tend towards the Center of it, being, as I afterwards found, and
+shall anon shew in the description of the figure Y, the Basis, as it were,
+of a Cone, which was terminated a little above the middle of the drop, all
+the rest of the Surface from CCC to A was flawed with an infinite number of
+small and parallel Rings, which as they were for the most part very round,
+so were they very thick and close together, but were not so exactly flaw’d
+as to make a perfect Ring, but each circular part was by irregular cracks
+flawed likewise into multitudes of irregular flakes or tiles; and this
+order was observed likewise the whole length of the neck.
+
+Now though I could not so exactly cut this _conical Body_ through the
+_Axis_, as is represented by the figure Y; yet by _anatomizing_, as it
+were, of several, and taking notice of divers particular circumstances, I
+was informed, that could I have artificially divided a flaw’d drop through
+the _Axis_ or _Center_, I should with a _Microscope_ have found it to
+appear much of this form, where A signifies the _Apex_, and B the blunt
+end, CC the Cone of the Basis, which is terminated at T the top or end of
+it, which seems to be the very middle of the blunt end in which, not only
+the conical body of the Basis CC is terminated, but as many of the parts of
+the drop as reach as high as DD.
+
+And it seemed to be the head or beginning of a Pith, as it were, or a part
+of the body which seemed more spungy then the rest, and much more
+irregularly flawed, which from T ascended by EE, though less visible, into
+the small neck towards A. The Grain, as it were, of all the flaws, that
+proceeds from all the outward Surface ADCCDA, was much the same, as is
+represented by the black strokes that meet in the middle DT, DT, DE, DE,
+&c.
+
+Nor is this kind of Grain, as I may call it, peculiar to Glass drops thus
+quenched; for (not to mention _Coperas-stones_, and divers other
+_Marchasites_ and _Minerals_, which I have often taken notice of to be in
+the very same manner flaked or grained, with a kind of Pith in the middle)
+I have observed the same in all manner of cast Iron, especially the coarser
+sort, such as Stoves, and Furnaces, and Backs, and Pots are made of: For
+upon the breaking of any of those Substances it is obvious to observe, how
+from the out-sides towards the middle, there is a kind of Radiation or
+Grain much resembling this of the Glass-drop; but this Grain is most
+conspicuous in Iron-bullets, if they be broken: the same _Phænomena_ may be
+produced by casting _regulus_ of _Antimony_ into a Bullet-mold, as also
+with _Glass of Antimony_, or with almost any such kind of _Vitrified
+substance_, either cast into a cold Mold or poured into Water.
+
+Others of these Drops I heat red hot in the fire, and then suffered them to
+cool by degrees. And these I found to have quite lost all their
+_fulminating_ or flying quality, as also their hard, brittle and springy
+texture; and to emerge of a much softer temper, and much easier to be
+broken or snapt with ones finger; but its strong and brittle quality was
+quite destroyed, and it seemed much of the same consistence with other
+green Glass well nealed in the Oven.
+
+The Figure and bigness of these for the most part was the same with that of
+the Figure Z; that is, all the surface of them was very smooth and polisht,
+and for the most part round, but very rugged or knobbed about D, and all
+the length of the stem was here and there pitted or flatted. About D, which
+is at the upper part of the drop under that side of the stem which is
+concave, there usually was made some one or more little Hillocks or
+Prominences. The drop it self, before it be broken, appears very
+transparent, and towards the middle of it, to be very full of small
+Bubbles, of some kind of aerial substance, which by the refraction of the
+outward surface appear much bigger then really they are; and this may be in
+good part removed, by putting the drop under the surface of clear Water,
+for by that means most part of the refraction of the convex Surface of the
+drop is destroyed, and the bubbles will appear much smaller. And this, by
+the by, minds me of the appearing magnitude of the _aperture_ of the
+_iris_, or _pupil_ of the eye, which though it appear, and be therefore
+judged very large, is yet not above a quarter of the bigness it appears of,
+by the _lenticular_ refraction of the _Cornea_.
+
+The cause of all which _Phænomena_ I imagine to be no other then this, That
+the Parts of the Glass being by the excessive heat of the fire kept off and
+separated one from another, and thereby put into a kind of sluggish fluid
+Consistence, are suffered to drop off with that heat or agitation remaining
+in them, into cold Water; by which means the outsides of the drop are
+presently cool’d and _crusted_, and are thereby made of a loose texture,
+because the parts of it have not time to settle themselves leisurely
+together, and so to lie very close together: And the innermost parts of the
+drop, retaining still much of their former heat and agitations, remain of a
+loose texture also, and, according as the cold strikes inwards from the
+bottom and sides, are quenched, as it were, and made rigid in that very
+posture wherein the cold finds them. For the parts of the _crust_ being
+already hardened, will not suffer the parts to shrink any more from the
+outward Surface inward; and though it shrink a little by reason of the
+small parcels of some Aerial substances dispersed through the matter of the
+Glass, yet that is not neer so much as it appears (as I just now hinted;)
+nor if it were, would it be sufficient for to consolidate and condense the
+body of Glass into a _tuff_ and close _texture_, after it had been so
+excessively rarified by the heat of the glass-Furnace.
+
+But that there may be such an expansion of the aerial substance contained
+in those little _blebbs_ or bubbles in the body of the drop, this following
+Experiment will make more evident.
+
+       *       *       *       *       *
+
+Take a small Glass-Cane about a foot long, seal up one end of it
+_hermetically_, then put in a very small bubble of Glass, almost of the
+shape of an Essence-viol with the open mouth towards the sealed end, then
+draw out the other end of the Pipe very small, and fill the whole Cylinder
+with water, then set this Tube by the Fire till the Water begin to boyl,
+and the Air in the bubble be in good part rarified and driven out, then by
+sucking at the smalling Pipe, more of the Air or vapours in the bubble may
+be suck’d out, so that it may sink to the bottom; when it is sunk to the
+bottom, in the flame of a Candle, or Lamp, nip up the slender Pipe and let
+it cool: whereupon it is obvious to observe, first, that the Water by
+degrees will subside and shrink into much less room: Next, that the Air or
+vapours in the Glass will expand themselves so, as to buoy up the little
+Glass: Thirdly, that all about the inside of the Glass-pipe there will
+appear an infinite number of small bubbles, which as the Water grows colder
+and colder will swell bigger and bigger, and many of them buoy themselves
+up and break at the top.
+
+From this _Disceding_ of the heat in Glass drops, that is, by the quenching
+or cooling Irradiations propagated from the Surface upwards and inwards, by
+the lines CT, CT, DT, DE, &c. the bubbles in the drop have room to expand
+themselves a little, and the parts of the Glass contract themselves; but
+this operation being too quick for the sluggish parts of the Glass, the
+contraction is performed very unequally and irregularly, and thereby the
+Particles of the Glass are bent, some one way, and some another, yet so as
+that most of them draw towards the Pith or middle TEEE, or rather from that
+outward: so that they cannot _extricate_ or unbend themselves, till some
+part of TEEE be broken and loosened, for all the parts about that are
+placed in the manner of an Arch, and so till their hold at TEEE be loosened
+they cannot fly asunder, but uphold, and shelter, and fix each other much
+like the stones in a Vault, where each stone does concurre to the stability
+of the whole Fabrick, and no one stone can be taken away but the whole Arch
+falls. And wheresoever any of those radiating wedges DTD, &c. are removed,
+which are the component parts of this Arch, the whole Fabrick presently
+falls to pieces; for all the Springs of the several parts are set at
+liberty, which immediately extricate themselves and fly asunder every way;
+each part by its spring contributing to the darting of it self and some
+other contiguous part. But if this drop be heat so hot as that the parts by
+degrees can unbend themselves, and be settled and annealed in that posture,
+and be then suffered gently to subside and cool; The parts by this nealing
+losing their springiness, constitute a drop of a more soft but less brittle
+texture, and the parts being not at all under a flexure, though any part of
+the middle or Pith TEEE be broken, yet will not the drop at all fly to
+pieces as before.
+
+This Conjecture of mine I shall indeavour to make out by explaining each
+particular Assertion with _analogous_ Experiments: The Assertions are
+these.
+
+    First, That the parts of the Glass, whilst in a fluid Consistence and
+    hot, are more rarified, or take up more room, then when hard and cold.
+
+    Secondly, That the parts of the drop do suffer a two-fold contraction.
+
+    Thirdly, That the dropping or quenching the glowing metal in the Water
+    makes it of a hard, springing, and rarified texture.
+
+    Fourthly, That there is a flexion or force remaining upon the parts of
+    the Glass thus quenched, from which they indeavour to extricate
+    themselves.
+
+    Fifthly, That the Fabrick of the drop, that is able to hinder the parts
+    from extricating themselves, is _analogus_ to that of an Arch.
+
+    Sixthly, That the sudden flying asunder of the parts proceeds from
+    their springiness.
+
+    Seventhly, That a gradual heating and cooling does anneal or reduce the
+    parts of Glass to a texture that is more loose, and easilier to be
+    broken, but not so brittle.
+
+That the first of these is true may be gathered from this, That _Heat is a
+property of a body arising from the motion or agitation of its parts_; and
+therefore whatever body is thereby toucht must necessarily receive some
+part of that motion, whereby its parts will be shaken and agitated, and so
+by degrees free and extricate themselves from one another, and each part so
+moved does by that motion _exert_ a _conatus_ of _protruding_ and
+displacing all the adjacent Particles. Thus Air included in a vessel, by
+being heated will burst it to pieces. Thus have I broke a Bladder held over
+the fire in my hand, with such a violence and noise, that it almost made me
+deaf for the present, and much surpassed the noise of a Musket: The like
+have I done by throwing into the fire small glass Bubbles hermetically
+sealed, with a little drop of Water included in them. Thus Water also, or
+any other Liquor, included in a convenient vessel, by being warmed,
+manifestly expands it self with a very great violence, so as to break the
+strongest vessel, if when heated it be narrowly imprisoned in it. This is
+very manifest by the _Sealed Thermometers_, which I have, by several
+tryals, at last brought to a great certainty and tenderness: for I have
+made some with stems above four foot long, in which the expanding Liquor
+would so far vary, as to be very neer the very top in the heat of Summer,
+and prety neer the bottom at the coldest time of the Winter. The Stems I
+use for them are very thick, straight, and even Pipes of Glass, with a very
+small _perforation_, and both the head and body I have made on purpose at
+the Glass-house, of the same metal whereof the Pipes are drawn: these I can
+easily in the flame of a Lamp, urged with the blast of a pair of Bellows,
+seal and close together, so as to remain very firm, close and even; by this
+means I joyn on the body first, and then fill both it and a part of the
+stem, proportionate to the length of the stem and the warmth of the season
+I fill it in with the best rectified _Spirit of Wine_ highly _ting’d_ with
+the lovely colour of _Cocheneel_, which I deepen the more by pouring some
+drops of common _Spirit of Urine_, which must not be too well rectified,
+because it will be apt to make the Liquor to curdle and stick in the small
+perforation of the stem. This Liquor I have upon tryal found the most
+tender of any spirituous Liquor, and those are much more sensibly affected
+with the variations of heat and cold then other more flegmatick and
+ponderous Liquors, and as capable of receiving a deep tincture, and keeping
+it, as any Liquor whatsoever; and (which makes it yet more acceptable) is
+not subject to be frozen by any cold yet known. When I have thus filled it,
+I can very easily in the forementioned flame of a Lamp seal and joyn on the
+head of it.
+
+Then, for graduating the stem, I fix that for the beginning of my division
+where the surface of the liquor in the stem remains when the ball is placed
+in common distilled water, that is so cold that it just begins to freeze
+and shoot into flakes; and that mark I fix at a convenient place of the
+stem, to make it capable of exhibiting very many degrees of cold, below
+that which is requisite to freeze water: the rest of my divisions, both
+above and below this (which I mark with a [0] or nought) I place according
+to the Degrees of _Expansion_, or _Contraction_ of the Liquor in proportion
+to the bulk it had when it indur’d the newly mention’d freezing cold. And
+this may be very easily and accurately enough done by this following way;
+Prepare a Cylindrical vessel of very thin plate Brass or Silver, ABCD of
+the figure Z; the Diameter AB of whose cavity let be about two inches, and
+the depth BC the same; let each end be cover’d with a flat and smooth plate
+of the same substance, closely soder’d on, and in the midst of the upper
+cover make a pretty large hole EF, about the bigness of a fifth part of the
+Diameter of the other; into this fasten very well with cement a straight
+and even Cylindrical pipe of Glass, EFGH, the Diameter of whose cavity let
+be exactly one tenth of the Diameter of the greater Cylinder. Let this pipe
+be mark’d at GH with a Diamant, so that G from E may be distant just two
+inches, or the same height with that of the cavity of the greater Cylinder,
+then divide the length EG exactly into 10 parts, so the capacity of the
+hollow of each of these divisions will be ¹⁄₁₀₀₀ part of the capacity of
+the greater Cylinder. This vessel being thus prepared, the way of marking
+and graduating the _Thermometers_ may be very easily thus performed:
+
+Fill this Cylindrical vessel with the same liquor wherewith the
+_Thermometers_ are fill’d, then place both it and the _Thermometer_ you are
+to _graduate_, in water that is ready to be frozen, and bring the surface
+of the liquor in the _Thermometer_ to the first marke or [0]; then so
+proportion the liquor in the Cylindrical vessel, that the surface of it may
+just be at the lower end of the small glass-Cylinder; then very gently and
+gradually warm the water in which both the _Thermometer_ and this
+Cylindrical vessel stand, and as you perceive the ting’d liquor to rise in
+both stems, with the point of a Diamond give several marks on the stem of
+the _Thermometer_ at those places, which by comparing the expansion in both
+Stems, are found to correspond to the divisions of the cylindrical vessel,
+and having by this means marked some few of these divisions on the Stem, it
+will be very easie by these to mark all the rest of the Stem, and
+accordingly to assign to every division a proper character.
+
+A _Thermometer_, thus marked and prepared, will be the fittest Instrument
+to make a Standard of heat and cold that can be imagined. For being sealed
+up, it is not at all subject to variation or wasting, nor is it liable to
+be changed by the varying pressure of the Air, which all other kind of
+_Thermometers_ that are open to the Air are liable to. But to proceed.
+
+This property of Expansion with Heat, and Contraction with Cold, is not
+peculiar to Liquors only, but to all kind of solid Bodies also, especially
+Metals, which will more manifestly appear by this Experiment.
+
+Take the Barrel of a Stopcock of Brass, and let the Key, which is well
+fitted to it, be riveted into it, so that it may slip, and be easily turned
+round, then heat this Cock in the fire, and you will find the Key so
+swollen, that you will not be able to turn it round in the Barrel; but if
+it be suffered to cool again, as soon as it is cold it will be as movable,
+and as easie to be turned as before.
+
+This Quality is also very observable in _Lead_, _Tin_, _Silver_,
+_Antimony_, _Pitch_, _Rosin_, _Bees-wax_, _Butter_, and the like; all
+which, if after they be melted you suffer gently to cool, you shall find
+the parts of the upper Surface to subside and fall inwards, losing that
+plumpness and smoothness it had whilst in fusion. The like I have also
+observed in the cooling of _Glass of Antimony_, which does very neer
+approach the nature of Glass,
+
+But because these are all Examples taken from other materials then Glass,
+and argue only, that possibly there may be the like property also in Glass,
+not that really there is; we shall by three or four Experiments indeavour
+to manifest that also.
+
+And the First is an Observation that is very obvious even in these very
+drops, to wit, that they are all of them terminated with an unequal or
+irregular Surface, especially about the smaller part of the drop, and the
+whole length of the stem; as about D, and from thence to A, the whole
+Surface, which would have been round if the drop had cool’d leisurely, is,
+by being quenched hastily, very irregularly flatted and pitted; which I
+suppose proceeds partly from the Waters unequally cooling and pressing the
+parts of the drop, and partly from the self-contracting or subsiding
+quality of the substance of the Glass: For the vehemency of the heat of the
+drop causes such hidden motions and bubbles in the cold Water, that some
+parts of the Water bear more forcibly against one part then against
+another, and consequently do more suddenly cool those parts to which they
+are contiguous.
+
+A Second Argument may be drawn from the Experiment of cutting Glasses with
+a hot Iron. For in that Experiment the top of the Iron heats, and thereby
+rarifies the parts of the Glass that lie just before the crack, whence each
+of those agitated parts indeavouring to expand its self and get elbow-room,
+thrusts off all the rest of the contiguous parts, and consequently promotes
+the crack that was before begun.
+
+A Third Argument may be drawn from the way of producing a crack in a sound
+piece or plate of Glass, which is done two wayes, either First, by suddenly
+heating a piece of Glass in one place more then in another. And by this
+means _chymists_ usually cut off the necks of Glass-bodies, by two kinds of
+Instruments, either by a glowing hot round Iron-Ring, which just
+incompasses the place that is to be cut, or else by a _Sulphur’d_ Threed,
+which is often wound about the place where the separation is to be made,
+and then fired. Or Secondly, A Glass may be cracked by cooling it suddenly
+in any place with Water, or the like, after it has been all leisurely and
+gradually heated very hot. Both which _Phænomena_ seem manifestly to
+proceed from the _expansion_ and contraction of the parts of the Glass,
+which is also made more probable by this circumstance which I have
+observed, that a piece of common window-glass being heated in the middle
+very suddenly with a live Coal or hot Iron, does usually at the first crack
+fall into pieces, whereas if the Plate has been gradually heated very hot,
+and a drop of cold Water and the like be put on the middle of it, it only
+flaws it, but does not break it asunder immediately.
+
+A Fourth Argument may be drawn from this Experiment; Take a Glass-pipe, and
+fit into a solid stick of Glass, so as it will but just be moved in it.
+Then by degrees heat them whilst they are one within another, and they will
+grow stiffer, but when they are again cold, they will be as easie to be
+turned as before. This Expansion of Glass is more manifest in this
+Experiment.
+
+Take a stick of Glass of a considerable length, and fit it so between the
+two ends or screws of a Lath, that it may but just easily turn, and that
+the very ends of it may be just toucht and susteined thereby; then applying
+the flame of the Candle to the middle of it, and heating it hot, you will
+presently find the Glass to stick very fast on those points, and not
+without much difficulty to be convertible on them, before that by removing
+the flame for a while from it, it be suffered to cool, and when you will
+find it as easie to be turned round as at the first.
+
+From all which Experiments it is very evident, that all those Bodies, and
+particularly Glass, suffers an Expansion by Heat, and that a very
+considerable one, whilst they are in a state of Fusion. For _Fluidity_, as
+I elsewhere mention, _being nothing but an effect of very strong and quick
+shaking motion, whereby the parts are, as it were, loosened from each
+other, and consequently leave an interjacent space or vacuity_; it follows,
+that all those shaken Particles must necessarily take up much more room
+then when they were at rest, and lay quietly upon each other. And this is
+further confirmed by a Pot of _boyling Alabaster_, which will manifestly
+rise a sixth or eighth part higher in the Pot, whilst it is boyling, then
+it will remain at, both before and after it be boyled. The reason of which
+odd _Phænomenon_ (to hint it here only by the way) is this, that there is
+in the curious powder of Alabaster, and other calcining Stones, a certain
+watery substance, which is so fixt and included with the solid Particles,
+that till the heat be very considerable they will not fly away; but after
+the heat is increased to such a degree, they break out every way in
+vapours, and thereby so shake and loosen the small corpuscles of the Powder
+from each other, that they become perfectly of the nature of a fluid body,
+and one may move a stick to and fro through it, and stir it as easily as
+water, and the vapours burst and break out in bubbles just as in boyling
+water, and the like; whereas, both before those watery parts are flying
+away, and after they are quite gone; that is, before and after it have done
+boyling, all those effects cease, and a stick is as difficultly moved to
+and fro in it as in sand, or the like. Which Explication I could easily
+prove, had I time; but this is not a fit place for it.
+
+To proceed therefore, I say, that the dropping of this expanded Body into
+cold Water, does make the parts of the Glass suffer a double contraction:
+The first is, of those parts which are neer the Surface of the Drop. For
+Cold, as I said before, contracting Bodies, that is, _by the abatement of
+the agitating faculty the parts falling neerer together_; the parts next
+adjoyning to the Water must needs lose much of their motion, and impart it
+to the Ambient water (which the Ebullition and commotion of it manifests)
+and thereby become a solid and hard crust, whilst the innermost parts
+remain yet fluid and expanded; whence, as they grow cold also by degrees,
+their parts must necessarily be left at liberty to be condensed, but
+because of the hardness of the outward crust, the contraction cannot be
+admitted that way; but there being many very small, and before
+inconspicuous, bubbles in the substance of the Glass, upon the subsiding of
+the parts of the Glass, the agil substance contained in them has liberty of
+expanding it self a little, and thereby those bubbles grow much bigger,
+which is the second Contraction. And both these are confirmed from the
+appearance of the Drop it self: for as for the outward parts, we see,
+first, that it is irregular and shrunk, as it were, which is caused by the
+yielding a little of the hardened Skin to a Contraction, after the very
+outmost Surface is settled; and as for the internal parts, one may with
+ones naked Eye perceive abundance of very conspicuous bubbles, and with the
+_Microscope_ many more.
+
+The Consideration of which Particulars will easily make the Third Position
+probable, that is, that the parts of the drop will be of a very hard,
+though of a rarified Texture; for if the outward parts of the Drop, by
+reason of its hard crust, will indure very little Contraction, and the agil
+Particles, included in those bubbles, by the losing of their agitation, by
+the decrease of the Heat, lose also most part of their Spring and Expansive
+power; it follows (the withdrawing of the heat being very sudden) that the
+parts must be left in a very loose Texture, and by reason of the
+implication of the parts one about another, which from their sluggishnes
+and glutinousness I suppose to be much after the manner of the sticks in a
+Thorn-bush, or a Lock of Wool; it will follow, I say, that the parts will
+hold each other very strongly together, and indeavour to draw each other
+neerer together, and consequently their Texture must be very hard and
+stiff, but very much rarified.
+
+And this will make probable my next Position, That _the parts of the Glass
+are under a kind of tension or flexure, out of which they indeavour to
+extricate and free themselves_, and thereby all the parts draw towards the
+Center or middle, and would, if the outward parts would give way, as they
+do when the outward parts cool leisurely (as in baking of Glasses) contract
+the bulk of the drop into a much less compass. For since, as I proved
+before, the Internal parts of the drop, when fluid, were of a very rarified
+Texture, and, as it were, tos’d open like a Lock of Wool, and if they were
+suffered leisurely to cool, would be again prest, as it were, close
+together: And since that the heat, which kept them bended and open, is
+removed, and yet the parts not suffered to get as neer together as they
+naturally would; It follows, that the Particles remain under a kind of
+_tension_ and _flexure_, and consequently have an indeavour to free
+themselves from that _bending_ and _distension_, which they do, as soon as
+either the tip be broken, or as soon as by a leisurely heating and cooling,
+the parts are nealed into another posture.
+
+And this will make my next Position probable, that _the parts of the Glass
+drops are contignated together in the form of an Arch_, cannot any where
+yield or be drawn inwards, till by the removing of some one part of it (as
+it happens in the removing one of the stones of an Arch) the whole Fabrick
+is shatter’d, and falls to pieces, and each of the Springs is left at
+liberty, suddenly to extricate it self: for since I have made it probable,
+that the internal parts of the Glass have a contractive power inwards, and
+the external parts are incapable of such a Contraction, and the figure of
+it being spherical; it follows, that the superficial parts must bear
+against each other, and keep one another from being condens’d into a less
+room, in the same manner as the stones of an Arch conduce to the upholding
+each other in that Figure. And this is made more probable by another
+Experiment which was communicated to me by an excellent Person, whose
+extraordinary Abilities in all kind of Knowledg, especially in that of
+Natural things, and his generous Disposition in communicating, incouraged
+me to have recourse to him on many occasions. The Experiment was this:
+Small Glass-balls (about the bigness of that represented in the _Figure
+&._) would, upon rubbing or scratching the inward Surface, fly all
+insunder, with a pretty brisk noise; whereas neither before nor after the
+inner Surface had been thus scratcht, did there appear any flaw or crack.
+And putting the pieces of one of those broken ones together again, the
+flaws appeared much after the manner of the black lines on the Figure, _&._
+These Balls were small, but exceeding thick bubbles of Glass, which being
+crack’d off from the _Puntilion_ whilst very hot, and so suffered to cool
+without nealing them in the Oven over the Furnace, do thereby (being made
+of white Glass, which cools much quicker then green Glass, and is thereby
+made much brittler) acquire a very _porous_ and very brittle _texture_: so
+that if with the point of a Needle or Bodkin, the inside of any of them be
+rubbed prety hard, and then laid on a Table, it will, within a very little
+while, break into many pieces with a brisk noise, and throw the parts above
+a span asunder on the Table: Now though the pieces are not so small as
+those of a _fulminating_ drop, yet they as plainly shew, that the outward
+parts of the Glass have a great _Conatus_ to fly asunder, were they not
+held together by the _tenacity_ of the parts of the inward Surface: for we
+see as soon as those parts are crazed by hard rubbing, and thereby their
+tenacity spoiled, the springiness of the more outward parts quickly makes a
+divulsion, and the broken pieces will, if the concave Surface of them be
+further scratcht with a Diamond, fly again into smaller pieces.
+
+From which preceding considerations it will follow Sixthly, That the sudden
+flying asunder of the parts as soon as this Arch is any where disordered or
+broken, proceeds from the springing of the parts; which, indeavouring to
+_extricate_ themselves as soon as they get the liberty, they perform it
+with such a quickness, that they throw one another away with very great
+violence: for the Particles that compose the Crust have a _Conatus_ to lye
+further from one another, and therefore as soon as the external parts are
+loosened they dart themselves outward with great violence, just as so many
+Springs would do, if they were detained and fastened to the body, as soon
+as they should be suddenly loosened; and the internal parts drawing inward,
+they contract so violently; that they rebound back again and fly into
+multitude of small shivers or sands. Now though they appear not, either to
+the naked Eye, or the _Microscope_, yet I am very apt to think there may be
+abundance of small flaws or cracks, which, by reason the strong reflecting
+Air is not got between the _contiguous_ parts, appear not. And that this
+may be so, I argue from this, that I have very often been able to make a
+crack or flaw, in some convenient pieces of Glass, to appear and disappear
+at pleasure, according as by pressing together, or pulling asunder the
+contiguous parts, I excluded or admitted the strong reflecting Air between
+the parts: And it is very probable, that there may be some Body, that is
+either very rarified Air, or something _analogous_ to it, which fills the
+bubbles of these drops; which I argue, first, from the roundness of them,
+and next, from the vivid reflection of Light which they exhibite: Now
+though I doubt not, but that the Air in them is very much rarified, yet
+that there is some in them, to such as well consider this Experiment of the
+disappearing of a crack upon the _extruding_ of the Air, I suppose it will
+seem more then probable.
+
+The Seventh and last therefore that I shall prove, is, _That the gradual
+heating and cooling of these so extended bodies does reduce the parts of
+the Glass to a looser and softer temper_. And this I found by heating them,
+and keeping them for a prety while very red hot in a fire; for thereby I
+found them to grow a little lighter, and the small Stems to be very easily
+broken and snapt any where, without at all making the drop fly; whereas
+before they were so exceeding hard, that they could not be broken without
+much difficulty; and upon their breaking the whole drop would fly in pieces
+with very great violence. The Reason of which last seems to be, that the
+leisurely heating and cooling of the parts does not only wast some part of
+the Glass it self, but ranges all the parts into a better order, and gives
+each Particle an opportunity of _relaxing_ its self, and consequently
+neither will the parts hold so strongly together as before, nor be so
+difficult to be broken: The parts now more easily yielding, nor will the
+other parts fly in pieces, because the parts have no bended Springs. The
+_relaxation_ also in the temper of hardned Steel, and hammered Metals, by
+nealing them in the fire, seems to proceed from much the same cause. For
+both by quenching suddenly such Metals as have _vitrified_ parts
+interspers’d, as Steel has, and by hammering of other kinds that do not so
+much abound with them, as Silver, Brass, &c. the parts are put into and
+detained in a bended posture, which by the agitation of Heat are shaken,
+and loosened, and suffered to unbend themselves.
+
+       *       *       *       *       *
+
+
+Observ. VIII. _Of the fiery Sparks struck from a Flint or Steel._
+
+It is a very common Experiment, by striking with a Flint against a Steel,
+to make certain fiery and shining Sparks to fly out from between those two
+compressing Bodies. About eight years since, upon casually reading the
+Explication of this odd _Phænomenon_, by the most Ingenious _Des Cartes_, I
+had a great desire to be satisfied, what that Substance was that gave such
+a shining and bright Light: And to that end I spread a sheet of white
+Paper, and on it, observing the place where several of these Sparks seemed
+to vanish, I found certain very small, black, but glistering Spots of a
+movable Substance, each of which examining with my _Microscope_, I found to
+be a small round _Globule_; some of which, as they looked prety small, so
+did they from their Surface yield a very bright and strong reflection on
+that side which was next the Light; and each look’d almost like a prety
+bright Iron-Ball, whose Surface was prety regular, such as is represented
+by the Figure A. In this I could perceive the Image of the Window prety
+well, or of a Stick, which I moved up and down between the Light and it.
+Others I found, which were, as to the bulk of the Ball, prety regularly
+round, but the Surface of them, as it was not very smooth, but rough, and
+more irregular, so was the reflection from it more faint and confused. Such
+were the Surfaces of B. C. D. and E. Some of these I found cleft or
+cracked, as C, others quite broken in two and hollow, as D. which seemed to
+be half the hollow shell of a Granado, broken irregularly in pieces.
+Several others I found of other shapes; but that which is represented by E,
+I observed to be a very big Spark of fire, which went out upon one side of
+the Flint that I struck fire withall, to which it stuck by the root F, at
+the end of which small Stem was fastened-on a _Hemisphere_, or half a
+hollow Ball, with the mouth of it open from the stemwards, so that it
+looked much like a Funnel, or an old fashioned Bowl without a foot. This
+night, making many tryals and observations of this Experiment, I met, among
+a multitude of the Globular ones which I had observed, a couple of
+Instances, which are very remarkable to the confirmation of my
+_Hypothesis_.
+
+And the First was of a pretty big Ball fastened on to the end of a small
+sliver of Iron, which _Compositum_ seemed to be nothing else but a long
+thin chip of Iron, one of whose ends was melted into a small round Globul;
+the other end remaining unmelted and irregular, and perfectly Iron.
+
+The Second Instance was not less remarkable then the First; for I found,
+when a Spark went out, nothing but a very small thin long sliver of Iron or
+Steel, unmelted at either end. So that it seems, that some of these Sparks
+are the slivers or chips of the Iron _vitrified_, Others are only the
+slivers melted into Balls without vitrification, And the third kind are
+only small slivers of the Iron, made red-hot with the violence of the
+stroke given on the Steel by the Flint.
+
+He that shall diligently examine the _Phænomena_ of this Experiment, will,
+I doubt not, find cause to believe, that the reason I have heretofore given
+of it, is the true and genuine cause of it, namely, That _the Spark,
+appearing so bright in the falling, is nothing else but a small piece of
+the Steel or Flint, but most commonly of the Steel, which by the violence
+of the stroke is at the same time sever’d and heat red-hot, and that
+sometimes to such a degree, as to make it melt together into a small
+Globule of Steel; and sometimes also is that heat so very intense, as
+further to melt it and vitrifie it; but many times the heat is so gentle,
+as to be able to make the sliver only red hot, which notwithstanding
+falling upon the tinder_ (that is only a very curious small Coal made of
+the small threads of Linnen burnt to coals and char’d) _it easily sets it
+on fire_. Nor will any part of this _Hypothesis_ seem strange to him that
+considers, First, that either hammering, or filing or otherwise violently
+rubbing of Steel, will presently make it so hot as to be able to burn ones
+fingers. Next, that the whole force of the stroke is exerted upon that
+small part where the Flint and Steel first touch: For the Bodies being each
+of them so very hard, the puls cannot be far communicated, that is, the
+parts of each can yield but very little, and therefore the violence of the
+concussion will be _exerted_ on that piece of Steel which is cut off by the
+Flint. Thirdly, that the filings or small parts of Steel are very apt, as
+it were, to take fire, and are presently red hot, that is, there seems to
+be a very _combustible sulphureous_ Body in Iron or Steel, which the Air
+very readily preys upon, as soon as the body is a little violently heated.
+
+And this is obvious in the filings of Steel or Iron cast through the flame
+of a Candle; for even by that sudden _transitus_ of the small chips of
+Iron, they are heat red hot, and that _combustible sulphureous_ Body is
+presently prey’d upon and devoured by the _aereal_ incompassing
+_Menstruum_, whose office in this Particular I have shewn in the
+Explication of Charcole.
+
+And in prosecution of this Experiment, having taken the filings of Iron and
+Steel, and with the point of a Knife cast them through the flame of a
+Candle, I observed where some conspicuous shining Particles fell, and
+looking on them with my _Microscope_, I found them to be nothing else but
+such round Globules, as I formerly found the Sparks struck from the Steel
+by a stroke to be, only a little bigger; and shaking together all the
+filings that had fallen upon the sheet of Paper underneath and observing
+them with the _Microscope_, I found a great number of small Globules, such
+as the former, though there were also many of the parts that had remained
+untoucht and rough filings or chips of Iron. So that, it seems, Iron does
+contain a very _combustible sulphureous_ Body, which is, in all likelihood,
+one of the causes of this _Phænomenon_, and which may be perhaps very much
+concerned in the business of its hardening and tempering: of which somewhat
+is said in the Description of _Muscovy-glass_.
+
+So that, these things considered, we need not trouble our selves to find
+out what kind of Pores they are, both in the Flint and Steel, that contain
+the _Atoms of fire_, nor how those _Atoms_ come to be hindred from running
+all out, when a dore or passage in their Pores is made by the concussion:
+nor need we trouble our selves to examine by what _Prometheus_ the Element
+of Fire comes to be fetcht down from above the Regions of the Air, in what
+Cells or Boxes it is kept, and what _Epimetheus_ lets it go: Nor to
+consider what it is that causes so great a conflux of the atomical
+Particles of Fire, which are said to fly to a flaming Body, like Vultures
+or Eagles to a putrifying Carcass, and there to make a very great pudder.
+Since we have nothing more difficult in this _Hypothesis_ to conceive,
+first, as to the kindling of Tinder, then how a large Iron-bullet, let fall
+red or glowing hot upon a heap of Small-coal, should set fire to those that
+are next to it first: Nor secondly, is this last more difficult to be
+explicated, then that a Body, as Silver for Instance, put into a weak
+_Menstruum_, as unrectified _Aqua fortis_ should, when it is put in a great
+heat, be there dissolved by it, and not before; which _Hypothesis_ is more
+largely explicated in the Description of Charcoal. To conclude, we see by
+this Instance, how much Experiments may conduce to the regulating of
+_Philosophical notions_. For if the most Acute _Des Cartes_ had applied
+himself experimentally to have examined what substance it was that caused
+that shining of the falling Sparks struck from a Flint and a Steel, he
+would certainly have a little altered his _Hypothesis_, and we should have
+found, that his Ingenious Principles would have admitted a very plausible
+Explication of this _Phænomenon_; whereas by not examining so far as he
+might, he has set down an Explication which Experiment do’s contradict.
+
+But before I leave this Description, I must not forget to take notice of
+the Globular form into which each of these is most curiously formed. And
+this _Phænomenon_, as I have elsewhere more largely shewn, proceeds from a
+propriety which belongs to all kinds of fluid Bodies more or less, and is
+caused by the Incongruity of the Ambient and included Fluid, which so acts
+and modulates each other, that they acquire, as neer as is possible, a
+_spherical_ or _globular_ form, which propriety and several of the
+_Phænomena_ that proceed from it, I have more fully explicated in the sixth
+Observation.
+
+One Experiment, which does very much illustrate my present Explication, and
+is in it self exceeding pretty, I must not pass by: And that is a way of
+making small _Globules_ or _Balls_ of Lead, or Tin, as small almost as
+these of Iron or Steel, and that exceeding easily and quickly, by turning
+the filings or chips of those Metals also into perfectly round _Globules_.
+The way, in short, as I received it from the _Learned Physitian Doctor_
+I.G. is this;
+
+Reduce the Metal you would thus shape, into exceeding fine filings, the
+finer the filings are, the finer will the Balls be: _Stratifie_ these
+filings with the fine and well dryed powder of quick Lime in a _Crucible_
+proportioned to the quantity you intend to make: When you have thus filled
+your _Crucible_, by continual _stratifications_ of the filings and powder,
+so that, as neer as may be, no one of the filings may touch another, place
+the _Crucible_ in a _gradual fire_, and by degrees let it be brought to a
+heat big enough to make all the filings, that are mixt with the quick Lime,
+to melt, and no more; for if the fire be too hot, many of these filings
+will joyn and run together; whereas if the heat be proportioned, upon
+washing the Lime-dust in fair Water, all those small filings of the Metal
+will subside to the bottom in a most curious powder, consisting all of
+exactly round _Globules_, which, if it be very fine, is very excellent to
+make Hour-glasses of.
+
+Now though quick Lime be the powder that this direction makes choice of,
+yet I doubt not, but that there may be much more convenient ones found out,
+one of which I have made tryal of, and found very effectual; and were it
+not for discovering, by the mentioning of it, another Secret, which I am
+not free to impart, I should have here inserted it.
+
+       *       *       *       *       *
+
+
+Observ. IX. _Of the Colours observable in Muscovy-Glass, and other thin
+Bodies_.
+
+Moscovy-glass, or _Lapis specularis_, is a Body that seems to have as many
+Curiosities in its Fabrick as any common Mineral I have met with: for
+first, It is transparent to a great thickness: Next, it is compounded of an
+infinite number of thin flakes joyned or generated one upon another so
+close & smooth, as with many hundreds of them to make one smooth and thin
+Plate of a transparent flexible substance, which with care and diligence
+may be slit into pieces so exceedingly thin as to be hardly perceivable by
+the eye, and yet even those, which I have thought the thinnest, I have with
+a good _Microscope_ found to be made up of many other Plates, yet thinner;
+and it is probable, that, were our _Microscopes_ much better, we might much
+further discover its divisibility. Nor are these flakes only regular as to
+the smoothness of their Surfaces, but thirdly, In many Plates they may be
+perceived to be terminated naturally with edges of the figure of a
+_Rhomboeid_. This Figure is much more conspicuous in our English talk, much
+whereof is found in the Lead Mines, and is commonly called _Spar_, and
+_Kauck_, which is of the same kind of substance with the _Selenitis_, but
+is seldom found in so large flakes as that is, nor is it altogether so
+tuff, but is much more clear and transparent, and much more curiously
+shaped, and yet may be cleft and flak’d like the other _Selenitis_. But
+fourthly, this stone has a property, which in respect of the _Microscope_,
+is more notable, and that is, that it exhibits several appearances of
+Colours, both to the naked Eye, but much more conspicuously to the
+_Microscope_; for the exhibiting of which, I took a piece of
+_Muscovy-glass_, and splitting or cleaving it into thin Plates, I found
+that up and down in several parts of them I could plainly perceive several
+white specks or flaws, and others diversly coloured with all the Colours of
+the _Rainbow_; and with the _Microscope_ I could perceive, that these
+Colours were ranged in rings that incompassed the white speck or flaw, and
+were round or irregular, according to the shape of the spot which they
+terminated; and the position of Colours, in respect of one another, was the
+very same as in the _Rainbow_. The consecution of those Colours from the
+middle of the spot outward being Blew, Purple, Scarlet, Yellow, Green;
+Blew, Purple, Scarlet, and so onwards, sometimes half a score times
+repeated, that is, there appeared six, seven, eight, nine or ten several
+coloured rings or lines, each incircling the other, in the same manner as I
+have often seen a very _vivid Rainbow_ to have four or five several Rings
+of Colours, that is, accounting all the Gradations between Red and Blew for
+one: But the order of the Colours in these Rings was quite contrary to the
+primary or innermost _Rainbow_, and the same with those of the secondary or
+outermost Rainbow; these coloured Lines or _Irises_, as I may so call them,
+were some of them much brighter then others, and some of them also very
+much broader, they being some of them ten, twenty, nay, I believe, neer a
+hundred times broader then others; and those usually were broadest which
+were neerest the center or middle of the flaw. And oftentimes I found, that
+these Colours reacht to the very middle of the flaw, and then there
+appeared in the middle a very large spot, for the most part, all of one
+colour, which was very vivid, and all the other Colours incompassing it,
+gradually ascending, and growing narrower towards the edges, keeping the
+same order, as in the _secundary Rainbow_, that is, if the middle were
+Blew, the next incompassing it would be a Purple, the third a Red, the
+fourth a Yellow, &c. as above; if the middle were a Red, the next without
+it would be a Yellow, the third a Green, the fourth a Blew, and so onward.
+And this order it alwayes kept whatsoever were the middle Colour.
+
+There was further observable in several other parts of this Body, many
+Lines or Threads, each of them of some one peculiar Colour, and those so
+exceedingly bright and vivid, that it afforded a very pleasant object
+through the _Microscope_. Some of these _threads_ I have observed also to
+be pieced or made up of several short lengths of differently coloured
+_ends_ (as I may so call them) as a line appearing about two inches long
+through the _Microscope_, has been compounded of about half an inch of a
+Peach colour, ⅛ of a lovely Grass-green, ¾ of an inch more of a bright
+Scarlet, and the rest of the line of a Watchet blew. Others of them were
+much otherwise coloured; the variety being almost infinite. Another thing
+which is very observable, is, that if you find any place where the colours
+are very broad and conspicuous to the naked eye, you may, by pressing that
+place with your finger, make the colours change places, and go from one
+part to another.
+
+There is one _Phænomenon_ more, which may, if care be used, exhibit to the
+beholder, as it has divers times to me, an exceeding pleasant, and not less
+instructive Spectacle; And that is, if curiosity and diligence be used, you
+may so split this admirable Substance, that you may have pretty large
+Plates (in companion of those smaller ones which you may observe in the
+Rings) that are perhaps an ⅛ or a ⅙ part of an inch over, each of them
+appearing through the _Microscope_ most curiously, intirely, and uniformly
+adorned with some one vivid colour: this, if examined with the
+_Microscope_, may be plainly perceived to be in all parts of it equally
+thick. Two, three, or more of these lying one upon another, exhibit
+oftentimes curious compounded colours, which produce such a _Compositum_,
+as one would scarce imagine should be the result of such _ingredients_: As
+perhaps a _faint yellow_ and a _blew_ may produce a very _deep purple_. But
+when anon we come to the more strict examination of these _Phænomena_, and
+to inquire into the causes and reasons of these productions, we shall, I
+hope, make it more conceivable how they are produced, and shew them to be
+no other then the natural and necessary effects arising from the peculiar
+union of concurrent causes.
+
+These _Phænomena_, being so various, and so truly admirable, it will
+certainly be very well worth our inquiry, to examine the causes and reasons
+of them, and to consider, whether from these causes demonstratively
+evidenced, may not be deduced the true causes of the production of all kind
+of Colours. And I the rather now do it, instead of an Appendix or
+Digression to this History, then upon the occasion of examining the Colours
+in Peacocks, or other Feathers, because this Subject, as it does afford
+more variety of particular Colours, so does it afford much better wayes of
+examining each circumstance. And this will be made manifest to him that
+considers, first, that this laminated body is more simple and regular then
+the parts of Peacocks feathers, this consisting only of an indefinite
+number of plain and smooth Plates, heaped up, or _incumbent_ on each other.
+Next, that the parts of this body are much more manageable, to be divided
+or joyned, then the parts of a Peacocks feather, or any other substance
+that I know. And thirdly, because that in this we are able from a
+colourless body to produce several coloured bodies, affording all the
+variety of Colours imaginable: And several others, which the subsequent
+Inquiry will make manifest.
+
+To begin therefore, it is manifest from several circumstances, that the
+material cause of the _apparition_ of these several Colours, is some
+_Lamina_ or Plate of a transparent or pellucid body of a thickness very
+determinate and proportioned according to the greater or less refractive
+power of the _pellucid_ body. And that this is so, abundance of Instances
+and particular Circumstances will make manifest.
+
+As _first_, if you take any small piece of the _Muscovy-glass_, and with a
+Needle, or some other convenient Instrument, cleave it oftentimes into
+thinner and thinner _Laminæ_, you shall find, that till you come to a
+determinate thinness of them, they shall all appear transparent and
+colourless, but if you continue to split and divide them further, you shall
+find at last, that each Plate, after it comes to such a determinate
+thickness, shall appear most lovely ting’d or imbued with a determinate
+colour. If _further_, by any means you so flaw a pretty thick piece, that
+one part does begin to cleave a little from the other, and between those
+two there be by any means gotten some pellucid _medium_, those _laminated_
+pellucid bodies that fill that space, shall exhibit several Rainbows or
+coloured Lines, the colours of which will be disposed and ranged according
+to the various thicknesses of the several parts of that Plate. That this is
+so, is yet _further_ confirmed by this Experiment.
+
+Take two small pieces of ground and polisht Looking-glass-plate, each about
+the bigness of a shilling, take these two dry, and with your fore-fingers
+and thumbs press them very hard and close together, and you shall find,
+that when they approach each other very near, there will appear several
+_Irises_ or coloured Lines, in the same manner almost as in the
+_Muscovy-glass_; and you may very easily change any of the Colours of any
+part of the interposed body, by pressing the Plates closer and harder
+together, or leaving them more lax; that is, a part which appeared coloured
+with a red, may be presently ting’d with a yellow, blew, green, purple, or
+the like, by altering the appropinquation of the terminating Plates. Now
+that air is not necessary to be the interposed body, but that any other
+transparent fluid will do much the same, may be tryed by wetting those
+approximated Surfaces with Water, or any other transparent Liquor, and
+proceeding with it in the same manner as you did with the Air; and you will
+find much the like effect, only with this difference, that those comprest
+bodies, which differ most, in their refractive quality, from the
+compressing bodies, exhibit the most strong and vivid tinctures. Nor is it
+necessary, that this _laminated_ and _ting’d_ body should be of a fluid
+substance, any other substance, provided it be thin enough and transparent,
+doing the same thing: this the _Laminæ_ of our _Muscovy-glass_ hint; but it
+may be confirm’d by multitudes of other Instances.
+
+And first, we shall find, that even Glass it self may, by the help of a
+Lamp, be blown thin enough to produce these _Phænomena_ of Colours: which
+_Phænomena_ accidentally happening, as I have been attempting to frame
+small Glasses with a Lamp, did not a little surprize me at first, having
+never heard or seen any thing of it before; though afterwards comparing it
+with the _Phænomena_, I had often observed in those Bubbles which Children
+use to make with Soap-water, I did the less wonder; especially when upon
+Experiment I found, I was able to produce the same _Phænomena_ in thin
+Bubbles made with any other transparent Substance. Thus have I produced
+them with Bubbles of _Pitch_, _Rosin_, _Colophony_, _Turpentine_,
+_Solutions_ of several _Gums_, as _Gum-Arabick_ in water; any _glutinous_
+Liquor, as _Wort_, _Wine_, _Spirit of Wine_, _Oyl of Turpentine_, _Glare of
+Snails_, &c.
+
+It would be needless to enumerate the several Instances, these being enough
+to shew the generality or universality of this propriety. Only I must not
+omit, that we have instances also of this kind even in metalline Bodies and
+animal; for those several Colours which are observed to follow each other
+upon the polisht surface of hardned Steel, when it is by a sufficient
+degree of heat gradually tempered or softened, are produced, from nothing
+else but a certain thin _Lamina_ of a _vitrum_ or _vitrified_ part of the
+Metal, which by that degree of heat, and the concurring action of the
+ambient Air, is driven out and fixed on the surface of the Steel.
+
+And this hints to me a very probable (at least, if not the true) cause of
+the hardning and tempering of Steel, which has not, I think, been yet
+given, nor, that I know of been so much as thought of by any. And that is
+this, that the hardness of it arises from a greater proportion of a
+vitrified Substance interspersed through the pores of the Steel. And that
+the tempering or softning of it arises from the proportionate or smaller
+parcels of it left within those pores. This will seem the more probable, if
+we consider these Particulars.
+
+First, That the pure parts of Metals are of themselves very _flexible_ and
+_tuff_; that is, will indure bending and hammering, and yet retain their
+continuity.
+
+Next, That the Parts of all vitrified Substances, as all kinds of Glass,
+the _Scoria_ of Metals, &c. are very hard, and also very brittle, being
+neither _flexible_ nor _malleable_, but may by hammering or beating be
+broken into small parts or powders.
+
+Thirdly, That all Metals (excepting Gold and Silver, which do not so much
+with the bare fire, unless assisted by other saline Bodies) do more or less
+_vitrifie_ by the strength of fire, that is, are corroded by a Saline
+Substance, which I elsewhere shew to be the true cause of fire; and are
+thereby, as by several other _Menstruums_ converted into _Scoria_; And this
+is called, _calcining_ of them, by Chimists. Thus Iron and Copper by
+heating and quenching do turn all of them by degrees into _Scoria_, which
+are evidently _vitrified_ Substances, and unite with Glass, and are easily
+_fusible_; and when cold, very hard, and very brittle.
+
+Fourthly, That most kind of _Vitrifications_ or _Calcinations_ are made by
+Salts, uniting and incorporating with the metalline Particles. Nor do I
+know any one _calcination_ wherein a _Saline_ body may not, with very great
+probability, be said to be an agent or coadjutor.
+
+Fifthly, That Iron is converted into Steel by means of the incorporation of
+certain salts, with which it is kept a certain time in the fire.
+
+Sixthly, That any Iron may, in a very little time, be _case hardned_, as
+the Tradesmen call it, by casing the iron to be hardned with clay, and
+putting between the clay and iron a good quantity of a mixture of _Urine_,
+_Soot_, _Sea-salt_, and _Horses hoofs_ (all which contein great quantities
+of Saline bodies) and then putting the case into a good strong fire, and
+keeping it in a considerable degree of heat for a good while, and
+afterwards heating, and quenching or cooling it suddenly in cold water.
+
+Seventhly, That all kind of vitrify’d substances, by being suddenly cool’d,
+become very hard and brittle. And thence arises the pretty _Phænomena_ of
+the Glass Drops, which I have already further explained in its own place.
+
+Eighthly, That those metals which are not so apt to vitrifie, do not
+acquire any hardness by quenching in water, as Silver, Gold, &c.
+
+These considerations premis’d, will, I suppose, make way for the more easie
+reception of this following Explication of the _Phænomena_ of hardned and
+temper’d Steel. That Steel is a substance made out of Iron, by means of a
+certain proportionate _Vitrification_ of several parts, which are so
+curiously and proportionately mixt with the more tough and unalter’d parts
+of the Iron, that when by the great heat of the fire this vitrify’d
+substance is melted, and consequently rarify’d, and thereby the pores of
+the Iron are more open, if then by means of dipping it in cold water it be
+suddenly cold, and the parts hardned, that is, stay’d in that same degree
+of _Expansion_ they were in when hot, the parts become very hard and
+brittle, and that upon the same account almost as small parcels of glass
+quenched in water grow brittle, which we have already explicated. If after
+this the piece of Steel be held in some convenient heat, till by degrees
+certain colours appear upon the surface of the brightned metal, the very
+hard and brittle tone of the metal, by degrees relaxes and becomes much
+more tough and soft; namely, the action of the heat does by degrees loosen
+the parts of the Steel that were before streached or set _atilt_ as it
+were, and stayed open by each other, whereby they become relaxed and set at
+liberty, whence some of the more brittle interjacent parts are thrust out
+and melted into a thin skin on the surface of the Steel, which from no
+colour increases to a deep Purple, and so onward by these _gradations_ or
+consecutions, _White, Yellow, Orange, Minium, Scarlet, Purple, Blew,
+Watchet_, &c. and the parts within are more conveniently, and
+proportionately mixt; and so they gradually subside into a texture which is
+much better proportion’d and closer joyn’d, whence that rigidness of parts
+ceases, and the parts begin to acquire their former _ductilness_.
+
+Now, that ’tis nothing but the vitrify’d metal that sticks upon the surface
+of the colour’d body, is evident from this, that if by any means it be
+scraped and rubb’d off, the metal underneath it is white and clear; and if
+it be kept longer in the fire, so as to increase to a considerable
+thickness, it may, by blows, be beaten off in flakes. This is further
+confirm’d by this observable, that that Iron or Steel will keep longer from
+rusting which is covered with this vitrify’d case: Thus also Lead will, by
+degrees, be all turn’d into a litharge; for that colour which covers the
+top being scum’d or shov’d aside, appears to be nothing else but a litharge
+or vitrify’d Lead.
+
+This is observable also in some sort, on Brass, Copper, Silver, Gold, Tin,
+but is most conspicuous in Lead: all those Colours that cover the surface
+of the Metal being nothing else, but a very thin vitrifi’d part of the
+heated Metal.
+
+The other Instance we have, is in Animal bodies, as in Pearls, Mother of
+Pearl-shels, Oyster-shels, and almost all other kinds of stony shels
+whatsoever. This have I also sometimes with pleasure observ’d even in
+Muscles and Tendons. Further, if you take any glutinous substance and run
+it exceedingly thin upon the surface of a smooth glass or a polisht
+metaline body, you shall find the like effects produced: and in general,
+wheresoever you meet with a transparent body thin enough, that is
+terminated by reflecting bodies of differing refractions from it, there
+will be a production of these pleasing and lovely colours.
+
+Nor is it necessary, that the two _terminating_ Bodies should be both of
+the same kind, as may appear by the _vitrified Laminæ_ on _Steel_, _Lead_,
+and other Metals, one surface of which _Laminæ_ is contiguous to the
+surface of the Metal, the other to that of the Air.
+
+Nor is it necessary, that these colour’d _Laminæ_ should be of an even
+thickness, that is, should have their edges and middles of equal thickness,
+as in a Looking-glass-plate, which circumstance is only requisite to make
+the Plate appear all of the same colour; but they may resemble a _Lens_,
+that is, have their middles thicker then their edges; or else a _double
+concave_, that is, be thinner in the middle then at the edges; in both
+which cases there will be various coloured rings or lines, with differing
+consecutions or orders of Colours; the order of the first from the middle
+outwards being Red, Yellow, Green, Blew, &c. And the latter quite contrary.
+
+But further, it is altogether necessary, that the Plate, in the places
+where the Colours appear, should be of a determinate thickness: First, It
+must not be more then such a thickness, for when the Plate is increased to
+such a thickness, the Colours cease; and besides, I have seen in a thin
+piece of _Muscovy-glass_, where the two ends of two Plates, which appearing
+both single, exhibited two distinct and differing Colours; but in that
+place where they were united, and constituted one double Plate (as I may
+call it) they appeared transparent and colourless. Nor, Secondly, may the
+Plates be _thinner_ then such a determinate _cize_; for we alwayes find,
+that the very outmost Rim of these flaws is terminated in a white and
+colourless Ring.
+
+Further, in this Production of Colours there is no need of a determinate
+Light of such a bigness and no more, nor of a determinate position of that
+Light, that it should be on this side, and not on that side; nor of a
+terminating shadow, as in the Prisme, and Rainbow, or Water-ball: for we
+find, that the Light in the open Air, either in or out of the Sun-beams,
+and within a Room, either from one or many Windows, produces much the same
+effect: only where the Light is brightest, there the Colours are most
+_vivid_. So does the light of a Candle, collected by a Glass-ball. And
+further, it is all one whatever side of the coloured Rings be towards the
+light; for the whole Ring keeps its proper Colours from the middle outwards
+in the same order as I before related, without varying at all, upon
+changing the position of the light.
+
+But above all it is most observable, that here are all kind of Colours
+generated in a _pellucid_ body, where there is properly no such refraction
+as _Des Cartes_ supposes his _Globules_ to acquire a _verticity_ by: For in
+the plain and even Plates it is manifest, that the second refraction
+(according to _Des Cartes_ his Principles in the _fifth Section of the
+eighth Chapter of his Meteors_) does regulate and restore the supposed
+_turbinated Globules_ unto their former uniform motion. This Experiment
+therefore will prove such a one as our _thrice excellent Verulam_ calls
+_Experimentum Crucis_, serving as a Guide or Land-mark, by which to direct
+our course in the search after the true cause of Colours. Affording us this
+particular negative Information, that for the production of Colours there
+is not necessary either a great refraction, as in the Prisme; nor Secondly,
+a determination of Light and shadow, such as is both in the Prisme and
+Glass-ball. Now that we may see likewise what affirmative and positive
+Instruction it yields, it will be necessary, to examine it a little more
+particularly and strictly; which that we may the better do, it will be
+requisite to premise somewhat in general concerning the nature of Light and
+Refraction.
+
+And first for Light it seems very manifest, that there is no luminous Body
+but has the parts of it in motion more or less.
+
+First, That all kind of _fiery burning Bodies_ have their parts in motion,
+I think, will be very easily granted me. That the _spark_ struck from a
+Flint and Steel is in a rapid agitation, I have elsewhere made probable.
+And that the Parts of _rotten Wood_, _rotten Fish_ and the like, are also
+in motion, I think, will as easily be conceded by those, who consider, that
+those parts never begin to shine till the Bodies be in a state of
+putrefaction; and that is now generally granted by all, to be caused by the
+motion of the parts of putrifying bodies. That the _Bononian stone_ shines
+no longer then it is either warmed by the Sun-beams, or by the flame of a
+Fire or of a Candle, is the general report of those that write of it, and
+of others that have seen it. And that heat argues a motion of the internal
+parts is (as I said before) generally granted.
+
+But there is one Instance more, which was first shewn to the _Royal
+Society_ by Mr. _Clayton_ a worthy Member thereof, which does make this
+Assertion more evident then all the rest: And that is, That a _Diamond_
+being _rub’d_, _struck_ or _heated_ in the dark, shines for a pretty while
+after, so long as that motion, which is imparted by any of those Agents,
+remains (in the same manner as a Glass, rubb’d, struck, or (by a means
+which I shall elsewhere mention) heated, yields a sound which lasts as long
+as the vibrating motion of that _sonorous_ body) several Experiments made
+on which Stone, are since published in a Discourse of Colours, by the truly
+honourable Mr. _Boyle_. What may be said of those _Ignes fatui_ that appear
+in the night, I cannot so well affirm, having never had the opportunity to
+examine them my self, nor to be inform’d by any others that had observ’d
+them: And the relations of them in Authors are so imperfect, that nothing
+can be built on them. But I hope I shall be able in another place to make
+it at least very probable, that there is even in those also a Motion which
+causes this effect. That the shining of _Sea-water_ proceeds from the same
+cause, may be argued from this, That it shines not till either it be beaten
+against a Rock, or be some other wayes broken or agitated by Storms, or
+Oars, or other _percussing_ bodies. And that the Animal _Energies_ or
+Spirituous _agil_ parts are very active in _Cats eyes_ when they shine,
+seems evident enough, because their eyes never shine but when they look
+very intensly either to find their prey, or being hunted in a dark room,
+when they seek after their adversary, or to find a way to escape. And the
+like may be said of the shining _Bellies of Gloworms_; since ’tis evident
+they can at pleasure either increase or extinguish that Radiation.
+
+It would be somewhat too long a work for this place _Zetetically_ to
+examine, and positively to prove, what particular kind of motion it is that
+must be the efficient of Light; for though it be a motion, yet ’tis not
+every motion that produces it, since we find there are many bodies very
+violently mov’d, which yet afford not such an effect; and there are other
+bodies, which to our other senses, seem not mov’d so much, which yet shine.
+Thus Water and quick-silver, and most other liquors heated, shine not; and
+several hard bodies, as Iron, Silver, Brass, Copper, Wood, &c. though very
+often struck with a hammer, shine not presently, though they will all of
+them grow exceeding hot; whereas rotten Wood, rotten Fish, Sea-water,
+Gloworms, &c. have nothing of tangible heat in them, and yet (where there
+is no stronger light to affect the Sensory) they shine some of them so
+Vividly, that one may make a shift to read by them.
+
+It would be too long, I say, here to insert the discursive progress by
+which I inquir’d after the proprieties of the motion of Light, and
+therefore I shall only add the result.
+
+And, First, I found it ought to be exceeding _quick_, such as those
+motions of _fermentation_ and _putrefaction_, whereby, certainly, the
+parts are exceeding nimbly and violently mov’d; and that, because we
+find those motions are able more minutely to shatter and divide the
+body, then the most violent heats or _menstruums_ we yet know. And that
+fire is nothing else but such a _dissolution_ of the Burning body, made
+by the most _universal menstruum_ of all _sulphureous bodies_, namely,
+the Air, we shall in an other place of this Tractate endeavour to make
+probable. And that, in all extreamly hot shining bodies, there is a
+very quick motion that causes Light, as well as a more robust that
+causes Heat, may be argued from the celerity wherewith the bodyes are
+dissolv’d.
+
+Next, it must be a _Vibrative motion_. And for this the newly mention’d
+_Diamond_ affords us a good argument; since if the motion of the parts did
+not return, the Diamond must after many rubbings decay and be wasted: but
+we have no reason to suspect the latter, especially if we consider the
+exceeding difficulty that is found in cutting or wearing away a Diamond.
+And a Circular motion of the parts is much more improbable, since, if that
+were granted, and they be suppos’d irregular and Angular parts, I see not
+how the parts of the Diamond should hold so firmly together, or remain in
+the same sensible dimensions, which yet they do. Next, if they be
+_Globular_, and mov’d only with a _turbinated_ motion, I know not any cause
+that can impress that motion upon the _pellucid medium_, which yet is done.
+Thirdly, any other _irregular_ motion of the parts one amongst another,
+must necessarily make the body of a fluid consistence, from which it is far
+enough. It must therefore be a _Vibrating_ motion.
+
+And Thirdly, That it is a very _short-vibrating motion_, I think the
+instances drawn from the shining of Diamonds will also make probable. For a
+Diamond being the hardest body we yet know in the World, and consequently
+the least apt to yield or bend, must consequently also have its
+_vibrations_ exceeding short.
+
+And these, I think, are the three principal proprieties of a motion,
+requisite to produce the effect call’d Light in the Object.
+
+The next thing we are to consider, is the way or manner of the _trajection_
+of this motion through the interpos’d pellucid body to the eye: And here it
+will be easily granted,
+
+First, That it must be a body _susceptible_ and _impartible_ of this motion
+that will deserve the name of a Transparent. And next, that the parts of
+such a body must be _Homogeneous_, or of the same kind. Thirdly, that the
+constitution and motion of the parts must be such, that the appulse of the
+luminous body may be communicated or propagated through it to the greatest
+imaginable distance in the least imaginable time, though I see no reason to
+affirm, that it must be in an instant: For I know not any one Experiment or
+observation that does prove it. And, whereas it may be objected, That we
+see the Sun risen at the very instant when it is above the sensible
+Horizon, and that we see a Star hidden by the body of the Moon at the same
+instant, when the Star, the Moon, and our Eye are all in the same line; and
+the like Observations, or rather suppositions, may be urg’d. I have this to
+answer, That I can as easily deny as they affirm; for I would fain know by
+what means any one can be assured any more of the Affirmative, then I of
+the Negative. If indeed the propagation were very slow, ’tis possible
+something might be discovered by Eclypses of the Moon; but though we should
+grant the progress of the light from the Earth to the Moon, and from the
+Moon back to the Earth again to be full two Minutes in performing, I know
+not any possible means to discover it; nay, there may be some instances
+perhaps of Horizontal Eclypses that may seem very much to favour this
+supposition of the slower progression of Light then most imagine. And the
+like may be said of the Eclypses of the Sun, &c. But of this only by the
+by. Fourthly, That the motion is propagated every way through an
+_Homogeneous medium_ by _direct_ or _straight_ lines extended every way
+like Rays from the center of a Sphere. Fifthly, in an _Homogeneous medium_
+this motion is propagated every way with _equal velocity_, whence
+necessarily every _pulse_ or _vibration_ of the luminous body will generate
+a Sphere, which will continually increase, and grow bigger, just after the
+same manner (though indefinitely swifter) as the waves or rings on the
+surface of the water do swell into bigger and bigger circles about a point
+of it, where, by the sinking of a Stone the motion was begun, whence it
+necessarily follows, that all the parts of these Spheres undulated through
+an _Homogeneous medium_ cut the Rays at right angles.
+
+But because all transparent _mediums_ are not _Homogeneous_ to one another,
+therefore we will next examine how this pulse or motion will be propagated
+through differingly transparent _mediums_. And here, according to the most
+acute and excellent Philosopher _Des Cartes_, I suppose the sign of the
+angle of inclination in the first _medium_ to be to the sign of refraction
+in the second, As the density of the first, to the density of the second.
+By density, I mean not the density in respect of gravity (with which the
+refractions or transparency of _mediums_ hold no proportion) but in respect
+onely to the _trajection_ of the Rays of light, in which respect they only
+differ in this; that the one propagates the pulse more easily and weakly,
+the other more slowly, but more strongly. But as for the pulses themselves,
+they will by the refraction acquire another propriety, which we shall now
+endeavour to explicate.
+
+We will suppose therefore in the first Figure ACFD to be a physical Ray, or
+ABC and DEF to be two Mathematical Rays, _trajected_ from a very remote
+point of a luminous body through an _Homogeneous_ transparent _medium_ LLL,
+and DA, EB, FC, to be small portions of the orbicular impulses which must
+therefore cut the Rays at right angles; these Rays meeting with the plain
+surface NO of a _medium_ that yields an easier _transitus_ to the
+propagation of light, and falling _obliquely_ on it, they will in the
+_medium_ MMM be refracted towards the perpendicular of the surface. And
+because this _medium_ is more easily _trajected_ then the former by a
+third, therefore the point C of the orbicular pulse FC will be mov’d to H
+four spaces in the same time that F the other end of it is mov’d to G three
+spaces, therefore the whole refracted pulse GH shall be _oblique_ to the
+refracted Rays CHK and GI; and the angle GHC shall be an acute, and so much
+the more acute by how much the greater the refraction be, then which
+nothing is more evident, for the sign of the inclination is to the sign of
+refraction as GF to TC the distance between the point C and the
+perpendicular from G on CK, which being as four to three, HC being longer
+then GF is longer also then TC, therefore the angle GHC is less than GTC.
+So that henceforth the parts of the pulses GH and IK are mov’d ascew, or
+cut the Rays at _oblique_ angles.
+
+It is not my business in this place to set down the reasons why this or
+that body should impede the Rays more, others less: as why Water should
+transmit the Rays more easily, though more weakly than air. Onely thus much
+in general I shall hint, that I suppose the _medium_ MMM to have less of
+the transparent undulating subtile matter, and that matter to be less
+implicated by it, whereas LLL I suppose to contain a greater quantity of
+the fluid undulating substance, and this to be more implicated with the
+particles of that _medium_.
+
+But to proceed, the same kind of _obliquity_ of the Pulses and Rays will
+happen also when the refraction is made out of a more easie into a more
+difficult _mediu_; as by the calculations of GQ & CSR which are refracted
+from the perpendicular. In both which calculations ’tis _obvious_ to
+observe, that always that part of the Ray towards which the refraction is
+made has the end of the _orbicular pulse_ precedent to that of the other
+side. And always, the oftner the refraction is made the same way, Or the
+greater the single refraction is, the more is this unequal progress. So
+that having found this odd propriety to be an inseparable concomitant of a
+refracted Ray, not streightned by a contrary refraction, we will next
+examine the refractions of the Sun-beams, as they are suffer’d onely to
+pass through a small passage, _obliquely_ out of a more difficult, into a
+more easie _medium_.
+
+Let us suppose therefore ABC in the second Figure to represent a large
+_Chemical Glass-body_ about two foot long, filled with very fair Water as
+high as AB, and inclin’d in a convenient posture with B towards the Sun:
+Let us further suppose the top of it to be cover’d with an _opacous_ body,
+all but the hole ab, through which the Sun-beams are suffer’d to pass into
+the Water, and are thereby refracted to cdef, against which part, if a
+Paper be expanded on the outside, there will appear all the colours of the
+Rainbow, that is, there will be generated the two principal colours,
+_Scarlet_ and _Blue_, and all the _intermediate_ ones which arise from the
+composition and dilutings of these two, that is, cd shall exhibit a
+_Scarlet_, which toward d is diluted into a _Yellow_; this is the
+refraction of the Ray, ik, which comes from the underside of the Sun; and
+the Ray ef shall appear of a deep _Blue_, which is gradually towards e
+diluted into a pale _Watchet-blue_. Between d and e the two _diluted_
+colours. _Blue_ and _Yellow_ are mixt and compounded into a _Green_; and
+this I imagine to be the reason why _Green_ is so acceptable a colour to
+the eye, and that either of the two extremes are, if intense, rather a
+little offensive, namely, the being plac’d in the middle between the two
+extremes, and compounded out of both those, _diluted_ also, or somewhat
+qualifi’d, for the _composition_, arising from the mixture of the two
+extremes _undiluted_, makes a _Purple_, which though it be a lovely colour,
+and pretty acceptable to the eye, yet is it nothing comparable to the
+ravishing pleasure with which a curious and well tempered _Green_ affects
+the eye. If removing the Paper, the eye be plac’d against cd, it will
+perceive the lower side of the Sun (or a Candle at night which is much
+better, because it offends not the eye, and is more easily manageable) to
+be of a deep _Red_, and if against ef it will perceive the upper part of
+the luminous body to be of a deep _Blue_; and these colours will appear
+deeper and deeper, according as the Rays from the luminous body fall more
+_obliquely_ on the surface of the Water, and thereby suffer a greater
+refraction, and the more distinct, the further cdef is removed from the
+trajecting hole.
+
+So that upon the whole, we shall find that the reason of the _Phænomena_
+seems to depend upon the _obliquity_ of the _orbicular pulse_, to the Lines
+of Radiation, and in particular, that the Ray cd which constitutes the
+_Scarlet_ has its inner parts, namely those which are next to the middle of
+the luminous body, precedent to the outermost which are contiguous to the
+dark and _unradiating_ skie. And that the Ray ef which gives a _Blue_, has
+its outward part, namely, that which is contiguous to the dark skie
+precedent to the pulse from the innermost, which borders on the bright
+_area_ of the luminous body.
+
+We may observe further, that the cause of the _diluting_ of the colours
+towards the middle, proceeds partly from the wideness of the hole through
+which the Rays pass, whereby the Rays from several parts of the luminous
+body, fall upon many of the same parts between c and f as is more manifest
+by the Figure: And partly also from the nature of the refraction it self,
+for the vividness or strength of the two terminating colours, arising
+chiefly as we have seen, from the very great difference that is betwixt the
+outsides of those _oblique undulations_ & the dark Rays circumambient, and
+that disparity betwixt the _approximate_ Rays, decaying gradually: the
+further inward toward the middle of the luminous body they are remov’d, the
+more must the colour approach to a white or an undisturbed light.
+
+Upon the calculation of the refraction and reflection from a Ball of Water
+or Glass, we have much the same _Phænomena_, namely, an _obliquity_ of the
+undulation in the same manner as we have found it here. Which, because it
+is very much to our present purpose, and affords such an _Instancia
+crucis_, as no one that I know has hitherto taken notice of, I shall
+further examine. For it does very plainly and positively distinguish, and
+shew, which of the two _Hypotheses_, either the _Cartesian_ or this is to
+be followed, by affording a generation of all the colors in the Rainbow,
+where according to the _Cartesian Principles_ there should be none at all
+generated. And secondly, by affording an instance that does more closely
+confine the cause of these _Phænomena_ of colours to this present
+_Hypothesis_.
+
+And first, for the _Cartesian_, we have this to object against it, That
+whereas he says (_Meteorum Cap. 8. Sect. 5._) _Sed judicabam unicam
+(refractione scilicet) ad minimum requiri, & quidem talem ut ejus effectus
+aliâ contrariâ (refractione) non destruatur: Nam experientia docet si
+superficies _NM_ & _NP_ (nempe refringentes) Parallelæ forent, radios
+tantundem per alteram iterum erectos quantum per unam frangerentur, nullos
+colores depicturos_; This Principle of his holds true indeed in a prisme
+where the refracting surfaces are plain, but is contradicted by the Ball or
+Cylinder, whether of Water or Glass, where the refracting surfaces are
+Orbicular or Cylindrical. For if we examine the passage of any _Globule_ or
+Ray of the primary _Iris_, we shall find it to pass out of the Ball or
+Cylinder again, with the same inclination and refraction that it enter’d in
+withall, and that that last refraction by means of the _intermediate_
+reflection shall be the same as if without any reflection at all the Ray
+had been twice refracted by two Parallel surfaces.
+
+And that this is true, not onely in one, but in every Ray that goes to the
+constitution of the Primary Iris; nay, in every Ray, that suffers only two
+refractions, and one reflection, by the surface of the round body, we shall
+presently see most evident, if we repeat the _Cartesian Scheme_, mentioned
+in the tenth _Section_ of the eighth _Chapter_ of his _Meteors_, where
+EFKNP in the third Figure[9] is one of the Rays of the Primary Iris, twice
+refracted at F and N, and once reflected at K by the surface of the
+Water-ball. For, first it is evident, that KF and KN are equal, because KN
+being the reflected part of KF they have both the same inclination on the
+surface K that is the angles FKT, and NKV made by the two Rays and the
+Tangent of K are equal, which is evident by the Laws of reflection; whence
+it will follow also, that KN has the same inclination on the surface N, or
+the Tangent of it XN that the Ray KF has to the surface F, or the Tangent
+of it FY, whence it must necessarily follow, that the refractions at F and
+N are equal, that is, KFE and KNP are equal. Now, that the surface N is by
+the reflection at K made parallel to the surface at F, is evident from the
+principles of reflection; for reflection being nothing but an inverting of
+the Rays, if we re-invert the Ray KNP, and make the same inclinations below
+the line TKV that it has above, it will be most evident, that KH the
+inverse of KN will be the continuation of the line FK, and that LHI the
+inverse of OX is parallel to FY. And HM the inverse of NP is Parallel to EF
+for the angle KHI is equal to KNO which is equal to KFY, and the angle KHM
+is equal to KNP which is equal to KFE which was to be prov’d.
+
+So that according to the above mentioned _Cartesian_ principles there
+should be generated no colour at all in a Ball of Water or Glass by two
+refractions and one reflection, which does hold most true indeed, if the
+surfaces be plain, as may be experimented with any kind of prisme where the
+two refracting surfaces are equally inclin’d to the reflecting; but in this
+the _Phænomena_ are quite otherwise.
+
+The cause therefore of the generation of colour must not be what _Des
+Cartes_ assigns, namely, a certain _rotation_ of the _Globuli ætherei_,
+which are the particles which he supposes to constitute the _Pellucid
+medium_, But somewhat else, perhaps what we have lately supposed, and shall
+by and by further prosecute and explain.
+
+But, First I shall crave leave to propound some other difficulties of his,
+notwithstanding exceedingly ingenious _Hypothesis_, which I plainly confess
+to me seem such; and those are,
+
+First, if that light be (as is affirmed, _Diopt._ cap. 1. §. 8.) not so
+properly a motion, as an action or propension to motion, I cannot conceive
+how the eye can come to be sensible of the _verticity_ of a _Globule_,
+which is generated in a drop of Rain, perhaps a mile off from it. For that
+_Globule_ is not carry’d to the eye according to his formerly recited
+Principle; and if not so, I cannot conceive how it can communicate its
+_rotation_, or circular motion to the line of the _Globules_ between the
+drop and the eye. It cannot be by means of every ones turning the next
+before him; for if so, then onely all the _Globules_ that are in the odd
+places must be turned the same way with the first, namely, the 3. 5. 7. 9.
+11, &c. but all the _Globules_ interposited between them in the even
+places; namely, the 2. 4. 6. 8. 10. &c. must be the quite contrary, whence,
+according to the _Cartesian Hypothesis_, there must be no distinct colour
+generated, but a confusion. Next, since the _Cartesian Globuli_ are
+suppos’d (_Principiorum Philosoph._ Part. 3. §. 86.) to be each of them
+continually in motion about their centers, I cannot conceive how the eye is
+able to distinguish this new generated motion from their former inherent
+one, if I may so call that other wherewith they are mov’d or _turbinated_,
+from some other cause than refraction. And thirdly, I cannot conceive how
+these motions should not happen sometimes to oppose each other, and then,
+in stead of a _rotation_, there would be nothing but a direct motion
+generated, and consequently no colour. And fourthly, I cannot conceive, how
+by the _Cartesian Hypothesis_ it is possible to give any plausible reason
+of the nature of the Colours generated in the thin _laminæ_ of these our
+_Microscopical Observations_; for in many of these, the refracting and
+reflecting surfaces are parallel to each other, and consequently no
+_rotation_ can be generated, nor is there any necessity of a shadow or
+termination of the bright Rays, such as is suppos’d (_Chap._ 8. §. 5. _Et
+præterea observavi umbram quoque, aut limitationem luminis requiri:_ and
+_Chap._ 8. §. 9.) to be necessary to the generation of any distinct
+colours; Besides that, here is oftentimes one colour generated without any
+of the other appendant ones, which cannot be by the _Cartesian Hypothesis_.
+
+There must be therefore some other propriety of refraction that causes
+colour. And upon the examination of the thing, I cannot conceive any one
+more general, inseparable, and sufficient, than that which I have before
+assign’d. That we may therefore see how exactly our _Hypothesis_ agrees
+also with the _Phænomena_ of the refracting round body, whether _Globe_ or
+_Cylinder_, we shall next subjoyn our _Calculation_ or _Examen_ of it.
+
+And to this end, we will calculate any two Rays: as for instance;[10] let
+EF be a Ray cutting the _Radius_ CD (divided into 20. parts) in G 16. parts
+distant from C, and ef another Ray, which cuts the same _Radius_ in g 17.
+parts distant, these will be refracted to K and k, and from thence
+reflected to N and n, and from thence refracted toward P and p; therefore
+the Arch Ff will be 5.d 5′. The Arch FK 106.d 30′. the Arch fk 101.d 2′.
+The line FG 6000. and fg 5267. therefore hf. 733. therefore Fc 980, almost.
+The line FK 16024. and fk 15436. therefore Nd 196. and no 147 almost, the
+line Nn 1019 the Arch Nn 5.d 51′. therefore the Angle Nno is 34.d 43′.
+therefore the Angle Non is 139.d 56′. which is almost 50.d more than a
+right Angle.
+
+It is evident therefore by this _Hypothesis_, that at the same time that ef
+touches f. EF is arrived at c. And by that time efkn is got to n, EFKN is
+got to d and when it touches N, the pulse of the other Ray is got to o. and
+no farther, which is very short of the place it should have arriv’d to, to
+make the Ray np to cut the _orbicular pulse_ No at right Angles: therefore
+the Angle Nop is an acute Angle, but the quite contrary of this will
+happen, if 17. and 18. be calculated in stead of 16. and 17. both which
+does most exactly agree with the _Phænomena_: For if the Sun, or a Candle
+(which is better) be placed about Ee, and the eye about Pp, the Rays EFef
+at 16. and 17. will paint the side of the luminous object toward np _Blue_,
+and towards NP _Red_. But the quite contrary will happen when EF is 17. and
+ef 18. for then towards NP shall be a _Blue_, and towards np a _Red_,
+exactly according to the calculation. And there appears the _Blue_ of the
+Rainbow, where the two _Blue_ sides of the two Images unite, and there the
+_Red_ where the two _Red_ sides unite, that is, where the two Images are
+just disappearing; which is, when the Rays EF and NP produc’d till they
+meet, make an Angle of about 41. and an half; the like union is there of
+the two Images in the Production of the _Secundary Iris_, and the same
+causes, as upon calculation may appear; onely with this difference, that it
+is somewhat more faint, by reason of the duplicate reflection, which does
+always weaken the impulse the oftner it is repeated.
+
+Now, though the second refraction made at Nn be convenient, that is, do
+make the Rays glance the more, yet is it not altogether requisite; for it
+is plain from the calculation, that the pulse dn is sufficiently _oblique_
+to the Rays KN and kn, as wel as the pulse fc is _oblique_ to the Rays FK &
+fk. And therefore if a piece of very fine Paper be held close against Nn
+and the eye look on it either through the Ball as from D, or from the other
+side, as from B. there shall appear a Rainbow, or colour’d line painted on
+it with the part toward X appearing _Red_, towards O, _Blue_; the same also
+shall happen, if the Paper be placed about Kk, for towards T shall appear a
+_Red_, and towards V a _Blue_, which does exactly agree with this my
+_Hypothesis_, as upon the calculation of the progress of the pulse will
+most easily appear.
+
+Nor do these two observations of the colours appearing to the eye about p
+differing from what they appear on the Paper at N contradict each other;
+but rather confirm and exactly agree with one another, as will be evident
+to him that examines the reasons set down by the ingenious. _Des Cartes_ in
+the 12. _Sect._ of the 8. _Chapter of his Meteors_, where he gives the true
+reason why the colours appear of a quite contrary order to the eye, to what
+they appear’d on the Paper if the eye be plac’d in steed of the Paper: And
+as in the Prisme, so also in the Water-drop, or Globe the _Phænomena_, and
+reason are much the same.
+
+Having therefore shewn that there is such a propriety in the _prisme_ and
+water _Globule_ whereby the pulse is made _oblique_ to the progressive, and
+that so much the more, by how much greater the refraction is, I shall in
+the next place consider, how this conduces to the production of colours,
+and what kind of impression it makes upon the bottom of the eye; and to
+this end it will be requisite to examine this _Hypothesis_ a little more
+particularly.
+
+First therefore, if we consider the manner of the progress of the pulse, it
+will seem rational to conclude, that that part or end of the pulse which
+precedes the other, must necessarily be somwhat more _obtunded_, or
+_impeded_ by the resistance of the transparent _medium_, than the other
+part or end of it which is subsequent, whose way is, as it were, prepared
+by the other; especially if the adjacent _medium_ be not in the same manner
+enlightned or agitated. And therefore (in the fourth _Figure_ of the sixth
+_Iconism_) the Ray AAAHB will have its side HH more deadened by the
+resistance of the dark or quiet _medium_ PPP, Whence there will be a kind
+of deadness superinduc’d on the side HHH, which will continually increase
+from B, and strike deeper and deeper into the Ray by the line BR; Whence
+all the parts of the triangle, RBHO will be of a dead _Blue_ colour, and so
+much the deeper, by how much the nearer they lie to the line BHH, which is
+most deaded or impeded, and so much the more _dilute_, by how much the
+nearer it approaches the line BR. Next on the other side of the Ray AAN,
+the end A of the pulse AH will be promoted, or made stronger, having its
+passage already prepar’d as ’twere by the other parts preceding, and so its
+impression wil be stronger; And because of its _obliquity_ to the Ray,
+there will be propagated a kind of faint motion into QQ the adjacent dark
+or quiet _medium_, which faint motion will spread further and further into
+QQ as the Ray is propagated further and further from A, namely, as far as
+the line MA, whence all the triangle MAN will be ting’d with a _Red_, and
+that _Red_ will be the deeper the nearer it approaches the line MA, and the
+_paler_ or _yellower_ the nearer it is the line NA. And if the Ray be
+continued, so that the lines AN and BR (which are the bounds of the _Red_
+and _Blue diluted_) do meet and cross each other, there will be beyond that
+intersection generated all kinds of _Greens_.
+
+Now, these being the proprieties of every single refracted Ray of light, it
+will be easie enough to consider what must be the result of very many such
+Rays collateral: As if we suppose infinite such Rays _interjacent_ between
+AKSB and ANOB, which are the terminating: For in this case the Ray AKSB
+will have its _Red_ triangle intire, as lying next to the dark or quiet
+_medium_, but the other side of it BS will have no _Blue_, because the
+_medium adjacent_ to it SBO, is mov’d or enlightned, and consequently that
+light does destroy the colour. So likewise will the Ray ANOB lose its
+_Red_, because the _adjacent medium_ is mov’d or enlightned, but the other
+side of the Ray that is _adjacent_ to the dark, namely, AHO will preserve
+its _Blue_ entire, and these Rays must be so far produc’d as till AN and BR
+cut each other, before there will be any _Green_ produc’d. From these
+Proprieties well consider’d, may be deduc’d the reasons of all the
+_Phænomena_ of the _prisme_, and of the _Globules_ or drops of Water which
+conduce to the production of the Rainbow.
+
+Next for the impression they make on the _Retina_, we will further examine
+this _Hypothesis_: Suppose therefore ABCDEF, in the fifth _Figure_, to
+represent the Ball of the eye: on the _Cornea_ of which ABC two Rays GACH
+and KCAI (which are the terminating Rays of a luminous body) falling, are
+by the refraction thereof collected or _converg’d_ into two points at the
+bottom of the eye. Now, because these terminating Rays, and all the
+_intermediate_ ones which come from any part of the luminous body, are
+suppos’d by some sufficient refraction before they enter the eye, to have
+their pulses made _oblique_ to their progression, and consequently each Ray
+to have potentially _superinduc’d_ two proprieties, or colours, viz. a
+_Red_ on the one side, and a _Blue_ on the other, which notwithstanding are
+never actually manifest, but when this or that Ray has the one or the other
+side of it bordering on a dark or unmov’d _medium_, therefore as soon as
+these Rays are entred into the eye and so have one side of each of them
+bordering on a dark part of the humours of the eye, they will each of them
+actually exhibit some colour; therefore ADC the production of GACH will
+exhibit a _Blue_, because the side CD is _adjacent_ to the dark _medium_
+CQDC, but nothing of a _Red_, because its side AD is _adjacent_ to the
+enlightned _medium_ ADFA: And all the Rays that from the points of the
+luminous body are collected on the parts of the _Retina_ between D and F
+shall have their _Blue_ so much the more _diluted_ by how much the farther
+these points of collection are distant from D towards F; and the Ray AFC
+the production of KCAI, will exhibit a _Red_, because the side AF is
+adjacent to the dark or quiet _medium_ of the eye APFA, but nothing of a
+_Blue_, because its side CF is _adjacent_ to the enlightned _medium_ CFDC,
+and all the Rays from the intermediate parts of the luminous body that are
+collected between F and D shall have their _Red_ so much the more diluted,
+by how much the farther they are distant from F towards D.
+
+Now, because by the refraction in the _Cornea_, and some other parts of the
+eye, the sides of each Ray, which before were almost parallel, are made to
+_converge_ and meet in a point at the bottom of the eye, therefore that
+side of the _pulse_ which preceded before these refractions, shall first
+touch the _Retina_, and the other side last. And therefore according as
+this or that side, or end of the pulse shall be impeded, accordingly will
+the _impressions_ on the _Retina_ be varied; therefore by the Ray GACH
+refracted by the _Cornea_ to D there shall be on that point a stroke or
+impression confus’d, whose weakest end, namely, that by the line CD shall
+precede, and the stronger, namely, that by the line AD shall follow. And by
+the Ray KCAI refracted to F, there shall be on that part a confus’d stroke
+or impression, whose strongest part, namely, that by the line CF shal
+precede, and whose weakest or impeded, namely, that by the line AF shall
+follow, and all the intermediate points between F and D will receive
+impressions from the _converg’d_ Rays so much the more like the impressions
+on F and D by how much the nearer they approach that or this.
+
+From the consideration of the proprieties of which impressions, we may
+collect these short definitions of Colours: That _Blue is an impression on
+the Retina of an oblique and confus’d pulse of light, whose weakest part
+precedes, and whose strongest follows._ And, that _Red is an impression on
+the Retina of an oblique and confus’d pulse of light, whose strongest part
+precedes, and whose weakest follows._
+
+Which proprieties, as they have been already manifested, in the Prisme and
+falling drops of Rain, to be the causes of the colours there generated, may
+be easily found to be the efficients also of the colours appearing in thin
+_laminated_ transparent bodies; for the explication of which, all this has
+been premised.
+
+And that this is so, a little closer examination of the _Phænomena_ and the
+_Figure_ of the body, by this _Hypothesis_ will make evident.
+
+For first (as we have already observed) the _laminated_ body must be of a
+determinate thickness, that is, it must not be thinner then such a
+determinate quantity; for I have always observ’d, that neer the edges of
+those which are exceeding thin, the colours disappear, and the part grows
+white; nor must it be thicker then another determinate quantity; for I have
+likewise observ’d, that beyond such a thickness, no colours appear’d, but
+the Plate looked white, between which two determinate thicknesses were all
+the colour’d Rings; of which in some substances I have found ten or twelve,
+in others not half so many, which I suppose depends much upon the
+transparency of the _laminated_ body. Thus though the consecutions are the
+same in the scum or the skin on the top of metals; yet in those
+consecutions in the same colour is not so often repeated as in the
+consecutions in thin Glass, or in Sope-water, or any other more transparent
+and glutinous liquor; for in these I have observ’d, _Red, Yellow, Green,
+Blue, Purple; Red, Yellow, Green, Blue, Purple; Red, Yellow, Green, Blue,
+Purple; Red, Yellow, &c._ to succeed each other, ten or twelve times, but
+in the other more _opacous_ bodies the consecutions will not be half so
+many.
+
+And therefore secondly, the _laminated_ body must be transparent, and this
+I argue from this, that I have not been able to produce any colour at all
+with an _opacous_ body, though never so thin. And this I have often try’d,
+by pressing small _Globule_ of _Mercury_ between two smooth Plates of
+Glass, whereby I have reduc’d that body to a much greater thinness then was
+requisite to exhibit the colours with a transparent body.
+
+Thirdly, there must be a considerable reflecting body adjacent to the under
+or further side of the _lamina_ or _plate_: for this I always found, that
+the greater that reflection was, the more vivid were the appearing colours.
+
+From which Observations, is most evident, that the reflection from the
+under or further side of the body is the principal cause of the production
+of these colours; which, that it is so, and how it conduces to that effect,
+I shall further explain in the following Figure, which is here described of
+a very great thickness, as if it had been view’d through the _Microscope_;
+and ’tis indeed much thicker than any _Microscope_ (I have yet us’d) has
+been able to shew me those colour’d plates of Glass, or _Muscovie-glass_,
+which I have not without much trouble view’d with it, for though I have
+endeavoured to magnifie them as much as the Glasses were capable of, yet
+are they so exceeding thin, that I have not hitherto been able positively
+to determine their thickness. This Figure therefore I here represent, is
+wholy _Hypothetical_.
+
+Let ABCDHFE in the sixth Figure be a _frustum_ of _Muscovy-glass_, thinner
+toward the end AE, and thicker towards DF. Let us first suppose the Ray
+aghb coming from the Sun, of some remote luminous object to fall
+_obliquely_ on the thinner plate BAE, part therefore is reflected back by
+cghd, the first _Superficies_; whereby the perpendicular pulse ab is after
+reflexion propagated by cd, cd, equally remote from each other with ab, ab,
+so that ag + gc, or bh + hd are either of them equal to aa, as is also cc,
+but the body BAE being transparent, a part of the light of this Ray is
+refracted in the surface AB, and propagated by gikh to the surface EF,
+whence it is reflected and refracted again by the surface AB. So that after
+two refractions and one reflection, there is propagated a kind of fainter
+Ray emnf, whose pulse is not only weaker by reason of the two refractions
+in the surface AB, but by reason of the time spent in passing and repassing
+between the two surfaces AB and EF, ef which is this fainter or weaker
+pulse comes behind the pulse cd; so that hereby (the surfaces AB, and EF
+being so neer together, that the eye cannot _discriminate_ them from one)
+this confus’d or _duplicated_ pulse, whose strongest part precedes, and
+whose weakest follows, does produce on the _Retina_, (or the _optick nerve_
+that covers the bottom of the eye) the sensation of a _Yellow_.
+
+And secondly, this _Yellow_ will appear so much the deeper, by how much the
+further back towards the middle between cd and cd the spurious pulse ef is
+remov’d, as in 2 where the surface BC being further remov’d from EF, the
+weaker pulse ef will be nearer to the middle, and will make an impression
+on the eye of a _Red_.
+
+But thirdly, if the two reflecting surfaces be yet further remov’d asunder
+(as in 3 CD and EF are) then will the weaker pulse be so farr behind, that
+it will be more then half the distance between cd and cd. And in this case
+it will rather seem to precede the following stronger pulse, then to follow
+the preceding one, and consequently a _Blue_ will be generated. And when
+the weaker pulse is just in the middle between two strong ones, then is a
+deep and lovely _Purple_ generated; but when the weaker pulse ef is very
+neer to cd, then is there generated a _Green_, which will be _bluer_, or
+_yellower_, according as the _approximate_ weak pulse does precede or
+follow the stronger.
+
+Now fourthly, if the thicker Plate chance to be cleft into two thinner
+Plates, as CDFE is divided into two Plates by the surface GH then from the
+composition arising from the three reflections in the surfaces CD, GH, and
+EF, there will be generated several compounded or mixt colours, which will
+be very differing, according as the proportion between the thicknesses of
+those two divided Plates CDHG, and GHFE are varied.
+
+And _fifthly_, if these surfaces CD and FE are further remov’d asunder, the
+weaker pulse will yet lagg behind much further, and not onely be
+_coincident_ with the second, cd, but lagg behind that also, and that so
+much the more, by how much the thicker the Plate be; so that by degrees it
+will be _coincident_ with the third cd backward also, and by degrees, as
+the Plate grows thicker with a fourth, and so onward to a fifth, sixth,
+seventh, or eighth; so that if there be a thin transparent body, that from
+the greatest thinness requisite to produce colours, does, in the manner of
+a Wedge, by degrees grow to the greatest thickness that a Plate can be of,
+to exhibit a colour by the reflection of Light from such a body, there
+shall be generated several consecutions of colours, whose order from the
+thin end towards the thick, shall be _Yellow, Red, Purple, Blue, Green;
+Yellow, Red, Purple, Blue, Green; Yellow, Red, Purple, Blue, Green;
+Yellow_, &c. and these so often repeated, as the weaker pulse does lose
+paces with its _Primary_, or first pulse, and is _coincident_ with a
+second, third, fourth, fifth, sixth, &c. pulse behind the first. And this,
+as it is _coincident_, or follows from the first _Hypothesis_ I took of
+colours, so upon experiment have I found it in multitudes of instances that
+seem to prove it. One thing which seems of the greatest concern in this
+_Hypothesis_, is to determine the greatest or least thickness requisite for
+these effects, which, though I have not been wanting in attempting, yet so
+exceeding thin are these coloured Plates, and so imperfect our
+_Microscope_, that I have not been hitherto successfull, though if my
+endeavours shall answer my expectations, I shall hope to gratifie the
+curious Reader with some things more remov’d beyond our reach hitherto.
+
+Thus have I, with as much brevity as I was able, endeavoured to explicate
+(_Hypothetically_ at least) the causes of the _Phænomena_ I formerly
+recited, on the consideration of which I have been the more particular.
+
+First, because I think these I have newly given are capable of explicating
+all the _Phænomena_ of colours, not onely of those appearing in the
+_Prisme_, Water-drop, or Rainbow, and in _laminated_ or plated bodies, but
+of all that are in the world, whether they be fluid or solid bodies,
+whether in thick or thin, whether transparent, or seemingly opacous, as I
+shall in the next Observation further endeavour to shew. And secondly,
+because this being one of the two ornaments of all bodies discoverable by
+the sight, whether looked on with, or without a _Microscope_, it seem’d to
+deserve (somewhere in this Tract, which contains a description of the
+Figure and Colour of some minute bodies) to be somewhat the more intimately
+enquir’d into.
+
+       *       *       *       *       *
+
+
+Observ. X. _Of _Metalline_, and other real Colours._
+
+Having in the former Discourse, from the Fundamental cause of Colour, made
+it probable, that there are but two Colours, and shewn, that the _Phantasm_
+of Colour is caus’d by the sensation of the _oblique_ or uneven pulse of
+Light which is capable of no more varieties than two that arise from the
+two sides of the _oblique_ pulse, though each of those be capable of
+infinite gradations or degrees (each of them beginning from _White_, and
+ending the one in the deepest _Scarlet_ or _Yellow_, the other in the
+deepest _Blue_) I shall in this _Section_ set down some Observations which
+I have made of other colours, such as _Metalline_ powders tinging or
+colour’d bodies and several kinds of tinctures or ting’d liquors, all
+which, together with those I treated of in the former Observation will, I
+suppose, comprise the several subjects in which colour is observ’d to be
+inherent, and the several manners by which it _inheres_, or is apparent in
+them. And here I shall endeavour to shew by what composition all kind of
+compound colours are made, and how there is no colour in the world but may
+be made from the various degrees of these two colours, together with the
+intermixtures of _Black_ and _White_.
+
+And this being so, as I shall anon shew, it seems an evident argument to
+me, that all colours whatsoever, whether in fluid or solid, whether in very
+transparent or seemingly _opacous_, have the same efficient cause, to wit,
+some kind of _refraction_ whereby the Rays that proceed from such bodies,
+have their pulse _obliquated_ or confus’d in the manner I explicated in the
+former _Section_; that is, a _Red_ is caus’d by a duplicated or confus’d
+pulse, whose strongest pulse precedes, and a weaker follows: and a _Blue_
+is caus’d by a confus’d pulse, where the weaker pulse precedes, and the
+stronger follows. And according as these are, more or less, or variously
+mixt and compounded, so are the _sensations_, and consequently the
+_phantasms_ of colours _diversified_.
+
+To proceed therefore; I suppose, that all transparent colour’d bodies,
+whether fluid or solid, do consist at least of two parts, or two kinds of
+substances, the one of a substance of a somewhat differing _refraction_
+from the other. That one of these substances which may be call’d the
+_tinging_ substance, does consist of distinct parts, or particles of a
+determinate bigness which are _disseminated_, or dispers’d all over the
+other: That these particles, if the body be equally and uniformly colour’d,
+are evenly rang’d and dispers’d over the other contiguous body; That where
+the body is deepest ting’d, there these particles are rang’d thickest, and
+where ’tis but faintly ting’d, they are rang’d much thinner, but uniformly.
+That by the mixture of another body that unites with either of these, which
+has a differing refraction from either of the other, quite differing
+effects will be produc’d, that is, the _consecutions_ of the confus’d
+pulses will be much of another kind, and consequently produce other
+_sensations_ and _phantasms_ of colours, and from a _Red_ may turn to a
+_Blue_, or from a _Blue_ to a _Red_, &c.
+
+Now, that this may be the better understood, I shall endeavour to explain
+my meaning a little more sensible by a _Scheme_: Suppose we therefore in
+the seventh _Figure_ of the sixth _Scheme_, that ABCD represents a Vessel
+holding a ting’d liquor, let IIIII, &c. be the clear liquor, and let the
+tinging body that is mixt with it be EE, &c. FF, &c. GG, &c. HH, &c. whose
+particles (whether round, or some other determinate Figure is little to our
+purpose) are first of a determinate and equal bulk. Next, they are rang’d
+into the form of _Quincunx_, or _Equilaterotriangular_ order, which that
+probably they are so, and why they are so, I shall elsewhere endeavour to
+shew. Thirdly, they are of such a nature, as does either more easily or
+more difficultly transmit the Rays of light then the liquor; if more
+easily, a _Blue_ is generated, and if more difficultly, a _Red_ or
+_Scarlet_.
+
+And first, let us suppose the tinging particles to be of a substance that
+does more _impede_ the Rays of light, we shall find that the pulse or wave
+of light mov’d from AD to BC, will proceed on, through the containing
+_medium_ by the pulses or waves KK, LL, MM, NN, OO; but because several of
+these Rays that go to the constitution of these pulses will be slugged or
+stopped by the tinging particles E, F, G, H; therefore there shall be
+_secundary_ and weak pulse that shall follow the Ray, namely PP which will
+be the weaker: first, because it has suffer’d many refractions in the
+impeding body; next, for that the Rays will be a little dispers’d or
+confus’d by reason of the refraction in each of the particles, whether
+_round_ or _angular_; and this will be more evident, if we a little more
+closely examine any one particular tinging _Globule_.
+
+Suppose we therefore AB in the eighth _Figure_ of the sixth _Scheme_, to
+represent a tinging _Globule_ or particle which has a greater refraction
+than the liquor in which it is contain’d: Let CD be a part of the pulse of
+light which is _propagated_ through the containing _medium_; this pulse
+will be a little stopt or impeded by the _Globule_, and so by that time the
+pulse is past to EF that part of it which has been impeded by passing
+through the _Globule_, will get but to LM, and so that pulse which has been
+_propagated_ through the _Globule_, to wit, LM, NO, PQ, will always come
+behind the pulses EF, GH, IK, &c.
+
+Next, by reason of the greater impediment in AB, and its _Globular_ Figure,
+the Rays that pass through it will be dispers’d, and very much scatter’d.
+Whence CA and DB which before went _direct_ and _parallel_, will after the
+refraction in AB, _diverge_ and spread by AP, and BQ; so that as the Rays
+do meet with more and more of these tinging particles in their way, by so
+much the more will the pulse of light further lagg behind the clearer
+pulse, or that which has fewer refractions, and thence the deeper will the
+colour be, and the fainter the light that is trajected through it; for not
+onely many Rays are reflected from the surfaces of AB, but those Rays that
+get through it are very much disordered.
+
+By this _Hypothesis_ there is no one experiment of colour that I have yet
+met with, but may be, I conceive, very rationably solv’d, and perhaps, had
+I time to examine several particulars requisite to the demonstration of it,
+I might prove it more than probable, for all the experiments about the
+changes and mixings of colours related in the Treatise of Colours,
+published by the _Incomparable_ Mr. _Boyle_, and multitudes of others which
+I have observ’d, do so easily and naturally flow from those principles,
+that I am very apt to think it probable, that they own their production to
+no other _secundary_ cause: As to instance in two or three experiments. In
+the twentieth Experiment, this _Noble Authour_ has shewn that the deep
+_bluish purple-colour_ of _Violets_, may be turn’d into a _Green_, by
+_Alcalizate Salts_, and to a _Red_ by acid; that is, a _Purple_ consists of
+two colours, a deep _Red_, and a deep _Blue_; when the _Blue_ is diluted,
+or altered, or destroy’d by _acid Salts_, the _Red_ becomes predominant,
+but when the _Red_ is diluted by _Alcalizate_, and the _Blue_ heightned,
+there is generated a _Green_; for of a _Red_ diluted, is made a _Yellow_,
+and _Yellow_ and _Blue_ make a _Green_.
+
+Now, because the _spurious_ pulses which cause a _Red_ and a _Blue_, do the
+one follow the clear pulse, and the other precede it, it usually follows,
+that those _Saline_ refracting bodies which do _dilute_ the colour of the
+one, do deepen that of the other. And this will be made manifest by almost
+all kinds of _Purples_, and many sorts of _Greens_, both these colours
+consisting of mixt colours; for if we suppose A and A in the ninth Figure,
+to represent two pulses of clear light, which follow each other at a
+convenient distance, AA, each of which has a _spurious_ pulse preceding it,
+as BB, which makes a _Blue_, and another following it, as CC, which makes a
+_Red_, the one caus’d by tinging particles that have a greater refraction,
+the other by others that have a less refracting quality then the liquor or
+_Menstruum_ in which these are dissolv’d, whatsoever liquor does so alter
+the refraction of the one, without altering that of the other part of the
+ting’d liquor, must needs very much alter the colour of the liquor; for if
+the refraction of the _dissolvent_ be increas’d, and the refraction of the
+tinging particles not altered, then will the preceding _spurious_ pulse be
+shortned or stopt, and not out-run the clear pulse so much; so that BB will
+become EE, and the _Blue_ be _diluted_, whereas the other _spurious_ pulse
+which follows will be made to lagg much more, and be further behind AA than
+before, and CC will become _ff_, and so the _Yellow_ or _Red_ will be
+heightned.
+
+A _Saline_ liquor therefore, mixt with another ting’d liquor, may alter the
+colour of it several ways, either by altering the refraction of the liquor
+in which the colour swims: or secondly by varying the refraction of the
+coloured particles, by uniting more intimately either with some particular
+_corpuscles_ of the tinging body, or with all of them, according as it has
+a _congruity_ to some more especially, or to all alike: or thirdly, by
+uniting and interweaving it self with some other body that is already
+joyn’d with the tinging particles, with which substance it may have a
+_congruity_, though it have very little with the particles themselves: or
+fourthly, it may alter the colour of a ting’d liquor by dis-joyning certain
+particles which were before united with the tinging particles, which though
+they were somewhat _congruous_ to these particles, have yet a greater
+_congruity_ with the newly _infus’d Saline menstruum_. It may likewise
+alter the colour by further dissolving the tinging substance into smaller
+and smaller _particles_, and so _diluting_ the colour; or by uniting
+several _particles_ together as in precipitations, and so deepning it, and
+some such other ways, which many experiments and comparisons of differing
+trials together, might easily inform one of.
+
+From these Principles applied, may be made out all the varieties of colours
+observable, either in liquors, or any other ting’d bodies, with great ease,
+and I hope intelligible enough, there being nothing in the _notion_ of
+colour, or in the suppos’d production, but is very conceivable, and may be
+possible.
+
+The greatest difficulty that I find against this _Hypothesis_, is, that
+there seem to be more distinct colours then two, that is, then Yellow and
+Blue. This Objection is grounded on this reason, that there are several
+Reds, which _diluted_, make not a Saffron or pale Yellow, and therefore
+Red, or Scarlet seems to be a third colour distinct from a deep degree of
+Yellow.
+
+To which I answer, that Saffron affords us a deep Scarlet tincture, which
+may be _diluted_ into as pale a Yellow as any, either by making a weak
+solution of the Saffron, by infusing a small parcel of it into a great
+quantity of liquor, as in spirit of Wine, or else by looking through a very
+thin quantity of the tincture, and which may be heightn’d into the
+loveliest Scarlet, by looking through a very thick body of this tincture,
+or through a thinner parcel of it, which is highly _impregnated_ with the
+tinging body, by having had a greater quantity of the Saffron dissolv’d in
+a smaller parcel of the liquor.
+
+Now, though there may be some particles of other tinging bodies that give a
+lovely Scarlet also, which though _diluted_ never so much with liquor, or
+looked on through never so thin a parcel of ting’d liquor, will not yet
+afford a pale Yellow, but onely a kind of faint Red; yet this is no
+argument but that those ting’d particles may have in them the faintest
+degree of Yellow, though we may be unable to make them exhibit it; For that
+power of being _diluted_ depending upon the divisibility of the ting’d
+body, if I am unable to make the tinging particles so thin as to exhibit
+that colour, it does not therefore follow, that the thing is impossible to
+be done; now, the tinging particles of some bodies are of such a nature,
+that unless there be found some way of comminuting them into less bulks
+then the liquor does dissolve them into, all the Rays that pass through
+them must necessarily receive a tincture so deep, as their appropriate
+refractions and bulks compar’d with the proprieties of the dissolving
+liquor must necessarily dispose them to empress, which may perhaps be a
+pretty deep Yellow, or pale Red.
+
+And that this is not _gratis dictum_, I shall add one instance of this
+kind, wherein the thing is most manifest.
+
+If you take Blue _Smalt_, you shall find, that to afford the deepest Blue,
+which _cæteris paribus_ has the greatest particles or sands; and if you
+further divide, or grind those particles on a Grindstone, or _porphyry_
+stone, you may by _comminuting_ the sands of it, _dilute_ the Blue into as
+pale a one as you please, which you cannot do by laying the colour thin;
+for wheresoever any single particle is, it exhibits as deep a Blue as the
+whole mass. Now, there are other Blues, which though never so much ground,
+will not be _diluted_ by grinding, because consisting of very small
+particles, very deeply ting’d, they cannot by grinding be actually
+separated into smaller particles then the operation of the fire, or some
+other dissolving _menstruum_, reduc’d them to already.
+
+Thus all kind of _Metalline_ colours, whether _precipitated_, _sublim’d_,
+_calcin’d_, or otherwise prepar’d, are hardly chang’d by grinding, as
+_ultra marine_ is not more _diluted_; nor is _Vermilion_ or _Red-lead_ made
+of a more faint colour by grinding; for the smallest particles of these
+which I have view’d with my greatest Magnifying-Glass, if they be well
+enlightned, appear very deeply ting’d with their peculiar colours; nor,
+though I have magnified and enlightned the particles exceedingly, could I
+in many of them, perceive them to be transparent, or to be whole particles,
+but the smallest specks that I could find among well ground _Vermilion_ and
+_Red-lead_, seem’d to be a Red mass, compounded of a multitude of less and
+less motes, which sticking together, compos’d a bulk, not one thousand
+thousandth part of the smallest visible sand or mote.
+
+And this I find generally in most _Metalline_ colours, that though they
+consist of parts so exceedingly small, yet are they very deeply ting’d,
+they being so ponderous, and having such a multitude of terrestrial
+particles throng’d into a little room; so that ’tis difficult to find any
+particle transparent or resembling a pretious stone, though not impossible;
+for I have observ’d divers such shining and resplendent colours intermixt
+with the particles of _Cinnaber_, both natural and artificial, before it
+hath been ground and broken or flaw’d into _Vermilion_: As I have also in
+_Orpiment_, _Red-lead_, and _Bise_, which makes me suppose, that those
+_metalline_ colours are by grinding, not onely broken and separated
+actually into smaller pieces, but that they are also flaw’d and brused,
+whence they, for the most part, become _opacous_, like flaw’d Crystal or
+Glass, &c. But for _Smalts_ and _verditures_, I have been able with a
+_Microscope_ to perceive their particles very many of them transparent.
+
+Now, that the others also may be transparent, though they do not appear so
+to the _Microscope_, may be made probable by this Experiment: that if you
+take _ammel_ that is almost _opacous_, and grind it very well on a
+_Porphyry_, or _Serpentine_, the small particles will by reason of their
+flaws, appear perfectly _opacous_; and that ’tis the flaws that produce
+this _opacousness_, may be argued from this, that particles of the same
+_Ammel_ much thicker if unflaw’d will appear somewhat transparent even to
+the eye; and from this also, that the most transparent and clear Crystal,
+if heated in the fire, and then suddenly quenched, so that it be all over
+flaw’d, will appear _opacous_ and white.
+
+And that the particles of _Metalline_ colours are transparent, may be
+argued yet further from this, that the Crystals, or _Vitriols_ of all
+Metals, are transparent, which since they consist of _metalline_ as well as
+_saline_ particles, those _metalline_ ones must be transparent, which is
+yet further confirm’d from this, that they have for the most part,
+_appropriate_ colours; so the _vitriol_ of Gold is Yellow; of Copper, Blue,
+and sometimes Green; of Iron, green; of Tinn and Lead, a pale White; of
+Silver, a pale Blue, _&._
+
+And next, the _Solution_ of all Metals into _menstruums_ are much the same
+with the _Vitriols_, or Crystals. It seems therefore very probable, that
+those colours which are made by the _precipitation_ of those particles out
+of the _menstruums_ by transparent _precipitating_ liquors should be
+transparent also. Thus Gold _precipitates_ with _oyl of Tartar_, or _spirit
+of Urine_ into a brown Yellow, Copper with spirit of _Urine_ into a Mucous
+blue, which retains its transparency. A solution of sublimate (as the same
+Illustrious Authour I lately mention’d shews in his 40. Experiment)
+_precipitates_ with oyl of _Tartar_ _per deliquium_, into an Orange
+colour’d _precipitate_; nor is it less probable, that the _calcination_ of
+those _Vitriols_ by the fire, should have their particles transparent: Thus
+_Saccarum Saturni_, or the _Vitriol of Lead_ by _calcination_ becomes a
+deep Orange-colour’d _minium_, which is a kind of _precipitation_ by some
+Salt which proceeds from the fire; common _Vitriol_ _calcin’d_, yields a
+deep Brown Red, &c.
+
+A third Argument, that the particles of Metals are transparent, is, that
+being _calcin’d_, and melted with Glass, they tinge the Glass with
+transparent colours. Thus the _Calx_ of Silver tinges the Glass on which it
+is anneal’d with a lovely Yellow, or Gold colour, &c.
+
+And that the parts of Metals are transparent, may be farther argued from
+the transparency of Leaf-gold, which held against the light, both to the
+naked eye, and the _Microscope_, exhibits a deep Green. And though I have
+never seen the other Metals _laminated_ so thin, that I was able to
+perceive them transparent, yet, for Copper and Brass, if we had the same
+conveniency for _laminating_ them, as we have for Gold, we might, perhaps,
+through such plates or leaves, find very differing degrees of Blue, or
+Green; for it seems very probable, that those Rays that rebound from them
+ting’d, with a deep Yellow, or pale Red, as from Copper, or with a pale
+Yellow, as from Brass, have past through them; for I cannot conceive how by
+reflection alone those Rays can receive a tincture, taking any _Hypothesis_
+extant.
+
+So that we see there may a sufficient reason be drawn from these instances,
+why those colours which we are unable to _dilute_ to the palest Yellow, or
+Blue, or Green, are not therefore to be concluded not to be a deeper degree
+of them; for supposing we had a great company of small _Globular_ essence
+Bottles, or round Glass bubbles, about the bigness of a Walnut, fill’d each
+of them with a very deep mixture of Saffron, and that every one of them did
+appear of a deep Scarlet colour, and all of them together did _exhibit_ at
+a distance, a deep dy’d Scarlet body. It does not follow, because after we
+have come nearer to this _congeries_, or mass, and divided it into its
+parts, and examining each of its parts severally or apart, we find them to
+have much the same colour with the whole mats; it does not, I say,
+therefore follow, that if we could break those _Globules_ smaller, or any
+other ways come to see a smaller or thinner parcel of the ting’d liquor
+that fill’d those bubbles, that that ting’d liquor must always appear Red,
+or of a Scarlet hue, since if Experiment be made, the quite contrary will
+ensue; for it is capable of being _diluted_ into the palest Yellow.
+
+Now, that I might avoid all the Objections of this kind, by exhibiting an
+Experiment that might by ocular proof convince those whom other reasons
+would not prevail with, I provided me a _Prismatical Glass_, made hollow,
+just in the form of a Wedge, such as is represented in the tenth _Figure_
+of the sixth _Scheme_. The two _parallelogram_ sides ABCD, ABEF, which met
+at a point, were made of the clearest Looking-glass plates well ground and
+polish’d that I could get; these were joyn’d with hard cement to the
+_triangular_ sides, BCE, ADF, which were of Wood; the _Parallelogram_ base
+BCEF, likewise was of Wood joyn’d on to the rest with hard cement, and the
+whole _Prismatical_ Box was exactly stopt every where, but onely a little
+hole near the base was left, whereby the Vessel could be fill’d with any
+liquor, or emptied again at pleasure.
+
+One of these Boxes (for I had two of them) I fill’d with a pretty deep
+tincture of _Aloes_, drawn onely with fair Water, and then stopt the hole
+with a piece of Wax, then, by holding this Wedge against the Light, and
+looking through it, it was obvious enough to see the tincture of the liquor
+near the edge of the Wedge where it was but very thin, to be a pale but
+well colour’d Yellow, and further and further from the edge, as the liquor
+grew thicker and thicker, this tincture appear’d deeper and deeper, so that
+near the blunt end, which was seven Inches from the edge and three Inches
+and an half thick; it was of a deep and well colour’d Red. Now, the clearer
+and purer this tincture be, the more lovely will the deep Scarlet be, and
+the fouler the tincture be, the more dirty will the Red appear; so that
+some dirty tinctures have afforded their deepest Red much of the colour of
+burnt Oker or _Spanish_ brown; others as lovely a colour as _Vermilion_,
+and some much brighter; but several others, according as the tinctures were
+worse or more foul, exhibited various kinds of Reds, of very differing
+degrees.
+
+The other of these Wedges, I fill’d with a most lovely tincture of Copper,
+drawn from the filings of it, with spirit of _Urine_, and this Wedge held
+as the former against the Light, afforded all manner of Blues, from the
+faintest to the deepest, so that I was in good hope by these two, to have
+produc’d all the varieties of colours imaginable; for I thought by this
+means to have been able by placing the two _Parallelogram_ sides together,
+and the edges contrary ways, to have so mov’d them to and fro one by
+another, as by looking through them in several places, and through several
+thicknesses, I should have compounded, and consequently have seen all those
+colours, which by other like compositions of colours would have ensued.
+
+But insteed of meeting with what I look’d for, I met with somewhat more
+admirable; and that was, that I found my self utterly unable to see through
+them when placed both together, though they were transparent enough when
+asunder; and though I could see through twice the thickness, when both of
+them were fill’d with the same colour’d liquors, whether both with the
+Yellow, or both with the Blue, yet when one was fill’d with the Yellow, the
+other with the Blue, and both looked through, they both appear’d dark,
+onely when the parts near the tops were look’d through, they exhibited
+Greens, and those of very great variety, as I expected, but the Purples and
+other colours, I could not by any means make, whether I endeavour’d to look
+through them both against the Sun, or whether I plac’d them against the
+hole of a darkned room.
+
+But notwithstanding this mis-ghessing, I proceeded on with my trial in a
+dark room, and having two holes near one another, I was able, by placing my
+Wedges against them, to mix the ting’d Rays that past through them, and
+fell on a sheet of white Paper held at a convenient distance from them as I
+pleas’d; so that I could make the Paper appear of what colour I would, by
+varying the thicknesses of the Wedges, and consequently the tincture of the
+Rays that past through the two holes, and sometimes also by varying the
+Paper, that is, insteed of a white Paper, holding a gray, or a black piece
+of Paper.
+
+Whence I experimentally found what I had before imagin’d, that all the
+varieties of colours imaginable are produc’d from several degrees of these
+two colours, namely, Yellow and Blue, or the mixture of them with light and
+darkness, that is, white and black. And all those almost infinite varieties
+which Limners and Painters are able to make by compounding those several
+colours they lay on their Shels or _Palads_, are nothing else, but some
+_compositum_, made up of some one or more, or all of these four.
+
+Now, whereas it may here again be objected, that neither can the Reds be
+made out of the Yellows, added together, or laid on in greater or less
+quantity, nor can the Yellows be made out of the Reds though laid never so
+thin; and as for the addition of White or Black, they do nothing but either
+whiten or darken the colours to which they are added, and not at all make
+them of any other kind of colour: as for instance, _Vermilion_, by being
+temper’d with White Lead, does not at all grow more Yellow, but onely there
+is made a whiter kind of Red. Nor does Yellow _Oker_, though laid never so
+thick, produce the colour of _Vermilion_, nor though it be temper’d with
+Black, does it at all make a Red; nay, though it be temper’d with White, it
+will not afford a fainter kind of Yellow, such as _masticut_, but onely a
+whiten’d Yellow; nor will the Blues be _diluted_ or deepned after the
+manner I speak of, as _Indico_ will never afford so fine a Blue as
+_Ultramarine_ or _Bise_; nor will it, temper’d with _Vermilion_, ever
+afford a Green, though each of them be never so much temper’d with white.
+
+To which I answer, that there is a great difference between _diluting_ a
+colour and whitening of it; for _diluting_ a colour, is to make the
+colour’d parts more thin, so that the ting’d light, which is made by
+trajecting those ting’d bodies, does not receive so deep a tincture; but
+whitening a colour is onely an intermixing of many clear reflections of
+light among the same ting’d parts; deepning also, and darkning or blacking
+a colour, are very different; for deepning a colour, is to make the light
+pass through a greater quantity of the same tinging body; and darkning or
+blacking a colour, is onely interposing a multitude of dark or black spots
+among the same ting’d parts, or placing the colour in a more faint light.
+
+First therefore, as to the former of these operations, that is, diluting
+and deepning, most of the colours us’d by the Limners and Painters are
+incapable of, to wit, _Vermilion_ and _Red-lead_, and _Oker_, because the
+ting’d parts are so exceeding small, that the most curious Grindstones we
+have, are not able to separate them into parts actually divided so small as
+the ting’d particles are; for looking on the most curiously ground
+_Vermilion_, and _Oker_, and _Red-lead_, I could perceive that even those
+small _corpuscles_ of the bodies they left were compounded of many pieces,
+that is, they seem’d to be small pieces compounded of a multitude of lesser
+ting’d parts: each piece seeming almost like a piece of Red Glass, or
+ting’d Crystal all flaw’d; so that unless the Grindstone could actually
+divide them into smaller pieces then those flaw’d particles were, which
+compounded that ting’d mote I could see with my _Microscope_, it would be
+impossible to _dilute_ the colour by grinding, which, because the finest we
+have will not reach to do in _Vermilion_ or _Oker_, therefore they cannot
+at all, or very hardly be _diluted_.
+
+Other colours indeed, whose ting’d particles are such as may be made
+smaller, by grinding their colour, may be _diluted_. Thus several of the
+Blues may be _diluted_, as _Smalt_ and _Bise_; and _Masticut_, which is
+Yellow, may be made more faint: And even _Vermilion_ it self may, by too
+much grinding, be brought to the colour of _Red-lead_, which is but an
+Orange colour, which is confest by all to be very much upon the Yellow.
+Now, though perhaps somewhat of this _diluting_ of _Vermilion_ by overmuch
+grinding may be attributed to the Grindstone, or muller, for that some of
+their parts may be worn off and mixt with the colour, yet there seems not
+very much, for I have done it on a Serpentine-stone with a muller made of a
+Pebble, and yet observ’d the same effect follow.
+
+And secondly, as to the other of these operations on colours, that is, the
+deepning of them, Limners and Painters colours are for the most part also
+uncapable. For they being for the most part _opacous_; and that
+_opacousness_, as I said before, proceeding from the particles, being very
+much flaw’d, unless we were able to joyn and reunite those flaw’d
+particles again into one piece, we shall not be able to deepen the colour,
+which since we are unable to do with most of the colours which are by
+Painters accounted _opacous_, we are therefore unable to deepen them by
+adding more of the same kind.
+
+But because all those _opacous_ colours have two kinds of beams or Rays
+reflected from them, that is, Rays unting’d, which are onely reflected from
+the outward surface, without at all penetrating of the body, and ting’d
+Rays which are reflected from the inward surfaces or flaws after they have
+suffer’d a two-fold refraction; and because that transparent liquors mixt
+with such _corpuscles_, do, for the most part, take off the former kind of
+reflection; therefore these colours mixt with Water or Oyl, appear much
+deeper than when dry, for most part of that white reflection from the
+outward surface is remov’d. Nay, some of these colours are very much
+deepned by the mixture with some transparent liquor, and that because they
+may perhaps get between those two flaws, and so consequently joyn two or
+more of those flaw’d pieces together; but this happens but in a very few.
+
+Now, to shew that all this is not _gratis dictum_, I shall set down some
+Experiments which do manifest these things to be probable and likely, which
+I have here deliver’d.
+
+For, first, if you take any ting’d liquor whatsoever, especially if it be
+pretty deeply ting’d, and by any means work it into a froth, the
+_congeries_ of that froth shall seem an _opacous_ body, and appear of the
+same colour, but much whiter than that of the liquor out of which it is
+made. For the abundance of reflections of the Rays against those surfaces
+of the bubbles of which the froth consists, does so often rebound the Rays
+backwards, that little or no light can pass through, and consequently the
+froth appears _opacous_.
+
+Again, if to any of these ting’d liquors that will endure the boiling there
+be added a small quantity of fine flower (the parts of which through the
+_Microscope_ are plainly enough to be perceiv’d to consist of transparent
+_corpuscles_) and suffer’d to boyl till it thicken the liquor, the mass of
+the liquor will appear _opacous_, and ting’d with the same colour, but very
+much whiten’d.
+
+Thus, if you take a piece of transparent Glass that is well colour’d, and
+by heating it, and then quenching it in Water, you flaw it all over, it
+will become _opacous_, and will exhibit the same colour with which the
+piece is ting’d, but fainter and whiter.
+
+Or, if you take a Pipe of this transparent Glass, and in the flame of a
+Lamp melt it, and then blow it into very thin bubbles, then break those
+bubbles, and collect a good parcel of those _laminæ_ together in a Paper,
+you shall find that a small thickness of those Plates will constitute an
+_opacous_ body, and that you may see through the mass of Glass before it be
+thus _laminated_, above four times the thickness: And besides, they will
+now afford a colour by reflection as other _opacous_ (as they are call’d)
+colours will, but much fainter and whiter than that of the Lump or Pipe out
+of which they were made.
+
+Thus also, if you take _Putty_, and melt it with any transparent colour’d
+Glass, it will make it become an _opacous_ colour’d lump, and to yield a
+paler and whiter colour than the lump by reflection.
+
+The same thing may be done by a preparation of _Antimony_, as has been
+shewn by the Learned _Physician_, Dr. _C.M._ in his Excellent Observations
+and Notes on _Nery’s Art of Glass_; and by this means all transparent
+colours become _opacous_, or _ammels_. And though by being ground they lose
+very much of their colour, growing much whiter by reason of the multitude
+of single reflections from their outward surface, as I shew’d afore, yet
+the fire that in the nealing or melting re-unites them, and so renews those
+_spurious_ reflections, removes also those whitenings of the colour that
+proceed from them.
+
+As for the other colours which Painters use, which are transparent, and
+us’d to varnish over all other paintings, ’tis well enough known that the
+laying on of them thinner or thicker, does very much _dilute_ or deepen
+their colour.
+
+Painters Colours therefore consisting most of them of solid particles, so
+small that they cannot be either re-united into thicker particles by any
+Art yet known, and consequently cannot be deepned; or divided into
+particles so small as the flaw’d particles that exhibit that colour, much
+less into smaller, and consequently cannot be _diluted_; It is necessary
+that they which are to imitate all kinds of colours, should have as many
+degrees of each colour as can be procur’d.
+
+And to this purpose, both Limners and Painters have a very great variety
+both of Yellows and Blues, besides several other colour’d bodies that
+exhibit very compounded colours, such as Greens and Purples; and others
+that are compounded of several degrees of Yellow, or several degrees of
+Blue, sometimes unmixt, and sometimes compounded with several other
+colour’d bodies.
+
+The Yellows, from the palest to the deepest Red or Scarlet, which has no
+intermixture of Blue, are _pale and deep Masticut, Orpament, English Oker,
+brown Oker, Red-Lead, and Vermilion, burnt English Oker, and burnt brown
+Oker_, which last have a mixture of dark or dirty parts with them, &c.
+
+Their Blues are several kinds of _Smalts_, and _Verditures_, and _Bise_,
+and _Ultramarine_, and _Indico_, which last has many dirty or dark parts
+intermixt with it.
+
+Their compounded colour’d bodies, as _Pink_, and _Verdigrese_, which are
+Greens, the one a _Popingay_, the other a _Sea-green_; then _Lac_, which is
+a very lovely _Purple_.
+
+To which may be added their Black and White, which they also usually call
+Colours, of each of which they have several kinds, such as _Bone Black_,
+made of _Ivory_ burnt in a close Vessel, and _Blue Black_, made of the
+small coal of _Willow_, or some other Wood; and _Cullens earth_, which is a
+kind of brown Black, &c. Their usual Whites are either artificial or
+natural _White Lead_, the last of which is the best they yet have, and with
+the mixing and tempering these colours together, are they able to make an
+imitation of any colour whatsoever: Their Reds or deep Yellows, they can
+_dilute_ by mixing pale Yellows with them, and deepen their pale by mixing
+deeper with them; for it is not with _Opacous_ colours as it is with
+transparent, where by adding more Yellow to yellow, it is deepned, but in
+_opacous_ _diluted_. They can whiten any colour by mixing White with it,
+and darken any colour by mixing Black, or some dark and dirty colour. And
+in a word, most of the colours, or colour’d bodies they use in Limning and
+Painting, are such, as though mixt with any other of their colours, they
+preserve their own hue, and by being in such very smal parts dispers’d
+through the other colour’d bodies, they both, or altogether represent to
+the eye a _compositum_ of all; the eye being unable, by reason of their
+smalness, to distinguish the peculiarly colour’d particles, but receives
+them as one intire _compositum_: whereas in many of these, the _Microscope_
+very easily distinguishes each of the compounding colours distinct, and
+exhibiting its own colour.
+
+Thus have I by gently mixing _Vermilion_ and _Bise_ dry, produc’d a very
+fine Purple, or mixt colour, but looking on it with the _Microscope_, I
+could easily distinguish both the Red and the Blue particles, which did not
+at all produce the _Phantasm_ of Purple.
+
+To summ up all therefore in a word, I have not yet found any solid colour’d
+body, that I have yet examin’d, perfectly _opacous_; but those that are
+least transparent are _Metalline_ and _Mineral_ bodies, whose particles
+generally, seeming either to be very small, or very much flaw’d, appear for
+the most part _opacous_, though there are very few of them that I have
+look’d on with a _Microscope_, that have not very plainly or
+circumstantially manifested themselves transparent.
+
+And indeed, there seem to be so few bodies in the world that are _in
+minimis_ opacous, that I think one may make it a rational _Query_, Whether
+there be any body absolutely thus _opacous_? For I doubt not at all (and I
+have taken notice of very many circumstances that make me of this mind)
+that could we very much improve the _Microscope_, we might be able to see
+all those bodies very plainly transparent, which we now are fain onely to
+ghess at by circumstances. Nay, the Object Glasses we yet make use of are
+such, that they make many transparent bodies to the eye, seem _opacous_
+through them, which if we widen the Aperture a little, and cast more light
+on the objects, and not charge the Glasses so deep, will again disclose
+their transparency.
+
+Now, as for all kinds of colours that are dissolvable in Water, or other
+liquors, there is nothing so manifest, as that all those ting’d liquors are
+transparent; and many of them are capable of being _diluted_ and compounded
+or mixt with other colours, and divers of them are capable of being very
+much chang’d and heightned, and fixt with several kinds of _Saline
+menstruums_. Others of them upon compounding, destroy or vitiate each
+others colours, and _precipitate_, or otherwise very much alter each others
+tincture. In the true ordering and _diluting_, and deepning, and mixing,
+and fixing of each of which, consists one of the greatest mysteries of the
+Dyers; of which particulars, because our _Microscope_ affords us very
+little information, I shall add nothing more at present; but onely that
+with a very few tinctures order’d and mixt after certain ways, too long to
+be here set down, I have been able to make an appearance of all the various
+colours imaginable, without at all using the help of _Salts_, or _Saline
+menstruums_ to vary them.
+
+As for the mutation of Colours by _Saline menstruums_, they have already
+been so fully and excellently handled by the lately mention’d Incomparable
+_Authour_, that I can add nothing, but that of a multitude of trials that I
+made, I have found them exactly to agree with his Rules and Theories; and
+though there may be infinite instances, yet may they be reduc’d under a few
+Heads, and compris’d within a very few Rules. And generally I find, that
+_Saline menstruums_ are most operative upon those colours that are Purple,
+or have some degree of Purple in them, and upon the other colours much
+less. The _spurious_ pulses that compose which, being (as I formerly noted)
+so very neer the middle between the true ones, that a small variation
+throws them both to one side, or both to the other, and so consequently
+must make a vast mutation in the formerly appearing Colour.
+
+       *       *       *       *       *
+
+
+Observ. XI. _Of _Figures_ observ’d in small Sand._
+
+Sand generally seems to be nothing else but exceeding small Pebbles, or at
+least some very small parcels of a bigger stone; the whiter kind seems
+through the _Microscope_ to consist of small transparent pieces of some
+_pellucid_ body, each of them looking much like a piece of _Alum_, or _Salt
+Gem_; and this kind of Sand is angled for the most part irregularly,
+without any certain shape, and the _granules_ of it are for the most part
+flaw’d, through amongst many of them it is not difficult to find some that
+are perfectly _pellucid_, like a piece of clear Crystal, and divers
+likewise most curiously shap’d, much after the manner of the bigger
+_Stiriæ_ of Crystal, or like the small Diamants I observ’d in certain
+Flints, of which I shall by and by relate; which last particular seems to
+argue, that this kind of Sand is not made by the comminution of greater
+transparent Crystaline bodies, but by the _concretion_ or _coagulation_ of
+Water, or some other fluid body.
+
+There are other kinds of courser Sands, which are browner, and have their
+particles much bigger; these, view’d with a _Microscope_, seem much courser
+and more _opacous_ substances, and most of them are of some irregularly
+rounded Figures; and though they seem not so _opacous_ as to the naked eye,
+yet they seem very foul and cloudy, but neither do these want curiously
+transparent, no more than they do regularly figur’d and well colour’d
+particles, as I have often found.
+
+There are multitudes of other kinds of Sands, which in many particulars,
+plainly enough discoverable by the _Microscope_, differ both from these
+last mention’d kinds of Sands, and from one another: there seeming to be as
+great variety of Sands, as there is of Stones. And as amongst Stones some
+are call’d precious from their excellency, so also are there Sands which
+deserve the same Epithite for their beauty; for viewing a small parcel of
+_East-India_ Sand (which was given me by my highly honoured friend, Mr.
+_Daniel Colwall_) and, since that, another parcel, much of the same kind, I
+found several of them, both very transparent like precious Stones, and
+regularly figur’d like Crystal, _Cornish_ Diamants, some Rubies, &c. and
+also ting’d with very lively and deep colours, like _Rubys_, _Saphyrs_,
+_Emeralds_, &c. These kinds of granules I have often found also in _English_
+Sand. And ’tis easie to make such a counterfeit Sand with deeply ting’d
+Glass, Enamels and Painters colours.
+
+It were endless to describe the multitudes of Figures I have met with in
+these kind of minute bodies, such as _Spherical_, _Oval_, _Pyramidal_,
+_Conical_, _Prismatical_, of each of which kinds I have taken notice.
+
+But amongst many others, I met with none more observable than this pretty
+Shell (described in the _Figure_ X. of the fifth _Scheme_) which, though as
+it was light on by chance, deserv’d to have been omitted (I being unable to
+direct any one to find the like) yet for its rarity was it not
+inconsiderable, especially upon the account of the information it may
+afford us. For by it we have a very good instance of the curiosity of
+Nature in another kind of Animals which are remov’d, by reason of their
+minuteness, beyond the reach of our eyes, so that as there are several
+sorts of Insects, as Mites, and others, so small as not yet to have had any
+names; (some of which I shall afterwards describe) and small Fishes, as
+Leeches in Vinegar; and smal vegetables, as Moss, and Rose-Leave-plants;
+and small Mushroms, as mould: so are there, it seems, small Shel-fish
+likewise, Nature shewing her curiosity in every Tribe of _Animals_,
+_Vegetables_, and _Minerals_.
+
+I was trying several small and single Magnifying Glasses, and casually
+viewing a parcel of white Sand, when I perceiv’d one of the grains exactly
+shap’d and wreath’d like a Shell, but endeavouring to distinguish it with
+my naked eye, it was so very small, that I was fain again to make use of
+the Glass to find it; then, whilest I thus look’d on it, with a Pin I
+separated all the rest of the granules of Sand, and found it afterwards to
+appear to the naked eye an exceeding small white spot, no bigger than the
+point of a Pin. Afterwards I view’d it every way with a better _Microscope_
+and found it on both sides, and edge-ways, to resemble the Shell of a small
+Water-Snail with a flat spiral Shell: it had twelve wreathings, a, b, c, d,
+e, &c. all very proportionably growing one less than another toward the
+middle or center of the Shell, where there was a very small round white
+spot. I could not certainly discover whether the Shell were hollow or not,
+but it seem’d fill’d with somewhat, and ’tis probable that it might be
+_petrify’d_ as other larger Shels often are, such as are mention’d in the
+seventeenth _Observation_.
+
+       *       *       *       *       *
+
+
+Observ. XII. _Of _Gravel_ in Urine._
+
+I Have often observ’d the Sand or Gravel of Urine, which seems to be a
+_tartareous_ substance, generated out of a _saline_ and a _terrestrial_
+substance _crystalliz’d_ together, in the form of _Tartar_, sometimes
+sticking to the sides of the _Urinal_, but for the most part sinking to the
+bottom, and there lying in the form of coorse common Sand; these, through
+the _Microscope_, appear to be a company of small bodies, partly
+transparent and partly _opacous_, some White, some Yellow, some Red, others
+of more brown and duskie colours.
+
+The Figure of them is for the most part flat, in the manner of Slats or
+such like plated Stones, that is, each of them seem to be made up of
+several other thinner Plates, much like _Muscovie Glass_, or _English Sparr_
+to the last of which, the white plated Gravel seems most likely; for they
+seem not onely plated like that, but their sides shap’d also into _Rhombs_,
+_Rhomboeids_, and sometimes into _Rectangles_ and _Squares_. Their bigness
+and Figure may be seen in the second _Figure_ of the seventh _Plate_, which
+represents about a dozen of them lying upon a plate ABCD, some of which, as
+a, b, c, d seem’d more regular than the rest, and e, which was a small one,
+sticking on the top of another, was a perfect _Rhomboeid_ on the top, and
+had four _Rectangular_ sides.
+
+The line E which was the measure of the _Microscope_, is ¹⁄₃₂ part of
+an _English_ Inch, so that the greatest bredth of any of them, exceeded not
+¹⁄₁₂₈ part of an Inch.
+
+Putting these into several liquors, I found _oyl of Vitriol_, _Spirit of
+Urine_, and several other _Saline menstruums_ to dissolve them; and the
+first of these in less than a minute without _Ebullition_, Water, and
+several other liquors, had no sudden operation upon them. This I mention,
+because those liquors that dissolve them, first make them very white, not
+_vitiating_, but rather rectifying their Figure, and thereby make them
+afford a very pretty object for the _Microscope_.
+
+How great an advantage it would be to such as are troubled with the Stone,
+to find some _menstruum_ might dissolve them without hurting the Bladder,
+is easily imagin’d, since some _injections_ made of such bodies might
+likewise dissolve the stone, which seems much of the same nature.
+
+It may therefore, perhaps, be worthy some Physicians enquiry, whether there
+may not be something mixt with the Urine in which the Gravel or Stone lies,
+which may again make it dissolve it, the first of which seems by it’s
+regular Figures to have been sometimes _Crystalliz’d_ out of it. For
+whether this _Crystallization_ be made in the manner as _Alum_, _Peter_,
+&c. are _crystallized_ out of a cooling liquor, in which, by boyling they
+have been dissolv’d; or whether it be made in the manner of _Tartarum
+Vitriolatum_, that is, by the _Coalition_ of an _acid_ and a _Sulphureous_
+substance, it seems not impossible, but that the liquor it lies in, may be
+again made a _dissolvent_ of it. But leaving these inquiries to Physicians
+or Chymists, to whom it does more properly belong, I shall proceed.
+
+       *       *       *       *       *
+
+
+Observ. XIII. _Of the small _Diamants_, or _Sparks_ in _Flints_._
+
+Chancing to break a Flint stone in pieces, I found within it a certain
+cavity all crusted over with a very pretty candied substance, some of the
+parts of which, upon changing the posture of the Stone, in respect of the
+_Incident_ light, exhibited a number of small, but very vivid reflections;
+and having made use of my _Microscope_, I could perceive the whole surface
+of that cavity to be all beset with a multitude of little _Crystaline_ or
+_Adamantine_ bodies, so curiously shap’d, that it afforded a not unpleasing
+object.
+
+Having considered those vivid _repercussions_ of light, I found them to be
+made partly from the plain external surface of these regularly figured
+bodies (which afforded the vivid reflections) and partly to be made from
+within the somewhat _pellucid_ body, that is, from some surface of the
+body, opposite to that superficies of it which was next the eye.
+
+And because these bodies were so small, that I could not well come to make
+Experiments and Examinations of them, I provided me several small _stiriæ_
+of Crystals or Diamants, found in great quantities in _Cornwall_ and are
+therefore commonly called _Cornish Diamants_: these being very _pellucid_,
+and growing in a hollow cavity of a Rock (as I have been several times
+informed by those that have observ’d them) much after the same manner as
+these do in the Flint, and having besides their outward surface very
+regularly shap’d, retaining very near the same Figures with some of those I
+observ’d in the other, became a convenient help to me for the Examination
+of the proprieties of those kinds of bodies.
+
+And first for the Reflections, in these I found it very observable, That
+the brightest reflections of light proceeded from within the _pellucid_
+body; that is, that the Rays admitted through the _pellucid_ substance in
+their getting out on the opposite side, were by the contiguous and strong
+reflecting surface of the Air very vividly reflected, so that more Rays
+were reflected to the eye by this surface, though the Ray in entring and
+getting out of the Crystal had suffer’d a double refraction, than there
+were from the outward surface of the Glass where the Ray had suffer’d no
+refraction at all.
+
+And that this was the surface of the Air that gave so vivid a
+_re-percussion_ I try’d by this means I sunk half of a _stiria_ in Water,
+so that only Water was contiguous to the under surface, and then the
+internal reflection was so exceedingly faint, that it was scarce
+discernable. Again, I try’d to alter this vivid reflection by keeping off
+the Air, with a body not fluid, and that was by rubbing and holding my
+finger very hard against the under surface, so as in many places the pulp
+of my finger did touch the Glass, without any _interjacent_ air between,
+then observing the reflection, I found, that wheresoever my finger or skin
+toucht the surface, from that part there was no reflection, but in the
+little furrows or creases of my skin, where there remain’d little small
+lines of air, from them was return’d a very vivid reflection as before. I
+try’d further, by making the surface of very pure Quicksilver to be
+contiguous to the under surface of this _pellucid_ body, and then the
+reflection from that was so exceedingly more vivid than from the air, as
+the reflection from air was than the reflection from the Water; from all
+which trials I plainly saw, that the strong reflecting air was the cause of
+this _Phænomenon_.
+
+And this agrees very well with the _Hypothesis_ of light and _Pellucid_
+bodies which I have mention’d in the description of _Muscovy-glass_; for we
+there suppose Glass to be a _medium_, which does less resist the pulse of
+light, and consequently, that most of the Rays incident on it enter into
+it, and are refracted towards the _perpendicular_; whereas the air I
+suppose to be a body that does more resist it, and consequently more are
+_re-percuss’d_ then do enter it: the same kind of trials have I made, with
+_Crystalline Glass_, with drops of fluid bodies, and several other ways,
+which do all seem to agree very exactly with this _Theory_. So that from
+this Principle well establish’d, we may deduce severall Corollaries not
+unworthy observation.
+
+And the first is; that it plainly appears by this, that the production of
+the Rainbow is as much to be ascribed to the reflection of the concave
+surface of the air, as to the refraction of the _Globular_ drops: this will
+be evidently manifest by these Experiments, if you _foliate_ that part of a
+Glass-ball that is to reflect an _Iris_, as in the _Cartesian_ Experiment,
+above mention’d, the reflections will be abundantly more strong, and the
+colours more vivid: and if that part of the surface be touch’d with Water,
+scarce affords any sensible colour at all.
+
+Next we learn, that the great reason why _pellucid_ bodies beaten small are
+white, is from the multitude of reflections, not from the particles of the
+body, but from the _contiguous_ surface of the air. And this is evidently
+manifested, by filling the _Interstitia_ of those powder’d bodies with
+Water, whereby their whiteness presently disappears. From the same reason
+proceeds the whiteness of many kinds of Sands, which in the _Microscope_
+appear to be made up of a multitude of little _pellucid_ bodies, whose
+brightest reflections may by the _Microscope_ be plainly perceiv’d to come
+from their internal surfaces; and much of the whiteness of it may be
+destroy’d by the affusion of fair Water to be contiguous to those surfaces.
+
+The whiteness also of froth, is for the most part to be ascribed to the
+reflection of the light from the surface of the air within the Bubbles, and
+very little to the reflection from the surface of the Water it self: for
+this last reflection does not return a quarter so many Rays, as that which
+is made from the surface of the air, as I have certainly found by a
+multitude of Observations and Experiments.
+
+The whiteness of _Linnen_, _Paper_, _Silk_, &c. proceeds much from the same
+reason, as the _Microscope_ will easily discover; for the Paper is made up
+of an abundance of _pellucid_ bodies, which afford a very plentifull
+reflection from within, that is, from the concave surface of the air
+contiguous to its component particles; wherefore by the affusion of Water,
+Oyl, Tallow, Turpentine, &c. all those reflections are made more faint, and
+the beams of light are suffer’d to traject & run through the Paper more
+freely.
+
+Hence further we may learn the reason of the whiteness of many bodies, and
+by what means they may be in part made _pellucid_: As white Marble for
+instance, for this body is composed of a _pellucid_ body exceedingly
+flaw’d, that is, there are abundance of thin, and very fine cracks or
+chinks amongst the multitude of particles of the body, that contain in them
+small parcels of air, which do so _re-percuss_ and drive back the
+penetrating beams, that they cannot enter very deep within that body; which
+the _Microscope_ does plainly inform us to be made up of a _Congeries_ of
+_pellucid_ particles. And I further found it somewhat more evidently by
+some attempts I made towards the making transparent Marble, for by heating
+the Stone a little, and soaking it in Oyl, Turpentine, Oyl of Turpentine,
+&c., I found that I was able to see much deeper into the body of Marble
+than before; and one trial, which was not with an unctuous substance,
+succeeded better than the rest, of which, when I have a better opportunity,
+I shall make further trial.
+
+This also gives us a probable reason of the so much admired _Phænomena_, of
+the _Oculus Mundi_, an _Oval_ stone, which commonly looks like white
+Alabaster, but being laid a certain time in Water, it grows _pellucid_, and
+transparent, and being suffer’d to lie again dry, it by degrees loses that
+transparency, and becomes white as before. For the Stone being of a hollow
+spongie nature, has in the first and last of these appearances, all those
+pores fill’d with the obtunding and reflecting air; whereas in the second,
+all those pores are fill’d with a _medium_ that has much the same
+refraction with the particles of the Stone, and therefore those two being
+_contiguous_, make, as ’twere, one _continued medium_, of which more is
+said in the 15. _Observation_.
+
+There are a multitude of other _Phænomena_, that are produc’d from this
+same Principle, which as it has not been taken notice of by any yet that I
+know, so I think, upon more diligent observation, will it not be found the
+least considerable. But I have here onely time to hint _Hypotheses_, and
+not to prosecute them so fully as I could wish; many of them having a vast
+extent in the production of a multitude of _Phænomena_, which have been by
+others, either not attempted to be explain’d, or else attributed to some
+other cause than what I have assign’d, and perhaps than the right; and
+therefore I shall leave this to the prosecution of such as have more
+leisure: onely before I leave it, I must not pretermit to hint, that by
+this Principle, multitudes of the _Phænomena_ of the air, as about _Mists_,
+_Clouds_, _Meteors_, _Haloes_, &c. are most plainly and (perhaps) truly
+explicable; multitudes also of the _Phænomena_ in colour’d bodies, as
+liquors, &c. are deducible from it.
+
+And from this I shall proceed to a second considerable _Phænomenon_ which
+these Diamants exhibit, and that is the regularity of their _Figure_, which
+is a propriety not less general than the former, It comprising within its
+extent, all kinds of _Metals_, all kinds of _Minerals_, most _Precious
+stones_, all kinds of _Salts_, multitudes of _Earths_, and almost all kinds
+of _fluid bodies_. And this is another propiety, which, though a little
+superficially taken notice of by some, has not, that I know, been so much
+as attempted to be explicated by any.
+
+This propriety of bodies, as I think it the most worthy, and next in order
+to be consider’d after the contemplation of the _Globular Figure_, so have
+I long had a desire as wel as a determination to have prosecuted it if I
+had had an opportunity, having long since propos’d to my self the method of
+my enquiry therein, it containing all the allurements that I think any
+enquiry is capable of: For, first I take it to proceed from the most simple
+principle that any kind of form can come from, next the _Globular_, which
+was therefore the first I set upon, and what I have therein perform’d, I
+leave the Judicious Reader to determine. For as that form proceeded from a
+propiety of fluid bodies, which I have call’d _Congruity_, or
+_Incongruity_; so I think, had I time and opportunity, I could make
+probable, that all these regular Figures that are so conspicuously
+_various_ and _curious_, and do so adorn and beautifie such multitudes of
+bodies, as I have above hinted, arise onely from three or four several
+positions or postures of _Globular_ particles, and those the most plain,
+obvious, and necessary conjunctions of such figur’d particles that are
+possible, so that supposing such and such plain and obvious causes
+concurring the _coagulating particles_ must necessarily compose a body of
+such a determinate regular Figure, and no other, and this with as much
+necessity and obviousness as a fluid body encompast with a _Heterogeneous_
+fluid must be protruded into a _Spherule_ or _Globe_. And this I have _ad
+oculum_ demonstrated with a company of bullets, and some few other very
+simple bodies; so that there was not any regular Figure, which I have
+hitherto met withall, of any of those bodies that I have above named, that
+I could not with the composition of bullets or globules, and one or two
+other bodies, imitate, even almost by shaking them together. And thus for
+instance may we find that the _Globular_ bullets will of themselves, if put
+on an inclining plain, so that they may run together, naturally run into a
+_triangular_ order, composing all the variety of figures that can be
+imagin’d to be made out of _æquilateral triangles_; and such will you find,
+upon trial, all the Surfaces of _Alum_ to be compos’d of: For three bullets
+lying on a plain, as close to one another as they can compose an
+_æquilatero-triangular_ form, as in A in the 7. _Scheme_. If a fourth be
+joyn’d to them on either side as closely as it can, they four compose the
+most regular Rhombus consisting of two _æquilateral triangles_, as B. If a
+fifth be joyn’d to them on either side in as close a position as it can,
+which is the propriety of the _Texture_, it makes a _Trapezium_, or
+four-sided Figure, two of whose angles are 120. and two 60. degrees, as C.
+If a sixth be added, as before, either it makes an _æquilateral triangle_,
+as D, or a Rhomboeid, as E, or an _Hexangular Figure_, as F, which is
+compos’d of two _primary Rhombs_. If a seventh be added, it makes either
+an _æquilatero-hexagonal_ Figure, as G, or some kind of six-sided _Figure_,
+as H, or I. And though there be never so many placed together, they may be
+rang’d into some of these lately mentioned Figures, all the angles of which
+will be either _60_. degrees, or 120. as the figure K. which is an
+_æquiangular hexagonal_ Figure is compounded of 12. _Globules_, or may be
+of 25, or 27, or 36, or 42, &c. and by these kinds of texture, or position
+of globular bodies, may you find out all the variety of regular shapes,
+into which the smooth surfaces of _Alum_ are form’d, as upon examination
+any one may easily find; nor does it hold only in superficies, but in
+solidity also, for it’s obvious that a fourth _Globule_ laid upon the third
+in this texture, composes a regular _Tetrahedron_, which is a very usual
+Figure of the _Crystals_ of _Alum_. And (to hasten) there is no one Figure
+into which _Alum_ is observ’d to be crystallized, but may by this texture
+of _Globules_ be imitated, and by no other.
+
+I could instance also in the Figure of _Sea-salt_, and _Sal-gem_, that it
+is compos’d of a texture of _Globules_, placed in a _cubical_ form, as L,
+and that all the Figures of those Salts may be imitated by this texture of
+_Globules_ and by no other whatsoever. And that the forms of _Vitriol_ and
+of _Salt-Peter_, as also of _Crystal_, _Hore-frost_, &c. are compounded of
+these two textures, but modulated by certain proprieties: But I have not
+here time to insist upon, as I have not neither to shew by what means
+_Globules_ come to be thus context, and what those _Globules_ are, and many
+other particulars requisite to a full and intelligible explication of this
+propriety of bodies. Nor have I hitherto found indeed an opportunity of
+prosecuting the inquiry so farr as I design’d; nor do I know when I may, it
+requiring abundance of time, and a great deal of assistance to go through
+with what I design’d; the model of which was this:
+
+First, to get as exact and full a collection as I could, of all the
+differing kinds of Geometrical figur’d bodies, some three or four several
+bodies of each kind.
+
+Secondly, with them to get as exact a History as possibly I could learn of
+their places of Generation or finding, and to enquire after as many
+circumstances that tended to the Illustrating of this Enquiry, as possibly
+I could observe.
+
+Thirdly, to make as many trials as upon experience I could find requisite,
+in Dissolutions and Coagulations of several crystallizing Salts; for the
+needfull instruction and information in this Enquiry.
+
+Fourthly, to make several trials on divers other bodies, as Metals,
+Minerals, and Stones, by dissolving them in several _Menstruums_, and
+crystalizing them, to see what Figures would arise from those several
+_Compositums_.
+
+Fifthly, to make Compositions and Coagulations of several Salts together
+into the same mass, to observe of what Figure the product of them would be;
+and in all, to note as many circumstances as I should judge conducive to my
+Enquiry.
+
+Sixthly, to enquire the closeness or rarity of the texture of these bodies,
+by examining their gravity, and their refraction, &c.
+
+Seventhly, to enquire particularly what operations the fire has upon
+several kinds of Salts, what changes it causes in their Figures, Textures,
+or Energies.
+
+Eighthly, to examine their manner of dissolution, or acting upon those
+bodies dissoluble in them; The texture of those bodies before and after the
+process. And this for the History.
+
+Next for the Solution, To have examin’d by what, and how many means, such
+and such Figures, actions and effects could be produc’d possibly.
+
+And lastly, from all circumstances well weigh’d, I should have endeavoured
+to have shewn which of them was most likely, and (if the informations by
+these Enquiries would have born it) to have demonstrated which of them it
+must be, and was.
+
+But to proceed, As I believe it next to the Globular the most simple; so do
+I, in the second place, judge it not less pleasant; for that which makes an
+Enquiry pleasant, are, first a noble _Inventum_ that promises to crown the
+successfull endeavour; and such must certainly the knowledge of the
+efficient and concurrent causes of all these curious Geometrical Figures
+be, which has made the Philosophers hitherto to conclude nature in these
+things to play the Geometrician, according to that saying of _Plato_,
+Ὁ Θεὸς γεομετρεῖ. Or next, a great variety of matter in the
+Enquiry; and here we meet with nothing less than the _Mathematicks_ of
+nature, having every day a new Figure to contemplate, or a variation of the
+same in another body,
+
+Which do afford us a third thing, which will yet more sweeten the Enquiry,
+and that is, a multitude of information; we are not so much to grope in the
+dark, as in most other Enquiries, where the _Inventum_ is great; for having
+such a multitude of instances to compare, and such easie ways of
+generating, or compounding and of destroying the form, as in the _Solution_
+and _Crystallization_ of Salts, we cannot but learn plentifull information
+to proceed by. And this will further appear from the universality of the
+Principle which Nature has made use of almost in all inanimate bodies. And
+therefore, as the contemplation of them all conduces to the knowledg of any
+one; so from a Scientifical knowledge of any one does follow the fame of
+all, and every one.
+
+And fourthly, for the usefulness of this knowledge, when acquir’d;
+certainly none can doubt, that considers that it caries us a step forward
+into the Labyrinth of Nature, in the right way towards the end we propose
+our selves in all Philosophical Enquiries. So that knowing what is the form
+of Inanimate or Mineral bodies, we shall be the better able to proceed in
+our next Enquiry after the forms of Vegetative bodies; and last of all, of
+Animate ones, that seeming to be the highest step of natural knowledge that
+the mind of man is capable of.
+
+       *       *       *       *       *
+
+
+Observ. XIV. _Of several kindes of frozen _Figures_._
+
+I have very often in a Morning, when there has been a great _hoar-frost_,
+with an indifferently magnifying _Microscope_, observ’d the small _Stiriæ_,
+or Crystalline beard, which then usually covers the face of most bodies
+that lie open to the cold air, and found them to be generally _Hexangular
+prismatical_ bodies, much like the long Crystals of _Salt-peter_, save
+onely that the ends of them were differing: for whereas those of _Nitre_
+are for the most part _pyramidal_, being terminated either in a point or
+edge; these of Frost were hollow, and the cavity in some seem’d pretty
+deep, and this cavity was the more plainly to be seen, because usually one
+or other of the six _parallelogram_ sides was wanting, or at least much
+shorter then the rest.
+
+But this was onely the Figure of the _Bearded hoar-frost_; and as for the
+particles of other kinds of _hoar-frosts_, they seem’d for the most part
+irregular, or of no certain Figure. Nay, the parts of those curious
+branchings, or _vortices_, that usually in cold weather tarnish the surface
+of Glass, appear through the _Microscope_ very rude and unshapen, as do
+most other kinds of frozen _Figures_, which to the naked eye seem exceeding
+neat and curious, such as the Figures of _Snow_, frozen _Urine_, _Hail_,
+several _Figures_ frozen in common Water, &c. Some Observations of each of
+which I shall hereunto annex, because if well consider’d and examin’d, they
+may, perhaps, prove very instructive for the finding out of what I have
+endeavoured in the preceding Observation to shew, to be (next the _Globular
+Figure_ which is caus’d by _congruity_, as I hope I have made probable in
+the sixth _Observation_) the most simple and plain operation of Nature, of
+which, notwithstanding we are yet ignorant.
+
+I.
+
+_Several Observables in the _six-branched_ Figures form’d on the surface of
+Urine by freezing._
+
+1 [11]The Figures were all frozen almost even with the surface of the
+_Urine_ in the Vessel; but the bigger stems were a little _prominent_ above
+that surface, and the parts of those stems which were nearest the center
+(a) were biggest above the surface.
+
+2 I have observ’d several kinds of these Figures, some smaller, no bigger
+then a Two-pence, others so bigg, that I have by measure found one of its
+stems or branches above four foot long; and of these, some were pretty
+round, having all their branches pretty neer alike; other of them were more
+extended towards one side, as usually those very large ones were, which I
+have observ’d in Ditches which have been full of foul water.
+
+3 None of all these Figures I have yet taken notice of, had any regular
+position in respect of one another, or of the sides of the Vessel; nor did
+I find any of them equally to exactness extended every way from the center
+a.
+
+4 Where ever there was a center, the branchings from it, ab, ac, ad, ae,
+af, ag, were never fewer, or more then six, which usually concurr’d, or met
+one another very neer in the same point or center, a; though oftentimes not
+exactly; and were enclin’d to each other by an angle, of very near sixty
+degrees, I say, very neer, because, though having endeavoured to measure
+them the most accurately I was able, with the largest Compasses I had, I
+could not find any sensible variation from that measure, yet the whole
+six-branched Figure seeming to compose a solid angle, they must necessarily
+be somewhat less.
+
+5 The middle lines or stems of these branches, ab, ac, ad, ae, af, ag,
+seem’d somewhat whiter, and a little higher then any of the _intermediate_
+branchings of these Figures; and the center a, was the most _prominent_
+part of the whole Figure, seeming the _apex_ of a solid angle or _pyramid_,
+each of the six plains being a little enclin’d below the surface of the
+_Urin_.
+
+6 The lateral branchings issuing out of the great ones, such as op, mq, &c.
+were each of them inclin’d to the great ones, by the same angle of about
+sixty degrees, as the great ones were one to another, and always the bigger
+branchings were _prominent_ above the less, and the less above the least,
+by proportionate _gradations_.
+
+7 The _lateral_ branches shooting out of the great ones, went all of them
+from the center, and each of them was parallel to that great branch, next
+to which it lay; so that as all the branches on one side were parallel to
+one another, so were they all of them to the _approximate_ great branch, as
+po, qr, as they were parallel to each other, and shot from the center, so
+were they parallel also to the great branch ab.
+
+8 Some of the stems of the six branches proceeded straight, and of a
+thickness that gradually grew sharper towards the end, as ag.
+
+9 Others of the stems of those branches grew bigger and knotty towards the
+middle, and the branches also as well as stems, from Cylinders grew into
+Plates, in a most admirable and curious order, so exceeding regular and
+delicate, as nothing could be more, as is visible in ab, ac, ad, ae, af,
+but towards the end of some of these stems, they began again to grow
+smaller and to recover their former branchings, as about k and n.
+
+10 Many of the _lateral_ branches had _collateral_ branches (if I may so
+call them) as qm had many such as st, and most of those again
+_subcollateral_, as vw, and these again had others less, which one may call
+_laterosubcollateral_, and these again others, and they others, &c. in
+greater Figures.
+
+11 The branchings of the main Stems joyn’d not together by any regular
+line, nor did one side of the one lie over the other side of the other, but
+the small _collateral_ and _subcollateral_ branches did lie at top of one
+another according to a certain order or method, which I always observ’d to
+be this.
+
+12 That side of a _collateral_ or _subcollateral_, &c. branch, lay over the
+side of the _approximate_ (as the feathers in the wing of a Bird) whose
+branchings proceeded parallel to the last biggest stem from which it
+sprung, and not to the biggest stem of all, unless that were a second stem
+backwards.
+
+13 This rule that held in the branchings of the _Sexangular Figure_ held
+also in the branchings of any other great or small stem, though it did not
+proceed from a center.
+
+14 The exactness and curiosity of the figuration of these branches, was in
+every particular so transcendent, that I judge it almost impossible for
+humane art to imitate.
+
+15 Tasting several cleer pieces of this _Ice_, I could not find any
+_Urinous_ taste in them, but those few I tasted, seem’d as _insipid_ as
+water.
+
+16 A figuration somewhat like this, though indeed in some particulars much
+more curious, I have several times observ’d in _regulus martis stellatus_,
+but with this difference, that all the stems and branchings are bended in a
+most excellent and regular order, whereas in _Ice_ the stems and branchings
+are streight, but in all other particulars it agrees with this, and seems
+indeed nothing but one of these stars, or branched Figures frozen on
+_Urine_, distorted, or wreathed a little, with a certain proportion: _Lead_
+also that has _Arsenick_ and some other things mixt with it, I have found
+to have its surface, when suffer’d to cool, figured somewhat like the
+branchings of _Urine_, but much smaller.
+
+17 But there is a _Vegetable_ which does exceedingly imitate these
+branches, and that is, _Fearn_, where the main stem may be observ’d to
+shoot out branches, and the stems of each of these _lateral_ branches, to
+send forth _collateral_, and those _subcollateral_ and those
+_laterosubcollateral_, &c. and all those much after the same order with the
+branchings, divisions, and subdivisions in the branchings of these Figures
+in frozen _Urine_; so that if the Figures of both be well consider’d, one
+would ghess that there were not much greater need of a _seminal principle_
+for the production of _Fearn_, then for the production of the branches of
+_Urine_, or the _Stella martis_, there seeming to be as much form and
+beauty in the one as in the other.
+
+And indeed, this Plant of _Fearn_, if all particulars be well consider’d,
+will seem of as simple, and uncompounded a form as any _Vegetable_, next to
+_Mould_ or _Mushromes_, and would next after the invention of the forms of
+those, deserve to be enquir’d into; for notwithstanding several have
+affirm’d it to have seed, and to be propagated thereby; yet, though I have
+made very diligent enquiry after that particular, I cannot find that there
+is any part of it that can be imagin’d to be more seminal then another: But
+this onely here by the by:
+
+For the freezing Figures in _Urine_, I found it requisite,
+
+First, that the Superficies be not disturbed with any wind, or other
+commotion of the air, or the like.
+
+Secondly, that it be not too long exposed, so as that the whole bulk be
+frozen, for oftentimes, in such cases, by reason of the swelling the of
+_Ice_, or from some other cause, the curious branched Figures disappear.
+
+Thirdly, an artificial freezing with _Snow_ and _Salt_, apply’d to the
+outside of the containing Vessel, succeeds not well, unless there be a very
+little quantity in the Vessel.
+
+Fourthly, If you take any cleer and smooth Glass, and wetting all the
+inside of it with _Urine_, you expose it to a very sharp freezing, you will
+find it cover’d with a very regular and curious Figure.
+
+II.
+
+_Observables in figur’d _Snow_._
+
+Exposing a piece of black Cloth, or a black Hatt to the falling _Snow_, I
+have often with great pleasure, observ’d such an infinite variety of
+curiously figur’d _Snow_, that it would be as impossible to draw the Figure
+and shape of every one of them, as to imitate exactly the curious and
+Geometrical _Mechanisme_ of Nature in any one. Some coorse draughts, such
+as the coldness of the weather, and the ill provisions, I had by me for
+such a purpose, would permit me to make, I have here added in the Second
+_Figure_ of the Eighth _Scheme_.[12]
+
+In all which I observ’d, that if they were of any regular Figures, they
+were always branched out with six principal branches, all of equal length,
+shape and make, from the center, being each of them inclin’d to either of
+the next branches on either side of it, by an angle of sixty degrees.
+
+Now, as all these stems were for the most part in one flake exactly of the
+same make, so were they in differing Figures of very differing ones; so
+that in a very little time I have observ’d above an hundred several cizes
+and shapes of these starry flakes.
+
+The branches also out of each stem of any one of these flakes, were exactly
+alike in the same flake; so that of whatever Figure one of the branches
+were, the other five were sure to be of the same, very exactly, that is, if
+the branchings of the one were small _Perallelipipeds_ or Plates, the
+branchings of the other five were of the same; and generally, the
+branchings were very conformable to the rules and method observ’d before,
+in the Figures on _Urine_, that is, the branchings from each side of the
+stems were parallel to the next stem on that side, and if the stems were
+plated, the branches also were the same; if the stems were very long, the
+branches also were so, &c.
+
+Observing some of these figur’d flakes with a _Microscope_, I found them
+not to appear so curious and exactly figur’d as one would have imagin’d,
+but like Artificial Figures, the bigger they were magnify’d, the more
+irregularities appear’d in them; but this irregularity seem’d ascribable to
+the thawing and breaking of the flake by the fall, and not at all to the
+defect of the _plastick_ virtue of Nature, whose curiosity in the formation
+of most of these kind of regular Figures, such as those of _Salt_,
+_Minerals_, &c. appears by the help of the _Microscope_, to be very many
+degrees smaller then the most acute eye is able to perceive without it. And
+though one of these six-branched Stars appear’d here below much of the
+shape described in the Third _Figure_ of the Eighth _Scheme_; yet I am very
+apt to think, that could we have a sight of one of them through a
+_Microscope_ as they are generated in the Clouds before their Figures are
+vitiated by external accidents, they would exhibit abundance of curiosity
+and neatness there also, though never so much magnify’d: For since I have
+observ’d the Figures of _Salts_ and _Minerals_ to be some of them so
+exceeding small, that I have scarcely been able to perceive them with the
+_Microscope_, and yet have they been regular, and since (as far as I have
+yet examin’d it) there seems to be but one and the same cause that produces
+both these effects, I think it not irrational to suppose that these pretty
+figur’d Stars of _Snow_, when at first generated might be also very regular
+and exact.
+
+III.
+
+_Several kinds of Figures in _Water_ frozen._
+
+Putting fair Water into a large capacious Vessel of _Glass_, and exposing
+it to the cold, I observ’d after a little time, several broad, flat, and
+thin _laminæ_, or plates of _Ice_, crossing the bulk of the water and one
+another very irregularly, onely most of them seem’d to turn one of their
+edges towards that side of the Glass which was next it, and seem’d to grow,
+as ’twere from the inside of the Vessel inwards towards the middle, almost
+like so many blades of _Fern_. Having taken several of these plates out of
+water on the blade of a Knife, I observ’d them figur’d much after the
+manner of _Herring bones_, or _Fern blades_, that is, there was one bigger
+stem in the middle like the back-bone, and out of it, on either side, were
+a multitude of small _stiriæ_, or _icicles_, like the smaller bones, or the
+smaller branches in _Fern_, each of these branches on the one side, were
+parallel to all the rest on the same side, and all of them seem’d to make
+an angle with the stem, towards the top, of sixty degrees, and towards the
+bottom or root of this stem, of 120. See the fourth _Figure_ of the 8.
+_Plate_.
+
+I observ’d likewise several very pretty Varieties of Figures in Water,
+frozen on the top of a broad flat Marble-stone, expos’d to the cold with a
+little Water on it, some like feathers, some of other shapes, many of them
+were very much of the shape exprest in the fifth Figure of the 8. _Scheme_,
+which is extremely differing from any of the other Figures.
+
+I observ’d likewise, that the shootings of _Ice_ on the top of Water,
+beginning to freeze, were in streight _prismatical_ bodies much like those
+of _roch-peter_, that they crost each other usually without any kind of
+order or rule, that they were always a little higher then the surface of
+the Water that lay between them; that by degrees those _interjacent_ spaces
+would be fill’d with _Ice_ also, which usually would be as high as the
+surface of the rest.
+
+In flakes of _Ice_ that had been frozen on the top of Water to any
+considerable thickness, I observ’d that both the upper and the under sides
+of it were curiously quill’d, furrow’d, or grain’d, as it were, which when
+the Sun shone on the Plate, was exceeding easily to be perceiv’d to be much
+after the shape of the lines in the 6. _Figure_ of the 8. _Scheme_, that
+is, they consisted of several streight ends of parallel Plates, which were
+of divers lengths and angles to one another without any certain order.
+
+The cause of all which regular Figures (and of hundreds of others, namely
+of _Salts_, _Minerals_, _Metals_, &c. which I could have here inserted,
+would it not have been too long) seems to be deducible from the same
+Principles, which I have (in the 13. _Observation_) hinted only, having not
+yet had time to compleat a _Theory_ of them. But indeed (which I there also
+hinted) I judge it the second step by which the _Pyramid_ of natural
+knowledge (which is the knowledge of the form of bodies) is to be ascended:
+And whosoever will climb it, must be well furnish’d with that which the
+Noble _Verulam_ calls _Scalam Intellectus_; he must have scaling Ladders,
+otherwise the steps are so large and high, there will be no getting up
+them, and consequently little hopes of attaining any higher station, such
+as to the knowledge of the most simple principle of Vegetation manifested
+in Mould and Mushromes, which, as I elsewhere endeavoured to shew, seems to
+be the third step; for it seems to me, that the Intellect of man is like
+his body, destitute of wings, and cannot move from a lower to a higher and
+more sublime station of knowledg, otherwise then step by step, nay even
+there where the way is prepar’d and already made passible; as in the
+_Elements of Geometry_, or the like, where it is fain to climb a whole
+_series_ of Propositions by degrees, before it attains the knowledge of one
+_Probleme_. But if the ascent be high, difficult and above its reach, it
+must have recourse to a _novum organum_, some new engine and contrivance,
+some new kind of _Algebra_, or _Analytick Art_ before it can surmount it.
+
+       *       *       *       *       *
+
+
+Observ. XV. _Of _Kettering-stone_, and of the pores of _Inanimate_ bodies._
+
+[13]This Stone which is brought from _Kettering_ in _Northampton-Shire_,
+and digg’d out of a Quarry, as I am inform’d, has a grain altogether
+admirable, nor have I ever seen or heard of any other stone that has the
+like. It is made up of an innumerable company of small bodies, not all of
+the same cize or shape, but for the most part, not much differing from a
+Globular form, nor exceed they one another in Diameter above three or four
+times; they appear to the eye, like the Cobb or Ovary of a _Herring_, or
+some smaller fishes, but for the most part, the particles seem somewhat
+less, and not so uniform; but their variation from a perfect globular ball,
+seems to be only by the pressure of the _contiguous_ bals which have a
+little deprest and protruded those toucht sides inward, and forc’d the
+other sides as much outwards beyond the limits of a Globe; just as it would
+happen, if a heap of exactly round Balls of soft Clay were heaped upon one
+another; or, as I have often seen a heap of small Globules of
+_Quicksilver_, reduc’d to that form by rubbing it much in a glaz’d Vessel,
+with some slimy or sluggish liquor, such as Spittle, when though the top of
+the upper Globules be very neer spherical, yet those that are prest upon by
+others, exactly imitate the forms of these lately mention’d grains.
+
+Where these grains touch each other, they are so firmly united or settled
+together, that they seldom part without breaking a hole in one or th’other
+of them, such as a, a, a, b, c, c, &c. Some of which fractions, as a, a, a,
+a, where the touch has been but light, break no more then the outward
+crust, or first shell of the stone, which is of a white colour, a little
+dash’d with a brownish Yellow, and is very thin, like the shell of an Egg:
+and I have seen some of those grains perfectly resemble some kind of Eggs,
+both in colour and shape: But where the union of the _contiguous granules_
+has been more firm, there the divulsion has made a greater Chasm, as at b,
+b, b, in so much that I have observ’d some of them quite broken in two, as
+at c, c, c, which has discovered to me a further resemblance they have to
+Eggs, they having an appearance of a white and yelk, by two differing
+substances that envelope and encompass each other.
+
+That which we may call the white was pretty whitish neer the yelk, but more
+duskie towards the shell; some of them I could plainly perceive to be shot
+or radiated like a _Pyrites_ or _fire-stone_; the yelk in some I saw
+hollow, in others fill’d with a duskie brown and porous substance like a
+kind of pith.
+
+The small pores, or _interstitia_ eeee betwixt the Globules, I plainly saw,
+and found by other trials to be every way pervious to air and water, for I
+could blow through a piece of this stone of a considerable thickness, as
+easily as I have blown through a Cane, which minded me of the pores which
+_Des Cartes_ allow his _materia subtilis_ between the _æthereal_ globules.
+
+The object, through the _Microscope_, appears like a _Congeries_ or heap of
+Pibbles, such as I have often seen cast up on the shore, by the working of
+the Sea after a great storm, or like (in shape, though not colour) a
+company of small Globules of Quicksilver, look’d on with a _Microscope_,
+when reduc’d into that form by the way lately mentioned. And perhaps, this
+last may give some hint at the manner of the formation of the former: For
+supposing some _Lapidescent_ substance to be generated, or some way brought
+(either by some commixture of bodies in the Sea it self, or protruded in,
+perhaps, out of some _subterraneous_ caverns) to the bottom of the Sea, and
+there remaining in the form of a liquor like Quicksilver, _heterogeneous_
+to the ambient _Saline_ fluid, it may by the working and tumblings of the
+Sea to and fro be jumbled and comminuted into such Globules as may
+afterwards be hardned into Flints, the lying of which one upon another,
+when in the Sea, being not very hard, by reason of the weight of the
+incompassing fluid, may cause the undermost to be a little, though not
+much, varied from a globular Figure. But this only by the by.
+
+After what manner this _Kettering-stone_ should be generated I cannot
+learn, having never been there to view the place, and observe the
+circumstances; but it seems to me from the structure of it to be generated
+from some substance once more fluid, and afterwards by degrees growing
+harder, almost after the same manner as I supposed the generation of Flints
+to be made.
+
+But whatever were the cause of its curious texture, we may learn this
+information from it; that even in those things which we account vile, rude,
+and coorse, Nature has not been wanting to shew abundance of curiosity and
+excellent Mechanisme.
+
+We may here find a Stone by help of a _Microscope_, to be made up of
+abundance of small Balls, which do but just touch each other, and yet there
+being so many contacts, they make a firm hard mass, or a Stone much harder
+then Free-stone.
+
+Next, though we can by a _Microscope_ discern so curious a shape in the
+particles, yet to the naked eye there scarce appears any such thing; which
+may afford us a good argument to think, that even in those bodies also,
+whose _texture_ we are not able to discern, though help’d with
+_Microscopes_, there may be yet _latent_ so curious a _Schematisme_, that
+it may abundantly satisfie the curious searcher, who shall be so happy as
+to find some way to discover it.
+
+Next, we here find a Stone, though to the naked eye a very close one, yet
+every way perforated with innumerable pores, which are nothing else but the
+_interstitia_, between those multitudes of minute globular particles, that
+compose the bulk it self, and these pores are not only discover’d by the
+_Microscope_, but by this contrivance.
+
+I took a pretty large piece of this stone, and covering it all over with
+cement, save only at two opposite parts, I found my self able, by blowing
+in at one end that was left open, to blow my spittle, with which I had wet
+the other end, into abundance of bubbles, which argued these pores to be
+open and pervious through the whole stone, which affords us a very pretty
+instance of the porousness of some seemingly close bodies, of which kind I
+shall anon have occasion to subjoyn many more, tending to prove the same
+thing.
+
+I must not here omit to take notice, that in this body there is not a
+_vegetative_ faculty that should so contrive this structure for any
+peculiar use of _Vegetation_ or growth, whereas in the other instances of
+vegetable porous bodies, there is an _anima_ or _forma informans_, that
+does contrive all the Structures and _Mechanisms_ of the constituting
+body, to make them subservient and usefull to the great Work or Function
+they are to perform. And so I ghess the pores in Wood, and other
+vegetables, in bones, and other Animal substances, to be as so many
+channels, provided by the Great and Alwise Creator, for the conveyance of
+appropriated juyces to particular parts. And therefore, that this may tend,
+or be pervious all towards one part, and may have impediments, as valves or
+the like, to any other; but in this body we have very little reason so
+suspect there should be any such design, for it is equally pervious every
+way, not onely forward, but backwards, and side-ways, and seems indeed much
+rather to be _Homogeneous_ or similar to those pores, which we may with
+great probability believe to be the channels of _pellucid_ bodies, not
+directed, or more open any one way, then any other, being equally pervious
+every way. And, according as these pores are more or greater in respect of
+the _interstitial_ bodies, the more transparent are the so constituted
+concretes; and the smaller those pores are, the weaker is the _Impulse_ of
+light communicated through them, though the more quick be the progress.
+
+Upon this Occasion, I hope it will not be altogether unseasonable, if I
+propound my conjectures and _Hypothesis_ about the _medium_ and conveyance
+of light.
+
+I suppose then, that the greatest part of the _Interstitia_ of the world,
+that lies between the bodies of the Sun and Starrs, and the Planets, and
+the Earth, to be an exceeding fluid body, very apt and ready to be mov’d,
+and to communicate the motion of any one part to any other part, though
+never so far distant: Nor do I much concern my self, to determine what the
+Figure of the particles of this exceedingly subtile fluid _medium_ must be,
+nor whether it have any interstitiated pores or vacuities, it being
+sufficient to solve all the _Phænomena_ to suppose it an exceedingly fluid,
+or the most fluid body in the world, and as yet impossible to determine the
+other difficulties.
+
+That being so exceeding fluid a body, it easily gives passage to all other
+bodies to move to and fro in it.
+
+That it neither receives from any of its parts, or from other bodies; nor
+communicates to any of its parts, or to any other body, any impulse, or
+motion in a direct line, that is not of a determinate quickness. And that
+when the motion is of such determinate swiftness, it both receives, and
+communicates, or propagates an impulse or motion to any imaginable distance
+in streight lines, with an unimaginable celerity and vigour.
+
+That all kind of solid bodies consist of pretty massie particles in respect
+of the particles of this fluid _medium_, which in many places do so touch
+each other, that none of this fluid _medium_ interposes much after the same
+manner (to use a gross similitude) as a heap of great stones compose one
+great _congeries_ or mass in the midst of the water.
+
+That all fluid bodies which we may call _tangible_, are nothing but some
+more subtile parts of those particles, that serve to constitute all
+_tangible_ bodies.
+
+That the water, and such other fluid bodies, are nothing but a _congeries_
+of particles agitated or made fluid by it in the same manner as the
+particles of _Salt_ are agitated or made fluid by a parcel of water, in
+which they are dissolv’d, and subsiding to the bottom of it, constitute a
+fluid body, much more massie and dense, and less fluid then the pure water
+it self.
+
+That the air on the other side is a certain company of particles of quite
+another kind, that is, such as are very much smaller, and more easily
+moveable by the motion of this fluid _medium_; much like those very subtile
+parts of _Cochenel_, other very deep tinging bodies, where by a very small
+parcel of matter is able to tinge and diffuse it self over a very great
+quantity of the fluid dissolvent; or somewhat after that manner, as smoak,
+and such like minute bodies, or steams, are observ’d to tinge a very great
+quantity of air; onely this last similitude is deficient in one propriety,
+and that is a perpetuity or continuance in that state of commixture with
+the air, but the former does more nearly approach to the nature and manner
+of the air’s being dissolv’d by this fluid or _Æther_. And this Similitude
+will further hold in these proprieties; that as those tinctures may be
+increased by certain bodies, so may they be precipitated by others, as I
+shall afterwards shew it to be very probable, that the like accidents
+happen even to the Air it self.
+
+Further, as these solutions and tinctures do alter the nature of these
+fluid bodies, as to their aptness to propagate a motion or impulse through
+them, even so does the particles of the Air, Water, and other fluid bodies,
+and of Glass, Crystal, &c. which are commixt with this bulk of the _Æther_
+alter the motion of the propagated pulse of light; that is, where these
+more bulkie particles are more plentifull, and consequently a lesser
+quantity of the _Æther_ between them to be mov’d, there the motion must
+necessarily be the swifter, though not so robust, which will produce those
+effects, which I have (I hope) with some probability, ascribed to it in the
+digression about Colours, at the end of the _Observations_ on
+_Muscovy-glass._
+
+Now, that other Stones, and those which have the closest and hardest
+textures, and seem (as far as we are able to discover with our eyes, though
+help’d with the best _Microscopes_) freest from pores, are yet
+notwithstanding replenish’d with them, an Instance or two will, I suppose,
+make more probable.
+
+A very solid and unflaw’d piece of cleer white _Marble_, if it be well
+polish’d and glaz’d, has so curiously smooth a surface, that the best and
+most polish’d surface of any wrought-glass, seems not to the naked eye, nor
+through a _Microscope_, to be more smooth, and less porous. And yet, that
+this hard close body is replenish’d with abundance of pores, I think these
+following Experiments will sufficiently prove.
+
+The first is, That if you take such a piece, and for a pretty while boyl it
+in Turpentine and Oyl of Turpentine, you shall find that the stone will be
+all imbu’d with it; and whereas before it look’d more white, but more
+opacous, now it will look more greasie, but be much more transparent, and
+if you let it lie but a little while, and then break off a part of it, you
+shall find the unctuous body to have penetrated it to such a determinate
+depth every way within the surface. This may be yet easier try’d with a
+piece of the same _Marble_, a little warm’d in the fire, and then a little
+Pitch or Tarr melted on the top of it; for these black bodies, by their
+insinuating themselves into the invisible pores of the stone, ting it with
+so black a hue, that there can be no further doubt of the truth of this
+assertion, that it abounds with small imperceptible pores.
+
+Now, that other bodies will also sink into the pores of _Marble_, besides
+unctuous, I have try’d, and found, that a very Blue tincture made in
+_spirit of Urine_ would very readily and easily sink into it, as would also
+several tinctures drawn with _spirit of Wine_.
+
+Nor is _Marble_ the only seemingly close stone, which by other kinds of
+Experiments may be found porous; for I have by this kind of Experiment on
+divers other stones found much the same effect, and in some, indeed much
+more notable. Other stones I have found so porous, that with the
+_Microscope_ I could perceive several small winding holes, much like
+Worm-holes, as I have noted in some kind of _Purbeck-stone_, by looking on
+the surface of a piece newly flaw’d off, for if otherwise, the surface has
+been long expos’d to the Air, or has been scraped with any tool, those
+small caverns are fill’d with dust, and disappear.
+
+And to confirm this _Conjecture_, yet further, I shall here insert an
+excellent account, given into the _Royal Society_ by that Eminently Learned
+Physician, Doctor _Goddard_, of an Experiment, not less instructive then
+curious and accurate, made by himself on a very hard and seemingly close
+stone call’d _Oculus Mundi_, as I find it preserv’d in the Records of that
+Honourable Society.
+
+    A small stone of the kind, call’d by some Authours, _Oculus Mundi_,
+    being dry and cloudy, weigh’d 5²⁰⁹⁄₂₅₆ _Grains_.
+
+    The same put under water for a night, and somewhat more, became
+    transparent, and the superficies being wiped dry, weighed 6³⁄₂₅₆
+    _Grains_.
+
+    The difference between these two weights, 0⁵⁰⁄₂₅₆ of a _Grain_.
+
+    The same Stone kept out of water one Day and becoming cloudy again
+    weighed, 5²²⁵⁄₂₅₆ _Graines_.
+
+    Which was more then the first weight, 0¹⁶⁄₂₅₆ of a _Grain_.
+
+    The same being kept two Days longer weighed, 5²⁰²⁄₂₅₆ _Graines_.
+
+    Which was less then at first, 0⁷⁄₂₅₆ a _Grain_.
+
+    Being kept dry something longer it did not grow sensibly lighter.
+
+    Being put under water for a night and becoming again transparent and
+    wiped dry, the weight was, _6³⁄₂₅₆ Grains_, the same with the first
+    after putting in water, and more then the last weight after keeping of
+    it dry, 0⁵⁷⁄₂₅₆ of a _Grain_.
+
+    Another Stone of the same kind being variegated with milky _white_ and
+    _gray_ like some sorts of _Agates_, while it lay under water, was
+    alwaies invironed with little Bubbles, such as appear in water a little
+    before boyling, next the sides of the Vessel.
+
+    There were also some the like Bubbles on the Surface of the water just
+    over it, as if either some exhalations came out of it, or that it did
+    excite some fermentation in the parts of the water contiguous to it.
+
+    There was little sensible difference in the transparency of this Stone,
+    before the putting under water, and after: To be sure the milky-_white_
+    parts continued as before, but more difference in weight then in the
+    former. For whereas before the putting into the water the weight was
+    18⁹⁷⁄₁₂₈ _Graines_. After it had lyen in about four and twenty hours
+    the weight was 20²⁷⁄₁₂₈ _Graines_, so the difference was, 1⁵⁸⁄₁₂₈
+    _Graines_.
+
+    The same Stone was infused in the water scalding hot, and so continued
+    for a while after it was cold, but got no more weight then upon
+    infusing in the cold, neither was there any sensible Difference in the
+    weight both times.
+
+In which Experiment, there are three Observables that seem very manifestly
+to prove the porousness of these seemingly close bodies: the first is their
+acquiring a transparency, and losing their whiteness after steeping in
+water, which will seem the more strongly to argue it, if what I have
+already said about the making transparent, or clarifying of some bodies, as
+the white powder of beaten Glass, and the froth of some glutinous
+transparent liquor be well consider’d; for thereby it will seem rational to
+think that this transparency arises from the insinuation of the water
+(which has much the same refraction with such stony particles, as may be
+discover’d by Sand view’d with a _Microscope_) into those pores which were
+formerly repleat with air (that has a very differing refraction, and
+consequently is very reflective) which seems to be confirm’d by the second
+Observable, namely, the increase of weight after keeping, and decrease upon
+drying. And thirdly, seem’d yet more sensibly confirm’d by the multitude of
+bubbles in the last Experiment.
+
+We find also most Acid Salts very readily to dissolve and separate the
+parts of this body one from another; which is yet a further Argument to
+confirm the porousness of bodies, and will serve as such, to shew that even
+Glass also has an abundance of pores in it, since there are several
+liquors, that with long staying in a Glass, will so _Corrode_ and eat into
+it, as at last, to make it pervious to the liquor it contain’d, of which I
+have seen very many Instances.
+
+Since therefore we find by other proofs, that many of those bodies which we
+think the most solid ones, and appear so to our sight, have notwithstanding
+abundance of those grosser kind of pores, which will admit several kinds of
+liquors into them, why should we not believe that Glass, and all other
+transparent bodies abound with them, since we have many other arguments,
+besides the propagation of light, which seem to argue for it?
+
+And whereas it may be objected, that the propagation of light is no
+argument that there are those atomical pores in glass, since there are
+_Hypotheses_ plausible enough to solve those _Phænomena_, by supposing the
+pulse onely to be communicated through the transparent body.
+
+To this I answer, that that _Hypothesis_ which the industrious _Mersennus_
+has publish’d about the slower motion of the end of a Ray in a denser
+_medium_, then in a more rare and thin, seems altogether unsufficient to
+solve abundance of _Phænomena_, of which this is not the least
+considerable, that it is impossible from that supposition, that any colours
+should be generated from the refraction of the Rays; for since by that
+_Hypothesis_ the _undulating pulse_ is always carried perpendicular, or at
+right angles with the Ray or Line of direction, it follows, that the stroke
+of the pulse of light, after it has been once or twice refracted (through a
+Prisme, for example) must affect the eye with the same kind of stroke as if
+it had not been refracted at all. Nor will it be enough for a Defendant of
+that _Hypothesis_, to say, that perhaps it is because the refractions have
+made the Rays more weak, for if so, then two refractions in the two
+parallel sides of a _Quadrangular Prisme_ would produce colours, but we
+have no such _Phænomena_ produc’d.
+
+There are several Arguments that I could bring to evince that there are in
+all transparent bodies such atomical pores. And that there is such a fluid
+body as I am arguing for, which is the _medium_, or Instrument, by which
+the pulse of Light is convey’d from the _lucid body_ to the enlightn’d. But
+that it being a digression from the Observations I was recording, about the
+Pores of _Kettering-Stone_, it would be too much such, if I should protract
+it too long; and therefore I shall proceed to the next _Observation_.
+
+       *       *       *       *       *
+
+
+Observ. XVI. _Of _Charcoal_, or burnt _Vegetables_._
+
+Charcoal, or a Vegetable burnt black, affords an object no less pleasant
+than instructive, for if you take a small round Charcoal, and break it
+short with your fingers, you may perceive it to break with a very smooth
+and sleek surface, almost like the surface of black sealing Wax; this
+surface, if it be look’d on with an ordinary _Microscope_, does manifest
+abundance of those pores which are also visible to the eye in many kinds of
+_Wood_, rang’d round the pith, both a in kind of circular order, and a
+radiant one. Of these there are a multitude in the substance of the Coal,
+every where almost perforating and drilling it from end to end; by means of
+which, be the Coal never so long, you may easily blow through it; and this
+you may presently find, by wetting one end of it with Spittle, and blowing
+at the other.
+
+But this is not all, for besides those many great and conspicuous irregular
+spots or pores, if a better _Microscope_ be made use of, there will appear
+an infinite company of exceedingly small, and very regular pores, so thick
+and so orderly set, and so close to one another, that they leave very
+little room or space between them to be fill’d with a solid body, for the
+apparent _interstitia_ or separating sides of these pores seem so thin in
+some places, that the texture of a Honey-comb cannot be more porous. Though
+this be not every where so, the intercurrent partitions in some places
+being very much thicker in proportion to the holes.
+
+Most of these small pores seem’d to be pretty round, and were rang’d in
+rows that radiated from the pith to the bark; they all of them seem’d to be
+continued open pores, running the whole length of the Stick; and that they
+were all perforated, I try’d by breaking off a very thin sliver of the Coal
+cross-ways, and then with my _Microscope_, diligently surveying them
+against the light, for by that means I was able to see quite through them.
+
+These pores were so exceeding small and thick, that in a line of them, ¹⁄₁₈
+part of an Inch long, I found by numbering them no less then 150. small
+pores; and therefore in a line of them an Inch long, must be no less then
+2700. pores, and in a circular _area_ of an Inch diameter, must be about
+5725350. of the like pores; so that a Stick of an Inch Diameter, may
+contain no less then seven hundred and twenty five thousand, besides 5
+Millions of pores, which would, I doubt not, seem even incredible, were not
+every one left to believe his own eyes. Nay, having since examin’d _Cocus,
+black and green Ebony, Lignum Vitæ_, &c. I found, that all these Woods have
+their pores, abundantly smaller then those of soft light Wood; in so much,
+that those of _Guajacum_ seem’d not above an eighth part of the bigness of
+the pores of Beech, but then the _Interstitia_ were thicker; so
+prodigiously curious are the contrivances, pipes, or sluces by which the
+_Succus nutritius_, or Juyce of a Vegetable is convey’d from place to
+place.
+
+This _Observation_ seems to afford us the true reason of several
+_Phænomena_ of Coals; as
+
+First, why they look black; and for this we need go no further then the
+_Scheme_, for certainly, a body that has so many pores in it as this is
+discover’d to have, from each of which no light is reflected, must
+necessarily look black, especially, when the pores are somewhat bigger in
+proportion to the intervals then they are cut in the _Scheme_, black being
+nothing else but a privation of Light, or a want of reflection; and
+wheresoever this reflecting quality is deficient, there does that part look
+black, whether it be from a porousness of the body, as in this Instance, or
+in a deadning and dulling quality, such as I have observ’d in the _Scoria_
+of Lead, Tin, Silver, Copper, &c.
+
+Next, we may also as plainly see the reason of its shining quality, and
+that is from the even breaking off of the stick, the solid _interstitia_
+having a regular termination or surface, and having a pretty strong
+reflecting quality, the many small reflections become united to the naked
+eye, and make a very pretty shining surface.
+
+Thirdly, the reason of its hardness and brittleness seems evident, for
+since all the watery or liquid substance that moistn’d and toughn’d those
+_Interstitia_ of the more solid parts, are evaporated and remov’d, that
+which is left behind becomes of the nature almost of a stone, which will
+not at all, or very little, bend without a _divulsion_ or _solution_ of its
+_continuity_.
+
+It is not my design at present, to examine the use and _Mechanisme_ of
+these parts of Wood, that being more proper to another Enquiry; but rather
+to hint, that from this Experiment we may learn,
+
+First, what is the cause of the blackness of many burnt bodies, which we
+may find to be nothing else but this; that the heat of the fire agitating
+and rarifying the waterish, transparent, and volatile water that is
+contain’d in them, by the continuation of that action, does so totally
+expel and drive away all that which before fill’d the pores, and was
+dispers’d also through the solid mass of it, and thereby caus’d an
+universal kind of transparency, that it not onely leaves all the pores
+empty, but all the _Interstitia_ also so dry and _opacous_, and perhaps
+also yet further perforated, that that light onely is reflected back which
+falls upon the very outward edges of the pores, all they that enter into
+the pores of the body, never returning, but being lost in it.
+
+Now, that the Charring or coaling of a body is nothing else, may be easily
+believ’d by one that shall consider the means of its production, which may
+be done after this, or any such manner. The body to be charr’d or coal’d,
+may be put into a _Crucible_, Pot, or any other Vessel that will endure to
+be made red-hot in the fire without breaking, and then cover’d over with
+Sand, so as no part of it be suffer’d to be open to the Air, then set into
+a good fire, and there kept till the Sand has continu’d red hot for a
+quarter, half, an hour or two, or more, according to the nature and bigness
+of the body to be coal’d or charr’d, then taking it out of the fire, and
+letting it stand till it be quite cold, the body may be taken out of the
+Sand well charr’d and cleans’d of its waterish parts; but in the taking of
+it out, care must be had that the Sand be very neer cold, for else, when it
+comes into the free air, it will take fire, and readily burn away.
+
+This maybe done also in any close Vessel of Glass, as a _Retort_, or the
+like, and the several fluid substances that come over may be receiv’d in a
+fit _Recipient_, which will yet further countenance this _Hypothesis_: And
+their manner of charring Wood in great quantity comes much to the same
+thing, namely, an application of a great heat to the body, and preserving
+it from the free access of the devouring air; this may be easily learn’d
+from the History of Charring of Coal, most excellently describ’d and
+publish’d by that most accomplish’d Gentleman, Mr. _John Evelin_, in the
+100, 101, 103, pages of his _Sylva_, to which I shall therefore refer the
+curious Reader that desires a full information of it.
+
+Next, we may learn what part of the Wood it is that is the _combustible_
+matter, for since we shall find that none, or very little of those fluid
+substances that are driven over into the Receiver are _combustible_, and
+that most of that which is left behind is so, it follows, that the solid
+_interstitia_ of the Wood are the _combustible_ matter. Further, the reason
+why uncharr’d Wood burns with a greater flame then that which is charr’d,
+is as evident, because those waterish or volatil parts issuing out of the
+fired Wood, every way, not onely shatter and open the body, the better for
+the fire to enter, but issuing out in vapours or wind, they become like so
+many little _æolipiles_, or Bellows, whereby they blow and agitate the
+fir’d part, and conduce to the more speedy and violent consumption or
+dissolution of the body.
+
+Thirdly, from the Experiment of charring of Coals (whereby we see that
+notwithstanding the great heat, and the duration of it, the solid parts of
+the Wood remain, whilest they are preserv’d from the free access of the air
+undissipated) we may learn, that which has not, that I know of, been
+publish’d or hinted, nay, not so much as thought of, by any; and that in
+short is this.
+
+First, _that the Air_ in which we live, move, and breath, and which
+encompasses very many, and cherishes most bodies it encompasses, that this
+Air is the _menstruum_, or universal dissolvent of all _Sulphureous_
+bodies.
+
+Secondly, _that this action_ it performs not, till the body be first
+sufficiently heated, as we find requisite also to the dissolution of many
+other bodies by several other _menstruums_.
+
+Thirdly, _that this action_ of dissolution, produces or generates a very
+great heat, and that which we call Fire; and this is common also to many
+dissolutions of other bodies, made by _menstruums_, of which I could give
+multitudes of Instances.
+
+Fourthly, _that this action_ is perform’d with so great a violence, and
+does so minutely act, and rapidly agitate the smallest parts of the
+_combustible_ matter, that it produces in the _diaphanous medium_ of the
+Air, the action or pulse of light, which what it is, I have else-where
+already shewn.
+
+Fifthly, _that the dissolution_ of sulphureous bodies is made by a
+substance inherent, and mixt with the Air, that is like, if not the very
+same, with that which is fixt in _Salt-peter_, which by multitudes of
+Experiments that may be made with _Salt-peter_, will, I think, most
+evidently be demonstrated.
+
+Sixthly, _that in this dissolution_ of bodies by the Air, a certain part is
+united and mixt, or dissolv’d and turn’d into the Air, and made to fly up
+and down with it in the same manner as a _metalline_ or other body
+dissolved into any _menstruums_, does follow the motions and progresses of
+that _menstruum_ till it be precipitated.
+
+Seventhly, That as there is one part that is dissoluble by the Air, so are
+there other parts with which the parts of the Air mixing and uniting, do
+make a _Coagulum_, or _precipitation_, as one may call it, which causes it
+to be separated from the Air, but this _precipitate_ is so light, and in so
+small and rarify’d or porous clusters, that it is very volatil, and is
+easily carry’d up by the motion of the Air, though afterwards, when the
+heat and agitation that kept it rarify’d ceases, it easily condenses, and
+commixt with other indissoluble parts, it sticks and adheres to the next
+bodies it meets withall; and this is a certain _Salt_ that may be extracted
+out of _Soot_.
+
+Eighthly, that many indissoluble parts being very apt and prompt to be
+rarify’d, and so, whilest they continue in that heat and agitation, are
+lighter then the Ambient Air, are thereby thrust and carry’d upwards with
+great violence, and by that means carry along with them, not onely that
+_Saline concrete_ I mention’d before, but many terrestrial, or indissoluble
+and irrarefiable parts, nay, many parts also which are dissoluble, but are
+not suffer’d to stay long enough in a sufficient heat to make them prompt
+and apt for that action. And therefore we find in _Soot_, not onely a part,
+that being continued longer in a competent heat, will be dissolv’d by the
+Air, or take fire and burn; but a part also which is fixt, terrestrial, and
+irrarefiable.
+
+Ninthly, that as there are these several parts that will rarifie and fly,
+or be driven up by the heat, so are there many others, that as they are
+indissoluble by the _aerial menstruum_, so are they of such sluggish and
+gross parts, that they are not easily rarify’d by heat, and therefore
+cannot be rais’d by it; the volatility or fixtness of a body seeming to
+consist only in this, that the one is of a texture, or has component parts
+that will be easily rarify’d into the form of Air, and the other, that it
+has such as will not, without much ado, be brought to such a constitution;
+and this is that part which remains behind in a white body call’d Ashes,
+which contains a substance, or _Salt_, which Chymists call _Alkali_: what
+the particular natures of each of these bodies are, I shall not here
+examine, intending it in another place, but shall rather add that this
+_Hypothesis_ does so exactly agree with all _Phænomena_, of Fire, and so
+genuinely explicate each particular circumstance that I have hitherto
+observ’d, that it is more then probable, that this cause which I have
+assign’d is the true adequate, real, and onely cause of those _Phænomena_;
+And therefore I shall proceed a little further, to shew the nature and use
+of the Air.
+
+Tenthly, therefore the dissolving parts of the Air are but few, that is, it
+seems of the nature of those _Saline menstruums_, or spirits, that have
+very much flegme mixt with the spirits, and therefore a small parcel of it
+is quickly glutted, and will dissolve no more; and therefore unless some
+fresh part of this _menstruum_ be apply’d to the body to be dissolv’d, the
+action ceases, and the body leaves to be dissolv’d and to shine, which is
+the Indication of it, though plac’d or kept in the greatest heat; whereas
+_Salt-peter_ is a _menstruum_, when melted and red-hot, that abounds more
+with those Dissolvent particles, and therefore as a small quantity of it
+will dissolve a great sulphureous body, so will the dissolution be very
+quick and violent.
+
+Therefore in the _Eleventh_ place, it is observable, that, as in other
+solutions, if a copious and quick supply of fresh _menstruum_, though but
+weak, be poured on, or applied to the dissoluble body, it quickly consumes
+it: So this _menstruum_ of the Air, if by Bellows, or any other such
+contrivance, it be copiously apply’d to the shining body, is found to
+dissolve it as soon, and as violently as the more strong _menstruum_ of
+melted _Nitre_.
+
+Therefore twelfthly, it seems reasonable to think that there is no such
+thing as an Element of Fire that should attract or draw up the flame, or
+towards which the flame should endeavour to ascend out of a desire or
+appetite of uniting with that as its _Homogeneal_ primitive and generating
+Element; but that that shining transient body which we call _Flame_, is
+nothing else but a mixture of Air, and volatil sulphureous parts of
+dissoluble or combustible bodies, which are acting upon each other whilst
+they ascend, that is, flame seems to be a mixture of Air, and the
+combustible volatil parts of any body, which parts the encompassing Air
+does dissolve or work upon, which action, as it does intend the heat of the
+_aerial_ parts of the dissolvent, so does it thereby further rarifie those
+parts that are acting, or that are very neer them, whereby they growing
+much lighter then the heavie parts of that _Menstruum_ that are more
+remote, are thereby protruded and driven upward; and this may be easily
+observ’d also in dissolutions made by any other _menstruum_, especially such
+as either create heat or bubbles. Now, this action of the _Menstruum_, or
+_Air_, on the dissoluble parts, is made with such violence, or is such,
+that it imparts such a motion or pulse to the _diaphanous_ parts of the
+Air, as I have elsewhere shewn is requisite to produce light.
+
+This _Hypothesis_ I have endeavoured to raise from an Infinite of
+Observations and Experiments, the process of which would be much too long
+to be here inserted, and will perhaps another time afford matter copious
+enough for a much larger Discourse, the Air being a Subject which (though
+all the world has hitherto liv’d and breath’d in, and been unconversant
+about) has yet been so little truly examin’d or explain’d, that a diligent
+enquirer will be able to find but very little information from what has
+been (till of late) written of it: But being once well understood, it will,
+I doubt not, inable a man to render an intelligible, nay probable, if not
+the true reason of all the _Phænomena_ of Fire, which, as it has been found
+by Writers and Philosophers of all Ages a matter of no small difficulty, as
+may be sufficiently understood by their strange _Hypotheses_, and
+unintelligible Solutions of some few _Phænomena_ of it; so will it prove a
+matter of no small concern and use in humane affairs, as I shall elsewhere
+endeavour to manifest when I come to shew the use of the Air in
+respiration, and for the preservation of the life, nay, for the
+conservation and restauration of the health and natural constitution of
+mankind as well as all other aereal _animals_, as also the uses of this
+principle or propriety of the Air in chymical, mechanical, and other
+operations. In this place I have onely time to hint an _Hypothesis_, which,
+if God permit me life and opportunity, I may elsewhere prosecute, improve
+and publish. In the mean time, before I finish this Discourse, I must not
+forget to acquaint the Reader, that having had the liberty granted me of
+making some trials on a piece of _Lignum fossile_ shewn to the Royal
+Society, by the eminently Ingenious and Learned Physician, Doctor _Ent_,
+who receiv’d it for a Present from the famous _Ingenioso Cavalliero de
+Pozzi_, it being one of the fairest and best pieces of _Lignum fossile_ he
+had seen; Having (I say) taken a small piece of this Wood, and examin’d it,
+I found it to burn in the open Air almost like other Wood, and insteed of a
+resinous smoak or fume, it yielded a very bituminous one, smelling much of
+that kind of sent: But that which I chiefly took notice of, was, that
+cutting off a small piece of it, about the bigness of my Thumb, and
+charring it in a _Crucible_ with Sand, after the manner I above prescrib’d,
+I found it infinitely to abound with the smaller sort of pores, so
+extreamly thick, and so regularly perforating the substance of it
+long-ways, that breaking it off across, I found it to look very like an
+Honey-comb; but as for any of the second, or bigger kind of pores, I could
+not find that it had any; so that it seems, whatever were the cause of its
+production, it was not without those small kind of pores which we have
+onely hitherto found in Vegetable bodies: and comparing them with the pores
+which I have found in the Charcoals that I by this means made of several
+other kinds of Wood, I find it resemble none so much as those of Firr, to
+which it is not much unlike in grain also, and several other proprieties.
+
+And therefore, what ever is by some, who have written of it, and
+particularly by _Francisco Stelluto_, wrote a Treatise in _Italian_ of that
+Subject, which was Printed at _Rome_, 1637, affirm’d that it is a certain
+kind of Clay or Earth, which in tract of time is turn’d into Wood; I rather
+suspect the quite contrary, that it was at first certain great Trees of Fir
+or Pine, which by some Earthquake, or other casualty, came to be buried
+under the Earth, and was there, after a long time’s residence (according to
+the several natures of the encompassing adjacent parts) either rotted and
+turn’d into a kind of Clay, or _petrify’d_ and turn’d into a kind of Stone,
+or else had its pores fill’d with certain Mineral juices, which being
+stay’d in them, and in tract of time coagulated, appear’d, upon cleaving
+out, like small Metalline Wires, or else from some flames or scorching forms
+that are the occasion oftentimes, and usually accompany Earthquakes, might
+be blasted and turn’d into Coal, or else from certain _subterraneous_ fires
+which are affirm’d by that Authour to abound much about those parts
+(namely, in a Province of _Italy_, call’d _Umbria_, now the _Dutchie_ of
+_Spoletto_, in the Territory of _Todi_, anciently call’d _Tudor_; and
+between the two Villages of _Collesecco_ and _Rosaro_ not far distant from
+the high-way leading to _Rome_, where it is found in greater quantity then
+elsewhere) are by reason of their being encompassed with Earth, and so kept
+close from the dissolving Air, charr’d and converted into Coal. It would be
+too long a work to describe the several kinds of pores which I met withall,
+and by this means discovered in several other Vegetable bodies; nor is it
+my present design to expatiate upon Instances of the same kind, but rather
+to give a Specimen of as many kinds as I have had opportunity as yet of
+observing, reserving the prosecution and enlarging on particulars till a
+more fit opportunity; and in prosecution of this design, I shall here add:
+
+       *       *       *       *       *
+
+
+Observ. XVII. _Of _Petrify’d wood_, and other _Petrify’d bodies_._
+
+Of this sort of substance, I observ’d several pieces of very differing
+kinds, both for their outward shape, colour, grain, _texture_, hardness,
+&c. some being brown and reddish; others gray, like a Hone; others black,
+and Flint-like: some soft, like a Slate or Whetstone, others as hard as a
+Flint, and as brittle. That which I more particular examin’d, was a piece
+about the bigness of a mans hand, which seem’d to have been a part of some
+large tree, that by rottenness had been broken off from it before it began
+to be _petrify’d_.
+
+And indeed, all that I have yet seen, seem to have been rotten Wood before
+the petrifaction was begun; and not long since, examining and viewing a
+huge great _Oak_, that seem’d with meer age to be rotten as it stood, I was
+very much confirm’d in this opinion; for I found, that the grain, colour,
+and shape of the Wood, was exactly like this _petrify’d_ substance; and
+with a _Microscope_, I found, that all those _Microscopical_ pores, which
+in sappy or firm and sound Wood are fill’d with the natural or innate
+juices of those Vegetables, in this they were all empty, like those of
+_Vegetables charr’d_; but with this difference, that they seem’d much
+larger then I have seen any in _Charcoals_; nay, even then those of Coals
+made of great blocks of Timber, which are commonly call’d _Old-coals_.
+
+The reason of which difference may probably be, that the charring of
+Vegetables, being an operation quickly perform’d, and whilest the Wood is
+sappy, the more solid parts may more easily shrink together, and contract
+the pores or _interstitia_ between them, then in the rotten Wood, where
+that natural juice seems onely to be wash’d away by _adventitious_ or
+unnatural moisture; and so though the natural juice be wasted from between
+the firm parts, yet those parts are kept asunder by the _adventitious_
+moystures, and so by degrees settled in those postures.
+
+And this I likewise found in the _petrify’d_ Wood, that the pores were
+somewhat bigger then those of _Charcoal_, each pore being neer upon half as
+bigg again, but they did not bear that disproportion which is exprest in
+the tenth _Scheme_, between the small specks or pores in the first Figure
+(which representeth the pores of Coal or Wood charr’d) and the black spots
+of the second Figure (which represent the like _Microscopical pores_ in the
+_petrify’d_ Wood) for these last were drawn by a _Microscope_ that
+magnify’d the object above six times more in Diameter then the _Microscope_
+by which those pores of Coal were observ’d.
+
+Now, though they were a little bigger, yet did they keep the exact figure
+and order of the pores of Coals and of rotten Wood, which last also were
+much of the same cize.
+
+The other Observations on this _petrify’d_ substance, that a while since,
+by the appointment of the _Royal Society_, I made, and presented to them an
+account of, were these that follow, which had the honour done them by the
+most accomplish’d Mr. _Evelin_, my highly honoured friend, to be inserted
+and published among those excellent Observations wherewith his _Sylva_ is
+replenish’d, and would therefore have been here omitted, had not the Figure
+of them, as they appear’d through the _Microscope_ been before that
+engraven.
+
+This _Petrify’d_ substance resembled Wood, in that
+
+First, all the parts of it seem’d not at all _dislocated_, or alter’d from
+their natural Position, whil’st they were Wood, but the whole piece
+retain’d the exact shape of Wood, having many of the conspicuous pores of
+wood still remaining pores, and shewing a manifest difference visible
+enough between the grain of the Wood and that of the bark, especially when
+any side of it was cut smooth and polite; for then it appear’d to have a
+very lovely grain, like that of some curious close Wood.
+
+Next (it resembled Wood) in that all the smaller and (if I may so call
+those which are onely visible with a good magnifying Glass) _Microscopical_
+pores of it appear (both when the substance is cut and polish’d
+_transversly_ and _parallel_ to the pores of it) perfectly like the
+_Microscopical_ pores of several kinds of Wood, especially like and equal
+to those of several sorts of rotten Wood which I have since observ’d,
+retaining both the shape, position and magnitude of such pores. It was
+differing from Wood:
+
+First; in _weight_, being to common water as 3¼ to 1. whereas there are few
+of our _English_ Woods, that when very dry are found to be full as heavie
+as water.
+
+Secondly, in _hardness_, being very neer as hard as a Flint; and in some
+places of it also resembling the grain of a Flint: and, like it, it would
+very readily cut Glass, and would not without difficulty, especially in
+some parts of it, be scratch’d by a black hard Flint: It would also as
+readily strike fire against a Steel, or against a Flint, as any common
+Flint.
+
+Thirdly, in the _closeness_ of it, for though all the _Microscopical_ pores
+of this _petrify’d_ substance were very conspicuous in one position, yet by
+altering that position of the polish’d surface to the light, it was also
+manifest, that those pores appear’d darker then the rest of the body, onely
+because they were fill’d up with a more duskie substance, and not because
+they were hollow.
+
+Fourthly, in its _incombustibleness_, in that it would not burn in the
+fire; nay, though I kept it a good while red-hot in the flame of a Lamp,
+made very _intense_ by the blast of a small Pipe, and a large Charcoal, yet
+it seem’d not at all to have diminish’d its extension; but only I found it
+to have chang’d its colour, and to appear of a more dark and duskie brown
+colour; nor could I perceive that those parts which seem’d to have been
+Wood at first, were any thing wasted, but the parts appear’d as solid and
+close as before. It was further observable also, that as it did not consume
+like Wood, so neither did it crack and flie like a Flint, or such like hard
+Stone, nor was it long before it appear’d red-hot.
+
+Fifthly, in its _dissolubleness_; for putting some drops of distill’d
+_Vinegar_ upon the Stone, I found it presently to yield very many Bubbles,
+just like those which may be observ’d in spirit of _Vinegar_ when it
+corrodes _corals_, though perhaps many of those small Bubbles might proceed
+from some small parcels of Air which were driven out of the pores of this
+_petrify’d_ substance by the insinuating liquid _menstruum_.
+
+Sixthly, in its _rigidness_, and _friability_, being not at all flexible
+but brittle like a Flint, insomuch that I could with one knock of a Hammer
+break off a piece of it, and with a few more, reduce that into a pretty
+fine powder.
+
+Seventhly, it seem’d also very differing from Wood to the _touch_,
+_feeling_ more cold then Wood usually does, and much like other close
+stones and Minerals.
+
+The Reasons of all which _Phænomena_ seem to be,
+
+That _petrify’d_ Wood having lain in some place where it was well soak’d
+with _petrifying_ water (that is, such a water as is well _impregnated_
+with stony and earthy particles) did by degrees separate, either by
+straining and _filtration_, or perhaps, by _precipitation_, _cohesion_ or
+_coagulation_, abundance of stony particles from the permeating water,
+which stony particles, being by means of the fluid _vehicle_ convey’d, not
+onely into the _Microscopical_ pores, and so perfectly stopping them up, but
+also into the pores or _interstitia_, which may, perhaps, be even in the
+texture or _Schematisme_ of that part of the Wood, which, through the
+_Microscope_, appears most solid, do thereby so augment the weight of the
+Wood, as to make it above three times heavier then water, and perhaps, six
+times as heavie as it was when Wood.
+
+Next, they thereby so lock up and fetter the parts of the Wood, that the
+fire cannot easily make them flie away, but the action of the fire upon
+them is onely able to _Char_ those parts, as it were, like a piece of Wood,
+if it be clos’d very fast up in Clay, and kept a good while red-hot in the
+fire, will by the heat of the fire be charr’d and not consum’d, which may,
+perhaps, also be somewhat of the cause, why the _petrify’d_ substance
+appear’d of a dark brown colour after it had been burnt.
+
+By this _intrusion_ of the _petrifying_ particles, this substance also
+becomes hard and _friable_; for the smaller pores of the Wood being
+perfectly wedg’d, and stuft up with those stony particles, the small parts
+of the Wood have no places or pores into which they may slide upon bending,
+and consequently little or no flexion or yielding at all can be caus’d in
+such a substance.
+
+The remaining particles likewise of the Wood among the stony particles, may
+keep them from cracking and flying when put into the fire, as they are very
+apt to do in a Flint.
+
+Nor is Wood the onely substance that may by this kind of _transmutation_ be
+chang’d into stone; for I my self have seen and examin’d very many kinds of
+substances, and among very credible Authours, we may meet with Histories of
+such _Metamorphoses_ wrought almost on all kind of substances, both
+_Vegetable_ and _Animal_, which Histories, it is not my business at
+present, either to relate, or _epitomise_, but only to set down some
+Observation I lately made on several kind of _petrify’d_ Shels, found about
+_Keinsham_, which lies within four or five miles of _Bristol_, which are
+commonly call’d _Serpentine-stones._
+
+Examining several of these very curiously figur’d bodies (which are
+commonly thought to be Stones form’d by some extraordinary _Plastick
+virtue_ _latent_ in the Earth it self) I took notice of these particulars:
+
+First, that these figured bodies, or stones, were of very differing
+substances, as to hardness: some of Clay, some Marle, some soft Stone,
+almost of the hardness of those soft stones which Masons call Fire-stone,
+others as hard as Portland stone, others as hard as Marble, and some as
+hard as a Flint or Crystal.
+
+Next, they were of very differing substances as to transparency and colour;
+some white, some almost black, some brown, some Metalline, or like
+Marchasites; some transparent like white Marble, others like flaw’d
+Crystal, some gray, some of divers colours; some radiated like those long
+_petrify’d drops_, which are commonly found at the _Peak_, and in other
+_subterraneous caverns_, which have a kind of pith in the middle.
+
+Thirdly, that they were very different as to the manner of their outward
+figuration; for some of them seem’d to have been the substance that had
+fill’d the Shell of some kind of Shel-fish; others, to have been the
+substance that had contain’d or enwrapp’d one of those Shels, on both
+which, the perfect impression either of the inside or outside of such
+Shells seem’d to be left, but for the most part, those impressions seem’d
+to be made by an imperfect or broken Shell, the great end or mouth of the
+Shell being always wanting, and oftentimes the little end, and sometimes
+half, and in some there were impressions, just as if there had been holes
+broken in the figurating, imprinting or moulding Shell; some of them seem’d
+to be made by such a Shell very much brused or flaw’d, insomuch that one
+would verily have thought that very figur’d stone had been broken or brused
+whilst a gelly, as ’twere, and so hardned, but within in the grain of the
+stone, there appear’d not the least sign of any such bruse or breaking, but
+onely on the very uttermost superficies.
+
+Fourthly, they were very different, as to their outward covering, some
+having the perfect Shell, both in figure, colour, and substance, sticking
+on upon its surface, and adhering to it, but might very easily be separated
+from it, and like other common _Cockle_ or _Scolop-shels_, which some of
+them most accurately resembled, were very dissoluble in common _Vinegar_,
+others of them, especially those _Serpentine_, or _Helical stones_ were
+cover’d or retained the shining or Pearl-colour’d substance of the inside
+of a Shel, which substance, on some parts of them, was exceeding thin, and
+might very easily be rubbed off; on other parts it was pretty thick, and
+retained a white coat, or flaky substance on the top, just like the
+outsides of such Shells; some of them had very large pieces of the Shell
+very plainly sticking on to them, which were easily to be broken or flaked
+off by degrees: they likewise, some of them retain’d all along the surface
+of them very pretty kind of _sutures_, such as are observ’d in the skulls
+of several kinds of living creatures, which _sutures_ were most curiously
+shap’d in the manner of leaves, and every one of them in the same Shell,
+exactly one like another, which I was able to discover plainly enough with
+my naked eye, but more perfectly and distinctly with my _Microscope_; all
+these sutures, by breaking some of these stones, I found to be the
+_termini_, or boundings of certain _diaphragms_, or partitions, which
+seem’d to divide the cavity of the Shell into a multitude of very
+proportionate and regular _cells_ or _caverns_, these _Diaphragms_, in many
+of them, I found very perfect and compleat, of a very distinct substance
+from that which fill’d the cavities, and exactly of the same kind with that
+which covered the outside, being for the most part whitish, or
+_mother of pearl_ colour’d.
+
+As for the cavities between those _Diaphragms_, I found some of them fill’d
+with Marle, and others with several kinds of stones, others, for the most
+part hollow, onely the whole cavity was usually covered over with a kind of
+_tartareous petrify’d_ substance, which stuck about the sides, and was
+there shot into very curious regular Figures, just as _Tartar_, or other
+dissolv’d Salts are observ’d to stick and _crystallize_ about the sides of
+the containing Vessels; or like those little _Diamants_ which I before
+observed to have covered the vaulted cavity of a Flint; others had these
+cavities all lin’d with a kind of _metalline_ or _marchasite-like_
+substance, which with a _Microscope_ I could as plainly see most curiously
+and regularly figured, as I had done those in a Flint.
+
+From all which, and several other particulars which I observ’d, I cannot
+but think, that all these, and most other kinds of stony bodies which are
+found thus strangely figured, do owe their formation and figuration, not to
+any kind of _Plastick virtue_ inherent in the earth, but to the Shells of
+certain Shel-fishes, which, either by some Deluge, Inundation, Earthquake,
+or some such other means, came to be thrown to that place, and there to be
+fill’d with some kind of Mudd or Clay, or _petrifying_ Water, or some other
+substance, which in tract of time has been settled together and hardned in
+those shelly moulds into those shaped substances we now find them; that the
+great and thin end of these Shells by that Earthquake, or what ever other
+extraordinary cause it was that brought them thither, was broken off; and
+that many others were otherwise broken, bruised and disfigured; that these
+Shells which are thus _spirallied_ and separated with _Diaphragmes_, were
+some kind of _Nautili_ or _Porcelane shells_; and that others were shells
+of _Cockles_, _Muscles_, _Periwincles_, _Scolops_, &c. of various sorts;
+that these Shells in many, from the particular nature of the containing or
+enclos’d Earth, or some other cause, have in tract of time rotted and
+mouldred away, and onely left their impressions, both on the containing and
+contained substances; and so left them pretty loose one within another, so
+that they may be easily separated by a knock or two of a Hammer. That
+others of these Shells, according to the nature of the substances adjacent
+to them, have, by a long continuance in that posture, been _petrify’d_ and
+turn’d into the nature of stone, just as I even now observ’d several sorts
+of Wood to be. That oftentimes the Shell may be found with one kind of
+substance within, and quite another without; having, perhaps, been fill’d
+in one place, and afterwards translated to another, which I have very
+frequently observ’d in _Cockle_, _Muscle_, _Periwincle_, and other shells,
+which I have found by the Sea side. Nay, further, that some parts of the
+same Shell may be fill’d in one place, and some other caverns in another,
+and others in a third, or a fourth, or a fifth place, for so many differing
+substances have I found in one of these _petrify’d_ Shells, and perhaps all
+these differing from the encompassing earth or stone; the means how all
+which varieties may be caus’d, I think, will not be difficult to conceive,
+to any one that has taken notice of those Shells, which are commonly found
+on the Sea shore: And he that shall throughly examine several kinds of such
+curiously form’d stones, will (I am very apt to think) find reason to
+suppose their generation or formation to be ascribable to some such
+accidents as I have mention’d, and not to any _Plastick virtue_: For it
+seems to me quite contrary to the infinite prudence of Nature, which is
+observable in all its works and productions, to design every thing to a
+determinate end, and for the attaining of that end, makes use of such ways
+as are (as farr as the knowledge of man has yet been able to reach)
+altogether consonant, and most agreeable to man’s reason, and of no way or
+means that does contradict, or is contrary to humane Ratiocination; whence
+it has a long time been a general observation and _maxime_, that _Nature
+does nothing in vain_; It seems, I say, contrary to that great Wisdom of
+Nature, that these prettily shap’d bodies should have all those curious
+Figures and contrivances (which many of them are adorn’d and contriv’d
+with) generated or wrought by a _Plastick virtue_, for no higher end, then
+onely to exhibite such a form; which he that shall throughly consider all
+the circumstances of such kind of Figur’d bodies, will, I think, have great
+reason to believe, though, I confess, one cannot presently be able to find
+out what Nature’s designs are. It were therefore very desirable, that a
+good collection of such kind of figur’d stones were collected; and as many
+particulars, circumstances, and informations collected with them as could
+be obtained, that from such a History of Observations well rang’d, examin’d
+and digested, the true original or production of all those kinds of stones
+might be perfectly and surely known; such as are _Thunder-stones_, _Lapides
+Stellares_, _Lapides Judaici_, and multitudes of other, whereof mention is
+made in _Aldonandus_, _Wormius_, and other Writers of Minerals.
+
+       *       *       *       *       *
+
+
+Observ. XVIII. _Of the _Schematisme_ or _Texture_ of _Cork_, and of the
+Cells and Pores of some other such frothy Bodies._
+
+I took a good clear piece of Cork, and with a Pen-knife sharpen’d as keen
+as a Razor, I cut a piece of it off, and thereby left the surface of it
+exceeding smooth, then examining it very diligently with a _Microscope_, me
+thought I could perceive it to appear a little porous; but I could not so
+plainly distinguish them, as to be sure that they were pores, much less
+what Figure they were of: But judging from the lightness and yielding
+quality of the Cork, that certainly the texture could not be so curious,
+but that possibly, if I could use some further diligence, I might find it
+to be discernable with a _Microscope_, I with the same sharp Penknife, cut
+off from the former smooth surface an exceeding thin piece of it, and
+placing it on a black object Plate, because it was it self a white body,
+and casting the light on it with a deep _plano convex Glass_, I could
+exceeding plainly perceive it to be all perforated and porous, much like a
+Honey-comb, but that the pores of it were not regular; yet it was not
+unlike a Honey-comb in these particulars.
+
+First, in that it had a very little solid substance, in comparison of the
+empty cavity that was contain’d between, as does more manifestly appear by
+the Figure A and B of the XI. _Scheme_, for the _Interstitia_, or walls (as
+I may so call them) or partitions of those pores were neer as thin in
+proportion to their pores, as those thin films of Wax in a Honey-comb
+(which enclose and constitute the _sexangular celts_) are to theirs.
+
+Next, in that these pores, or cells, were not very deep, but consisted of a
+great many little Boxes, separated out of one continued long pore, by
+certain _Diaphragms_, as is visible by the Figure B, which represents a
+sight of those pores split the long-ways.
+
+I no sooner discern’d these (which were indeed the first _microscopical_
+pores I ever saw, and perhaps, that were ever seen, for I had not met with
+any Writer or Person, that had made any mention of them before this) but me
+thought I had with the discovery of them, presently hinted to me the true
+and intelligible reason of all the _Phænomena_ of Cork; As,
+
+First, if I enquir’d why it was so exceeding light a body? my _Microscope_
+could presently inform me that here was the same reason evident that there
+is found for the lightness of froth, an empty Honey-comb, Wool, a Spunge, a
+Pumice-stone, or the like; namely, a very small quantity of a solid body,
+extended into exceeding large dimensions.
+
+Next, it seem’d nothing more difficult to give an intelligible reason, why
+Cork is a body so very unapt to suck and drink in Water, and consequently
+preserves it self, floating on the top of Water, though left on it never so
+long: and why it is able to stop and hold air in a Bottle, though it be
+there very much condens’d and consequently presses very strongly to get a
+passage out, without suffering the least bubble to pass through its
+substance. For, as to the first, since our _Microscope_ informs us that the
+substance of Cork is altogether fill’d with Air, and that that Air is
+perfectly enclosed in little Boxes or Cells distinct from one another. It
+seems very plain, why neither the Water, nor any other Air can easily
+insinuate it self into them, since there is already within them an _intus
+existens_, and consequently, why the pieces of Cork become so good floats
+for Nets, and stopples for Viols, or other close Vessels.
+
+And thirdly, if we enquire why Cork has such a springiness and swelling
+nature when compress’d? and how it comes to suffer so great a compression,
+or seeming penetration of dimensions, so as to be made a substance as
+heavie again and more, bulk for bulk, as it was before compression, and yet
+suffer’d to return, is found to extend it self again into the same space?
+Our _Microscope_ will easily inform us, that the whole mass consists of an
+infinite company of small Boxes or Bladders of Air, which is a substance of
+a springy nature, and that will suffer a considerable condensation (as I
+have several times found by divers trials, by which I have most evidently
+condens’d it into less then a twentieth part of its usual dimensions neer
+the Earth, and that with no other strength then that of my hands without
+any kind of forcing Engine, such as Racks, Leavers, Wheels, Pullies, or the
+like, but this onely by and by) and besides, it seems very probable that
+those very films or sides of the pores, have in them a springing quality,
+as almost all other kind of Vegetable substances have, so as to help to
+restore themselves to their former position.
+
+And could we so easily and certainly discover the _Schematisme_ and
+_Texture_ even of these films, and of several other bodies, as we can these
+of Cork; there seems no probable reason to the contrary, but that we might
+as readily render the true reason of all their _Phænomena_; as namely, what
+were the cause of the springiness, and toughness of some, both as to their
+flexibility and restitution. What, of the friability or brittleness of some
+others, and the like; but till such time as our _Microscope_, or some other
+means, enable us to discover the true _Schematism_ and _Texture_ of all
+kinds of bodies, we must grope, as it were, in the dark, and onely ghess at
+the true reasons of things by similitudes and comparisons.
+
+But, to return to our Observation. I told several lines of these pores, and
+found that there were usually about threescore of these small Cells placed
+end-ways in the eighteenth part of an Inch in length, whence I concluded
+there must be neer eleven hundred of them, or somewhat more then a thousand
+in the length of an Inch, and therefore in a square Inch above a Million,
+or 1166400. and in a Cubick Inch, above twelve hundred Millions, or
+1259712000. a thing almost incredible, did not our _Microscope_ assure us
+of it by ocular demonstration; nay, did it not discover to us the pores of
+a body, which were they _diaphragm’d_, like those of Cork, would afford us
+in one Cubick Inch, more then ten times as many little Cells, as is evident
+in several charr’d Vegetables; so prodigiously curious are the works of
+Nature, that even these conspicuous pores of bodies, which seem to be the
+channels or pipes through which the _Succus nutritius_, or natural juices
+of Vegetables are convey’d, and seem to correspond to the veins, arteries
+and other Vessels in sensible creatures, that these pores I say, which seem
+to be the Vessels of nutrition to the vastest body in the World, are yet so
+exceeding small, that the _Atoms_ which _Epicurus_ fancy’d would go neer to
+prove too bigg to enter them, much more to constitute a fluid body in them.
+And how infinitely smaller then must be the Vessels of a Mite, or the pores
+of one of those little Vegetables I have discovered to grow on the
+back side of a Rose-leaf, and shall anon more fully describe, whose bulk is
+many millions of times less then the bulk of the small shrub it grows on;
+and even that shrub, many millions of times less in bulk then several trees
+(that have heretofore grown in _England_, and are this day flourishing in
+other hotter Climates, as we are very credibly inform’d) if at least the
+pores of this small Vegetable should keep any such proportion to the body
+of it, as we have found these pores of other Vegetables to do to their
+bulk. But of these pores I have said more elsewhere.
+
+To proceed then, Cork seems to be by the transverse constitution of the
+pores, a kind of _Fungus_ or Mushrome, for the pores lie like so many Rays
+tending from the center, or pith of the tree, outwards; so that if you cut
+off a piece from a board of Cork transversly, to the flat of it, you will,
+as it were, split the pores, and they will appear just as they are
+express’d in the Figure B of the XI. _Scheme_. But if you shave off a very
+thin piece from this board, parallel to the plain of it, you will cut all
+the pores transversly, and they will appear almost as they are express’d in
+the Figure A, save onely the solid _Interstitia_ will not appear so thick
+as they are there represented.
+
+So that Cork seems to suck its nourishment from the subjacent bark of the
+Tree immediately, and to be a kind of excrescence, or a substance distinct
+from the substances of the entire Tree, something _analogus_ to the
+Mushrome, or Moss on other Trees, or to the hairs on Animals. And having
+enquir’d into the History of Cork, I find it reckoned as an excrescency of
+the bark of a certain Tree, which is distinct from the two barks that lie
+within it, which are common also to other trees; That ’tis some time before
+the Cork that covers the young and tender sprouts comes to be discernable;
+That it cracks, flaws, and cleaves into many great chaps, the bark
+underneath remaining entire; That it may be separated and remov’d from the
+Tree, and yet the two under-barks (such as are also common to that with
+other Trees) not at all injur’d, but rather helped and freed from an
+external injury. Thus _Jonstonus_ in _Dendrologia_, speaking _de Subere_,
+says, _Arbor est procera, Lignum est robustum, dempto cortice in aquis non
+fluitat, Cortice in orbem detracto juvatur, crascescens enim præstringit &
+strangulat, intra triennium iterum repletur: Caudex ubi adolescit crassus,
+cortex superior densus carnosus, duos digitos crassus, scaber, rimosus, &
+qui nisi detrahatur dehiscit, alioque subnascente expellitur, interior qui
+subest novellus ita rubet ut arbor minio picta videatur_. Which Histories,
+if well consider’d, and the tree, substance, and manner of growing, if well
+examin’d, would, I am very apt to believe, much confirm this my conjecture
+about the origination of Cork.
+
+Nor is this kind of Texture peculiar to Cork onely; for upon examination
+with my _Microscope_, I have found that the pith of an Elder, or almost any
+other Tree, the inner pulp or pith of the Cany hollow stalks of several
+other Vegetables: as of Fennel, Carrets, Daucus, Bur-docks, Teasels, Fearn,
+some kinds of Reeds, &c. have much such a kind of _Schematisme_, as I have
+lately shewn that of Cork, save onely that here the pores are rang’d the
+long-ways, or the same ways with the length of the Cane, whereas in Cork
+they are transverse.
+
+The pith also that fills that part of the stalk of a Feather that is above
+the Quil, has much such a kind of texture, save onely that which way soever
+I set this light substance, the pores seem’d to be cut transversly; so that
+I ghess this pith which fills the Feather, not to consist of abundance of
+long pores separated with Diaphragms, as Cork does, but to be a kind of
+solid or hardned froth, or a _congeries_ of very small bubbles consolidated
+in that form, into a pretty stiff as well as tough concrete, and that each
+Cavern, Bubble, or Cell, is distinctly separate from any of the rest,
+without any kind of hole in the encompassing films, so that I could no more
+blow through a piece of this kinde of substance, then I could through a
+piece of Cork, or the sound pith of an Elder.
+
+But though I could not with my _Microscope_, nor with my breath, nor any
+other way I have yet try’d, discover a passage out of one of those cavities
+into another, yet I cannot thence conclude, that therefore there are none
+such, by which the _Succus nutritius_, or appropriate juices of Vegetables,
+may pass through them; for, in several of those Vegetables, whil’st green,
+I have with my _Microscope_, plainly enough discover’d these Cells or Poles
+fill’d with juices, and by degrees sweating them out; as I have also
+observed in green Wood all those long _Microscopical_ pores which appear in
+Charcoal perfectly empty of any thing but Air.
+
+Now, though I have with great diligence endeavoured to find whether there
+be any such thing in those _Microscopical_ pores of Wood or Piths, as the
+_Valves_ in the heart, veins, and other passages of Animals, that open and
+give passage to the contain’d fluid juices one way, and shut themselves,
+and impede the passage of such liquors back again, yet have I not hitherto
+been able to say any thing positive in it; though, me thinks, it seems very
+probable, that Nature has in these passages, as well as in those of Animal
+bodies, very many appropriated Instruments and contrivances, whereby to
+bring her designs and end to pass, which ’tis not improbable, but that some
+diligent Observer, if help’d with better _Microscopes_, may in time detect.
+
+And that this may be so, seems with great probability to be argued from the
+strange _Phænomena_ of sensitive Plants, wherein Nature seems to perform
+several Animal actions with the same _Schematism_ or _Orginization_ that is
+common to all Vegetables, as may appear by some no less instructive then
+curious Observations that were made by divers Eminent Members of the _Royal
+Society_ on some of these kind of Plants, whereof an account was delivered
+in to them by the most Ingenious and Excellent _Physician_, Doctor _Clark_,
+which, having that liberty granted me by that most Illustrious Society, I
+have hereunto adjoyn’d.
+
+_Observations on the _Humble_ and _Sensible Plants_ in _M Chiffin’s_ Garden
+in Saint _James_’s Park, made _August_ the _9th, 1661_._ _Present, the_
+Lord _Brouncker_, Sr. _Robert Moray_, Dr. _Wilkins_, Mr. _Evelin_, Dr.
+_Henshaw_, _and_ Dr. _Clark_.
+
+    There are four Plants, two of which are little shrub Plants, with a
+    little short stock, about an Inch above the ground, from whence are
+    spread several sticky branches, round, streight, and smooth in the
+    distances between the Sprouts, but just under the Sprouts there are two
+    sharp thorny prickles, broad in the letting on, as in the Bramble, one
+    just under the Sprout, the other on the opposite side of the branch.
+
+    [14]The distances betwixt the Sprouts are usually something more then
+    an Inch, and many upon a Branch, according to its length, and they grew
+    so, that if the lower Sprout be on the left side of the Branch, the
+    next above is on the right, and so to the end, not sprouting by pairs.
+
+    At the end of each Sprout are generally four sprigs, two at the
+    Extremity, and one on each side, just under it. At the first sprouting
+    of these from the Branch to the Sprig where the leaves grow, they are
+    full of little short white hairs, which wear off as the leaves grow,
+    and then they are smooth as the Branch.
+
+    Upon each of these sprigs, are, for the most part, eleven pair of
+    leaves, neatly set into the uppermost part of the little sprig, exactly
+    one against another, as it were in little _articulations_, such as
+    Anatomists call _Enarthrosis_, where the round head of a Bone is
+    received into another fitted for its motion; and standing very fitly to
+    shut themselves and touch, the pairs just above them closing somewhat
+    upon them, as in the shut sprig; so is the little round _Pedunculus_ of
+    this leaf fitted into a little cavity of the sprig, visible to the eye
+    in a sprig new pluck’d, or in a sprig withered on the Branch, from
+    which the leaves easily fall by touching.
+
+    The leaf being almost an oblong square, and set into the _Pedunculus_,
+    at one of the lower corners, receiveth from that not onely a _Spine_,
+    as I may call it, which, passing through the leaf, divides it so
+    length-ways that the outer-side is broader then the inner next the
+    sprig, but little _fibres_ passing obliquely towards the opposite
+    broader side, seem to make it here a little muscular, and fitted to
+    move the whole leaf, which, together with the whole sprig, are set full
+    with little short whitish hairs.
+
+    One of these Plants, whose branch seem’d to be older and more grown
+    then the other, onely the tender Sprouts of it, after the leaves are
+    shut, fall and hang down; of the other, the whole branches fall to the
+    ground, if the Sun shine very warm, upon the first taking off the
+    Glass, which I therefore call the _humble Plant_.
+
+    The other two, which do never fall, nor do any of their branches flag
+    and hang down, shut not their leaves, but upon somewhat a hard stroke;
+    the stalks seem to grow up from a root, and appear more _herbaceous_,
+    they are round and smooth, without any prickle, the Sprouts from them
+    have several pairs of sprigs, with much less leaves then the other on
+    them, and have on each sprig generally seventeen pair.
+
+    Upon touching any of the sprigs with leaves on, all the leaves on that
+    sprig contracting themselves by pairs, joyned their upper superficies
+    close together.
+
+    Upon the dropping a drop of _Aqua fortis_ on the sprig betwixt the
+    leaves, ff all the leaves above shut presently, those below by pairs
+    successively after, and by the lower leaves of the other branches, ll,
+    kk, &c. and so every pair successively, with some little distance of
+    time betwixt, to the top of each sprig, and so they continu’d shut all
+    the time we were there. But I returning the next day, and several days
+    since, found all the leaves dilated again on two of the sprigs; but
+    from ff, where the _Aqua fortis_ had dropped upwards, dead and
+    withered; but those below on the same sprig, green, and closing upon
+    the touch, and are so to this day, _August_ 14.
+
+    With a pair of Scissers, as suddenly as it could be done, one of the
+    leaves bb was clipped off in the middle, upon which that pair, and the
+    pair above, closed presently, after a little interval, dd, then ee, and
+    so the rest of the pairs, to the bottom of the sprig, and then the
+    motion began in the lower pairs, ll, on the other sprigs, and so shut
+    them by pairs upwards, though not with such distinct distances.
+
+    Under a pretty large branch with its sprigs on, there lying a large
+    Shell betwixt two and three Inches below it, there was rubbed on a
+    strong scented oyl, after a little time all the leaves on that sprig
+    were shut, and so they continued all the time of our stay there, but at
+    my returne the next day, I found the position of the Shell alter’d, and
+    the leaves expanded as before, and closing upon the touch.
+
+    Upon the application of the Sun-beams by a Burning-glass, the more
+    _humble Plant_ fell, the other shut their leaves.
+
+    We could not so apply the smoak of _Sulpher_, as to have any visible
+    effect from that, at two or three times trial; but on another trial,
+    the smoak touching the leaves, it succeeded.
+
+    The _humble Plant_ fell upon taking off the Glass wherewith it was
+    covered.
+
+    Cutting off one of the little Sprouts, two or three drops of liquor
+    were thrust out of the part from whence that was cut, very cleer, and
+    pellucid, of a bright greenish colour, tasting at first a little
+    bitterish, but after leaving a licorish-like taste in my mouth.
+
+    Since, going two or three times when it was cold, I took the Glasses
+    from the more _humble Plant_, and it did not fall as formerly, but shut
+    its leaves onely. But coming afterwards, when the Sun shone very warm,
+    as soon as it was taken off, it fell as before.
+
+    Since I pluck’d off another sprig, whose leaves were all shut, and had
+    been so some time, thinking to observe the liquor should come from that
+    I had broken off, but finding none, though with pressing, to come, I,
+    as dexterously as I could, pull’d off one whose leaves were expanded,
+    and then had upon the shutting of the leaves, a little of the mention’d
+    liquor, from the end of the sprig I had broken from the Plant. And this
+    twice successively, as often almost as I durst rob the Plant.
+
+    But my curiosity carrying me yet further, I cut off one of the harder
+    branches of the stronger Plant, and there came of the liquor, both from
+    that I had cut, and that I had cut it from, without pressure.
+
+    Which made me think, that the motion of this Plant upon touching, might
+    be from this, that there being a constant _intercourse_ betwixt every
+    part of this Plant and its root, either by a _circulation_ of this
+    liquor, or a constant pressing of the subtiler parts of it to every
+    extremity of the Plant. Upon every pressure, from whatsoever it
+    proceeds, greater then that which keeps it up, the subtile parts of
+    this liquor are thrust downwards, towards its _articulations_ of the
+    leaves, where, not having room presently to get into the sprig, the
+    little round _pedunculus_, from whence the _Spine_ and those oblique
+    _Fibres_ I mentioned rise, being dilated, the _Spine_ and _Fibres_
+    (being continued from it) must be contracted and shortned, and so draw
+    the leaf upwards to joyn with its fellow in the same condition with it
+    self, where, being closed, they are held together by the implications
+    of the little whitish hair, as well as by the still retreating liquor,
+    which distending the _Fibres_ that are continued lower to the branch
+    and root, shorten them above; and when the liquor is so much forced
+    from the Sprout, whose _Fibres_ are yet tender, and not able to support
+    themselves, but by that tensness which the liquor filling their
+    _interstices_ gives them, the Sprout hangs and flags.
+
+    But, perhaps, he that had the ability and leisure to give you the exact
+    _Anatomy_ of this pretty Plant, to shew you its _Fibres_, and visible
+    _Canales_, through which this fine liquor circulateth, or is moved, and
+    had the faculty of better and more copiously expressing his
+    Observations and conceptions, such a one would easily from the motion
+    of this liquor, solve all the _Phænomena_, and would not fear to
+    affirm, that it is no obscure sensation this Plant hath. But I have
+    said too much, I humbly submit, and am ready to stand corrected.
+
+I have not yet made so full and satisfactory Observations as I desire on
+this Plant, which seems to be a Subject that will afford abundance of
+information. But as farr as I have had opportunity to examine it, I have
+discovered with my _Microscope_ very curious structures and contrivances;
+but designing much more accurate examinations and trials, both with my
+_Microscope_, and otherwise, as soon as the season will permit, I shall not
+till then add any thing of what I have already taken notice of; but as farr
+as I have yet observ’d, I judge the motion of it to proceed from causes
+very differing from those by which Gut-strings, or Lute-strings, the beard
+of a wilde _Oat_, or the beard of the Seeds of _Geranium_, _Moscatum_, or
+_Musk-grass_ and other kinds of _Cranes-bill_, move themselves. Of which I
+shall add more in the subsequent Observations on those bodies.
+
+       *       *       *       *       *
+
+
+Observ. XIX. _Of a _Plant_ growing in the blighted or yellow specks of
+_Damask-rose-leaves_, _Bramble-leaves_, and some other kind of leaves._
+
+I have for several years together, in the Moneths of _June_, _July_,
+_August_, and _September_ (when any of the green leaves of _Roses_ begin to
+dry and grow yellow) observ’d many of them, especially the leaves of the
+old shrubs of _Damask Roses_, all bespecked with yellow stains; and the
+undersides just against them, to have little yellow hillocks of a gummous
+substance, and several of them to have small black spots in the midst of
+those yellow ones, which, to the naked eye, appear’d no bigger then the
+point of a Pin, or the smallest black spot or tittle of Ink one is able to
+make with a very sharp pointed Pen.
+
+Examining these with a _Microscope_, I was able plainly to distinguish, up
+and down the surface, several small yellow knobs, of a kind of yellowish
+red gummy substance, out of which I perceiv’d there sprung multitudes of
+little cases or black bodies like Seed-cods, and those of them that were
+quite without the hillock of Gumm, disclos’d themselves to grow out of it
+with a small Straw-colour’d and transparent stem, the which seed and stem
+appear’d very like those of common Moss (which I elsewhere describe) but
+that they were abundantly less, many hundreds of them being not able to
+equalize one single seed Cod of Moss.
+
+I have often doubted whether they were the seed Cods of some little Plant,
+or some kind of small Buds, or the Eggs of some very small Insect, they
+appear’d of a dark brownish red, some almost quite black, and of a Figure
+much resembling the seed-cod of Moss, but their stalks on which they grew
+were of a very fine transparent substance, almost like the stalk of mould,
+but that they seem’d somewhat more yellow.
+
+That which makes me to suppose them to be Vegetables, is for that I
+perceiv’d many of those hillocks bare or destitute, as if those bodies lay
+yet conceal’d, as G. In others of them, they were just springing out of
+their gummy hillocks, which all seem’d to shoot directly outwards, as at A.
+In others, as at B, I found them just gotten out, with very little or no
+stalk, and the Cods of an indifferent cize; but in others, as C, I found
+them begin to have little short stalks, or stems; in others, as D, those
+stems were grown bigger, and larger; and in others, as at E, F, H, I, K, L,
+&c. those stems and Cods were grown a great deal bigger, and the stalks
+were more bulky about the root, and very much taper’d towards the top, as
+at F and L is most visible.
+
+I did not find that any of them had any seed in them, or that any of them
+were hollow, but as they grew bigger and bigger, I found those heads or
+Cods begin to turn their tops towards their roots, in the same manner as I
+had observ’d that of Moss to do; so that in all likelihood, Nature did
+intend in that posture, what she does in the like seed-cods of greater
+bulk, that is, that the seed, when ripe, should be shaken out and dispersed
+at the end of it, as we find in Columbine Cods, and the like.
+
+The whole Oval OOOO in the second _Figure_ of the 12. _Scheme_ represents a
+small part of a Rose-leaf, about the bigness of the little Oval in the
+hillock, C, marked with the Figure X. in which I have not particularly
+observ’d all the other forms of the surface of the Rose-leaf, as being
+little to my present purpose.
+
+Now, if these Cods have a seed in them so proportion’d to the Cod, as thole
+of _Pinks_, and _Carnations_, and _Columbines_, and the like, how
+unimaginably small must each of those seeds necessarily be, for the whole
+length of one of the largest of those Cods was not ¹⁄₅₀₀ part of an Inch;
+some not above ¹⁄₁₀₀₀, and therefore certainly, very many thousand of them
+would be unable to make a bulk that should be visible to the naked eye; and
+if each of these contain the Rudiments of a young Plant of the same kind,
+what must we say of the pores and constituent parts of that?
+
+The generation of this Plant seems in part, ascribable to a kind of
+_Mildew_ or _Blight_, whereby the parts of the leaves grow scabby, or
+putrify’d, as it were, so as that the moisture breaks out in little scabs
+or spots, which, as I said before, look like little knobs of a red gummous
+substance.
+
+From this putrify’d scab breaks out this little Vegetable; which may be
+somewhat like a _Mould_ or _Moss_; and may have its _equivocal_ generation
+much after the same manner as I have supposed _Moss_ or _Mould_ to have,
+and to be a more simple and uncompounded kind of vegetation, which is set a
+moving by the _putrefactive_ and _fermentative_ heat, joyn’d with that of
+the ambient aerial, when (by the putrifaction and decay of some other parts
+of the vegetable, that for a while staid its progress) it is unfetter’d and
+left at liberty to move in its former course, but by reason of its
+_regulators_, moves and acts after quite another manner then it did when a
+_coagent_ in the more compounded _machine_ of the more perfect Vegetable.
+
+And from this very same Principle, I imagine the _Misleto_ of Oaks, Thorns,
+Appletrees, and other Trees, to have its original: It seldom or never
+growing on any of those Trees, till they begin to wax decrepid, and decay
+with age, and are pester’d with many other infirmities.
+
+Hither also may be referr’d those multitudes and varieties of _Mushroms_,
+such as that, call’d _Jews-ears_, all sorts of _gray_ and _green_ Mosses,
+&c. which infest all kind of Trees, shrubs, and the like, especially when
+they come to any bigness. And this we see to be very much the method of
+Nature throughout its operations, _putrifactive Vegetables_ very often
+producing a Vegetable of a much less compounded nature, and of a much
+inferiour tribe; and _putrefactive_ animal substances degenerating into
+some kind of animal production of a much inferiour rank, and of a more
+simple nature.
+
+Thus we find the humours and substances of the body, upon _putrifaction_,
+to produce strange kinds of moving Vermine: _the putrifaction_ of the
+slimes and juices of the Stomack and Guts, produce Worms almost like
+Earth-worms, the Wheals in childrens hands produce a little Worm, call’d a
+_Wheal-worm_: The bloud and milk, and other humours, produce other kinds of
+Worms, at least, if we may believe what is deliver’d to us by very famous
+Authors; though, I confess, I have not yet been able to discover such my
+self.
+
+And whereas it may seem strange that _Vinegar_, _Meal_, musty _Casks_, &c.
+are observ’d to breed their differing kinds of Insects, or living
+creatures, whereas they being Vegetable substances, seem to be of an
+inferiour kind, and so unable to produce a creature more noble, or of a
+more compounded nature then they themselves are of, and so without some
+concurrent seminal principle, may be thought utterly unfit for such an
+operation; I must add, that we cannot presently positively say, there are
+no animal substances, either mediately, as by the soil or fatning of the
+Plant from whence they sprung, or more immediately, by the real mixture or
+composition of such substances, join’d with them; or perchance some kind of
+Insect, in such places where such kind of _putrifying_ or _fermenting_
+bodies are, may, by a certain instinct of nature, eject some sort of
+seminal principle, which cooperating with various kinds of _putrifying_
+substances, may produce various kinds of Insects, or Animate bodies: For we
+find in most sorts of those lower degrees of Animate bodies, that the
+_putrifying_ substances on which these Eggs, Seeds, or seminal principles
+are cast by the Insect, become, as it were, the _Matrices_ or Wombs that
+conduce very much to their generation, and may perchance also to their
+variation and alteration, much after the same manner, as, by strange and
+unnatural copulations, several new kinds of Animals are produc’d, as
+_Mules_, and the like, which are usually call’d Monstrous, because a little
+unusual, though many of them have all their principal parts as perfectly
+shap’d and adapted for their peculiar uses, as any of the most perfect
+Animals. If therefore the _putrifying_ body, on which any kind of seminal
+or vital principle chances to be cast, become somewhat more then meerly a
+nursing and fostering helper in the generation and production of any kind
+of Animate body, the more neer it approaches the true nature of a Womb, the
+more power will it have on the by-blow it incloses. But of this somewhat
+more in the description of the _Water-gnat_. Perhaps some more accurate
+Enquiries and Observations about these matters might bring the Question to
+some certainty, which would be of no small concern in Natural Philosophy.
+
+But that _putrifying_ animal substances may produce animals of an inferior
+kind, I see not any so very great a difficulty, but that one may, without
+much absurdity, admit: For as there may be multitudes of contrivances that
+go to the making up of one compleat Animate body; so, That some of those
+_coadjutors_, in the perfect existence and life of it, may be vitiated, and
+the life of the whole destroyed, and yet several of the constituting
+contrivances remain intire, I cannot think it beyond imagination or
+possibility; no more then that a like accidental process, as I have
+elswhere hinted, may also be supposed to explicate the method of Nature in
+the _Metamorphosis_ of Plants. And though the difference between a Plant
+and an Animal be very great, yet I have not hitherto met with any so
+_cogent_ an Argument, as to make me positive in affirming these two to be
+altogether _Heterogeneous_ and of quite differing kinds of Nature: And
+besides, as there are many _Zoophyts_, and sensitive Plants (divers of
+which I have seen, which are of a middle nature, and seem to be Natures
+transition from one degree to another, which may be observ’d in all her
+other passages, wherein she is very seldom observ’d to leap from one step
+to another) so have we, in some Authors, Instances of Plants turning into
+Animals, and Animals into Plants, and the like; and some other very strange
+(because unheeded) proceedings of Nature; something of which kind may be
+met with, in the description of the _Water-Gnat_, though it be not
+altogether so direct to the present purpose.
+
+But to refer this Discourse of Animals to their proper places, I shall add,
+that though one should suppose, or it should be prov’d by Observations;
+that several of these kinds of Plants are accidentally produc’d by a casual
+_putrifaction_, I see not any great reason to question, but that,
+notwithstanding its own production was as ’twere casual, yet it may
+germinate and produce seed, and by it propagate its own, that is, a new
+Species. For we do not know, but that the Omnipotent and All-wise Creator
+might as directly design the structure of such a Vegetable, or such an
+Animal to be produc’d out of such or such a _putrifaction_ or change of
+this or that body, towards the constitution or structure of which, he knew
+it necessary, or thought it fit to make it an ingredient; as that the
+digestion or moderate heating of an Egg, either by the Female, or the Sun,
+or the heat of the Fire, or the like, should produce this or that Bird; or
+that _Putrifactive_ and warm steams should, out of the blowings, as they
+call them, that is, the Eggs of a Flie, produce a living Magot, and that,
+by degrees, be turn’d into an _Aurelia_, and that, by a longer and a
+proportion’d heat, be _transmuted_ into a Fly. Nor need we therefore to
+suppose it the more imperfect in its kind, then the more compounded
+Vegetable or Animal of which it is a part; for he might as compleatly
+furnish it with all kinds of contrivances necessary for its own existence,
+and the propagation of its own Species, and yet make it a part of a more
+compounded body: as a Clock-maker might make a Set of Chimes to be a part
+of a Clock, and yet, when the watch part or striking part are taken away,
+and the hindrances of its motion remov’d, this chiming part may go as
+accurately, and strike its tune as exactly, as if it were still a part of
+the compounded _Automaton_. So, though the original cause, or seminal
+principle from which this minute Plant on Rose leaves did spring; were,
+before the corruption caus’d by the Mill-dew, a component part of the leaf
+on which it grew, and did serve as a _coagent_ in the production and
+constitution of it, yet might it be so consummate, as to produce a seed
+which might have a power of propagating the same species: the works of the
+Creator seeming of such an excellency, that though they are unable to help
+to the perfecting of the more compounded existence of the greater Plant or
+Animal, they may have notwithstanding an ability of acting singly upon
+their own internal principle, so as to produce a Vegetable body, though of
+a less compounded nature, and to proceed so farr in the method of other
+Vegetables, as to bear flowers and seeds, which may be capable of
+propagating the like. So that the little cases which appear to grow on the
+top of the slender stalks, may, for ought I know, though I should suppose
+them to spring from the perverting of the usual course of the parent
+Vegetable, contain a seed, which, being scatter’d on other leaves of the
+same Plant, may produce a Plant of much the same kind.
+
+Nor are Damask-Rose leaves the onely leaves that produce these kinds of
+Vegetable sproutings; for I have observ’d them also in several other kinds
+of Rose leaves, and on the leaves of several sorts of Briers, and on
+Bramble leaves they are oftentimes to be found in very great clusters; so
+that I have found in one cluster, three, four, or five hundred of them,
+making a very conspicuous black spot or scab on the back side of the leaf.
+
+       *       *       *       *       *
+
+
+Observ. XX. _Of _blue Mould_, and of the first Principles of Vegetation
+arising from _Putrefaction_._
+
+The Blue and White and several kinds of hairy mouldy spots, which are
+observable upon divers kinds of _putrify’d_ bodies, whether Animal
+substances, or Vegetable, such as the skin, raw or dress’d, flesh, bloud,
+humours, milk, green Cheese, &c. or rotten sappy Wood, or Herbs, Leaves,
+Barks, Roots, &c. of Plants, are all of them nothing else but several kinds
+of small and variously figur’d Mushroms, which, from convenient materials
+in those _putrifying_ bodies, are, by the concurrent heat of the Air,
+excited to a certain kind of vegetation, which will not be unworthy our
+more serious speculation and examination, as I shall by and by shew. But,
+first, I must premise a short description of this _Specimen_, which I have
+added of this Tribe, in the first Figure of the XII. _Scheme_, which is
+nothing else but the appearance of a small white spot of hairy mould,
+multitudes of which I found to bespeck & whiten over the red covers of a
+small book, which, it seems, were of Sheeps skin, that being more apt to
+gather mould, even in a dry and clean room, then other leathers. These
+spots appear’d, through a good _Microscope_, to be a very pretty shap’d
+Vegetative body, which, from almost the same part of the Leather, shot out
+multitudes of small long cylindrical and transparent stalks, not exactly
+streight, but a little bended with the weight of a round and white knob
+that grew on the top of each of them; many of these knobs I observ’d to be
+very round, and of a smooth surface, such as A, A, &c. others smooth
+likewise, but a little oblong, as B; several of them a little broken, or
+cloven with chops at the top, as C; others flitter’d as ’twere, or flown
+all to pieces, as D, D. The whole substance of these pretty bodies was of a
+very tender constitution, much like the substance of the softer kind of
+common white Mushroms, for by touching them with a Pin, I found them to be
+brused and torn; they seem’d each of them to have a distinct root of their
+own; for though they grew neer together in a cluster, yet I could perceive
+each stem to rise out of a distinct part or pore of the Leather; some of
+these were small and short, as seeming to have been but newly sprung up, of
+these the balls were for the most part round, others were bigger, and
+taller, as being perhaps of a longer growth, and of these, for the most
+part, the heads were broken, and some much wasted, as E; what these heads
+contain’d I could not perceive; whether they were knobs and flowers, or
+seed cases, I am not able to say, but they seem’d most likely to be of the
+same nature with those that grow on Mushroms, which they did, some of them,
+not a little resemble.
+
+Both their smell and taste, which are active enough to make a sensible
+impression upon those organs, are unpleasant and noisome.
+
+I could not find that they would so quickly be destroy’d by the actual
+flame of a Candle, as at first sight of them I conceived they would be, but
+they remain’d intire after I had past that part of the Leather on which
+they stuck three or four times through the flame of a Candle; so that, it
+seems they are not very apt to take fire, no more then the common white
+Mushroms are when they are sappy.
+
+There are a multitude of other shapes, of which these _Microscopical_
+Mushroms are figur’d, which would have been a long Work to have described,
+and would not have suited so well with my design in this Treatise, onely,
+amongst the rest, I must not forget to take notice of one that was a little
+like to, or resembled, a Spunge, consisting of a multitude of little
+Ramifications almost as that body does, which indeed seems to be a kind of
+Water-Mushrom, of a very pretty texture, as I else-where manifest. And a
+second, which I must not omit, because often mingled, and neer adjoining to
+these I have describ’d, and this appear’d much like a Thicket of bushes, or
+brambles, very much branch’d, and extended, some of them, to a great
+length, in proportion to their Diameter, like creeping brambles.
+
+The manner of the growth and formation of this kind of Vegetable, is the
+third head of Enquiry, which, had I time, I should follow: the figure and
+method of Generation in this concrete seeming to me, next after the Enquiry
+into the formation, figuration; or chrystalization of Salts, to be the most
+simple, plain, and easie; and it seems to be a _medium_ through which he
+must necessarily pass, that would with any likelihood investigate the
+_forma informans_ of Vegetables: for as I think that he shall find it a
+very difficult task, who undertakes to discover the form of Saline
+crystallizations, without the consideration and prescience of the nature
+and reason of a Globular form, and as difficult to explicate this
+configuration of Mushroms, without the previous consideration of the form
+of Salts; so will the enquiry into the forms of Vegetables be no less, if
+not much more difficult, without the fore-knowledge of the forms of
+Mushroms, these several Enquiries having no less dependance one upon
+another then any select number of Propositions in Mathematical Elements may
+be made to have.
+
+Nor do I imagine that the skips from the one to another will be found very
+great, if beginning from fluidity, or body without any form, we descend
+gradually, till we arrive at the highest form of a bruite Animal’s Soul,
+making the steps or foundations of our Enquiry, _Fluidity_, _Orbiculation_,
+_Fixation_, _Angulization_, or _Crystallization Germination_ or
+_Ebullition_, _Vegetation_, _Plantanimation_, _Animation_, _Sensation_,
+_Imagination_.
+
+Now, that we may the better proceed in our Enquiry, It will be requisite to
+consider:
+
+First, that Mould and Mushroms require no seminal property, but the former
+may be produc’d at any time from any kind of _putrifying_ Animal, or
+Vegetable Substance, as Flesh, &c. kept moist and warm, and the latter, if
+what _Mathiolus_ relates be true, of making them by Art, are as much within
+our command, of which Matter take the _Epitomie_ which Mr. _Parkinson_ has
+deliver’d in his _Herbal_, in his Chapter of _Mushroms_, because I have not
+_Mathiolus_ now by me: _Unto these Mushroms_ (saith he) _may also be
+adjoyn’d those which are made of Art (whereof _Mathiolus_ makes mention)
+that grow naturally among certain stones in _Naples_, and that the stones
+being digg’d up, and carried to _Rome_, and other places, where they set
+them in their Wine Cellars, covering them with a little Earth, and
+sprinkling a little warm water thereon, would within four days produce
+Mushroms fit to be eaten, at what time one will: As also that Mushroms may
+be made to grow at the foot of a wilde _Poplar Tree_, within four days
+after, warm water wherein some leaves have been dissolv’d shall be pour’d
+into the Root (which must be slit) and the stock above ground._
+
+Next, that as Mushroms may be generated without seed, so does it not appear
+that they have any such thing as seed in any part of them; for having
+considered several kinds of them, I could never find any thing in them that
+I could with any probability ghess to be the seed of it, so that it does
+not as yet appear (that I know of) that Mushroms may be generated from a
+seed, but they rather seem to depend merely upon a convenient constitution
+of the matter out of which they are made, and a concurrence of either
+natural or artificial heat.
+
+Thirdly, that by several bodies (as Salts and Metals both in Water and in
+the air, and by several kinds of sublimations in the Air) actuated and
+guided with a congruous heat, there may be produc’d several kinds of bodies
+as curiously, if not of a more compos’d Figure; several kinds of rising or
+Ebulliating Figures seem to manifest; as witness the shooting in the
+Rectification of spirits of _Urine_, _Hart-horn_, _Bloud_, &c. witness also
+the curious branches of evaporated dissolutions, some of them against the
+sides of the containing Jar: others standing up, or growing an end, out of
+the bottom, of which I have taken notice of a very great variety. But above
+all the rest, it is a very pretty kind of Germination which is afforded us
+in the Silver Tree, the manner of making which with Mercury and Silver, is
+well known to the Chymists, in which there is an Ebullition or Germination,
+very much like this of Mushroms, if I have been rightly inform’d of it.
+
+Fourthly, I have very often taken notice of, and also observ’d with a
+_Microscope_, certain excrescencies or Ebullitions in the snuff of a
+Candle, which, partly from the sticking of the smoaky particles as they are
+carryed upwards by the current of the rarify’d Air and flame, and partly
+also from a kind of Germination or Ebullition of some actuated unctuous
+parts which creep along and filter through some small string of the Week,
+are formed into pretty round and uniform heads, very much resembling the
+form of hooded Mushroms, which, being by any means expos’d to the fresh
+Air, or that air which encompasses the flame, they are presently lick’d up
+and devour’d by it, and vanish.
+
+The reason of which _Phænomenon_ seems to me, to be no other then this:
+
+That when a convenient thread of the Week is so bent out by the sides of
+the snuff that are about half an Inch or more, remov’d above the bottom, or
+lowest part of the flame, and that this part be wholly included in the
+flame; the Oyl (for the reason of filtration, which I have elsewhere
+rendred) being continualy driven up the snuff is driven likewise into this
+ragged bended-end, and this being remov’d a good distance, as half an Inch
+or more, above the bottom of the flame, the parts of the air that passes by
+it, are already, almost satiated with the dissolution of the boiling
+unctuous steams that issued out below, and therefore are not onely glutted,
+that is, can dissolve no more then what they are already acting upon, but
+they carry up with them abundance of unctuous and sooty particles, which
+meeting with that rag of the Week, that is plentifully fill’d with Oyl, and
+onely spends it as fast as it evaporates, and not at all by dissolution or
+burning, by means of these steamy parts of the filtrated Oyl issuing out
+at the sides of this ragg, and being inclos’d with an air that is already
+satiated and cannot prey upon them nor burn them, the ascending sooty
+particles are stay’d about it and fix’d, so as that about the end of that
+ragg or filament of the snuff, whence the greatest part of the steams
+issue, there is conglobated or fix’d a round and pretty uniform cap, much
+resembling the head of a Mushrom, which, if it be of any great bigness, you
+may observe that its underside will be bigger then that which is above the
+ragg or stem of it; for the Oyl that is brought into it by filtration,
+being by the bulk of the cap a little shelter’d from the heat of the flame,
+does by that means issue as much out beneath from the stalk or downwards,
+as it does upwards, and by reason of the great access of the adventitious
+smoak from beneath, it increases most that way. That this may be the true
+reason of this _Phænomenon_, I could produce many Arguments and Experiments
+to make it probable: As,
+
+First, that the _Filtration_ carries the Oyl to the top of the Week, at
+least as high as these raggs, is visible to one that will observe the snuff
+of a burning Candle with a _Microscope_, where he may see an Ebullition or
+bubbling of the Oyl, as high as the snuff looks black.
+
+Next, that it does steam away more then burn; I could tell you of the dim
+burning of a Candle, the longer the snuff be which arises from the
+abundance of vapours out of the higher parts of it.
+
+And, thirdly, that in the middle of the flame of the Candle, neer the top
+of the snuff, the fire or dissolving principle is nothing neer so strong,
+as neer the bottom and out edges of the flame, which may be observ’d by the
+burning asunder of a thread, that will first break in those parts that the
+edges of the flame touch, and not in the middle.
+
+And I could add several Observables that I have taken notice of in the
+flame of a Lamp actuated with Bellows, and very many others that confirm me
+in my opinion, but that it is not so much to my present purpose, which is
+onely to consider this concreet in the snuff of a Candle, so farr as it has
+any resemblance of a Mushrom, to the consideration of which, that I may
+return, I say, we may also observe:
+
+In the fifth place, that the droppings or trillings of Lapidescent waters
+in Vaults under ground, seem to constitute a kind of _petrify’d_ body,
+form’d almost like some kind of Mushroms inverted, in so much that I have
+seen some knobb’d a little at the lower end, though for the most part,
+indeed they are otherwise shap’d, and taper’d towards the end; the
+generation of which seems to be from no other reason but this, that the
+water by soaking through the earth and Lime (for I ghess that substance to
+add much to it _petrifying_ quality) does so impregnate it self with stony
+particles, that hanging in drops in the roof of the Vault, by reason that
+the soaking of the water is but slow, it becomes expos’d to the Air, and
+thereby the outward part of the drop by degrees grows hard, by reason that
+the water gradually evaporating the stony particles neer the outsides of
+the drop begin to touch, and by degrees, to dry and grow closer together,
+and at length constitute a crust or shell about the drop; and this soaking
+by degrees, being more and more supply’d, the drop grows longer and longer,
+and the sides harden thicker and thicker into a Quill or Cane, and at
+length, that hollow or pith becomes almost stop’d up, and solid: afterwards
+the soaking of the _petrifying_ water, finding no longer a passage through
+the middle, bursts out, and trickles down the outside, and as the water
+evaporates, leaves new superinduc’d shells, which more and more swell the
+bulk of those Iceicles, and because of the great supply from the Vault, of
+_petrifying_ wafer, those bodies grow bigger and bigger next to the Vault,
+and taper or sharpen towards the point; for the access from the arch of the
+Vault being but very slow, and consequently the water being spread very
+thinly over the surface of the Iceicle, the water begins to settle before
+it can reach to the bottom, or corner end of it; whence, if you break one
+of these, you would almost imagine it a stick of Wood _petrify’d_, it
+having so pretty a resemblance of pith and grain, and if you look on the
+outside of a piece, or of one whole, you would think no less, both from its
+vegetable roundness and tapering form; but whereas all Vegetables are
+observ’d to shoot and grow perpendicularly upwards, this does shoot or
+propend directly downwards.
+
+By which last Observables, we see that there may be a very pretty body
+shap’d and concreeted by Mechanical principles, without the least shew or
+probability of any other seminal _formatrix_.
+
+And since we find that the great reason of the _Phænomena_ of this pretty
+_petrifaction_, are to be reduc’d from the gravity of a fluid and pretty
+volatil body impregnated with stony particles, why may not the _Phænomena_
+of Ebullition or Germination be in part possibly enough deduc’d from the
+levity of an impregnated liquor, which therefore perpendicularly ascending
+by degrees, evaporates and leaves the more solid and fix’d parts behind in
+the form of a Mushrom, which is yet further diversify’d and specificated by
+the forms of the parts that impregnated the liquor, and compose or help to
+constitute the Mushrom.
+
+That the foremention’d Figures of growing Salts, and the Silver Tree, are
+from this principle, I could very easily manifest, but that I have not now
+a convenient opportunity of following it, nor have I made a sufficient
+number of Experiments and Observations to propound, explicate, and prove so
+usefull a _Theory_ as this of Mushroms: for, though the contrary principle
+to that of _petrify’d_ Iceicles may be in part a cause, yet I cannot but
+think, that there is somewhat a more complicated cause, though yet
+Mechanical, and possible to be explain’d.
+
+We therefore have further to enquire of it, what makes it to be such a
+liquor, and to ascend, whether the heat of the Sun and Air, or whether
+that _firmentiation_ and _putrifaction_, or both together; as also
+whether there be not a third or fourth; whether a Saline principle
+be not a considerable agent in this business also as well as heat;
+whether also a fixation, precipitation or settling of certain parts
+out of the aerial menstruum may not be also a considerable coadjutor
+in the business. Since we find that many pretty beards or _stiriæ_ of
+the particles of Silver may be precipitated upon a piece of Brass put
+into a _solution_ of Silver very much diluted with fair water, which
+look not unlike a kind of mould or hoar upon that piece of metal; and
+the hoar frost looks like a kind of mould; and whether there may not be
+several others that do concurr to the production of a Mushrom, having
+not yet had sufficient time to prosecute according to my desires,
+I must refer this to a better opportunity of my own, or leave and
+recommend it to the more diligent enquiry and examination of such as
+can be masters both of leisure and conveniencies for such an Enquiry.
+
+And in the mean time, I must conclude, that as far as I have been able to
+look into the nature of this Primary kind of life and vegetation, I cannot
+find the least probable argument to perswade me there is any other
+concurrent cause then such as is purely Mechanical, and that the effects or
+productions are as necessary upon the concurrence of those causes as that a
+Ship, when the Sails are hoist up, and the Rudder is set to such a
+position, should, when the Wind blows, be mov’d in such a way or course to
+that or t’other place; Or, as that the brused Watch, which I mention in the
+description of Moss, should, when those parts which hindred its motion were
+fallen away, begin to move, but after quite another manner then it did
+before.
+
+       *       *       *       *       *
+
+
+Observ. XXI. _Of _Moss_, and several other small vegetative Substances._
+
+Moss is a Plant, that the wisest of Kings thought neither unworthy his
+speculation, nor his Pen, and though amongst Plants it be in bulk one of
+the smallest, yet it is not the least considerable: For, as to its shape,
+it may compare for the beauty of it with any Plant that grows, and bears a
+much bigger breadth; it has a root almost like a seedy Parsnep, furnish’d
+with small strings and suckers, which are all of them finely branch’d, like
+those of the roots of much bigger Vegetables; out of this springs the stem
+or body of the Plant, which is somewhat _Quadrangular_, rather then
+_Cylindrical_, most curiously _fluted_ or strung with small creases, which
+run, for the most part, _parallel_ the whole stem; on the sides of this are
+close and thick set, a multitude of fair, large, well-shap’d leaves, some
+of them of a rounder, others of a longer shape, according as they are
+younger or older when pluck’d; as I ghess by this, that those Plants that
+had the stalks growing from the top of them, had their leaves of a much
+longer shape, all the surface of each side of which, is curiously cover’d
+with a multitude of little oblong transparent bodies, in the manner as you
+see it express’d in the leaf B, in the XIII. _Scheme_.
+
+This Plant, when young and springing up, does much resemble a Housleek,
+having thick leaves, almost like that, and seems to be somwhat of kin to it
+in other particulars; also from the top of the leaves, there shoots out a
+small white and transparent hair, or thorn: This stem, in time, come to
+shoot out into a long, round and even stalk, which by cutting transversly,
+when dry, I manifestly found to be a stiff, hard, and hollow Cane, or Reed,
+without any kind of knot, or stop, from its bottom, where the leaves
+encompass’d it, to the top, on which there grows a large seed case, A,
+cover’d with a thin, and more whitish skin, B, terminated in a long thorny
+top, which at first covers all the Case, and by degrees, as that swells,
+the skin cleaves, and at length falls off, with its thorny top and all
+(which is a part of it) and leaves the seed Case to ripen, and by degrees,
+to shatter out its seed at a place underneath this cap, B, which before the
+seed is ripe, appears like a flat barr’d button, without any hole in the
+middle; but as it ripens, the button grows bigger, and a hole appears in
+the middle of it, E, out of which, in all probability, the seed falls: For
+as it ripens by a provision of Nature, that end of this Case turns downward
+after the same manner as the ears of Wheat and Barley usually do; and
+opening several of these dry red Cases, F, I found them to be quite hollow,
+without anything at all in them; whereas when I cut them asunder with a
+sharp Pen-knife when green, I found in the middle of this great Case,
+another smaller round Case, between which two, the _interstices_ were
+fill’d with multitudes of stringie _fibres_, which seem’d to suspend the
+lesser Case in the middle of the other, which (as farr as I was able to
+discern) seem’d full of exceeding small white seeds, much like the
+seed-bagg in the knop of a Carnation, after the flowers have been two or
+three days, or a week, fallen off; but this I could not so perfectly
+discern, and therefore cannot positively affirm it.
+
+After the seed was fallen away, I found both the Case, Stalk, and Plant,
+all grow red and wither, and from other parts of the root continually to
+spring new branches or slips, which by degrees increased, and grew as bigg
+as the former, seeded, ripen’d, shatter’d, and wither’d.
+
+I could not find that it observ’d any particular seasons for these several
+kinds of growth, but rather found it to be springing, mature, ripe, seedy,
+and wither’d at all times of the year; But I found it most to flourish and
+increase in warm and moist weather.
+
+It gathers its nourishments, for the most part, out of some _Lapidescent_,
+or other substance corrupted or chang’d from its former texture, or
+substantial form; for I have found it to grow on the rotten parts of Stone,
+of Bricks, of Wood, of Bones, of Leather, &c.
+
+It oft grows on the barks of several Trees, spreading it self, sometimes
+from the ground upwards, and sometimes from some chink or cleft of the bark
+of the Tree, which has some _putrify’d_ substance in it, but this seems of
+a distinct kind from that which I observ’d to grow on _putrify’d_ inanimate
+bodies, and rotten earth.
+
+There are also great varieties of other kinds of Mosses, which grow on
+Trees, and several other Plants, of which I shall here make no mention, nor
+of the Moss growing on the skull of a dead man, which much resembles that
+of Trees.
+
+Whether this Plant does sometimes originally spring or rise out of
+corruption, without any disseminated seed, I have not yet made trials
+enough to be very much, either positive or negative; for as it seems very
+hard to conceive how the seed should be generally dispers’d into all parts
+where there is a corruption begun, unless we may rationally suppose, that
+this seed being so exceeding small, and consequently exceeding light, is
+thereby taken up, and carried to and fro in the Air into every place, and
+by the falling drops of rain is wash’d down out of it, and so dispers’d
+into all places, and there onely takes root and propagates, where it finds
+a convenient soil or matrix for it to thrive in; so if we will have it to
+proceed from corruption, it is not less difficult to conceive,
+
+First, how the corruption of any Vegetable, much less of any Stone or
+Brick, should be the Parent of so curiously figur’d, and so perfect a Plant
+as this is. But here indeed, I cannot but add, that it seems rather to be a
+product of the Rain in those bodies where it is stay’d, then of the very
+bodies themselves, since I have found it growing on Marble, and Flint, but
+always the _Microscope_, if not the naked eye, would discover some little
+hole of Dirt in which it was rooted.
+
+Next, how the corruption of each of those exceedingly differing bodies
+should all conspire to the production of the same Plant, that is, that
+Stones, Bricks, Wood, or vegetable substances, and Bones, Leather, Horns,
+or animate substances, unless we may with some plausibleness say, that Air
+and Water are the coadjutors, or _menstruums_, all kinds of
+_putrifactions_, and that thereby the bodies (though whil’st they retain’d
+their substantial forms, were of exceeding differing natures, yet) since
+they are dissolv’d and mixt into another, they may be very _Homogeneous_,
+they being almost resolv’d again into Air, Water, and Earth; retaining,
+perhaps, one part of their vegetative faculty yet entire, which meeting
+with congruous assistants, such as the heat of the Air, and the fluidity of
+the Water, and such like coadjutors and conveniences, acquires a certain
+vegetation for a time, wholly differing perhaps from that kind of
+vegetation it had before.
+
+To explain my meaning a little better by a gross Similitude:
+
+Suppose a curious piece of Clock-work, that had had several motions and
+contrivances in it, which, when in order, would all have mov’d in their
+design’d methods and Periods. We will further suppose, by some means, that
+this Clock comes to be broken, brused, or otherwise disordered, so that
+several parts of it being dislocated, are impeded, and so stand still, and
+not onely hinder its own progressive motion, and produce not the effect
+which they were design’d for, but because the other parts also have a
+dependence upon them, put a stop to their motion likewise; and so the whole
+Instrument becomes unserviceable, and not fit for any use. This Instrument
+afterwards, by some shaking and tumbling, and throwing up and down, comes
+to have several of its parts shaken out, and several of its curious
+motions, and contrivances, and particles all fallen asunder; here a Pin
+falls out, and there a Pillar, and here a Wheel, and there a Hammer, and a
+Spring, and the like, and among the rest, away falls those parts also which
+were brused and disorder’d, and had all this while impeded the motion of
+all the rest; hereupon several of those other motions that yet remain,
+whole springs were not quite run down, being now at liberty, begin each of
+them to move, thus or thus, but quite after another method then before,
+there being many regulating parts and the like, fallen away and lost. Upon
+this, the Owner, who chances to hear and observe some of these effects,
+being ignorant of the Watch-makers Art, wonders what is betid his Clock,
+and presently imagines that some Artist has been at work, and has set his
+Clock in order, and made a new kind of Instrument of it, but upon examining
+circumstances, he finds there was no such matter, but that the casual
+slipping out of a Pin had made several parts of his Clock fall to pieces,
+and that thereby the obstacle that all this while hindred his Clock,
+together with other usefull parts were fallen out, and so his Clock was set
+at liberty. And upon winding up those springs again when run down, he finds
+his Clock to go, but quite after another manner then it was wont
+heretofore.
+
+And thus may it be perhaps in the business of Moss, and Mould, and
+Mushroms, and several other spontaneous kinds of vegetations, which may be
+caus’d by a vegetative principle, which was a coadjutor to the life and
+growth of the greater Vegetable, and was by the destroying of the life of
+it stopt and impeded in performing its office; but afterwards, upon a
+further corruption of several parts that had all the while impeded it, the
+heat of the Sun winding up, as it were, the spring, sets it again into a
+vegetative motion, and this being single, and not at all regulated as it
+was before (when a part of that greater _machine_ the pristine vegetable)
+is mov’d after quite a differing manner, and produces effects very
+differing from those it did before.
+
+But this I propound onely as a conjecture, not that I am more enclin’d to
+this _Hypothesis_ then the seminal, which upon good reason I ghess to be
+Mechanical also, as I may elsewhere more fully shew: But because I may, by
+this, hint a possible way how this appearance may be solv’d; supposing we
+should be driven to confess from certain Experiments and Observations made,
+that such or such Vegetables were produc’d out of the corruption of
+another, without any concurrent seminal principle (as I have given some
+reason to suppose, in the description of a _Microscopical_ Mushrome)
+without derogating at all from the infinite wisdom of the Creator. For this
+accidental production, as I may call it, does manifest as much, if not very
+much more, of the excellency of his contrivance as any thing in the more
+perfect vegetative bodies of the world, even as the accidental motion of
+the _Automaton_ does make the owner see, that there was much more
+contrivance in it then at first he imagin’d. But of this I have added more
+in the description of Mould, and the Vegetables on Rose leaves, &c. those
+being much more likely to have their original from such a cause then this
+which I have here described, in the 13. _Scheme_, which indeed I cannot
+conceive otherwise of, then as of a most perfect Vegetable, wanting nothing
+of the perfections of the most conspicuous and vastest Vegetables of the
+world, and to be of a rank so high, as that it may very properly be
+reckon’d with the tall Cedar of _Lebanon_, as that Kingly Botanist has
+done.
+
+We know there may be as much curiosity of contrivance, and excellency of
+form in a very small Pocket-clock, that takes not up an Inch square of
+room, as there may be in a Church-clock that fills a whole room; And I know
+not whether all the contrivances and _Mechanisms_ requisite to a perfect
+Vegetable, may not be crowded into an exceedingly less room then this of
+Moss, as I have heard of a striking Watch so small, that it serv’d for a
+Pendant in a Ladies ear; and I have already given you the description of a
+Plant growing on Rose leaves, that is abundantly smaller then Moss;
+insomuch, that neer 1000. of them would hardly make the bigness of one
+single Plant of Moss. And by comparing the bulk of Moss, with the bulk of
+the biggest kind of Vegetable we meet with in Story (of which kind we find
+in some hotter climates, as _Guine_, and _Brasile_, the stock or body of
+some Trees to be twenty foot in Diameter, whereas the body or stem of Moss,
+for the most part, is not above one sixtieth part of an Inch) we shall find
+that the bulk of the one will exceed the bulk of the other, no less then
+2985984 Millions, or 2985984000000, and supposing the production on a Rose
+leaf to be a Plant, we shall have of those _Indian_ Plants to exceed a
+production of the same Vegetable kingdom no less then 1000 times the former
+number; so prodigiously various are the works of the Creator, and so
+All-sufficient is he to perform what to man would seem unpossible, they
+being both alike easie to him, even as one day, and a thousand years are to
+him as one and the same time.
+
+I have taken notice of such an infinite variety of those smaller kinds of
+vegetations, that should I have described every one of them, they would
+almost have fill’d a Volume, and prov’d bigg enough to have made a new
+Herbal, such multitudes are there to be found in moist hot weather,
+especially in the Summer time, on all kind of putrifying substances, which,
+whether they do more properly belong to the _Classis_ of _Mushrooms_, or
+_Moulds_, or _Mosses_, I shall not now dispute, there being some that seem
+more properly of one kind, others of another, their colours and magnitudes
+being as much differing as their Figures and substances.
+
+Nay, I have observ’d, that putting fair Water (whether Rain-water or
+Pump-water, or _May-dew_ or Snow-water, it was almost all one) I have often
+observ’d, I say, that this Water would, with a little standing, tarnish and
+cover all about the sides of the Glass that lay under water, with a lovely
+green; but though I have often endeavour’d to discover with my _Microscope_
+whether this green were like Moss, or long striped Sea-weed, or any other
+peculiar form, yet so ill and imperfect are our _Microscopes_, that I could
+not certainly discriminate any.
+
+Growing Trees also, and any kinds of Woods, Stones, Bones, &c. that have
+been long expos’d to the Air and Rain, will be all over cover’d with a
+greenish scurff, which will very much foul and green any kind of cloaths
+that are rubb’d against it; viewing this, I could not certainly perceive in
+many parts of it any determinate form, though in many I could perceive a
+Bed as ’twere of young Moss, but in other parts it look’d almost like green
+bushes, and very confus’d, but always of what ever irregular Figures the
+parts appear’d of, they were always green, and seem’d to be either some
+Vegetable, or to have some vegetating principle.
+
+       *       *       *       *       *
+
+
+Observ. XXII. _Of common _Sponges_, and several other _Spongie_ fibrous
+bodies._
+
+A Sponge is commonly reckon’d among the _Zoophyts_, or Plant Animals; and
+the _texture_ of it, which the _Microscope_ discovers, seems to confirm it;
+for it is of a form whereof I never observ’d any other Vegetable, and
+indeed, it seems impossible that any should be of it, for it consists of an
+infinite number of small short _fibres_, or nervous parts, much of the same
+bigness, curiously jointed or contex’d together in the form of a Net, as is
+more plainly manifest by the little Draught which I have added, in the
+third _Figure_ of the IX. _Scheme_, of a piece of it, which you may
+perceive represents a confus’d heap of the fibrous parts curiously jointed
+and implicated. The joints are, for the most part, where three _fibres_
+onely meet, for I have very seldom met with any that had four.
+
+At these joints there is no one of the three that seems to be the stock
+whereon the other grow, but each of the _fibres_ are, for the most part, of
+an equal bigness, and seem each of them to have an equal share in the
+joint; the _fibres_ are all of them much about the same bigness, not
+smaller towards the top of the Sponge, and bigger neerer the bottom or
+root, as is usuall in Plants, the length of each between the joints, is
+very irregular and different; the distance between some two joints, being
+ten or twelve times more then between some others.
+
+Nor are the joints regular, and of an _equitriagonal Figure_, but, for the
+most part, the three _fibres_ so meet, that they compose three angles very
+differing all of them from one another.
+
+The meshes likewise, and holes of this reticulated body, are not less
+various and irregular: some _bilateral_, others _trilateral_, and
+_quadrilateral_ Figures; nay, I have observ’d some meshes to have 5, 6, 7,
+8, or 9. sides, and some to have onely one, so exceeding various is the
+_Lusus Naturæ_ in this body.
+
+As to the outward appearance of this Vegetative body, they are so usuall
+everywhere, that I need not describe them, consisting of a soft and porous
+substance, representing a Lock, sometimes a fleece of Wool; but it has
+besides these small _microscopical_ pores which lie between the _fibres_, a
+multitude of round pores or holes, which, from the top of it, pierce into
+the body, and sometimes go quite through to the bottom.
+
+I have observ’d many of these Sponges, to have included likewise in the
+midst of their fibrous contextures, pretty large friable stones, which must
+either have been inclos’d whil’st this Vegetable was in formation, or
+generated in those places after it was perfectly shap’d. The later of which
+seems the more improbable, because I did not find that any of these stony
+substances were perforated with the _fibres_ of the Sponge.
+
+I have never seen nor been enform’d of the true manner of the growing of
+Sponges on the Rock; whether they are found to increase from little to
+great, like Vegetables, that is, part after part, or like Animals, all
+parts equally growing together; or whether they be _matrices_ or feed-baggs
+of any kind of Fishes, or some kind of watry Insect; or whether they are at
+any times more soft and tender, or of another nature and texture, which
+things, if I knew how, I should much desire to be informed of: but from a
+cursory view that I at first made with my _Microscope_, and some other
+trials, I supposed it to be some Animal substance cast out, and fastned
+upon the Rocks in the form of a froth, or _congeries_ of bubbles, like that
+which I have often observ’d on Rosemary, and other Plants (wherein is
+included a little Insect) that all the little films which divide these
+bubbles one from another, did presently, almost after the substance began
+to grow a little harder, break, and leave onely the thread behind, which
+might be, as ’twere, the angle or thread between the bubbles, that the
+great holes or pores observable in these Sponges were made by the eruption
+of the included _Heterogeneous_ substance (whether air, or some other body,
+for many other fluid bodies will do the same thing) which breaking out of
+the lesser, were collected into very large bubbles, and so might make their
+way out of the Sponge, and in their passage might leave a round cavity; and
+if it were large, might carry up with it the adjacent bubbles, which may be
+perceiv’d at the outside of the Sponge, if it be first throughly wetted,
+and sufferr’d to plump itself into its natural form, or be then wrung dry,
+and suffer’d to expand it self again, which it will freely do whil’st
+moist: for when it has thus plump’d it self into its natural shape and
+dimensions, ’tis obvious enough that the mouths of the larger holes have a
+kind of lip or rising round about them, but the other smaller pores have
+little or none. It may further be found, that each of these great pores has
+many other small pores below, that are united unto it, and help to
+constitute it, almost like so many rivulets or small streams that
+contribute to the maintenance of a large River. Nor from this _Hypothesis_
+would it have been difficult to explicate, how those little branches of
+_Coral_, smal _Stones_, _shells_, and the like, come to be included by
+these frothy bodies: But this indeed was but a conjecture; and upon a more
+accurate enquiry into the form of it with the _Microscope_, it seems not to
+be the true origine of them; for whereas Sponges have onely three arms
+which join together at each knot, if they had been generated from bubbles
+they must have had four.
+
+But that they are Animal Substances, the _Chymical_ examination of them
+seems to manifest, they affording a volatil Salt and spirit, like
+_Harts-Horn_, as does also their great strength and toughness, and their
+smell when burn’d in the Fire or a Candle, which has a kind of fleshy sent,
+not much unlike to hair. And having since examin’d several Authors
+concerning them, among others; I find this account given by _Bellonius_, in
+the XI. _Chap._ of his 2d Book, _De Aquatilibus_. _Spongiæ recentes_, says
+he, _à siccis longe diversæ, scopulis aquæ marinæ ad duos vel tres cubitos,
+nonnunquam quatuor tantum digitos immersis, ut fungi arboribus adhærent,
+sordido quodam succo aut mucosa potius sanie ræfertæ, usque adeò fœtida,
+ut vel eminus nauseam excitet, continetur autem iis cavernis, quas inanes
+in siccis & lotis Spongiis cernimus: Putris pulmonis modo nigræ
+conspiciuntur, verùm quæ in sublimi aquæ nascuntur multo magis opaca
+nigredine suffusæ sunt. Vivere quidem Spongias adhærendo _Aristoteles_
+censet: absolute vero minime: sensumque aliquem habere, vel eo argumento
+(inquit) credantur, quod difficillime abstrahantur, nisi clanculum agatur:
+Atq; ad avulsoris accessum ita contrahantur, ut eas evellere difficile sit,
+quod idem etiam faciunt quoties flatus tempestatésque urgent. Puto autem
+illis succum sordidum quem supra diximus carnis loco à natura attributum
+fuisse: atque meatibus latioribus tanquam intestinis aut interaneis uti.
+Cæterum pars ea quæ Spongiæ cautibus adhærent est tanquam folii petiolus, à
+quo veluti collum quoddam gracile incipit: quod deinde in latitudinem
+diffusum capitis globum facit. Recentibus nihil est fistulosum, hæsitantque
+tanquam radicibus. Superne omnes propemodum meatus concreti latent: inferne
+verò quaterni aut quini patent, per quos eas sugere existimamus_. From
+which Description, they seem to be a kind of Plant-Animal that adheres to a
+Rock, and these small _fibres_ or threads which we have described, seem to
+have been the Vessels which (’tis very probable) were very much bigger
+whil’st the _Interstitia_ were fill’d (as he affirms) with a mucous, pulpy
+or fleshy substance; but upon the drying were shrunk into the bigness they
+now appear.
+
+The texture of it is such, that I have not yet met with any other body in
+the world that has the like, but onely one of a larger sort of Sponge
+(which is preserv’d in the _Museum Harveanum_ belonging to the most
+Illustrious and most learned Society of the _Physicians_ of _London_) which
+is of a horney, or rather of a _petrify’d_ substance. And of this indeed,
+the texture and make is exactly the same with common Sponges, but onely
+that both the holes and the _fibres_, or texture of it is exceedingly much
+bigger, for some of the holes were above an Inch and half over, and the
+_fibres_ and _texture_ of it was bigg enough to be distinguished easily
+with ones eye, but conspicuously with an ordinary single _Microscope_. And
+these indeed, seem’d to have been the habitation of some Animal; and
+examining _Aristotle_, I find a very consonant account hereunto, namely,
+that he had known a certain little Animal, call’d _Pinnothera_, like a
+Spider, to be bred in those caverns of a Sponge, from within which, by
+opening and closing those holes, he insnares and catches the little Fishes;
+and in another place he says, That ’tis very confidently reported, that
+there are certain Moths or Worms that reside in the cavities of a Sponge,
+and are there nourished: Notwithstanding all which Histories, I think it
+well worth the enquiring into the History and nature of a Sponge, it
+seeming to promise some information of the Vessels in Animal substances,
+which (by reason of the solidity of the interserted flesh that is not
+easily remov’d, without destroying also those interspers’d Vessels) are
+hitherto undiscover’d; whereas here in a Sponge, the _Parenchyma_, it
+seems, is but a kind of mucous gelly, which is very easily and clearly
+wash’d away.
+
+The reason that makes me imagine, that there may probably be some such
+texture in Animal substances, is, that examining the texture of the
+filaments of tann’d Leather, I find it to be much of the same nature and
+strength of a Sponge; and with my _Microscope_, I have observ’d many such
+joints and knobs, as I have described in Sponges, the _fibres_ also in the
+hollow of several sorts of Bones, after the Marrow has been remov’d, I have
+found somewhat to resemble this texture, though, I confess, I never yet
+found any texture exactly the same, nor any for curiosity comparable to it.
+
+The filaments of it are much smaller then those of Silk, and through the
+_Microscope_ appear very neer as transparent, nay, some parts of them I
+have observ’d much more.
+
+Having examin’d also several kinds of Mushroms, I finde their texture to be
+somewhat of this kind, that is, to consist of an infinite company of small
+filaments, every way contex’d and woven together, so as to make a kind of
+cloth, and more particularly, examining a piece of Touch-wood (which is a
+kind _Jews-ear_, or Mushrom, growing here in _England_ also, on several
+sorts of Trees, such as Elders, Maples, Willows, &c. and is commonly call’d
+by the name of _Spunk_; but that we meet with to be sold in Shops, is
+brought from beyond Seas) I found it to be made of an exceeding delicate
+texture: For the substance of it feels, and looks to the naked eye, and may
+be stretch’d any way, exactly like a very fine piece of _Chamois_ Leather,
+or wash’d Leather, but it is of somewhat a browner hew, and nothing neer so
+strong; but examining it with my _Microscope_, I found it of somewhat
+another make then any kind of Leather; for whereas both _Chamois_, and all
+other kinds of Leather I have yet view’d, consist of an infinite company of
+filaments, somewhat like bushes interwoven one within another, that is, of
+bigger parts or stems, as it were, and smaller branchings that grow out of
+them; or like a heap of Ropes ends, where each of the larger Ropes by
+degrees seem to split or untwist, into many smaller Cords, and each of
+those Cords into smaller Lines, and those Lines into Threads, &c. and these
+strangely intangled, or interwoven one within another: The texture of this
+Touch-wood seems more like that of a Lock or a Fleece of Wool, for it
+consists of an infinite number of small filaments, all of them, as farr as
+I could perceive, of the same bigness like those of a Sponge, but that the
+_filaments_ of this were not a twentieth part of the bigness of those of a
+Sponge; and I could not so plainly perceive their joints, or their manner
+of interweaving, though, as farr as I was able to discern with that
+_Microscope_ I had, I suppose it to have some kind of resemblance, but the
+joints are nothing neer so thick, nor without much trouble visible.
+
+The filaments I could plainly enough perceive to be even, round,
+cylindrical, transparent bodies, and to cross each other every way, that
+is, there were not more seem’d to lie _horizontally_ then _perpendicularly_
+and thwartway, so that it is somewhat difficult to conceive how they
+should grow in that manner. By tearing off a small piece of it, and looking
+on the ragged edge, I could among several of those _fibres_ perceive small
+joints, that is, one of those hairs split into two, each of the same
+bigness with the other out of which they seem’d to grow, but having not
+lately had an opportunity of examining their manner of growth, I cannot
+positively affirm any thing of them.
+
+But to proceed, The swelling of Sponges upon wetting, and the rising of the
+Water in it above the surface of the Water that it touches, are both from
+the same cause, of which an account is already given in the sixth
+Observation.
+
+The substance of them indeed, has so many excellent properties, scarce to
+be met with in any other body in the world, that I have often wondered that
+so little use is made of it, and those onely vile and sordid; certainly, if
+it were well consider’d, it would afford much greater conveniencies.
+
+That use which the Divers are said to make of it, seems, if true, very
+strange, but having made trial of it my self, by dipping a small piece of
+it in very good Sallet-oyl, and putting it in my mouth, and then keeping my
+mouth and nose under water, I could not find any such thing; for I was as
+soon out of breath as if I had had no Sponge, nor could I fetch my breath
+without taking in water at my mouth; but I am very apt to think, that were
+there a contrivance whereby the expir’d air might be forc’d to pass through
+a wet or oyly Sponge before it were again inspir’d, it might much cleanse,
+and strain away from the Air divers fuliginous and other noisome steams,
+and the dipping of it in certain liquors might, perhaps, so renew that
+property in the Air which it loses in the Lungs, by being breath’d, that
+one square foot of Air might last a man for respiration much longer,
+perhaps, then ten will now serve him of common Air.
+
+       *       *       *       *       *
+
+
+Observ. XXIII. _Of the curious texture of _Sea-weeds_._
+
+For curiosity and beauty, I have not among all the Plants or Vegetables I
+have yet observ’d, seen any one comparable to this Sea-weed I have here
+describ’d, of which I am able to say very little more then what is
+represented by the second _Figure_ of the ninth _Scheme_: Namely, that it
+is a Plant which grows upon the Rocks under the water, and increases and
+spreads it self into a great tuft, which is not onely handsomely branch’d
+into several leaves, but the whole surface of the Plant is cover’d over
+with a most curious kind of carv’d work, which consists of a texture much
+resembling a Honey-comb; for the whole surface on both sides is cover’d
+over with a multitude of very small holes, being no bigger then so many
+holes made with the point of a small Pinn, and rang’d in the neatest and
+most delicate order imaginable, they being plac’d in the manner of a
+_Quincunx_, or very much like the rows of the eyes of a Fly, the rows or
+orders being very regular, which way soever they are observ’d: what the
+texture was, as it appear’d through a pretty bigg Magnifying _Microscope_,
+I have here adjoin’d in the first _Figure_ of the 14. _Scheme._ which round
+Area ABCD represents a part of the surface about one eighth part of an Inch
+in Diameter: Those little holes, which to the eye look’d round, like so
+many little spots, here appear’d very regularly shap’d holes, representing
+almost the shape of the sole of a round toed shoe, the hinder part of
+which, is, as it were, trod on or cover’d by the toe of that next below it;
+these holes seem’d wall’d about with a very thin and transparent substance,
+looking of a pale straw-colour; from the edge of which, against the middle
+of each hole, were sprouted out four small transparent straw-colour’d
+Thorns, which seem’d to protect and cover those cavities, from either side
+two; neer the root of this Plant, were sprouted out several small branches
+of a kind of bastard _Coralline_, curiously branch’d, though small.
+
+And to confirm this, having lately the opportunity of viewing the large
+Plant (if I may so call it) of a Sponge _petrify’d_, of which I made
+mention in the last Observation, I found, that each of the Branches or
+Figures of it, did, by the range of its pores, exhibit just such a texture,
+the rows of pores crossing one another, much after the manner as the rows
+of eyes do which are describ’d in the 26. _Scheme_: _Coralline_ also, and
+several sorts of white _Coral_, I have with a _Microscope_ observ’d very
+curiously shap’d. And I doubt not, but that he that shall observe these
+several kinds of Plants that grow upon Rocks, which the Sea sometimes
+overflows, and those heaps of others which are vomited out of it upon the
+shore, may find multitudes of little Plants, and other bodies, which like
+this will afford very beautifull objects for the _Microscope_; and this
+_Specimen_ here is adjoin’d onely to excite their curiosities who have
+opportunity of observing to examine and collect what they find worthy their
+notice; for the Sea, among terrestrial bodies, is also a _prolifick_
+mother, and affords as many Instances of _spontaneous_ generations as
+either the Air or Earth.
+
+       *       *       *       *       *
+
+
+Observ. XXIV. _Of the surfaces of _Rosemary_, and other leaves._
+
+This which is delineated within the circle of the second _Figure_ of the
+14. _Scheme_, is a small part of the back or under side of a leaf of
+Rosemary, which I did not therefore make choice of because it had any thing
+peculiar which was not observable with a _Microscope_ in several other
+Plants, but because it exhibits at one view,
+
+First, a smooth and shining surface, namely, AB, which is a part of the
+upper side of the leaf, that by a kind of hem or doubling of the leaf
+appears on this side. There are multitudes of leaves, whose surfaces are
+like this smooth, and as it were quilted, which look like a curious quilted
+bagg of green Silk, or like a Bladder, or some such pliable transparent
+substance, full stuffed out with a green juice or liquor; the surface of
+Rue, or Herbgrass, is polish’d, and all over indented, or pitted, like the
+Silk-worm’s Egg, which I shall anon describe; the smooth surfaces of other
+Plants are otherwise quilted, Nature in this, as it were, expressing her
+Needle-work, or imbroidery.
+
+Next a downy or bushy surface, such as is all the under side almost,
+appearing through the _Microscope_ much like a thicket of bushes, and with
+this kind of Down or Hair the leaves and stalks of multitudes of Vegetables
+are covered; and there seems to be as great a variety in the shape, bulk,
+and manner of the growing of these secundary Plants, as I may call them
+(they being, as it were, a Plant growing out of a Plant, or somewhat like
+the hairs of Animals) as there is to be found amongst small shrubs that
+compose bushes; but for the most part, they consist of small transparent
+parts, some of which grow in the shape of small Needles or Bodkins, as on
+the Thistle, Cowag-ecod and Nettle; others in the form of Cat’s claws, as
+in Cliders, the beards of Barley, the edges of several sorts of Grass and
+Reeds, &c. in other, as Coltsfoot, Rose-campion, Aps, Poplar, Willow, and
+almost all other downy Plants, they grow in the form of bushes very much
+diversify’d in each particular Plant, That which I have before in the 19.
+Observation noted on Rose leaves, is of a quite differing kind, and seems
+indeed a real Vegetable, distinct from the leaf.
+
+Thirdly, among these small bushes are observable an infinite company of
+small round Balls, exactly Globular, and very much resembling Pearls,
+namely, CCCC, of these there maybe multitudes observ’d in Sage, and several
+other Plants, which I suppose was the reason why _Athanasius Kircher_
+supposed them to be all cover’d with Spiders Eggs, or young Spiders, which
+indeed is nothing else but some kind of gummous exsudation, which is always
+much of the same bigness. At first sight of these, I confess, I imagin’d
+that they might have been some kind of _matrices_, or nourishing
+receptacles for some small Insect, just as I have found Oak-apples, and
+multitudes of such other large excrescencies on the leaves and other parts
+of Trees and shrubs to be for Flyes, and divers other Insects, but
+observing them to be there all the year, and scarce at all to change their
+magnitude, that conjecture seem’d not so probable. But what ever be the use
+of it, it affords a very pleasant object through the _Microscope_, and may,
+perhaps, upon further examination, prove very luciferous.
+
+       *       *       *       *       *
+
+
+Observ. XXV. _Of the stinging points and juice of _Nettles_, and some other
+venomous Plants._
+
+A Nettle is a Plant so well known to every one, as to what the appearance
+of it is to the naked eye, that it needs no description; and there are very
+few that have not felt as well as seen it; and therefore it will be no news
+to tell that a gentle and slight touch of the skin by a Nettle, does
+oftentime, not onely create very sensible and acute pain, much like that of
+a burn or scald, but often also very angry and hard swellings and
+inflamations of the parts, such as will presently rise, and continue swoln
+divers hours. These observations, I say, are common enough; but how the
+pain is so suddenly created, and by what means continued, augmented for a
+time, and afterwards diminish’d, and at length quite exstinguish’d, has
+not, that I know, been explain’d by any.
+
+And here we must have recourse to our _Microscope_, and that will, if
+almost any part of the Plant be looked on, shew us the whole surface of it
+very thick set with turn-Pikes, or sharp Needles, of the shape of those
+represented in the 15. _Scheme_ and first _Figure_ by AB, which are visible
+also to the naked eye; each of which consists of two parts very distinct
+for shape, and differing also in quality from one another. For the part A,
+is shaped very much like a round Bodkin, from B tapering till it end in a
+very sharp point; it is of substance very hard and stiff, exceedingly
+transparent and cleer, and, as I by many trials certainly found, is hollow
+from top to bottom.
+
+This I found by this Experiment, I had a very convenient _Microscope_ with
+a single Glass which drew about half an Inch, this I had fastned into a
+little frame, almost like a pair of Spectacles, which I placed before mine
+eyes, and so holding the leaf of a Nettle at a convenient distance from my
+eye, I did first, with the thrusting of several of these bristles into my
+skin, perceive that presently after I had thrust them in I felt the burning
+pain begin; next I observ’d in divers of them, that upon thrusting my
+finger against their tops, the Bodkin (if I may so call it) did not in the
+least bend, but I could perceive moving up and down within it a certain
+liquor, which upon thrusting the Bodkin against its basis, or bagg B, I
+could perceive to rise towards the top, and upon taking away my hand, I
+could see it again subside, and shrink into the bagg; this I did very
+often, and saw this _Phænomenon_ as plain as I could ever see a parcel of
+water ascend and descend in a pipe of Glass. But the basis underneath these
+Bodkins on which they were fast, were made of a more pliable substance, and
+looked almost like a little bagg of green Leather, or rather resembled the
+shape and surface of a wilde Cucumber, or _cucumeris asinini_, and I could
+plainly perceive them to be certain little baggs, bladders, or receptacles
+full of water, or as I ghess, the liquor of the Plant, which was poisonous,
+and those small Bodkins were but the Syringe-pipes, or Glyster-pipes, which
+first made way into the skin, and then served to convey that poisonous
+juice, upon the pressing of those little baggs, into the interior and
+sensible parts of the skin, which being so discharg’d, does corrode, or, as
+it were, burn that part of the skin it touches; and this pain will
+sometimes last very long, according as the impression is made deeper or
+stronger.
+
+The other parts of the leaf or surface of the Nettle, have very little
+considerable, but what is common to most of these kinds of Plants, as the
+ruggedness or indenting, and hairiness, and other roughnesses of the
+surface or outside of the Plant, of which I may say more in another place.
+As I shall likewise of certain little pretty cleer Balls or Apples which I
+have observed to stick to the sides of these leaves, both on the upper and
+under side, very much like the small Apples which I have often observ’d to
+grow on the leaves of an Oak call’d _Oak-apples_ which are nothing but the
+_Matrices_ of an Infect, as I elsewhere shew.
+
+The chief thing therefore is, how this Plant comes, by so slight a touch,
+to create so great a pain; and the reason of this seems to be nothing else,
+but the corrosive penetrant liquor contain’d in the small baggs or
+bladders, upon which grow out those sharp Syringe-pipes, as I before noted;
+and very consonant to this, is the reason of the pain created by the sting
+of a Bee, Wasp, &c. as I elsewhere shew: For by the Dart, which is likewise
+a pipe, is made a deep passage into the skin, and then by the anger of the
+Fly, is his gally poisonous liquor injected; which being admitted among the
+sensible parts, and so mix’d with the humours or _stagnating_ juices of
+that part, does create an Ebullition perhaps, or _effervescens_, as is
+usually observ’d in the mingling of two differing _Chymical saline_
+liquors, by which means the parts become swell’d, hard, and very painfull;
+for thereby the nervous and sensible parts are not onely stretch’d and
+strain’d beyond their natural _tone_, but are also prick’d, perhaps, or
+corroded by the pungent and incongruous parts of the intruded liquor.
+
+And this seems to be the reason, why _Aqua fortis_, and other _saline_
+liquors, if they come to touch the sensitive parts, as in a cut of the
+skin, or the like, do so violently and intollerably _excruciate_ and
+torment the Patient. And ’tis not unlikely, but the Inventors of that
+Diabolical practice of poisoning the points of Arrows and Ponyards, might
+receive their first hint from some such Instance in natural contrivances,
+as this of the Nettle: for the ground why such poison’d weapons kill so
+infallibly as they do, seems no other then this of our Nettle’s stinging;
+for the Ponyard or Dart makes a passage or entrance into the sensitive or
+vital parts of the body, whereby the contagious substance comes to be
+dissolv’d by, and mix’d with the fluid parts or humours of the body, and by
+that means spreads it self by degrees into the whole liquid part of the
+body, in the same manner, as a few grains of Salt, put into a great
+quantity of Water, will by degrees diffuse it self over the whole.
+
+And this I take to be the reason of killing of Toads, Frogs, Effs, and
+several Fishes, by strewing Salt on their backs (which Experiment was shewn
+to the _Royal Society_ by a very ingenious Gentleman, and a worthy Member
+of it) for those creatures having always a continual exsudation, as it
+were, of slimy and watry parts, sweating out of the pores of their skin,
+the _saline_ particles, by that means obtain a _vehicle_, which conveys
+them into the internal and vital parts of the body.
+
+This seems also to be the reason why bathing in Mineral waters are such
+soveraign remedies for multitudes of distempers, especially chronical; for
+the liquid & warm _vehicles_ of the Mineral particles, which are known to
+be in very considerable quantities in those healing baths, by the body’s
+long stay in them, do by degrees steep and insinuate themselves into the
+pores and parts of the skin, and thereby those Mineral particles have their
+ways and passages open’d to penetrate into the inner parts, and mingle
+themselves with the _stagnant_ juices of the several parts; besides, many
+of those offensive parts which were united with those _stagnant_ juices,
+and which were contrary to the natural constitution of the parts, and so
+become irksome and painfull to the body, but could not be discharged,
+because Nature had made no provision for such accidental mischiefs, are, by
+means of this soaking, and filling the pores of the skin with a liquor,
+afforded a passage through that liquor that fills the pores into the
+ambient fluid, and thereby the body comes to be discharged.
+
+So that ’tis very evident, there may be a good as well as an evil
+application of this Principle. And the ingenious Invention of that
+Excellent person, Doctor _Wren_ of injecting liquors into the veins of an
+Animal, seems to be reducible to this head: I cannot stay, nor is this a
+fit place, to mention the several Experiments made of this kind by the most
+incomparable Mr. _Boyle_, the multitudes made by the lately mention’d
+_Physician_ Doctor _Clark_, the History whereof, as he has been pleas’d to
+communicate to the _Royal Society_, so he may perhaps be prevail’d with to
+make publique himself: But I shall rather hint, that certainly, if this
+Principle were well consider’d, there might, besides the further improving
+of Bathing and Syringing into the veins, be thought on several ways,
+whereby several obstinate distempers of a humane body, such as the Gout,
+Dropsie, Stone, &c. might be master’d, and expell’d; and good men might
+make as good a use of it, as evil men have made a perverse and Diabolical.
+
+And that the filling of the pores of the skin with some fluid _vehicle_, is
+of no small efficacy towards the preparing a passage for several kinds of
+penetrant juices, and other dissoluble bodies, to insinuate themselves
+within the skin, and into the sensitive parts of the body, may be, I think,
+prov’d by an Instance given us by _Bellonius_, in the 26. _Chapter_ of the
+second Book of his _Observations_, which containing a very remarkable Story
+I have here transcrib’d: _Cum Chamæleonis nigri radices_ (says he) _apud
+Pagum quendam Livadochorio nuncupatum erui curaremus, plurimi Græci & Turcæ
+spectatum venerunt quid erueremus, eas vero frustulatim secabamus, & filo
+trajiciebamus ut facilius exsiccari possent. Turcæ in eo negotio occupatos
+nos videntes, similiter eas radices tractare & secare voluerunt: at cum
+summus esset æstus, & omnes sudore maderent, quicunque eam radicem manibus
+tractaverant sudoremque absterserant, aut faciem digitis scalpserant,
+tantam pruriginem iis locis quos attigerant postea senserunt, ut aduri
+viderentur. Chamæleonis enim nigri radix ea virtute pollet, ut cuti
+applicata ipsam adeo inflammet, ut nec squillæ, nec urticæ ullæ centesima
+parte ita adurent: At prurigo non adeo celeriter sese prodit. Post unam aut
+alteram porro horam, singuli variis faciei locis cutem adeo inflammatam
+habere cæpimus ut tota sanguinea videretur, atque quo magis eam
+confricabamus, tanto magis excitabatur prurigo. Fonti assidebamus sub
+platano, atque initio pro ludicro habebamus & ridebamus: at tandem illi
+plurimum indignati sunt, & nisi asseverassemus nunquam expertos tali
+virtute eam plantam pollere, haud dubie male nos multassent, Attamen nostra
+excusatio fuit ab illis facilitus accepta, cum eodem incommodo nos affectos
+conspicerent. Mirum sane quod in tantillo radice tam ingentem efficaciam
+nostro malo experti sumus._
+
+By which observation of his, it seems manifest, that their being all
+cover’d with sweat who gather’d and cut this root of the black _Chameleon_
+Thistle, was the great reason why they suffer’d that inconvenience, for it
+seems the like circumstance had not been before that noted, nor do I find
+any mention of such a property belonging to this Vegetable in any of the
+Herbals I have at present by me.
+
+I could give very many Observations which I have made of this kind, whereby
+I have found that the best way to get a body to be insinuated into the
+substance or insensible pores of another, is first, to find a fluid
+_vehicle_ that has some congruity, both to the body to be insinuated, and
+to the body into whose pores you would have the other convey’d. And in this
+Principle lies the great mystery of staining several sorts of bodies, as
+Marble, Woods, Bones, &c. and of Dying Silks, Cloaths, Wools, Feathers, &c.
+But these being digressions, I shall proceed to:
+
+       *       *       *       *       *
+
+
+Observ. XXVI. _Of _Cowage_, and the itching operation of some bodies._
+
+There is a certain Down of a Plant, brought from the _East-Indies_, call’d
+commonly, though very improperly, _Cow-itch_, the reason of which mistake
+is manifest enough from the description of it, which Mr. _Parkinson_ sets
+down in his _Herbal_, Tribe XI. Chap. 2. _Phasiolus siliqua hirsuta; The
+hairy Kidney-bean, called in _Zurratte_ where it grows, Couhage: We have
+had_ (says he) _another of this kind brought us out of the _East-Indies_,
+which being planted was in shew like the former, but came not to
+perfection, the unkindly season not suffering it to shew the flower; but of
+the Cods that were brought, some were smaller, shorter, and rounder then
+the Garden kind; others much longer, and many growing together, as it were
+in clusters, and cover’d all over with a brown short hairiness, so fine,
+that if any of it be rubb’d, or fall on the back of ones hand, or other
+tender parts of the skin, it will cause a kind of itching, but not strong,
+nor long induring, but passing quickly away, without either danger or harm;
+the Beans were smaller then ordinary, and of a black shining colour._
+
+Having one of these Cods given me by a Sea-Captain, who had frequented
+those parts, I found it to be a small Cod, about three Inches long, much
+like a short Cod of _French Beans_, which had six Beans in it, the whole
+surface of it was cover’d over with a very thick and shining brown Down or
+Hair, which was very fine, and for its bigness stiff; taking some of this
+Down, and rubbing it on the back of my hand, I found very little or no
+trouble, only I was sensible that several of these little downy parts with
+rubbing did penetrate, and were sunk, or stuck pretty deep into my skin.
+After I had thus rubb’d it for a pretty while, I felt very little or no
+pain, in so much that I doubted, whether it were the true Couhage; but
+whil’st I was considering; I found the Down begin to make my hand itch, and
+in some places to smart again, much like the stinging of a Flea or Gnat,
+and this continued a pretty while, so that by degrees I found my skin to be
+swell’d with little red pustules, and to look as if it had been itchie. But
+suffering it without rubbing or scratching, the itching tickling pain
+quickly grew languid, and within an hour I felt nothing at all, and the
+little _protuberancies_ were vanish’d.
+
+The cause of which odd _Phænomenon_, I suppose to be much the same with
+that of the stinging of a Nettle, for by the _Microscope_, I discover’d
+this Down to consist of a multitude of small and slender conical bodies,
+much resembling Needles or Bodkins, such as are represented by AB. CD. EF.
+of the first Figure of the XVI. _Scheme_; that their ends AAA, were very
+sharp, and the substance of them stiff and hard, much like the substance of
+several kinds of Thorns and crooks growing on Trees. And though they
+appear’d very cleer and transparent, yet I could not perceive whether they
+were hollow or not, but to me they appear’d like solid transparent bodies,
+without any cavity in them; whether, though they might not be a kind of
+Cane, fill’d with some transparent liquor which was hardned (because the
+Cod which I had was very dry) I was not able to examine.
+
+Now, being such stiff, sharp bodies, it is easie to conceive, how with
+rubbing they might easily be thrust into the tender parts of the skin, and
+there, by reason of their exceeding fineness and driness, not create any
+considerable trouble or pain, till by remaining in those places moistned
+with the humours of the body, some caustick part sticking on them, or
+residing within them might be dissolv’d and mix’d with the ambient juices
+of that place, and thereby those _fibres_ and tender parts adjoyning become
+affected, and as it were corroded by it; whence, while that action lasts,
+the pains created are pretty sharp and pungent, though small, which is the
+essential property of an itching one.
+
+That the pain also caused by the stinging of a Flea, a Gnat, a Flie, a
+Wasp, and the like, proceeds much from the very same cause, I elsewhere in
+their proper places endeavour to manifest. The stinging also of shred
+Hors-hair, which in meriment is often strew’d between the sheets of a Bed,
+seems to proceed from the same cause.
+
+       *       *       *       *       *
+
+
+Observ. XXVII. _Of the _Beard_ of a wilde _Oat_, and the use that may be
+made of it for exhibiting always to the Eye the temperature of the Air, as
+to driness and moisture._
+
+This Beard of a wild _Oat_, is a body of a very curious structure, though
+to the naked Eye it appears very slight, and inconsiderable, it being only
+a small black or brown Beard or Bristle, which grows out of the side of the
+inner Husk that covers the Grain of a wild _Oat_; the whole length of it,
+when put in Water, so that it may extend it self to its full length, is not
+above an Inch and a half, and for the most part somewhat shorter, but when
+the Grain is ripe, and very dry, which is usually in the Moneths of _July_,
+and _August_, this Beard is bent somewhat below the middle, namely, about
+⅖ from the bottom of it, almost to a right Angle, and the under part of
+it is wreath’d lik a With; the substance of it is very brittle when dry,
+and it will very easily be broken from the husk on which it grows.
+
+If you take one of these Grains, and wet the Beard in Water, you will
+presently see the small bended top to turn and move round, as if it were
+sensible; and by degrees, if it be continued wet enough, the joint or knee
+will streighten it self; and if it be suffer’d to dry again, it will by
+degrees move round another way, and at length bend again into its former
+posture.
+
+If it be view’d with an ordinary single _Microscope_, it will appear like a
+small wreath’d Sprig, with two clefts; and if wet as before, and then
+look’d on with this _Microscope_, it will appear to unwreath it self, and
+by degrees, to streighten its knee, and the two clefts will become
+streight, and almost on opposite sides of the small cylindrical body.
+
+If it be continued to be look’d on a little longer with a _Microscope_, it
+will within a little while begin to wreath it self again, and soon after
+return to its former posture, bending it self again neer the middle, into a
+kind of knee or angle.
+
+Several of those bodies I examin’d with larger _Microscopes_, and there
+found them much of the make of those two long wreath’d cylinders delineated
+in the second Figure of the 15. _Scheme_, which two cylinders represent the
+wreathed part broken into two pieces, whereof the end AB is to be suppos’d
+to have join’d to the end CD, so that EACF does represent the whole
+wreath’d part of the Beard, and EG a small piece of the upper part of the
+Beard which is beyond the knee, which as I had not room to insert, so was
+it not very considerable, either for its form, or any known property; but
+the under or wreathed part is notable for both: As to its form, it
+appear’d, if it were look’d on side-ways, almost like a Willow, or a small
+tapering rod of _Hazel_, the lower or bigger half of which onely, is
+twisted round several times, in some three, in others more, in others less,
+according to the bigness and maturity of the Grain on which it grew, and
+according to the driness and moisture of the ambient Air, as I shall shew
+more at large by and by.
+
+The whole outward Superficies of this Cylindrical body is curiously adorned
+or fluted with little channels, and interjacent ridges, or little
+_protuberances_ between them, which run the whole length of the Beard, and
+are streight where the Beard is not twisted, and wreath’d where it is, just
+after the same manner: each of those sides is beset pretty thick with small
+Bristes or Thorns, somewhat in form resembling that of _Porcupines_ Quills,
+such as _aaaaa_ in the Figure; all whose points are directed like so many
+Turn-pikes towards the small end or top of the Beard, which is the reason,
+why, if you endeavour to draw the Beard between your fingers the contrary
+way, you will find it to stick, and grate, as it were, against the skin.
+
+The proportion of these small conical bodies _aaaaa_ to that whereon they
+grow, the Figure will sufficiently shew, as also their manner of growing,
+their thickness, and nearness to each other, as, that towards the root or
+bottom of the Beard, they are more thin, and much shorter, insomuch that
+there is usually left between the top of the one, and the bottom of that
+next above it, more then the length of one of them, and that towards the
+top of the Beard they grow more thick and close (though there be fewer
+ridges) so that the root, and almost half the upper are hid by the tops of
+those next below them.
+
+I could not perceive any _transverse_ pores, unless the whole wreath’d part
+were separated and cleft, in those little channels, by the wreathing into
+so many little strings as there were ridges, which was very difficult to
+determine; but there were in the wreathed part two very conspicuous
+channels or clefts, which were continued from the bottom F to the elbow 
+EH or all along the part which was wreath’d, which seem’d to divide the
+wreath’d Cylinder into two parts, a bigger and a less; the bigger was that
+which was at the _convex_ side of the knee, namely, on the side A, and was
+wreath’d by OOOOO; this, as it seem’d the broader, so did it also the
+longer, the other PPPPP, which was usually purs’d or wrinckled in the
+bending of the knee, as about E, seem’d both the shorter and narrower, so
+that at first I thought the wreathing and unwreathing of the Beard might
+have been caus’d by the shrinking or swelling of that part; but upon
+further examination, I found that the clefts, KK, LL, were stuft up with a
+kind of Spongie substance, which, for the most part, was very conspicuous
+neer the knee, as in the cleft KK, when the Beard was dry; upon the
+discovery of which, I began to think, that it was upon the swelling of this
+porous pith upon the access of moisture or water that the Beard, being made
+longer in the midst, was streightned, and by the shrinking or subsiding of
+the parts of that Spongie substance together, when the water or moisture
+was exhal’d or dried, the pith or middle parts growing shorter, the whole
+became twisted.
+
+But this I cannot be positive in, for upon cutting the wreath’d part in
+many places transversly, I was not so well satisfy’d with the shape and
+manner of the pores of the pith; for looking on these transverse Sections
+with a very good _Microscope_, I found that the ends of those transverse
+Sections appear’d much of the manner of the third Figure of the 15.
+_scheme_ ABCFE, and the middle of pith CC, seem’d very full of pores
+indeed, but all of them seem’d to run the long-ways.
+
+This Figure plainly enough shews in what manner those clefts, K and L
+divided the wreath’d Cylinder into two unequal parts, and also of what kind
+of substance the whole body consists; for by cutting the same Beard in many
+places, with transverse Sections, I found much the same appearance with
+this express’d; so that those pores seem to run, as in most other such Cany
+bodies, the whole length of it.
+
+The clefts of this body KK, and LL, seem’d (as is also express’d in the
+Figure) to wind very oddly in the inner part of the wreath, and in some
+parts of them, they seem’d stuffed, as it were, with that Spongie
+substance, which I just now described.
+
+This so oddly constituted Vegetable substance, is first (that I have met
+with) taken notice of by _Baptista Porta_, in his _Natural Magick_, as a
+thing known to children and Juglers, and it has been call’d by some of
+those last named persons, the better to cover their cheat, the Legg of an
+_Arabian Spider_, or the Legg of an inchanted _Egyptian fly_, and has been
+used by them to make a small Index, Cross, or the like, to move round upon
+the wetting of it with a drop of Water, and muttering certain words.
+
+But the use that has been made of it, for the discovery of the various
+constitutions of the Air, as to driness and moistness, is incomparably
+beyond any other, for this it does to admiration: The manner of contriving
+it so, as to perform this great effect, is onely thus:
+
+Provide a good large Box of Ivory, about four Inches over, and of what
+depth you shall judge convenient (according to your intention of making use
+of one, two, three, or more of these small Beards, ordered in the manner
+which I shall by and by describe) let all the sides of this Box be turned
+of Basket-work (which here in _London_ is easily enough procur’d) full of
+holes, in the manner almost of a Lettice, the bigger, or more the holes
+are, the better, that so the Air may have the more free passage to the
+inclosed Beard, and may the more easily pass through the Instrument; it
+will be better yet, though not altogether so handsom, if insteed of the
+Basket-work on the sides of the Box, the bottom and top of the Box be
+join’d together onely with three or four small Pillars, after the manner
+represented in the 4. Figure of the 15. _Scheme_. Or, if you intend to make
+use of many of these small Beards join’d together, you may have a small
+long Case of Ivory, whose sides are turn’d of Basket-work, full of holes,
+which may be screw’d on to the underside of a broad Plate of Ivory, on the
+other side of which is to be made the divided Ring or Circle, to which
+divisions the pointing of the Hand or Index, which is moved by the
+conjoin’d Beard, may shew all the _Minute_ variations of the Air.
+
+There may be multitudes of other ways for contriving this small Instrument,
+so as to produce this effect, which any one may, according to his peculiar
+use, and the exigency of his present occasion, easily enough contrive and
+take, on which I shall not therefore insist. The whole manner of making any
+one of them is thus: Having your Box or frame AABB, fitly adapted for the
+free passage of the Air through it, in the midst of the bottom BBB, you
+must have a very small hole C, into which the lower end of the Beard is to
+be fix’d, the upper end of which Beard ab, is to pass through a small hole
+of a Plate, or top AA, if you make use onely of a single one, and on the
+top of it e, is to be fix’d a small and very light _Index_ fg, made of a
+very thin sliver of a Reed or Cane; but if you make use of two or more
+Beards, they must be fix’d and bound together, either with a very fine
+piece of Silk, or with a very small touch of hard Wax, or Glew, which is
+better, and the _Index_ fg, is to be fix’d on the top of the second, third,
+or fourth in the same manner as on the single one.
+
+Now, because that in every of these contrivances, the _Index_ fg, will with
+some temperatures of Air, move two, three, or more times round, which
+without some other contrivance then this, will be difficult to distinguish,
+therefore I thought of this Expedient: The _Index_ or _Hand_ fg, being
+rais’d a pretty way above the surface of the Plate AA, fix in at a little
+distance from the middle of it a small Pin h, so as almost to touch the
+surface of the Plate AA, and then in any convenient place of the surface of
+the Plate, fix a small Pin, on which put on a small piece of Paper, or thin
+Pastboard, Vellom, or Parchment, made of a convenient cize, and shap’d in
+the manner of that in the Figure express’d by ik, so that having a
+convenient number of teeth every turn or return of the Pin h, may move this
+small indented Circle, a tooth forward or backwards, by which means the
+teeth of the Circle, being mark’d, it will be thereby very easie to know
+certainly, how much variation any change of weather will make upon the
+small wreath’d body. In the making of this Secundary Circle of Vellom, or
+the like, great care is to be had, that it be made exceeding light, and to
+move very easily, for otherwise a small variation will spoil the whole
+operation. The Box may be made of Brass, Silver, Iron, or any other
+substance, if care be taken to make it open enough, to let the Air have a
+sufficiently free access to the Beard. The _Index_ also may be various ways
+contrived, so as to shew both the number of the revolutions it makes, and
+the _Minute_ divisions of each revolution.
+
+I have made several trials and Instruments for discovering the driness and
+moisture of the Air with this little wreath’d body, and find it to vary
+exceeding sensibly with the least change in the constitution of the Air, as
+to driness and moisture, so that with one breathing upon it, I have made it
+untwist a whole bout, and the _Index_ or _Hand_ has shew’d or pointed to
+various divisions on the upper Face or Ring of the Instrument, according as
+it was carried neerer and neerer to the fire, or as the heat of the Sun
+increased upon it.
+
+Other trials I have made with Gut-strings, but find them nothing neer so
+sensible, though they also may be so contriv’d as to exhibit the changes of
+the Air, as to driness and moisture, both by their stretching and shrinking
+in length, and also by their wreathing and unwreathing themselves; but
+these are nothing neer so exact or so tender, for their varying property
+will in a little time change very much. But there are several other
+Vegetable substances that are much more sensible then even this Beard of a
+wilde _Oat_; such I have found the Beard of the seed of Musk-grass, or
+_Geranium moschatum_, and those of other kinds of _Cranes-bil_ seeds, and
+the like. But always the smaller the wreathing substance be, the more
+sensible is it of the mutations of the Air, a conjecture at the reason of
+which I shall by and by add.
+
+The lower end of this wreath’d Cylinder being stuck upright in a little
+soft Wax, so that the bended part or _Index_ of it lay _horizontal_, I have
+observ’d it always with moisture to unwreath it self from the East (For
+instance) by the South to the West, and so by the North to the East again,
+moving with the Sun (as we commonly say) and with heat and drouth to
+re-twist; and wreath it self the contrary way, namely, from the East, (for
+instance) by the North to the West, and so onwards.
+
+The cause of all which _Phænomena_, seems to be the differing texture of
+the parts of these bodies, each of them (especially the Beard of a wilde
+_Oat_, and of _Mosk-grass_ seed) seeming to have two kind of substances,
+one that is very porous, loose, and spongie, into which the watry steams of
+the Air may be very easily forced, which will be thereby swell’d and
+extended in its dimensions, just as we may observe all kind of Vegetable
+substance upon steeping in water to swell and grow bigger and longer. And a
+second that is more hard and close, into which the water can very little,
+or not at all penetrate, this therefore retaining always very neer the same
+dimensions, and the other stretching and shrinking, according as there is
+more or less moisture or water in its pores, by reason of the make and
+shape of the parts, the whole body must necessarily unwreath and wreath it
+self.
+
+And upon this Principle, it is very easie to make several sorts of
+contrivances that should thus wreath and unwreath themselves, either by
+heat and cold, or by driness and moisture, or by any greater or less force,
+from whatever cause it proceed, whether from gravity or weight, or from
+wind which is motion of the Air, or from some springing body, or the like.
+
+This, had I time, I should enlarge much more upon; for it seems to me to be
+the very first footstep of _Sensation_, and Animate motion, the most plain,
+simple, and obvious contrivance that Nature has made use of to produce a
+motion; next to that of Rarefaction and Condensation by heat and cold. And
+were this Principle very well examin’d, I am very apt to think, it would
+afford us a very great help to find out the _Mechanism_ of the Muscles,
+which indeed, as farr as I have hitherto been able to examine, seems to me
+not so very perplex as one might imagine, especially upon the examination
+which I made of the Muscles of _Crabs_, _Lobsters_, and several sorts of
+large Shell-fish, and comparing my Observations on them, with the
+circumstances I observ’d in the muscles of terrestrial Animals.
+
+Now, as in this Instance of the Beard of a wilde _Oat_, we see there is
+nothing else requisite to make it wreath and unwreath it self, and to
+streighten and bend its knee, then onely a little breath of moist or dry
+Air, or a small _atome_ almost of water or liquor, and a little heat to
+make it again evaporate, for, by holding this Beard, plac’d and fix’d as I
+before directed, neer a Fire, and dipping the tip of a small shred of Paper
+in well rectify’d spirit of Wine, and then touching the wreath’d
+_Cylindrical_ part, you may perceive it to untwist it self; and presently
+again, upon the _avolation_ of the spirit, by the great heat, it will
+re-twist it self, and thus will it move forward and backwards as oft as you
+repeat the touching it with the spirit of Wine; so may, perhaps, the
+shrinking and relaxing of the muscles be by the influx and evaporation of
+some kind of liquor or juice. But of this Enquiry I shall add more
+elsewhere.
+
+       *       *       *       *       *
+
+
+Observ. XXVIII. _Of the Seeds of _Venus_ looking-glass, or _Corn_ Violet._
+
+From the Leaves, and Downs, and Beards of Plants, we come at last to the
+Seeds; and here indeed seems to be the Cabinet of Nature, wherein are laid
+up its Jewels. The providence of Nature about Vegetables, is in no part
+manifested more, then in the various contrivances about the seed, nor
+indeed is there in any part of the Vegetable so curious carvings, and
+beautifull adornments, as about the seed; this in the larger sorts of seeds
+is most evident to the eye; nor is it lest manifest through the
+_Microscope_, in those seeds whose shape and structure, by reason of their
+smalness, the eye is hardly able to distinguish.
+
+Of these there are multitudes, many of which I have observ’d through a
+_Microscope_, and find, that they do, for the most part, every one afford
+exceeding pleasant and beautifull objects. For besides those that have
+various kinds of carv’d surfaces, there are other that have smooth and
+perfectly polish’d surfaces, others a downy hairy surface; some are cover’d
+onely with a skin, others with a kind of shell, others with both, as is
+observable also in greater seeds.
+
+Of these seeds I have onely described four sorts which may serve as a
+_specimen_ of what the inquisitive observers are likely to find among the
+rest. The first of these seeds which are described in the 17. _Scheme_, are
+those of Corn-Violets, the seed is very small, black, and shining, and, to
+the naked eye, looks almost like a very small Flea; But through the
+_Microscope_, it appears a large body, cover’d with a tough thick and
+bright reflecting skin very irregularly shrunk and pitted, insomuch that
+it is almost an impossibility to find two of them wrinkled alike, so great
+a variety may there be even in this little seed.
+
+This, though it appear’d one of the most promising seeds for beauty to the
+naked eye, yet through the _Microscope_ it appear’d but a rude misshapen
+seed, which I therefore drew, that I might thereby manifest how unable we
+are by the naked eye to judge of beauteous or less curious _microscopical_
+Objects; cutting some of them in sunder, I observ’d them to be fill’d with
+a greenish yellow pulp, and to have a very thick husk, in proportion to the
+pulp.
+
+       *       *       *       *       *
+
+
+Observ. XXIX. _Of the Seeds of _Tyme_._
+
+These pretty fruits here represented, in the 18. _Scheme_, are nothing
+else, but nine several seeds of Tyme; they are all of them in differing
+posture, both as to the eye and the light; nor are they all of them exactly
+of the same shape, there being a great variety both in the bulk and figure
+of each seed; but they all agreed in this, that being look’d on with a
+_Microscope_, they each of them exactly resembled a Lemmon or Orange dry’d;
+and this both in shape and colour. Some of them are a little rounder, of
+the shape of an Orange, as A and B, they have each of them a very
+conspicuous part by which they were join’d to their little stalk, and one
+of them had a little piece of stalk remaining on; the opposite side of the
+seed, you may perceive very plainly by the Figure, is very copped and
+prominent, as is very usual in Lemmons; which prominencies are express’d in
+D, E and F.
+
+They seem’d each of them a little creas’d or wrinckled, but E was very
+conspicuously furrow’d, as if the inward make of this seed had been
+somewhat like that of a Lemmon also, but upon dividing several seeds with a
+very sharp Pen-knife, and examining them afterward, I found their make to
+be in nothing but bulk differing from that of Peas, that is, to have a
+pretty thick coat, and all the rest an indifferent white pulp, which seem’d
+very close; so that it seems Nature does not very much alter her method in
+the manner of inclosing and preserving the vital Principle in the seed, in
+these very small grains, from that of Beans, Peas, &c.
+
+The Grain affords a very pretty Object for the _Microscope_, namely, a Dish
+of Lemmons plac’d in a very little room; should a Lemmon or Nut be
+proportionably magnify’d to what this seed of Tyme is, it would make it
+appear as bigg as a large Hay-reek and it would be no great wonder to see
+_Homers Iliads_, and _Homer_ and all, cramm’d into such a Nutshell. We may
+perceive even in these small Grains, as well as in greater, how curious and
+carefull Nature is in preserving the seminal principle of Vegetable bodies,
+in what delicate, strong and most convenient Cabinets she lays them and
+closes them in a pulp for their safer protection from outward dangers, and
+for the supply of convenient alimental juice, when the heat of the Sun
+begins to animate and move these little _automatons_ or Engines; as if she
+would, from the ornaments wherewith she has deckt these Cabinets, hint to
+us, that in them she has laid up her Jewels and Master-pieces. And this, if
+we are but diligent in observing, we shall find her method throughout.
+There is no curiosity in the Elemental kingdom, if I may so call the bodies
+of Air, Water, Earth, that are comparable in form to those of Minerals, Air
+and Water having no form at all, unless a potentiality to be form’d into
+Globules; and the clods and parcels of Earth are all irregular, whereas in
+Minerals she does begin to _Geometrize_, and practise, as ’twere, the first
+principles of _Mechanicks_, shaping them of plain regular figures, as
+triangles, squares, &c. and _tetraedrons_, cubes, &c. But none of their
+forms are comparable to the more compounded ones of Vegetables; For here
+she goes a step further, forming them both of more complicated shapes, and
+adding also multitudes of curious Mechanick contrivances in their
+structure; for whereas in Vegetables there was no determinate number of the
+leaves or branches, nor no exactly certain figure of leaves, or flowers, or
+seeds, in Animals all those things are exactly defin’d and determin’d; and
+whereever there is either an excess or defect of those determinate parts
+or limbs, there has been some impediment that has spoil’d the principle
+which was most regular: Here we shall find, not onely most curiously
+compounded shapes, but most stupendious Mechanisms and contrivances, here
+the ornaments are in the highest perfection, nothing in all the Vegetable
+kingdom that is comparable to the deckings of a Peacock; nay, to the
+curiosity of any feather, as I elsewhere shew; nor to that of the smallest
+and most despicable Fly. But I must not stay on these speculations, though
+perhaps it were very well worth while for one that had leisure, to see what
+Information may be learn’d of the nature, or use, or virtues of bodies, by
+their several forms and various excellencies and properties. Who knows but
+_Adam_ might from some such contemplation, give names to all creatures? If
+at least his names had any significancy in them of the creatures nature on
+which he impos’d it; as many (upon what grounds I know not) have suppos’d:
+And who knows, but the Creator may, in those characters, have written and
+engraven many of his most mysterious designs and counsels, and given man a
+capacity, which, assisted with diligence and industry, may be able to read
+and understand them. But not to multiply my digression more then I can the
+time, I will proceed to the next, which is,
+
+       *       *       *       *       *
+
+
+Observ. XXX. _Of the Seeds of _Poppy_._
+
+The small seeds of Poppy, which are described in the 19. _Scheme_, both for
+their smalness, multiplicity and prettiness, as also for their admirable
+soporifick quality, deserve to be taken notice of among the other
+_microscopical_ seeds of Vegetables: For first, though they grow in a Case
+or Hive oftentimes bigger then one of these Pictures of the _microscopical_
+appearance, yet are they for the most part so very little, that they exceed
+not the bulk of a small Nitt, being not above ¹⁄₃₂ part of an Inch in
+Diameter, whereas the Diameter of the Hive of them oftentimes exceeds two
+Inches, so that it is capable of containing near two hundred thousand, and
+so in all likelihood does contain a vast quantity, though perhaps not that
+number. Next, for their prettiness, they may be compar’d to any
+_microscopical_ seed I have yet seen; for they are of a dark brownish red
+colour, curiously Honey-comb’d all over with a very pretty variety of
+Net-work, or a small kind of imbosment of very orderly rais’d ridges, the
+surface of them looking not unlike the inside of a Beev’s stomack. But that
+which makes it most considerable of all, is, the medicinal virtues of it,
+which are such as are not afforded us by any Mineral preparation; and that
+is for the procuring of sleep, a thing as necessary to the well-being of a
+creature as his meat, and that which refreshes both the voluntary and
+rational faculties, which, whil’st this affection has seis’d the body, are
+for the most part unmov’d, and at rest. And, methinks, Nature does seem to
+hint some very notable virtue or excellency in this Plant from the
+curiosity it has bestow’d upon it. First, in its flower, it is of the
+highest scarlet-Dye, which is indeed the prime and chiefest colour, and has
+been in all Ages of the world most highly esteem’d: Next, it has as much
+curiosity shew’d also in the husk or case of the seed, as any one Plant I
+have yet met withall; and thirdly, the very seeds themselves, the
+_Microscope_ discovers to be very curiously shap’d bodies; and lastly,
+Nature has taken such abundant care for the propagation of it, that one
+single seed grown into a Plant, is capable of bringing some hundred
+thousands of seeds.
+
+It were very worthy some able man’s enquiry whether the intention of
+Nature, as to the secundary end of Animal and Vegetable substances might
+not be found out by some such characters and notable impressions as these,
+or from divers other circumstances, as the figure, colour, place, time of
+flourishing, springing and fading, duration, taste, smell, &c. For if such
+there are (as an able _Physician_ upon good grounds has given me cause to
+believe) we might then, insteed of studying Herbals (where so little is
+deliver’d of the virtues of a Plant, and less of truth) have recourse to
+the Book of Nature it self, and there find the most natural, usefull, and
+most effectual and specifick Medicines, of which we have amongst
+Vegetables, two very noble Instances to incourage such a hope, the one of
+the _Jesuite powder_ for the cure of _intermitting Feavers_, and the other
+of the juice of _Poppy_ for the curing the defect of sleeping.
+
+       *       *       *       *       *
+
+
+Observ. XXXI. _Of _Purslane-seed_._
+
+The Seeds of _Purslane_ seem of very notable shapes, appearing through the
+_Microscope_ shap’d somewhat like a _nautilus_ or _Porcelane_ shell, as may
+be seen in the XX. _Scheme_, it being a small body, coyl’d round in the
+manner of a Spiral, at the greater end whereof, which represents the mouth
+or orifice of the Shell, there is left a little white transparent
+substance, like a skin, represented by BBBB, which seems to have been the
+place whereunto the stem was join’d. The whole surface of this _Coclea_ or
+Shell, is cover’d over with abundance of little _prominencies_ or buttons
+very orderly rang’d into Spiral rows, the shape of each of which seem’d
+much to resemble a Wart upon a mans hand. The order, variety, and curiosity
+in the shape of this little seed, makes it a very pleasant object for the
+_Microscope_, one of them being cut asunder with a very sharp Penknife,
+discover’d this carved Casket to be of a brownish red, and somewhat
+transparent substance, and manifested the inside to be fill’d with a
+whitish green substance or pulp, the Bed wherein the seminal principle lies
+_invelop’d_.
+
+There are multitudes of other seeds which in shape represent or imitate the
+forms of divers other sorts of Shells: as the seed of _Scurvy-grass_ very
+much resembles the make of a _Concha Venerea_, a kind of Purcelane Shell;
+others represent several sorts of larger fruits, sweat Marjerome and
+Pot-marjerome represent Olives. Carret seeds are like a cleft of a Coco-Nut
+Husk, others are like Artificial things, as Succory seeds are like a Quiver
+full of Arrows, the seeds of _Amaranthus_ are of an exceeding lovely shape,
+somewhat like an Eye: The skin of the black and shrivled seeds of Onyons
+and Leeks, are all over knobbed like a Seals skin. Sorrel has a pretty
+black shining three-square seed, which is picked at both ends with three
+ridges, that are bent the whole length of it. It were almost endless to
+reckon up the several shapes, they are so many and so various; Leaving them
+therefore to the curious observer, I shall proceed to the Observations on
+the parts of Animals.
+
+       *       *       *       *       *
+
+
+Observ. XXXII. _Of the Figure of several sorts of _Hair_, and of the
+texture of the _skin_._
+
+Viewing some of the Hairs of my Head with a very good _Microscope_, I took
+notice of these particulars:
+
+1. That they were, for the most part, _Cylindrical_, some of them were
+somewhat _Prismatical_, but generally they were very neer round, such as
+are represented in the second Figure of the 5. _Scheme_, by the _Cylinders_
+EEE. nor could I find any that had sharp angles.
+
+2. That that part which was next the top, was bigger then that which was
+neerer the root.
+
+3. That they were all along from end to end transparent, though not very
+cleer, the end next the root appearing like a black transparent piece of
+Horn, the end next the top more brown, somewhat like transparent Horn.
+
+4. That the root of the Hairs were pretty smooth, tapering inwards, almost
+like a Parsneb; nor could I find that it had any filaments, or any other
+vessels, such as the _fibres_ of Plants.
+
+5. That the top when split (which is common in long Hair) appear’d like the
+end of a stick, beaten till it be all flitter’d, there being not onely two
+splinters, but sometimes half a score and more.
+
+6. That they were all, as farr as I was able to find, solid _Cylindrical_
+bodies, not pervious, like a Cane or Bulrush; nor could I find that they
+had any Pith, or distinction of Rind, or the like, such as I had observ’d
+in Horse-hairs, the Bristles of a Cat, the _Indian_ Deer’s Hair, &c.
+
+_Observations on several other sorts of _Hair_._
+
+For the Brisles of a Hogg, I found them to be first a hard transparent
+horny substance, without the least appearance of pores or holes in it; and
+this I try’d with the greatest care I was able, cutting many of them with a
+very sharp Razor, so that they appear’d, even in the Glass, to have a
+pretty smooth surface, but somewhat waved by the sawing to and fro of the
+Razor, as is visible in the end of the _Prismatical_ body A of the same
+Figure; and then making trials with causing the light to be cast on them
+all the various ways I could think of, that was likely to make the pores
+appear, if there had been any, I was not able to discover any.
+
+Next, the Figure of the Brisles was very various, neither perfectly round,
+nor sharp edg’d, but _Prismatical_, with divers sides, and round angles, as
+appears in the Figure A. The bending of them in any part where they before
+appear’d cleer, would all flaw them, and make them look white.
+
+The Mustacheos of a Cat (part of one of which is represented by the short
+_Cylinder_ B of the same Figure) seem’d to have, all of them that I
+observ’d, a large pith in the middle, like the pith of an Elder, whose
+texture was so close, that I was not able to discover the least sign of
+pores; and those parts which seem to be pores, as they appear’d in one
+position to the light, in another I could find a manifest reflection to be
+cast from them.
+
+This I instance in, to hint that it is not safe to conclude any thing to be
+positively this or that, though it appear never so plain and likely when
+look’d on with a _Microscope_ in one posture, before the same be examin’d
+by placing it in several other positions.
+
+And this I take to be the reason why many have believed and asserted the
+Hairs of a man’s head to be hollow, and like so many small pipes perforated
+from end to end.
+
+Now, though I grant that by an _Analogie_ one may suppose them so, and from
+the _Polonian_ disease one may believe them such, yet I think we have not
+the least encouragement to either from the _Microscope_, much less
+positively to assert them such. And perhaps the very essence of the _Plica
+Polonica_ may be the hairs growing hollow, and of an unnatural
+constitution.
+
+And as for the _Analogie_, though I am apt enough to think that the hairs
+of several Animals may be perforated somewhat like a Cane, or at least have
+a kind of pith in them, first, because they seem as ’twere a kind of
+Vegetable growing on an Animal, which growing, they say, remains a long
+while after the Animal is dead, and therefore should like other Vegetables
+have a pith; and secondly, because Horns and Feathers, and Porcupine’s
+Quils, and Cats Brisles, and the long hairs of Horses, which come very
+neer the nature of a mans hair, seem all of them to have a kind of pith,
+and some of them to be porous, yet I think it not (in these cases, where we
+have such helps for the sense as the _Microscope_ affords) safe concluding
+or building on more then we sensibly know, since we may, with examining,
+find that Nature does in the make of the same kind of substance, often vary
+her method in framing of it: Instances enough to confirm this we may find
+in the Horns of several creatures: as what a vast difference is there
+between the Horns of an Oxe, and those of some sorts of Staggs as to their
+shape? and even in the hairs of several creatures, we find a vast
+difference, as the hair of a man’s head seems, as I said before, long,
+_Cylindrical_ and sometime a little _Prismatical_, solid or impervious, and
+very small; the hair of an _Indian_ Deer (a part of the middle of which is
+described in the third Figure of the fifth _Scheme_, marked with F) is
+bigger in compass through all the middle of it, then the Bristle of an
+Hogg, but the end of it is smaller then the hair of any kind of Animal (as
+may be seen by the Figure G) the whole belly of it, which is about two or
+three Inches long, looks to the eye like a thread of course Canvass, that
+has been newly unwreath’d, it being all wav’d or bended to and fro, much
+after that manner, but through the _Microscope_, it appears all perforated
+from side to side, and Spongie, like a small kind of spongy Coral, which is
+often found upon the _English_ shores; but though I cut it transversly, I
+could not perceive that it had any pores that ran the long way of the hair:
+the long hairs of Horses CC and D, seem _Cylindrical_ and somewhat pithy;
+the Bristles of a Cat B, are conical and pithy: the Quils of Porcupines and
+Hedghoggs, being cut transversly, have a whitish pith, in the manner of a
+Starr, or Spur-rowel: Piggs-hair (A) is somewhat _triagonal_, and seems to
+have neither pith nor pore: And other kinds of hair have quite a differing
+structure and form. And therefore I think it no way agreeable to a true
+natural Historian, to pretend to be so sharp-sighted, as to see what a
+preconceiv’d _Hypothesis_ tells them should be there, where another man,
+though perhaps as seeing, but not forestall’d, can discover no such matter.
+
+But to proceed; I observ’d several kind of hairs that had been Dyed, and
+found them to be a kind of horny _Cylinder_, being of much about the
+transparency of a pretty cleer piece of Oxe horn; these appear’d quite
+throughout ting’d with the colours they exhibited. And ’tis likely, that
+those hairs being boyl’d or steep’d in those very hot ting’d liquors in the
+Dye-fat, And the substance of the hair being much like that of an Oxes
+Horn, the penetrant liquor does so far mollifie and soften the substance,
+that it sinks into the very center of it, and so the ting’d parts come to
+be mix’d and united with the very body of the hair, and do not (as some
+have thought) only stick on upon the outward surface. And this, the boiling
+of Horn will make more probable; for we shall find by that action, that the
+water will insinuate it self to a pretty depth within the surface of it,
+especially if this penetrancy of the water be much helped by the Salts that
+are usually mix’d with the Dying liquors. Now, whereas Silk may be dyed or
+ting’d into all kind of colours without boiling or dipping into hot
+liquors, I ghess the reason to be two-fold: First, because the filaments,
+or small cylinders of Silk, are abundantly smaller and finer, and so have a
+much less depth to be penetrated then most kind of hairs; and next, because
+the substance or matter of Silk, is much more like a Glew then the
+substance of Hair is. And that I have reason to suppose: First, because
+when it is spun or drawn out of the Worm, it is a perfect glutinous
+substance, and very easily sticks and cleaves to any adjacent body, as I
+have several times observed, both in Silk-worms and Spiders. Next, because
+that I find that water does easily dissolve and mollifie the substance
+again, which is evident from their manner of ordering those bottoms or pods
+of the Silk-worm before they are able to unwind them. It is no great wonder
+therefore, if those Dyes or ting’d liquors do very quickly mollifie and
+tinge the surfaces of so small and so glutinous a body. And we need not
+wonder that the colours appear so lovely in the one, and so dull in the
+other, if we view but the ting’d cylinders of both kinds with a good
+_Microscope_; for whereas the substance of Hair, at best, is but a dirty
+duskish white somewhat transparent, the filaments of Silk have a most
+lovely transparency and cleerness, the difference between those two being
+not much less then that between a piece of Horn, and a piece of Crystal;
+the one yielding a bright and vivid reflection from the concave side of the
+cylinder, that is, from the concave surface of the Air that incompasses the
+back-part of the cylinder; the other yielding a dull and perturb’d
+reflection from the several _Heterogeneous_ parts that compose it. And this
+difference will be manifest enough to the eye, if you get a couple of small
+Cylinders, the smaller of Crystal Glass, the other of Horn, and then
+varnishing them over very thinly with some transparent colour, which will
+represent to the naked eye much the same kind of object which is
+represented to it from the filaments of Silk and Hair by the help of the
+_Microscope_. Now, since the threads of Silk and Serge are made up of a
+great number of these filaments, we may henceforth cease to wonder at the
+difference. From much the same reason proceeds the vivid and lovely colours
+of Feathers, wherein they very farr exceed the natural as well as
+Artificial colours of hair, of which I shall say more in its proper place.
+
+The Teguments indeed of creatures are all of them adapted to the peculiar
+use and convenience of that Animal which they inwrap; and very much also
+for the ornament and beauty of it, as will be most evident to any one that
+shall attentively consider the various kinds of cloathings wherewith most
+creatures are by Nature invested and cover’d. Thus I have observed, that
+the hair or furr of those Northern white Bears that inhabite the colder
+Regions, is exceeding thick and warm: the like have I observ’d of the hair
+of a _Greenland_ Deer, which being brought alive to _London_, I had the
+opportunity of viewing; its hair was so exceeding thick, long and soft,
+that I could hardly with my hand, grasp or take hold of his skin, and it
+seem’d so exceeding warm, as I had never met with any before. And as for
+the ornamentative use of them, it is most evident in a multitude of
+creatures, not onely for colour, as the Leopards, Cats, Rhein Deer, _&c._
+but for the shape, as in Horses manes, Cats beards, and several other of
+the greater sort of terrestrial Animals, but is much more conspicuous, in
+the Vestments of Fishes, Birds, Insects, of which I shall by and by give
+some Instances.
+
+As for the skin, the _Microscope_ discovers as great a difference between
+the texture of those several kinds of Animals, as it does between their
+hairs; but all that I have yet taken notice of, when tann’d or dress’d, are
+of a Spongie nature, and seem to be constituted of an infinite company of
+small long _fibres_ or hairs, which look not unlike a heap of Tow or Okum;
+every of which _fibres_ seem to have been some part of a Muscle, and
+probably, whil’st the Animal was alive, might have its distinct function,
+and serve for the contraction and relaxation of the skin, and for the
+stretching and shrinking of it this or that way.
+
+And indeed, without such a kind of texture as this, which is very like that
+of _Spunk_ it would seem very strange, how any body so strong as the skin
+of an Animal usually is, and so close as it seems, whil’st the Animal is
+living, should be able to suffer so great an extension any ways, without at
+all hurting or dilacerating any part of it. But, since we are inform’d by
+the _Microscope_, that it consists of a great many small filaments, which
+are implicated, or intangled one within another, almost no otherwise then
+the hairs in a lock of Wool, or the flakes in a heap of Tow, though not
+altogether so loose, but the filaments are here and there twisted, as
+’twere, or interwoven, and here and there they join and unite with one
+another, so as indeed the whole skin seems to be but one piece, we need not
+much wonder: And though these _fibres_ appear not through a _Microscope_
+exactly jointed and contex’d, as in Sponge; yet, as I formerly hinted, I am
+apt to think, that could we find some way of discovering the texture of it,
+whil’st it invests the living Animal, or had some very easie way of
+separating the pulp or intercurrent juices, such as in all probability fill
+those _Interstitia_, without dilacerating, brusing, or otherwise spoiling
+the texture of it (as it seems to be very much by the ways of tanning and
+dressing now us’d) we might discover a much more curious texture then I
+have hitherto been able to find; perhaps somewhat like that of Sponges.
+
+That of _Chamoise_ Leather is indeed very much like that of _Spunk_, save
+onely that the _filaments_ seem nothing neer so even and round, nor
+altogether so small, nor has it so curious joints as _Spunk_ has, some of
+which I have lately discover’d like those of a Sponge, and perhaps all
+these three bodies may be of the same kind of substance, though two of them
+indeed are commonly accounted Vegetable (which, whether they be so or no, I
+shall not now dispute) But this seems common to all three, that they
+undergo a tanning or dressing, whereby the interspers’d juices are wasted
+and wash’d away before the texture of them can be discover’d.
+
+What their way is of dressing, or curing Sponges, I confess, I cannot
+learn; but the way of dressing _Spunk_, is, by boiling it a good while in a
+strong _Lixivium_, and then beating it very well; and the manner of
+dressing Leather is sufficiently known.
+
+It were indeed extremely desirable, if such a way could be found whereby
+the _Parenchyma_ or flesh of the Muscles, and several other parts of the
+body, might be wash’d, or wafted clean away, without vitiating the form of
+the _fibrous_ parts or vessells of it, for hereby the texture of those
+parts, by the help of a good _Microscope_, might be most accurately found.
+
+But to digress no further, we may, from this discovery of the _Microscope_,
+plainly enough understand how the skin, though it looks so close as it
+does, comes to give a passage to so vast a quantity of _excrementitious_
+substances, as the diligent _Sanctorius_ has excellently observed it to do,
+in his _medicina statica_; for it seems very probable, from the texture
+after dressing, that there are an infinite of pores that every way pierce
+it, and that those pores are onely fill’d with some kind of juice, or some
+very pulpy soft substance, and thereby the steams may almost as easily find
+a passage through such a fluid _vehicle_ as the vaporous bubbles which are
+generated at the bottom of a Kettle of hot water do find a passage through
+that fluid _medium_ into the ambient Air.
+
+Nor is the skin of animals only thus pervious, but even those of vegetables
+also seem to be the same; for otherwise I cannot conceive why, if two
+sprigs of Rosemary (for Instance) be taken as exactly alike in all
+particulars as can be, and the one be set with the bottom in a Glass of
+water, and the other be set just without the Glass, but in the Air onely,
+though you stop the lower end of that in the Air very carefully with Wax,
+yet shall it presently almost wither, whereas the other that seems to have
+a supply from the subjacent water by its small pipes, or _microscopical_
+pores, preserves its greenness for many days, and sometimes weeks.
+
+Now, this to me, seems not likely to proceed from any other cause then the
+_avolation_ of the juice through the skin; for by the Wax, all those other
+pores of the stem are very firmly and closely stop’d up. And from the more
+or less porousness of the skins or rinds of Vegetables may, perhaps, be
+somewhat of the reason given, why they keep longer green, or sooner wither;
+for we may observe by the bladdering and craking of the leaves of Bays,
+Holly, Laurel, &c. that their skins are very close, and do not suffer so
+free a passage through them of the included juices.
+
+But of this, and of the Experiment of the Rosemary, I shall elsewhere more
+fully consider, seeming to me an extreme luciferous Experiment, such as
+seems indeed very plainly to prove the _Schematism_ or structure of
+Vegetables altogether _mechanical_, and as necessary, that (water and
+warmth being apply’d to the bottom of the sprig of a Plant) some of it
+should be carried upwards into the stem, and thence distributed into the
+leaves, as that the water of the _Thames_ covering the bottom of the Mills
+at the Bridge foot of _London_, and by the ebbing and flowing of it,
+passing strongly by them, should have some part of it convey’d to the
+Cesterns above, and thence into several houses and Cesterns up and down the
+City.
+
+       *       *       *       *       *
+
+
+Observ. XXXIII. _Of the _Scales_ of a _Soal_, and other Fishes._
+
+Having hinted somewhat of the skin and covering of terrestrial Animals, I
+shall next add an Observation I made on the skin and Scales of a _Soal_, a
+small Fish, commonly enough known; and here in Fishes, as well as other
+Animals, Nature follows its usual method, framing all parts so, as that
+they are both usefull and ornamental in all its composures, mingling
+_utile_ and _dulce_ together; and both these designs it seems to follow,
+though our unassisted senses are not able to perceive them: This is not
+onely manifest in the covering of this Fish, but in multitudes of others,
+which it would be too long to enumerate, witness particularly that small
+Sand Shell, which I mention’d in the XI. Observation, and infinite other
+small Shells and Scales, divers of which I have view’d. This skin I view’d,
+was flead from a pretty large _Soal_, and then expanded and dry’d, the
+inside of it, when dry, to the naked eye, look’d very like a piece of
+Canvass, but the _Microscope_ discover’d that texture to be nothing else,
+but the inner ends of those curious Scolop’d Scales I, I, I, in the second
+_Figure_ of the XXI. _Scheme_, namely, the part of GGGG (of the larger
+representation of a single Scale, in the first _Figure_ of the same
+_Scheme_) which on the back side, through an ordinary single Magnifying
+Glass, look’d not unlike the Tyles on an house.
+
+The outside of it, to the naked eye, exhibited nothing more of ornament,
+save the usual order of ranging the Scales into a _triagonal_ form, onely
+the edges seem’d a little to shine, the finger being rubb’d from the
+tail-wards towards the head, the Scales seem’d to stay and raze it; But
+through an ordinary Magnifying glass, it exhibited a most curiously carved
+and adorned surface, such as is visible in the second _Figure_, each of
+those (formerly almost imperceptible) Scales appearing much of the shape I,
+I, I, that is, they were round, and protuberant, and somewhat shap’d like a
+Scolop, the whole Scale being creas’d with curiously wav’d and indented
+ridges, with proportionable furrows between; each of which was terminated
+with a very sharp transparent bony substance, which, like so many small
+Turnpikes, seem’d to arm the edges.
+
+The back part KKK was the skin into which each of these Scales were very
+deeply fix’d, in the curious regular order, visible in the second _Figure_.
+The length and shape of the part of the Scale which was buried by the skin,
+is evidenced by the first _Figure_; which is the representation of one of
+them pluck’d out and view’d through a good _Microscope_, namely, the part
+LFGGFL, wherein is also more plainly to be seen, the manner of carving of
+the scolopt part of every particular Scale, how each ridge or barr EEE is
+alternately hollowed or engraven, and how every gutter between them is
+terminated with very transparent and hard pointed spikes, and how every
+other of these, as AAAA, are much longer then the interjacent ones, DDD.
+
+The texture or form also of the hidden part appears, namely, the middle
+part, GGG, seems to consist of a great number of small quills or pipes, by
+which, perhaps, the whole may be nourished; and the side parts FF consist
+of a more fibrous texture, though indeed the whole Scale seem’d to be of a
+very tough gristly substance like the larger Scales of other Fishes.
+
+The Scales of the skin of a Dog-fish (which is us’d by such as work in
+Wood, for the smoothing of their work, and consists plainly enough to the
+naked eye, of a great number off small horny points) through the
+_Microscope_ appear’d each of them curiously ridg’d, and very neatly
+carved; and indeed, you can hardly look on the scales of any Fish, but you
+may discover abundance of curiosity and beautifying; and not only in these
+Fishes, but in the shells and crusts or armour of most sorts of _Marine_
+Animals so invested.
+
+       *       *       *       *       *
+
+
+Observ. XXXIV. _Of the Sting of a Bee._
+
+The Sting of a _Bee_, delineated in the second Figure of the XVI. _Scheme_,
+seems to be a weapon of offence, and is as great an Instance, that Nature
+did really intend revenge as any, and that first, because there seems to be
+no other use of it. Secondly, by reason of its admirable shape, seeming to
+be purposely shap’d for that very end. Thirdly, from the virulency of the
+liquor it ejects, and the sad effects and symptoms that follow it.
+
+But whatever be the use of it, certain it is, that the structure of it is
+very admirable; what it appears to the naked eye, I need not describe, the
+thing being known almost to every one, but it appears through the
+_Microscope_, to consist of two parts, the one a sheath, without a chape or
+top, shap’d almost like the Holster of a Pistol, beginning at d, and ending
+at b, this sheath I could most plainly perceive to be hollow, and to
+contain in it, both a Sword or Dart, and the poisonous liquor that causes
+the pain. The sheath or case seem’d to have several joints or settings
+together, marked by fghiklmno, it was arm’d moreover neer the top, with
+several crooks or forks (pqrst) on one side, and (pqrstu) on the other,
+each of which seem’d like so many Thorns growing on a briar, or rather like
+so many Cat’s Claws; for the crooks themselves seem’d to be little sharp
+transparent points or claws, growing out of little _protuberancies_ on the
+side of the sheath, which, by observing the Figure diligently, is easie
+enough to be perceiv’d; and from several particulars, I suppose the Animal
+has a power of displaying them, and shutting them in again as it pleases,
+as a Cat does its claws, or as an Adder or Viper can its teeth or fangs.
+
+The other part of the Sting was the Sword, as I may so call it, which is
+sheath’d, as it were, in it, the top of which ab appears quite through at
+the smaller end, just as if the chape of the sheath of a Sword were lost,
+and the end of it appear’d beyond the Scabbard; the end of this Dart(a) was
+very sharp, and it was arm’d likewise with the like Tenter-hooks or claws
+with those of the sheath, such as (vxy, xyzz) these crooks, I am very apt
+to think, can be clos’d up also, or laid flat to the sides of the Sword
+when it is drawn into the Scabbard, as I have several times observ’d it to
+be, and can be spred again or extended when ever the Animal pleases.
+
+The consideration of which very pretty structure, has hinted to me, that
+certainly the use of these claws seems to be very considerable, as to the
+main end of this Instrument, for the drawing in, and holding the sting in
+the flesh; for the point being very sharp, the top of the Sting or Dagger
+(ab) is very easily thrust into an Animal’s body, which being once entred,
+the Bee, by endeavouring to pull it into the sheath, draws (by reason of
+the crooks (vxy) and (xyzz) which lay hold of the skin on either side) the
+top of the sheath (tsrv) into the skin after it, and the crooks t, s, and
+r, v, being entred, when the Bee endeavours to thrust out the top of the
+sting out of the sheath again, they lay hold of the skin on either side,
+and do not onely keep the sheath from sliding back, but helps the top
+inwards, and thus, by an alternate and successive retracting and emitting
+of the Sting in and out of the sheath, the little enraged creature by
+degrees makes his revengfull weapon pierce the toughest and thickest Hides
+of his enemies, in so much that some few of these stout and resolute
+soldiers with these little engines, do often put to flight a huge masty
+Bear, one of their deadly enemies, and thereby shew the world how much more
+considerable in Warr a few skilfull Engineers and resolute soldiers
+politickly order’d, that know how to manage such engines, are, then a vast
+unweildy rude force, that confides in, and acts onely by, its strength. But
+(to proceed) that he thus gets in his Sting into the skin, I conjecture,
+because, when I have observ’d this creature living, I have found it to move
+the Sting thus, to and fro, and thereby also, perhaps, does, as ’twere,
+pump or force out the poisonous liquor, and make it hang at the end of the
+sheath about b in a drop. The crooks, I suppose also to be the cause why
+these angry creatures, hastily removing themselves from their revenge, do
+often leave these weapons behind them, sheath’d, as ’twere, in the flesh,
+and, by that means, cause the painfull symptoms to be greater, and more
+lasting, which are very probably caus’d, partly by the piercing and tearing
+of the skin by the Sting, but chiefly by the corrosive and poisonous liquor
+that is by this Syringe-pipe convey’d among the sensitive parts thereof and
+thereby more easily gnaws and corrodes those tender _fibres_: As I have
+shewed in the description of a Nettle and of Cowhage.
+
+       *       *       *       *       *
+
+
+Observ. XXXV. _Of the contexture and shape of the particles of _Feathers_._
+
+Examining several sorts of _Feathers_, I took notice of these particulars
+in all sorts of wing-Feathers, especially in those which serv’d for the
+beating of the air in the action of flying.
+
+That the outward surface of the Quill and Stem was of a very hard, stiff,
+and horny substance, which is obvious enough, and that the part above the
+Quill was fill’d with a very white and light pith, and, with the
+_Microscope_, I found this pith to be nothing else, but a kind of natural
+_congeries_ of small bubbles, the films of which seem to be of the same
+substance with that of the Quill, that is, of a stiff transparent horny
+substance.
+
+Which particular seems to me, very worthy a more serious consideration; For
+here we may observe Nature, as ’twere, put to its shifts, to make a
+substance, which shall be both light enough, and very stiff and strong,
+without varying from its own establish’d principles, which we may observe
+to be such, that very strong bodies are for the most part very heavie also,
+a strength of the parts usually requiring a density, and a density a
+gravity; and therefore should Nature have made a body so broad and so
+strong as a Feather, almost, any other way then what it has taken, the
+gravity of it must necessarily have many times exceeded this; for this pith
+seems to be like so many stops or cross pieces in a long optical tube,
+which do very much contribute to the strength of the whole, the pores of
+which were such, as that they seem’d not to have any communication with one
+another, as I have elsewhere hinted.
+
+But the Mechanism of Nature is usually so excellent, that one and the same
+substance is adapted to serve for many ends. For the chief use of this,
+indeed, seems to be for the supply of nourishment to the downy or feathery
+part of the stem; for ’tis obvious enough in all sorts of Feathers, that
+’tis plac’d just under the roots of the branches that grow out of either
+side of the quill or stalk, and is exactly shap’d according to the ranking
+of those branches, coming no lower into the quill, then just the beginning
+of the downy branches, and growing onely on the under side of the quill
+where those branches do so. Now, in a ripe Feather (as one may call it) it
+seems difficult to conceive how the _Succus nutritius_ should be convey’d
+to this pith; for it cannot, I think, be well imagin’d to pass through the
+substance of the quill, since, having examin’d it with the greatest
+diligence I was able, I could not find the least appearance of pores; but
+he that shall well examine an unripe or pinn’d Feather, will plainly enough
+perceive the Vessel for the conveyance of it to be the thin filmy pith (as
+’tis call’d) which passes through the middle of the quill.
+
+As for the make and contexture of the Down it self, it is indeed very rare
+and admirable, and such as I can hardly believe, that the like is to be
+discover’d in any other body in the world; for there is hardly a large
+Feather in the wing of a Bird, but contains neer a million of distinct
+parts, and every one of them shap’d in a most regular & admirable form,
+adapted to a particular Design: For examining a middle ciz’d Goose-quill, I
+easily enough found with my naked eye, that the main stem of it contain’d
+about 300. longer and more Downy branchings upon one side, and as many on
+the other of more stiff but somewhat shorter branchings. Many of these long
+and downy branchings, examining with an ordinary _Microscope_, I found
+divers of them to contain neer 1200. small leaves (as I may call them, such
+as EF of the first Figure of the 22. _Scheme_) and as many stalks on the
+other side, such as IK of the same Figure, each of the leaves or
+branchings, EF, seem’d to be divided into about sixteen or eighteen small
+joints, as may be seen plainly enough in the Figure, out of most of which
+there seem to grow small long _fibres_, such as are express’d in the
+Figure, each of them very proportionably shap’d according to its position,
+or place on the stalk EF; those on the under side of it, namely, 1, 2, 3,
+4, 5, 6, 7, 8, 9, &c. being much longer then those directly opposite to
+them on the upper; and divers of them, such as 2, 3, 4, 5, 6, 7, 8, 9, &c.
+were terminated with small crooks, much resembling those small crooks,
+which are visible enough to the naked eye, in the seed-buttons of
+Bur-docks. The stalks likewise, IK on the other side, seem’d divided into
+neer as many small knotted joints, but without any appearance of strings or
+crooks, each of them about the middle K, seem’d divided into two parts by a
+kind of fork, one side of which, namely, KL, was extended neer the length
+of KI, the other, M, was very short.
+
+The transverse Sections of the stems of these branchings, manifested the
+shape or figure of it to be much like INOE, which consisted of a horny skin
+or covering, and a white seemingly frothy pith, much like the make of the
+main stem of a Feather.
+
+The use of this strange kind of form, is indeed more admirable then all the
+rest, and such as deserves to be much more seriously examin’d and
+consider’d, then I have hitherto found time or ability to do; for
+certainly, it may very much instruct us in the nature of the Air,
+especially as to some properties of it.
+
+The stems of the Downy branches INOE, being rang’d in the order visible
+enough to the naked eye, at the distance of IF, or somewhat more, the
+_collateral_ stalks and leaves (if I may so call those bodies I newly
+described) are so rang’d, that the leaves or hairy stalks of the one side
+lie at top, or are incumbent on the stalks of the other, and cross each
+other, much after the manner express’d in the second Figure of the 22.
+_Scheme_, by which means every of those little hooked _fibres_ of the
+leaved stalk get between the naked stalks, and the stalks being full of
+knots, and a prety way dis-join’d, so as that the _fibres_ can easily get
+between them, the two parts are so closely and admirably woven together,
+that it is able to impede, for the greatest part, the transcursion of the
+Air; and though they are so exceeding small, as that the thickness of one
+of these stalks amounts not to a 500. part of an Inch, yet do they compose
+so strong a texture, as, notwithstanding the exceeding quick and violent
+beating of them against the Air, by the strength of the Birds wing, they
+firmly hold together. And it argues an admirable providence of Nature in
+the contrivance and fabrick of them; for their texture is such, that though
+by any external injury the parts of them are violently disjoyn’d, so as
+that the leaves and stalks touch not one another, and consequently several
+of these rents would impede the Bird’s flying; yet, for the most part, of
+themselves they readily re-join and re-contex themselves, and are easily by
+the Birds stroking the Feather, or drawing it through its Bill, all of them
+settled and woven into their former and natural posture; for there are such
+an infinite company of those small _fibres_ in the under side of the
+leaves, and most of them have such little crooks at their ends, that they
+readily catch and hold the stalks they touch.
+
+From which strange contexture, it seems rational to suppose that there is a
+certain kind of mesh or hole so small, that the Air will not very easily
+pass through it, as I hinted also in the sixth Observation about small
+Glass Canes, for otherwise it seems probable, that Nature would have drawn
+over some kind of thin film which should have covered all those almost
+square meshes or holes, there seeming through the _Microscope_ to be more
+then half of the surface of the Feather which is open and visibly pervious;
+which conjecture will yet seem more probable from the texture of the
+brushie wings of the _Tinea argentea_, or white Feather wing’d moth, which
+I shall anone describe. But Nature, that knows best its own laws, and the
+several properties of bodies, knows also best how to adapt and fit them to
+her designed ends, and whoso would know those properties, must endeavour to
+trace Nature in its working, and to see what course she observes. And this
+I suppose will be no inconsiderable advantage which the _Schematisms_ and
+Structures of Animate bodies will afford the diligent enquirer, namely,
+most sure and excellent instructions, both as to the practical part of
+_Mechanicks_ and to the _Theory_ and knowledge of the nature of the bodies
+and motions.
+
+       *       *       *       *       *
+
+
+Observ. XXXVI. _Of _Peacocks_, _Ducks_, and other _Feathers_ of   changeable
+colours._
+
+The parts of the Feathers of this glorious Bird appear, through the
+_Microscope_, no less gaudy then do the whole Feathers; for, as to the
+naked eye ’tis evident that the stem or quill of each Feather in the tail
+sends out multitudes of _Lateral_ branches, such as AB in the third Figure
+of the 22. _Scheme_ represents a small part of about ¹⁄₃₂ part of an Inch
+long, and each of the _lateral_ branches emit multitudes of little sprigs,
+threads or hairs on either side of them, such as CD, CD, CD, so each of
+those threads in the _Microscope_ appears a large long body, consisting of
+a multitude of bright reflecting parts, whose Figure ’tis no easie matter
+to determine, as he that examines it shall find; for every new position of
+it to the light makes it perfectly seem of another form and shape, and
+nothing what it appear’d a little before; nay, it appear’d very differing
+ofttimes from so seemingly inconsiderable a circumstance, that the
+interposing of ones hand between the light and it, makes a very great
+change, and the opening or shutting a Casement and the like, very much
+diversifies the appearance. And though, by examining the form of it very
+many ways, which would be tedious here to enumerate, I suppose I have
+discover’d the true Figure of it, yet oftentimes, upon looking on it in
+another posture, I have almost thought my former observations deficient,
+though indeed, upon further examination, I have found even those also to
+confirm them.
+
+These threads therefore I find to be a _congeries_ of small _Laminæ_ or
+plates, as eeeee, &c. each of them shap’d much like this of abcd, in the
+fourth _Figure_, the part ac being a ridge, prominency, or stem, and b and
+d the corners of two small thin Plates that grow unto the small stalk in
+the middle, so that they make a kind of little feather; each of these
+Plates lie one close to another, almost like a company of sloping ridge or
+gutter Tyles; they grow on each side of the stalk opposite to one another,
+by two and two, from top to bottom, in the manner express’d in the fifth
+Figure, the tops of the lower covering the roots of the next above them;
+the under side of each of these laminated bodies, is of a very dark and
+opacous substance, and suffers very few Rays to be trajected, but reflects
+them all toward that side from whence they come, much like the foil of a
+Looking-glass; but their upper sides seem to me to consist of a multitude
+of thin plated bodies, which are exceeding thin, and lie very close
+together, and thereby, like mother of Pearl shells, do not onely reflect a
+very brisk light, but tinge that light in a most curious manner; and by
+means of various positions, in respect of the light, they reflect back now
+one colour, and then another, and those most vividly.
+
+Now, that these colours are onely _fantastical_ ones, that is, such as
+arise immediately from the refractions of the light, I found by this, that
+water wetting these colour’d parts, destroy’d their colours, which seem’d
+to proceed from the alteration of the reflection and refraction. Now,
+though I was not able to see those hairs at all transparent by a common
+light, yet by looking on them against the Sun, I found them to be ting’d
+with a darkish red colour, nothing a-kin to the curious and lovely greens
+and blues they exhibited.
+
+What the reason of colour seems to be in such thin plated bodies, I have
+elsewhere shewn. But how water cast upon those threads destroys their
+colours, I suppose to be perform’d thus; The water falling upon these
+plated bodies from its having a greater congruity to Feathers then the Air,
+insinuates it self between those Plates, and so extrudes the strong
+reflecting Air, whence both these parts grow more transparent, as the
+_Microscope_ informs, and colourless also, at best retaining a very faint
+and dull colour. But this wet being wasted away by the continual
+evaporations and steams that pass through them from the Peacock, whil’st
+that Bird is yet alive, the colours again appear in their former luster,
+the _interstitia_ of these Plates being fill’d with the strongly reflecting
+Air.
+
+The beauteous and vivid colours of the Feathers of this Bird, being found
+to proceed from the curious and exceeding smalness and fineness of the
+reflecting parts, we have here the reason given us of all those gauderies
+in the apparel of other Birds also, and how they come to exceed the colours
+of all other kinds of Animals, besides Insects; for since (as we here, and
+elsewhere also shew) the vividness of a colour, depends upon the fineness
+and transparency of the reflecting and refracting parts; and since our
+_Microscope_ discovers to us, that the component parts of feathers are
+such, and that the hairs of Animals are otherwise; and since we find also
+by the Experiment of that Noble and most Excellent Person I formerly named;
+that the difference between Silk and Flax, as to its colour, is nothing
+else (for Flax reduc’d to a very great fineness of parts, both white and
+colour’d, appears as white and as vivid as any Silk, but loses that
+brightness and its Silken aspect as soon as it is twisted into thread, by
+reason that the component parts, though very small and fine, are yet
+pliable flakes, and not cylinders, and thence, by twisting, become united
+into one opacous body, whereas the threads of Silk and Feathers retain
+their lustre, by preserving their cylindrical form intire without mixing;
+so that each reflected and refracted beam that composes the gloss of Silk,
+preserves its own property of modulating the light intire); And since we
+find the same confirm’d by many other Experiments elsewhere mentioned, I
+think we may safely conclude this for an Axiome, that wheresoever we meet
+with transparent bodies, spun out into very fine parts, either cleer, or
+any ways ting’d, the colours resulting from such a _composition_ must
+necessarily be very glorious, vivid, and cleer, like those of Silk and
+Feathers. This may perhaps hint some usefull way of making other bodies,
+besides Silk, be susceptible of bright tinctures, but of this onely by the
+by.
+
+The changeable colour’d Feathers also of Ducks, and several other Birds, I
+have found by examination with my _Microscope_, to proceed from much the
+same causes and textures.
+
+       *       *       *       *       *
+
+
+Observ. XXXVII. _Of the Feet of _Flies_, and several other _Insects_._
+
+The foot of a Fly (delineated in the first _Figure_ of the 23. _Scheme_,
+which represents three joints, the two Tallons, and the two Pattens in a
+flat posture; and in the second _Figure_ of the same _Scheme_, which
+represents onely one joint, the Tallons and Pattens in another posture) is
+of a most admirable and curious contrivance, for by this the Flies are
+inabled to walk against the sides of Glass, perpendicularly upwards, and to
+contain themselves in that posture as long as they please; nay, to walk and
+suspend themselves against the under surface of many bodies, as the ceiling
+of a room, or the like, and this with as great a seeming facility and
+firmness, as if they were a kind of _Antipodes_, and had a _tendency_
+upwards, as we are sure they have the contrary, which they also evidently
+discover, in that they cannot make themselves so light, as to stick or
+suspend themselves on the under surface of a Glass well polish’d and
+cleans’d; their suspension therefore is wholly to be ascrib’d to some
+Mechanical contrivance in their feet; which, what it is, we shall in brief
+explain, by shewing, that its Mechanism consists principally in two parts,
+that is, first its two Claws, or Tallons, and secondly, two Palms, Pattens,
+or Soles.
+
+The two Tallons are very large, in proportion to the foot, and handsomely
+shap’d in the manner describ’d in the _Figures_, by AB, and AC, the bigger
+part of them from A to _dd_, is all hairy, or brisled, but toward the top,
+at C and B smooth, the tops or points, which seem very sharp turning
+downwards and inwards, are each of them mov’d on a joint at A, by which the
+Fly is able to open or shut them at pleasure, so that the points B and C
+being entered in any pores, and the Fly endeavouring to shut them, the
+Claws not onely draw one against another, and so fasten each other, but
+they draw the whole foot, GGADD forward, so that on a soft footing, the
+tenters or points GGGG, (whereof a Fly has about ten in each foot, to wit,
+two in every joint) run into the pores, if they find any, or at least make
+their way; and this is sensible to the naked eye, in the feet of a
+_Chafer_, which, if he be suffer’d to creep over the hand, or any other
+part of the skin of ones body, does make his steps as sensible to the touch
+as the sight.
+
+But this contrivance, as it often fails the _Chafer_, when he walks on hard
+and close bodies, so would it also our Fly, though he be a much lesser, and
+nimbler creature, and therefore Nature has furnish’d his foot with another
+_additament_ much more curious and admirable, and that is, with a couple of
+Palms, Pattens or Soles DD, the structure of which is this:
+
+From the bottom or under part of the last joint of his foot, K, arise two
+small thin plated horny substances, each consisting of two flat pieces, DD,
+which seem to be flexible, like the covers of a Book, about FF, by which
+means, the plains of the two sides EE, do not always lie in the same plain,
+but may be sometimes shut closer, and so each of them may take a little
+hold themselves on a body; but that is not all, for the under sides of
+these Soles are all beset with small brisles, or tenters, like the Wire
+teeth of a Card used for working Wool, the points of all which tend
+forwards, hence the two Tallons drawing the feet forwards, as I before
+hinted, and these being applied to the surface of the body with all the
+points looking the contrary way, that is, forwards and outwards, if there
+be any irregularity or yielding in the surface of the body, the Fly
+suspends it self very firmly and easily, without the access or need of any
+such Sponges fill’d with an imaginary _gluten_, as many have, for want of
+good Glasses, perhaps, or a troublesome and diligent examination, suppos’d.
+
+Now, that the Fly is able to walk on Glass, proceeds partly from some
+ruggedness of the surface: and chiefly from a kind of tarnish, or dirty
+smoaky substance, which adheres to the surface of that very hard body; and
+though the pointed parts cannot penetrate the substance of Glass, yet may
+they find pores enough in the tarnish, or at least make them.
+
+This Structure I somewhat the more diligently survey’d, because I could not
+well comprehend, how, if there were such a glutinous matter in those
+supposed Sponges, as most (that have observ’d that Object in a
+_Microscope_) have hitherto believ’d, how, I say, the Fly could so readily
+unglew and loosen its feet: and, because I have not found any other
+creature to have a contrivance any ways like it, and chiefly, that we might
+not be cast upon unintelligible explications of the _Phænomena_ of Nature,
+at least others then the true ones, where our senses were able to furnish
+us with an intelligible, rationall and true one.
+
+Somewhat a like contrivance to this of Flies shall we find in most other
+Animals, such as all kinds of Flies and case-wing’d creatures; nay, in a
+Flea, an Animal abundantly smaller then this Fly. Other creatures, as
+Mites, the Land-Crab, &c. have onely one small very sharp Tallon at the end
+of each of their legs, which all drawing towards the center or middle of
+their body, inable these exceeding light bodies to suspend and fasten
+themselves to almost any surface.
+
+Which how they are able to do, will not seem strange, if we consider,
+first, how little body there is in one of these creatures compar’d to their
+superficies, or outside, their thickness, perhaps, oftentimes, not
+amounting to the hundredth part of an Inch: Next, the strength and agility
+of these creatures compar’d to their bulk, being, proportionable to their
+bulk, perhaps, an hundred times stronger then an Horse or Man. And thirdly,
+if we consider that Nature does always appropriate the instruments, so as
+they are the most fit and convenient to perform their offices, and the most
+simple and plain that possibly can be; this we may see further verify’d
+also in the foot of a Louse which is very much differing from those I have
+been describing, but more convenient and necessary for the place of its
+habitation, each of his leggs being footed with a couple of small claws
+which he can open or shut at pleasure, shap’d almost like the claws of a
+Lobster or Crab, but with appropriated contrivances for his peculiar use,
+which being to move its body to and fro upon the hairs of the creature it
+inhabits, Nature has furnish’d one of its claws with joints, almost like
+the joints of a man’s fingers, so as thereby it is able to encompass or
+grasp a hair as firmly as a man can a stick or rope.
+
+Nor, is there a less admirable and wonderfull _Mechanism_ in the foot of a
+Spider, whereby he is able to spin, weave, and climb, or run on his curious
+transparent clew, of which I shall say more in the description of that
+Animal.
+
+And to conclude, we shall in all things find, that Nature does not onely
+work Mechanically, but by such excellent and most compendious, as well as
+stupendious contrivances, that it were impossible for all the reason in the
+world to find out any contrivance to do the same thing that should have
+more convenient properties. And can any be so sottish, as to think all
+those things the productions of chance? Certainly, either their
+Ratiocination must be extremely depraved, or they did never attentively
+consider and contemplate the Works of the Al-mighty.
+
+       *       *       *       *       *
+
+
+Observ. XXXVIII. _Of the Structure and motion of the Wings of _Flies_._
+
+The Wings of all kinds of Insects, are, for the most part, very beautifull
+Objects, and afford no less pleasing an Object to the mind to speculate
+upon, then to the eye to behold. This of the blue Fly, among the rest,
+wants not its peculiar ornaments and contrivances; it grows out of the
+_Thorax_, or middle part of the body of a Fly, and is seated a little
+beyond the center of gravity in the body towards the head, but that
+_Excentricly_ is curiously balanc’d; first, by the expanded _Area_ of the
+wings which lies all more backwards then the root, by the motion of them,
+whereby the center of their vibration is much more backwards towards the
+tail of the Fly then the root of the wing is. What the vibrative motion of
+the wings is, and after what manner they are moved, I have endeavoured by
+many trials to find out: And first for the manner of their motion, I
+endeavoured to observe several of those kind of small spinning Flies, which
+will naturally suspend themselves, as it were, pois’d and steady in one
+place of the air, without rising or falling, or moving forwards or
+backwards; for by looking down on those, I could by a kind of faint shadow,
+perceive the utmost extremes of the vibrative motion of their wings, which
+shadow, whil’st they so endeavoured to suspend themselves, was not very
+long, but when they endeavour’d to flie forwards, it was somewhat longer;
+next, I tried it, by fixing the leggs of a Fly upon the top of the stalk of
+a feather, with Glew, Wax, &c. and then making it endeavour to flie away;
+for being thereby able to view it in any posture, I collected that the
+motion of the wing was after this manner. The extreme limits of the
+vibrations were usually somewhat about the length of the body distant from
+one another, oftentimes shorter, and sometimes also longer; that the
+formost limit was usually a little above the back, and the hinder somwhat
+beneath the belly; between which two limits, if one may ghess by the sound,
+the wing seem’d to be mov’d forwards and backwards with an equal velocity:
+And if one may (from the shadow or faint representation the wings afforded,
+and from the consideration of the nature of the thing) ghess at the posture
+or manner of the wings moving between them, it seem’d to be this: The wing
+being suppos’d placed in the upmost limit, seems to be put so that the
+plain of it lies almost _horizontal_, but onely the forepart does dip a
+little, or is somewhat more deprest; in this position is the wing vibrated
+or mov’d to the lower limit, being almost arrived at the lower limit, the
+hinder part of the wing moving somewhat faster then the former, the _Area_
+of the wing begins to dip behind, and in that posture seems it to be mov’d
+to the upper limit back again, and thence back again in the first posture,
+the former part of the _Area_ dipping again, as it is moved downwards by
+means of the quicker motion of the main stem which terminates or edges the
+forepart of the wing. And these vibrations or motions to and fro between
+the two limits seem so swift, that ’tis very probable (from the sound it
+affords, if it be compar’d with the vibration of a musical string, tun’d
+unison to it) it makes many hundreds, if not some thousands of vibrations
+in a second minute of time. And, if we may be allow’d to ghess by the
+sound, the wing of a Bee is yet more swift, for the tone is much more
+acute, and that, in all likelihood, proceeds from the exceeding swift
+beating of the air by the small wing. And it seems the more likely too,
+because the wing of a Bee is less in proportion to its body, then the other
+wing to the body of a Fly; so that for ought I know, it may be one of the
+quickest vibrating _spontaneous_ motions of any in the world; and though
+perhaps there may be many Flies in other places that afford a yet more
+shrill note with their wings, yet ’tis most probable that the quickest
+vibrating _spontaneous_ motion is to be found in the wing of some creature.
+Now, if we consider the exceeding quickness of these Animal spirits that
+must cause these motions, we cannot chuse but admire the exceeding
+vividness of the governing faculty or _Anima_ of the Insect, which is able
+to dispose and regulate so the motive faculties, as to cause every
+peculiar organ, not onely to move or act so quick, but to do it also so
+regularly.
+
+Whil’st I was examining and considering the curious _Mechanism_ of the
+wings, I observ’d that under the wings of most kind of Flies, Bees, &c.
+there were plac’d certain _pendulums_ or extended drops (as I may so call
+them from their resembling motion and figure) for they much resembled a
+long hanging drop of some transparent viscous liquor; and I observed them
+constantly to move just before the wings of the Fly began to move, so that
+at the first sight I could not but ghess, that there was some excellent
+use, as to the regulation of the motion of the wing, and did phancy, that
+it might be something like the handle of a Cock, which by vibrating to and
+fro, might, as ’twere, open and shut the Cock, and thereby give a passage
+to the determinate influences into the Muscles; afterwards, upon some other
+trials, I suppos’d that they might be for some use in respiration, which
+for many reasons I suppose those Animals to use, and, me thought, it was
+not very improbable, but that they might have convenient passages under the
+wings for the emitting, at least, of the air, if not admitting, as in the
+gills of Fishes is most evident; or, perhaps, this _Pendulum_ might be
+somewhat like the staff to a Pump, whereby these creatures might exercise
+their _Analogous_ lungs, and not only draw in, but force out, the air they
+live by: but these were but conjectures, and upon further examination
+seem’d less probable.
+
+The fabrick of the wing, as it appears through a moderately magnifying
+_Microscope_, seems to be a body consisting of two parts, as is visible in
+the 4. _Figure_ of the 23. _Scheme_; and by the 2. _Figure_ of the 26.
+_Scheme_; the one is a quilly or finny substance, consisting of several
+long, slender and variously bended quills or wires, something resembling
+the veins of leaves; these are, as ’twere, the finns or quills which
+stiffen the whole _Area_, and keep the other part distended, which is a
+very thin transparent skin or membrane variously folded, and platted, but
+not very regularly, and is besides exceeding thickly bestuck with
+innumerable small bristles, which are onely perceptible by the bigger
+magnifying _Microscope_, and not with that neither, but with a very
+convenient augmentation of sky-light projected on the Object with a burning
+Glass, as I have elsewhere shew’d, or by looking through it against the
+light.
+
+In steed of these small hairs, in several other Flies, there are infinite
+of small Feathers, which cover both the under and upper sides of this thin
+film as in almost all the sorts of Butterflies and Moths: and those small
+parts are not onely shap’d very much like the feathers of Birds, but like
+those variegated with all the variety of curious bright and vivid colours
+imaginable; and those feathers are likewise so admirably and delicately
+rang’d, as to compose very fine flourishings and ornamental paintings, like
+_Turkie_ and _Persian_ Carpets, but of far more surpassing beauty, as is
+evident enough to the naked eye, in the painted wings of Butterflies, but
+much more through an ordinary _Microscope_.
+
+Intermingled likewise with these hairs, may be perceived multitudes of
+little pits, or black spots, in the extended membrane, which seem to be the
+root of the hairs that grow on the other side; these two bodies seem
+dispers’d over the whole surface of the wing.
+
+The hairs are best perceiv’d, by looking through it against the light, or,
+by laying the wing upon a very white piece of Paper, in a convenient light,
+for thereby every little hair most manifestly appears; a _Specimen_ of
+which you may observe drawn in the fourth _Figure_ of the 23. _Scheme_, AB,
+CD, EF whereof represent some parts of the bones or quills of the wing,
+each of which you may perceive to be cover’d over with a multitude of
+scales, or bristles, the former AB, is the biggest stem of all the wing,
+and may be properly enough call’d the cut-air, it being that which
+terminates and stiffens the formost edge of the wing; the fore-edge of this
+is arm’d with a multitude of little brisles, or Tenter-hooks, in some
+standing regular and in order, in others not; all the points of which are
+directed from the body towards the tip of the wing, nor is this edge onely
+thus fring’d, but even all the whole edge of the wing is covered with a
+small fringe, consisting of short and more slender brisles.
+
+This Subject, had I time, would afford excellent matter for the
+contemplation of the nature of wings and of flying, but, because I may,
+perhaps, get a more convenient time to prosecute that speculation, and
+recollect several Observations that I have made of that particular. I shall
+at present proceed to
+
+       *       *       *       *       *
+
+
+Observ. XXXIX. _Of the Eyes and Head of a _Grey drone-Fly_,
+and of several other creatures._
+
+I took a large grey _Drone-Fly_, that had a large head, but a small and
+slender body in proportion to it, and cutting off its head, I fix’d it with
+the forepart or face upwards upon my Object Plate (this I made choice of
+rather then the head of a great blue Fly, because my enquiry being now
+about the eyes, I found this Fly to have, first the biggest clusters of
+eyes in proportion to his head, of any small kind of Fly that I have yet
+seen, it being somewhat inclining towards the make of the large
+_Dragon-Flies_. Next, because there is a greater variety in the knobs or
+balls of each cluster, then is of any small Fly.) Then examining it
+according to my usual manner, by varying the degrees of light, and altering
+its position to each kinde of light, I drew that representation of it which
+is delineated in the 24. _Scheme_, and found these things to be as plain
+and evident, as notable and pleasant.
+
+_First_, that the greatest part of the face, nay, of the head, was nothing
+else but two large and _protuberant_ bunches, or _prominent_ parts, ABCDEA,
+the surface of each of which was all cover’d over, or shap’d into a
+multitude of small _Hemispheres_, plac’d in a _triagonal_ order, that being
+the closest and most compacted, and in that order, rang’d over the whole
+surface of the eye in very lovely rows, between each of which, as is
+necessary, were left long and regular trenches, the bottoms of every of
+which, were perfectly intire and not at all perforated or drill’d through,
+which I most certainly was assured of, by the regularly reflected Image of
+certain Objects which I mov’d to and fro between the head and the light.
+And by examining the _Cornea_ or outward skin, after I had stript it off
+from the several substances that lay within it, and by looking both upon
+the inside and against the light.
+
+_Next_, that of those multitudes of _Hemispheres_, there were observable
+two degrees of bigness, the half of them that were lowermost, and look’d
+toward the ground or their own leggs, namely, CDE, CDE being a pretty deal
+smaller then the other, namely, ABCE, ABCE, that look’d upward, and
+side-ways, or foreright, and backward, which variety I have not found in
+any other small Fly.
+
+_Thirdly_, that every one of these _Hemispheres_, as they seem’d to be
+pretty neer the true shape of a _Hemisphere_, so was the surface exceeding
+smooth and regular, reflecting as exact, regular, and perfect an Image of
+any Object from the surface of them, as a small Ball of Quick-silver of
+that bigness would do, but nothing neer so vivid, the reflection from these
+being very languid, much like the reflection from the outside of Water,
+Glass, Crystal, &c. In so much that in each of these _Hemispheres_, I have
+been able to discover a Land-scape of those things which lay before my
+window, one thing of which was a large Tree, whose trunk and top I could
+plainly discover, as I could also the parts of my window, and my hand and
+fingers, if I held it between the Window and the Object; a small draught of
+nineteen of which, as they appear’d in the bigger Magnifying-glass to
+reflect the Image of the two windows of my Chamber, are delineated in the
+third _Figure_ of the 23. _Scheme_.
+
+_Fourthly_, that these rows were so dispos’d, that there was no quarter
+visible from his head that there was not some of these _Hemispheres_
+directed against, so that a Fly may be truly said to have _an eye every
+way_, and to be really _circumspect_. And it was further observable, that
+that way where the trunk of his body did hinder his prospect backward,
+these _protuberances_ were elevated, as it were, above the plain of his
+shoulders and back, so that he was able to see backwards also over his
+back.
+
+_Fifthly_, in living Flies, I have observ’d, that when any small mote or
+dust, which flies up and down the air, chances to light upon any part of
+these knobs, as it is sure to stick firmly to it and not fall, though
+through the _Microscope_ it appears like a large stone or stick (which one
+would admire, especially since it is no ways probable that there is any wet
+or glutinous matter upon these _Hemispheres_, but I hope I shall render the
+reason in another place) so the Fly presently makes use of his two
+fore-feet in stead of eye-lids, with which, as with two Brooms or Brushes,
+they being all bestuck with Brisles, he often sweeps or brushes off what
+ever hinders the prospect of any of his _Hemispheres_, and then, to free
+his leggs from that dirt, he rubs them one against another, the pointed
+Brisles or Tenters of which looking both one way, the rubbing of them to
+and fro one against another, does cleanse them in the same manner as I have
+observ’d those that Card Wool, to cleanse their Cards, by placing their
+Cards, so as the teeth of both look the same way, and then rubbing them one
+against another. In the very same manner do they brush and cleanse their
+bodies and wings, as I shall by and by shew; other creatures have other
+contrivances for the cleansing and cleering their eyes.
+
+_Sixthly_ that the number of the _Pearls_ or _Hemispheres_ in the clusters
+of this Fly, was neer 14000. which I judged by numbering certain rows of
+them several ways, and casting up the whole content, accounting each
+cluster to contain about seven thousand Pearls, three thousand of which
+were of a size, and consequently the rows not so thick, and the foure
+thousand I accounted to be the number of the smaller Pearls next the feet
+and _proboscis_. Other Animals I observ’d to have yet a greater number, as
+the _Dragon-Fly_ or _Adderbolt_: And others to have a much less company, as
+an _Ant_, &c. and several other small Flies and Insects.
+
+_Seventhly_, that the order of these eies or _Hemispheres_ was altogether
+curious and admirable, they being plac’d in all kind of Flies, and _aerial_
+animals, in a most curious and regular ordination of triangular rows, in
+which order they are rang’d the neerest together that possibly they can,
+and consequently leave the least pits or trenches between them. But in
+_Shrimps_, _Crawfishes_, _Lobsters_, and such kinds of _Crustaceous_ water
+Animals, I have yet observ’d them rang’d in a quadrangular order, the rows
+cutting each other at right angles, which as it admits of a less number of
+Pearls in equal surfaces; so have those creatures a recompence made them,
+by having their eyes a little movable in their heads, which the other
+altogether want. So infinitely wise and provident do we find all the
+Dispensations in Nature, that certainly _Epicurus_, and his followers, must
+very little have consider’d them, who ascrib’d those things to the
+production of chance, that wil, to a more attentive considerer, appear the
+products of the highest Wisdom and Providence.
+
+Upon the Anatomy or Dissection of the Head, I observ’d these particulars:
+
+First, that this outward skin, like the _Cornea_ of the eyes of the greater
+Animals, was both flexible and transparent, and seem’d, through the
+_Microscope_ perfectly to resemble the very substance of the _Cornea_ of a
+man’s eye; for having cut out the cluster, and remov’d the dark and
+_mucous_ stuff that is subjacent to it, I could see it transparent like a
+thin piece of skin, having as many cavities in the inside of it, and rang’d
+in the same order as it had _protuberances_ on the outside, and this
+propriety, I found the same in all the Animals that had it, whether Flies
+or Shell-Fish.
+
+Secondly, I found that all Animals that I have observ’d with those kind of
+eyes; have within this _Cornea_, a certain cleer liquor or juice, though in
+a very little quantity, and,
+
+I observ’d thirdly, that within that cleer liquor, they had a kind of dark
+_mucous_ lining, which was all spread round within the cavity of the
+clutter, and seem’d very neer adjoining to it, the colour of which, in some
+Flies, was grey; in others, black, in others red; in others, of a mix’d
+colour; in others, spotted; and that the whole clusters, when look’d on
+whilst the Animal was living, or but newly kill’d, appear’d of the same
+colour that this coat (as I may so call it) appear’d of, when that outward
+skin, or _Cornea_, was remov’d.
+
+Fourthly, that the rest of the capacity of the clusters was in some, as in
+Dragon Flies, &c. hollow, or empty; in others fill’d with some kind of
+substance; in blue Flies, with a reddish musculous substance, with _fibres_
+tending from the center or bottom outwards; and divers other, with various
+and differing kinds of substances.
+
+That this curious contrivance is the organ of sight to all those various
+_Crustaceous_ Animals, which are furnish’d with it, I think we need not
+doubt, if we consider but the several congruities it has with the eyes of
+greater creatures.
+
+As first, that it is furnish’d with a _Cornea_, with a _transparent
+humour_, and with a _uvea_ or _retina_, that the Figure of each of the
+small _Hemispheres_ are very _Spherical_, exactly polish’d, and most vivid,
+lively and plump, when the Animal is living, as in greater Animals, and in
+like manner dull, flaccid, and irregular, or shrunk, when the Animal is
+dead.
+
+Next, that those creatures that are furnish’d with it, have no other organs
+that have any resemblance to the known eyes of other creatures.
+
+Thirdly, that those which they call the eyes of Crabs, Lobsters, Shrimps,
+and the like, and are really so, are _Hemispher’d_, almost in the same
+manner as these of Flies are. And that they really are so, I have very
+often try’d, by cutting off these little movable knobs, and putting the
+creature again into the water, that it would swim to and fro, and move up
+and down as well as before, but would often hit it self against the rocks
+or stones; and though I put my hand just before its head, it would not at
+all start or fly back till I touch’d it, whereas whil’st those were
+remaining, it would start back, and avoid my hand or a stick at a good
+distance before it touch’d it. And if in _crustaceous_ Sea-animals, then it
+seems very probable also, that these knobs are the eyes in _crustaceous_
+Insects, which are also of the same kind, onely in a higher and more active
+Element; this the conformity or congruity of many other parts common to
+either of them, will strongly argue, their _crustaceous_ armour, their
+number of leggs, which are six, beside the two great claws, which answer to
+the wings in Insects; and in all kind of Spiders, as also in many other
+Insects that want wings, we shall find the compleat number of them, and not
+onely the number, but the very shape, figure, joints, and claws of Lobsters
+and Crabs, as is evident in Scorpions and Spiders, as is visible in the
+second _Figure_ of the 31. _Scheme_, and in the little Mite-worm, which I
+call a Land-crab, describ’d in the second Figure of the 33. _Scheme_, but
+in their manner of generation being oviparous, &c. And it were very worthy
+observation, whether there be not some kinds of transformation and
+metamorphosis in the several states of _crustaceous_ water-animals, as
+there is in several sorts of Insects; for if such could be met with, the
+progress of the variations would be much more conspicuous in those larger
+Animals, then they can be in any kind of Insects our colder Climate
+affords.
+
+These being their eyes, it affords us a very pretty Speculation to
+contemplate their manner of vision, which, as it is very differing from
+that of _biocular_ Animals, so is it not less admirable.
+
+That each of these Pearls or _Hemispheres_ is a perfect eye, I think we
+need not doubt, if we consider onely the outside or figure of any one of
+them, for they being each of them cover’d with a transparent protuberant
+_Cornea_, and containing a liquor within them, resembling the watry or
+glassie humours of the eye, must necessarily refract all the parallel Rays
+that fall on them out of the air, into a point not farr distant within
+them, where (in all probability) the _Retina_ of the eye is placed, and
+that opacous, dark, and mucous inward coat that (I formerly shew’d) I found
+to subtend the concave part of the cluster is very likely to be that
+_tunicle_ or coat, it appearing through the _Microscope_ to be plac’d a
+little more than a Diameter of those Pearls below or within the _tunica
+cornea_. And if so, then is there in all probability, a little Picture or
+Image of the objects without, painted or made at the bottom of the _Retina_
+against every one of those Pearls, so that there are as many impressions on
+the _Retina_ or opacous skin, as there are Pearls or _Hemispheres_ on the
+cluster. But because it is impossible for any protuberant surface
+whatsoever, whether _sphærial_ or other, so to refract the Rays that come
+from farr remote _lateral_ points of any Object as to collect them again,
+and unite them each in a distinct point, and that onely those Rays which
+come from some point that lies in the _Axis_ of the Figure produc’d, are so
+accurately refracted to one and the same point again, and that the
+_lateral_ Rays, the further they are remov’d, the more imperfect is their
+refracted confluence; It follows therefore, that onely the Picture of those
+parts of the external objects that lie in, or neer, the _Axis_ of each
+_Hemisphere_, are discernably painted or made on the _Retina_ of each
+_Hemisphere_, and that therefore each of them can distinctly sensate or see
+onely those parts which are very neer perpendicularly oppos’d to it, or lie
+in or neer its optick _Axis_. Now, though there may be by each of these
+eye-pearls, a representation to the Animal of a whole _Hemisphere_ in the
+same manner as in a man’s eye there is a picture or sensation in the
+_Retina_ of all the objects lying almost in an _Hemisphere_; yet, as in a
+man’s eye also, there are but some very few points which liyng in, or neer,
+the optick _Axis_ are distinctly discern’d: So there may be multitudes of
+Pictures made of an Object in the several Pearls, and yet but one, or some
+very few that are distinct; The representation of any object that is made
+in any other Pearl, but that which is directly, or very neer directly,
+oppos’d, being altogether confus’d and unable to produce a distinct vision.
+
+So that we see, that though it has pleas’d the All-wise Creator, to indue
+this creature with such multitudes of eyes, yet has he not indued it with
+the faculty of seeing more then another creature; for whereas this cannot
+move his head, at least can move it very little, without moving his whole
+body, _biocular_ creatures can in an instant (or _the twinkling of an eye_,
+which, being very quick, is vulgarly used in the same signification) move
+their eyes so as to direct the optick _Axis_ to any point; nor is it
+probable, that they are able to see attentively at one time more then one
+Physical point; for though there be a distinct Image made in every eye, yet
+’tis very likely, that the observing faculty is only imploy’d about some
+one object for which they have most concern.
+
+Now, as we accurately distinguish the site or position of an Object by the
+motion of the Muscles of the eye requisite to put the optick Line in a
+direct position, and confusedly by the position of the imperfect Picture of
+the object at the bottom of the eye; so are these _crustaceous_ creatures
+able to judge confusedly of the position of objects by the Picture or
+impression made at the bottom of the opposite Pearl, and distinctly by the
+removal of the attentive or observing faculty, from one Pearl to another,
+but what this faculty is, as it requires another place, so a much deeper
+speculation. Now, because it were impossible, even with this multitude of
+eye-balls, to see any object distinct (for as I hinted before, onely those
+parts that lay in, or very neer, the optick Lines could be so) the
+Infinitely wise Creator has not left the creature without a power of moving
+the head a little in _Aerial crustaceous_ animals, and the very eyes also
+in _crustaceous_ Sea-animals; so that by these means they are inabled to
+direct some optick line or other against any object, and by that means they
+have the visive faculty as compleat as any Animal that can move its eyes.
+
+Distances of Objects also, ’tis very likely they distinguish, partly by the
+consonant impressions made in some two convenient Pearls, one in each
+cluster; for, according as those congruous impressions affect, two Pearls
+neerer approach’d to each other, the neerer is the Object, and the farther
+they are distant, the more distant is the Object: partly also by the
+alteration of each Pearl, requisite to make the Sensation or Picture
+perfect; for ’tis impossible that the Pictures of two Objects, variously
+distant, can be perfectly painted, or made on the same _Retina_ or bottom
+of the eye not altered, as will be very evident to any one that shall
+attentively consider the nature of refraction. Now, whether this alteration
+may be in the Figure of the _Cornea_, in the motion of access or recess of
+the _Retina_ towards the _Cornea_, or in the alteration of a crystalline
+humour, if such there be, I pretend not to determine; though I think we
+need not doubt, but that there may be as much curiosity of contrivance and
+structure in every one of these Pearls, as in the eye of a Whale or
+Elephant, and the almighty’s _Fiat_ could as easily cause the existence of
+the one as the other; and as one day and a thousand years are the same with
+him, so may one eye and ten thousand.
+
+This we may be sure of, that the filaments or sensative parts of the
+_Retina_ must be most exceedingly curious and minute, since the whole
+Picture it self is such; what must needs the component parts be of that
+_Retina_, which distinguishes the part of an object’s Picture that must be
+many millions of millions less then that in a man’s eye? And how exceeding
+curious and subtile must the component parts of the _medium_ that conveys
+light be, when we find the instrument made for its reception or refraction
+to be so exceedingly small? we may, I think, from this speculation be
+sufficiently discouraged from hoping to discover by any optick or other
+instrument the determinate bulk of the parts of the _medium_ that conveys
+the pulse of light, since we find that there is not less accurateness shewn
+in the Figure and polish of those exceedingly minute lenticular surfaces,
+then in those more large and conspicuous surfaces of our own eyes. And yet
+can I not doubt, but that there is a determinate bulk of those parts, since
+I find them unable to enter between the parts of Mercury, which being in
+motion, must necessarily have pores, as I shall elsewhere shew, and here
+pass by, as being a digression.
+
+As concerning the horns FF, the feelers or smellers, GG, the _Proboscis_
+HH, and I, the hairs and brisles, KK, I shall indeavour to describe in the
+42. _Observation_.
+
+       *       *       *       *       *
+
+
+Observ. XL. _Of the Teeth of a _Snail_._
+
+I have little more to add of the Teeth of a Snail, besides the Picture of
+it, which is represented in the first _Figure_ of the 25. _Scheme_, save
+that his bended body, ABCDEF, which seem’d fashioned very much like a row
+of small teeth, orderly plac’d in the Gums, and looks as if it were divided
+into several smaller and greater black teeth, was nothing but one small
+bended hard bone, which was plac’d in the upper jaw of the mouth of a
+House-Snail, with which I observ’d this very Snail to feed on the leaves of
+a Rose-tree, and to bite out pretty large and half round bits, not unlike
+the Figure of a (C) nor very much differing from it in bigness, the upper
+part ABCD of this bone, I found to be much whiter, and to grow out of the
+upper chap of the Snail, GGG, and not to be any thing neer so much creas’d
+as the lower and blacker part of it HIIHKKH which was exactly shap’d like
+teeth, the bone growing thinner, or tapering to an edge towards KKK. It
+seem’d to have nine teeth, or prominent parts IK, IK, IF, &c. which were
+join’d together by the thinner interpos’d parts of the bone. The Animal to
+which these teeth belong, is a very _anomalous_ creature, and seems of a
+kind quite distinct from any other terrestrial Animal or Insect, the
+Anatomy whereof exceedingly differing from what has been hitherto given of
+it I should have inserted, but that it will be more proper in another
+place. I have never met with any kind of Animal whose teeth are all join’d
+in one, save onely that I lately observ’d, that all the teeth of a
+Rhinocerot, which grow on either side of its mouth, are join’d into one
+large bone, the weight of one of which I found to be neer eleven pound
+_Haverdupois_. So that it seems one of the biggest sort of terrestrial
+Animals, as well as one of the smallest, has his teeth thus shap’d.
+
+       *       *       *       *       *
+
+
+Observ. XLI. _Of the Eggs of _Silk-worms_, and other Insects._
+
+The Eggs of Silk-worms (one of which I have describ’d in the second
+_Figure_ of 25. _Scheme_) afford a pretty Object for a _Microscope_ that
+magnifies very much, especially if it be bright weather, and the light of a
+window be cast or collected on it by a deep _Convex glass_, or Water-ball.
+For then the whole surface of the Shell may be perceiv’d all cover’d over
+with exceeding small pits or cavities with interposed edges, almost in the
+manner of the surface of a Poppy-seed, but that these holes are not an
+hundredth part scarce of their bigness; the Shell, when the young ones were
+hatch’d (which I found an easie thing to do, if the Eggs were kept in a
+warm place) appear’d no thicker in proportion to its bulk, then that of an
+Hen’s or Goos’s Egg is to its bulk, and all the Shell appear’d very white
+(which seem’d to proceed from its transparency) whence all those pittings
+did almost vanish, so that they could not, without much difficulty, be
+discern’d, the inside of the Shell seem’d to be lin’d also with a kind of
+thin film, not unlike (keeping the proportion to its Shell) that with which
+the shell of an Hen-egg is lin’d; and the shell it self seem’d like common
+Egg-shells; very brittle, and crack’d. In divers other of these Eggs I
+could plainly enough, through the shell, perceive the small Insect lie
+coyled round the edges of the shell. The shape of the Egg it self, the
+Figure pretty well represents (though by default of the Graver it does not
+appear so rounded, and lying above the Paper, as it were, as it ought to
+do) that is, it was for the most part pretty oval end-ways, somewhat like
+an Egg, but the other way it was a little flatted on two opposite sides.
+Divers of these Eggs, as is common to most others, I found to be barren, or
+addle, for they never afforded any young ones. And those I usually found
+much whiter then the other that were prolifick. The Eggs of other kinds of
+Oviparous Insects I have found to be perfectly round every way, like so
+many Globules, of this sort I have observ’d some sorts of Spiders Eggs; and
+chancing the last Summer to inclose a very large and curiously painted
+Butterfly in a Box, intending to examine its gaudery with my _Microscope_,
+I found within a day or two after I inclos’d her, almost all the inner
+surface of the Box cover’d over with an infinite of exactly round Eggs,
+which were stuck very fast to the sides of it, and in so exactly regular
+and close an order, that made me call to mind my _Hypothesis_, which I had
+formerly thought on for the making out of all the regular Figures of Salt,
+which I have elsewhere hinted; for here I found all of them rang’d into a
+most exact _triagonal_ order, much after the manner as the _Hemispheres_
+are place on the eye of a Fly; all which Eggs I found after a little time
+to be hatch’d, and out of them to come a multitude of small Worms, very
+much resembling young Silk-worms, leaving all their thin hollow shells
+behind them, sticking on the Box in their _triagonal_ posture; these I
+found with the _Microscope_ to have much such a substance as the Silk-worms
+Eggs, but could not perceive them pitted. And indeed, there is as great a
+variety in the shape of the Eggs of Oviparous Insects as among those of
+Birds.
+
+Of these Eggs, a large and lusty Fly will at one time lay neer four or five
+hundred, so that the increase of these kind of Insects must needs be very
+prodigious, were they not prey’d on by multitudes of Birds, and destroy’d
+by Frosts and Rains; and hence ’tis those hotter Climates between the
+_Tropicks_ are infested with such multitudes of Locusts, and such other
+Vermine.
+
+       *       *       *       *       *
+
+
+Observ. XLII. _Of a blue _Fly_._
+
+This kind of Fly, whereof a _Microscopical_ Picture is delineated in the
+first _Figure_ of the 26. _Scheme_, is a very beautifull creature, and has
+many things about it very notable; divers of which I have already partly
+describ’d, namely, the feet, wings, eyes, and head, in the preceding
+Observations.
+
+And though the head before describ’d be that of a grey _Drone-Fly_, yet for
+the main it is very agreeable to this. The things wherein they differ most,
+will be easily enough found by the following particulars:
+
+First, the clusters of eyes of this Fly, are very much smaller then those
+of the _Dron-Fly_, in proportion to the head.
+
+And next, all the eyes of each cluster seem’d much of the same bigness one
+with another, not differing as the other, but rang’d in the same
+_triagonal_ order.
+
+Thirdly, between these two clusters, there was a scaly prominent _front_ B,
+which was arm’d and adorn’d with large tapering sharp black brisles, which
+growing out in rows on either side, were so bent toward each other neer the
+top, as to make a kind of arched arbour of Brisles, which almost cover’d
+the former _front_.
+
+Fourthly, at the end of this Arch, about the middle of the face, on a
+prominent part C, grew two small oblong bodies, DD, which through a
+_Microscope_ look’d not unlike the Pendants in Lillies, these seem’d to be
+jointed on to two small parts at C, each of which seem’d again jointed into
+the front.
+
+Fifthly, out of the upper part and outsides of these horns (as I may call
+them, from the Figure they are of, in the 24. _Scheme_, where they are
+marked with FF) there grows a single feather, or brushy Brisle, EE,
+somewhat of the same kind with the tufts of a Gnat, which I have before
+described.
+
+What the use of these kind of horned and tufted bodies should be, I cannot
+well imagine, unless they serve for smelling or hearing, though how they
+are adapted for either, it seems very difficult to describe: they are in
+almost every several kind of Flies of so various a shape; though certainly
+they are some very essential part of the head, and have some very notable
+office assign’d them by Nature, since in all Insects they are to be found
+in one or other form.
+
+Sixthly, at the under part of the face FF, were several of the former sort
+of bended Brisles, and below all, the mouth, out of the middle of which,
+grew the _proboscis_ GHI, which, by means of several joints, whereof it
+seem’d to consist, the Fly was able to move to and fro, and thrust it in
+and out as it pleas’d; the end of this hollow body (which was all over
+cover’d with small short hairs or brisles) was, as ’twere, bent at H, and
+the outer or formost side of the bended part HI, slit, as it were, into two
+chaps, HI, HI, all the outside of which where cover’d with hairs, and
+pretty large brisles; these he could, like two chaps, very readily open and
+shut, and when he seem’d to suck any thing from the surface of a body, he
+would spread abroad those chaps, and apply the hollow part of them very
+close to it.
+
+From either side of the _Proboscis_, within the mouth, grew two other small
+horns, or fingers, KK, which were hairy, but small in this Figure; but of
+another shape, and bigger in proportion, in the 24. _Scheme_, where they
+are marked with GG, which two indeed seem’d a kind of smellers, but whether
+so or not, I cannot positively determine.
+
+The _Thorax_ or middle part of this Fly, was cas’d, both above and beneath,
+with a very firm crust of armour, the upper part more round, and covered
+over with long _conical_ brisles, all whose ends pointed backwards; out of
+the hinder and under part of this grew out in a cluster six leggs, three of
+which are apparent in the Figure, the other three were hid by the body
+plac’d in that posture. The leggs were all much of the same make, being all
+of them cover’d with a strong hairy scale or shel, just like the legs of a
+Crab or Lobster, and the contrivance of the joints seem’d much the same,
+each legg seem’d made up of eight parts, 1, 2, 3, 4, 5, 6, 7, 8, to the
+eighth or last of which, grew the soles and claws, described before in the
+38. _Observation_.
+
+Out of the upper part of this trunk grew the two wings, which I mention’d
+in the 38. _Observation_, consisting of a film, extended on certain small
+stiff wires or bones: these in a blue Fly, were much longer then the body,
+but in other kind of Flies they are of very differing proportions to the
+body. These films, in many Flies, were so thin, that, like several other
+plated bodies (mention’d in the ninth _Observation_) they afforded all
+varieties of fantastical or transient colours (the reason of which I have
+here endeavoured to explain) they seem’d to receive their nourishment from
+the stalks or wires, which seem’d to be hollow, and neer the upper part of
+the wing LL several of them seem’d jointed, the shape of which will
+sufficiently appear by the black lines in the second Figure of the 26.
+_Scheme_, which is a delineation of one of those wings expanded directly to
+the eyes.
+
+All the hinder part of its body is cover’d with a most curious blue shining
+armour, looking exactly like a polish’d piece of steel brought to that blue
+colour by annealing, all which armour is very thick bestuck with abundance
+of tapering brisles, such as grow on its back, as is visible enough by the
+Figure.
+
+Nor was the inside of this creature less beautifull then its outside, for
+cutting off a part of the belly, and then viewing it, to see if I could
+discover any Vessels, such as are to be found in a greater Animals, and
+even in Snails exceeding manifestly, I found, much beyond my expectation,
+that there were abundance of branchings of Milk-white vessels, no less
+curious then the branchings of veins and arteries in bigger terrestrial
+Animals, in one of which, I found two notable branches, joining their two
+main stocks, as it were, into one common _ductus_; now, to what veins or
+arteries these Vessells were _analogus_, whether to the _vena porta_, or
+the _meseraick vessells_, or the like, or indeed, whether they were veins
+and arteries, or _vasa lactea_, properly so called, I am not hitherto able
+to determine, having not yet made sufficient enquiry; but in all
+particulars, there seems not to be any thing less of curious contrivance in
+these Insects, then in those larger terrestrial Animals, for I had never
+seen any more curious branchings of Vessels, then those I observ’d in two
+or three of these Flies thus opened.
+
+It is a creature active and nimble, so as there are very few creatures like
+it, whether bigger or smaller, in so much, that it will scape and avoid a
+small body, though coming on it exceeding swiftly, and if it sees any thing
+approaching it, which it fears, it presently squats down, as it were, that
+it may be the more ready for its rise.
+
+Nor is it less hardy in the Winter, then active in the Summer, induring all
+the Frosts, and surviving till the next Summer, notwithstanding the bitter
+cold of our Climate; nay, this creature will indure to be frozen, and yet
+not be destroy’d, for I have taken one of them out of the Snow whereon it
+has been frozen almost white, with the Ice about it, and yet by thawing it
+gently by the warmth of a fire, it has quickly reviv’d and flown about.
+
+This kind of Fly seems by the steams or taste of fermenting and putrifying
+meat (which it often kisses, as ’twere, with its _proboscis_ as it trips
+over it) to be stimulated or excited to eject its Eggs or Seed on it,
+perhaps, from the same reason as Dogs, Cats, and many other brute creatures
+are excited to their particular lusts, by the smell of their females, when
+by Nature prepared for generation; the males seeming by those kind of
+smells, or other incitations, to be as much necessitated thereto, as _Aqua
+Regis_ strongly impregnated with a solution of Gold, is forced to
+precipitate it by the affusion of spirit of _Urine_, or a solution of
+_Salt_ of _Tartar_.
+
+One of these put in spirit of _Wine_, was very quickly seemingly kill’d,
+and both its eys and mouth began to look very red, but upon the taking of
+it out, and suffering it to lie three or four hours, and heating it with
+the Sun beams cast through a Burning-glass, it again reviv’d, seeming, as
+it were, to have been all the intermediate time, but dead drunk, and after
+certain hours to grow fresh again and sober.
+
+       *       *       *       *       *
+
+
+Observ. XLIII. _Of the _Water Insect_ or _Gnat_._
+
+This little creature, described in the first _Figure_ of the 27. _Scheme_,
+was a small scaled or crusted Animal, which I have often observ’d to be
+generated in Rain-water; I have also observ’d it both in Pond and
+River-water. It is suppos’d by some, to deduce its first original from the
+putrifaction of Rain-water, in which, if it have stood any time open to the
+air, you shall seldom miss, all the Summer long, of store of them frisking
+too and fro.
+
+’Tis a creature, wholly differing in shape from any I ever observ’d; nor is
+its motion less strange: It has a very large head, in proportion to its
+body, all covered with a shell, like other _testaceous_ Animals, but it
+differs in this, that it has, up and down several parts of it, several
+tufts of hairs, or brisles, plac’d in the order express’d in the Figure; It
+has two horns, which seem’d almost like the horns of an Oxe, inverted, and,
+as neer as I could guess, were hollow, with tufts of brisles, likewise at
+the top; these horns they could move easily this or that way, and might,
+perchance, be their nostrils. It has a pretty large mouth, which seem’d
+contriv’d much like those of Crabs and Lobsters, by which, I have often
+observ’d them to feed on water, or some imperceptible nutritive substance
+in it.
+
+I could perceive, through the transparent shell, while the Animal surviv’d,
+several motions in the head, thorax, and belly, very distinctly, of
+differing kinds which I may, perhaps, elsewhere endeavour more accurately
+to examine, and to shew of how great benefit the use of a _Microscope_ may
+be for the discovery of Nature’s course in the operations perform’d in
+Animal bodies, by which we have the opportunity of observing her through
+these delicate and pellucid teguments of the bodies of Insects acting
+according to her usual course and way, undisturbed, whereas, when we
+endeavour to pry into her secrets by breaking open the doors upon her, and
+dissecting and mangling creatures whil’st there is life yet within them, we
+find her indeed at work, but put into such disorder by the violence
+offer’d, as it may easily be imagin’d, how differing a thing we should
+find, if we could, as we can with a _Microscope_ in these smaller
+creatures, quietly peep in at the windows, without frighting her out of her
+usual byas.
+
+The form of the whole creature, as it appear’d in the _Microscope_, may,
+without troubling you with more descriptions, be plainly enough perceiv’d
+by the _Scheme_, the hinder part or belly consisting of eight several
+jointed parts, namely, ABCDEFGH, of the first _Figure_, from the midst of
+each of which, on either side issued out three or four small brisles or
+hairs, I, I, I, I, I, the tail was divided into two parts of very differing
+make; one of them, namely, K, having many tufts of hair or brisles, which
+seem’d to serve both for the finns and tail, for the Oars and Ruder of this
+little creature, wherewith it was able, by frisking and bending its body
+nimbly to and fro, to move himself any whither, and to skull and steer
+himself as he pleas’d, the other part, L, seem’d to be, as ’twere, the
+ninth division of his belly, and had many single brisles on either side.
+From the end V, of which, through the whole belly, there was a kind of Gut
+of a darker colour, MMM, wherein, by certain _Peristaltick_ motions there
+was a kind of black substance mov’d upwards and downwards through it from
+the orbicular part of it, N, (which seem’d the _Ventricle_, or stomach) to
+the tail V, and so back again, which _peristaltick_ motion I have observ’d
+also in a Louse, a Gnat, and several other kinds of transparent body’d
+Flies. The _Thorax_ or chest of this creature OOOO, was thick and short,
+and pretty transparent, for through it I could see the white heart (which
+is the colour also of the bloud in these, and most other Insects) to beat,
+and several other kind of motions. It was bestuck and adorn’d up and down
+with several tufts of brisles, such as are pointed out by P, P, P, P, the
+head Q was likewise bestuck with several of those tufts, SSS; it was broad
+and short, had two black eyes, TT, which I could not perceive at all
+pearl’d, as they afterwards appear’d, and two small horns, RR, such as I
+formerly describ’d.
+
+Both its motion and rest is very strange, and pleasant, and differing from
+those of most other creatures I have observ’d; for, where it ceases from
+moving its body, the tail of it seeming much lighter then the rest of its
+body, and a little lighter then the water it swims in, presently boys it up
+to the top of the water, where it hangs suspended with the head always
+downward; and like our _Antipodes_, if they do by a frisk get below that
+superficies, they presently ascend again unto it, if they cease moving,
+until they tread, as it were, under that superficies with their tails; the
+hanging of these in this posture, put me in mind of a certain creature I
+have seen in _London_, that was brought out of _America_, which would very
+firmly suspend it self by the tail, with the head downwards, and was said
+to keep in that posture, with her young ones in her false belly, which is a
+Purse, provided by Nature for the production, nutrition, and preservation
+of her young ones, which is described by _Piso_ in the 24. Chapter of the
+fifth Book of his Natural History of _Brasil_.
+
+The motion of it was with the tail forwards, drawing its self backwards, by
+the striking to and fro of that tuft which grew out of one of the stumps of
+its tail. It had another motion, which was more sutable to that of other
+creatures, and that is, with the head forward; for by the moving of his
+chaps (if I may so call the parts of his mouth) it was able to move it self
+downwards very gently towards the bottom, and did, as ’twere, eat up its
+way through the water.
+
+But that which was most observable in this creature, was, its Metamorphosis
+or change; for having kept several of these Animals in a Glass of
+Rain-water, in which they were produc’d, I found, after about a fortnight
+or three weeks keeping, that several of them flew away in Gnats, leaving
+their husks behind them in the water floating under the surface, the place
+where these Animals were wont to reside, whil’st they were inhabitants of
+the water: this made me more diligently to watch them, to see if I could
+find them at the time of their transformation; and not long after, I
+observ’d several of them to be changed into an unusual shape, wholly
+differing from that they were of before, their head and body being grown
+much bigger and deeper, but not broader, and their belly, or hinder part
+smaller, and coyl’d, about this great body much of the fashion represented
+by the prick’d line in the second _Figure_ of the 27. _Scheme_, the head
+and horns now swam uppermost, and the whole bulk of the body seem’d to be
+grown much lighter; for when by my frighting of it, it would by frisking
+out of its tail (in the manner express’d in the Figure by BC) sink it self
+below the surface towards the bottom; the body would more swiftly
+re-ascend, then when it was in its former shape.
+
+I still marked its progress from time to time, and found its body still to
+grow bigger and bigger, Nature, as it were, fitting and accoutring it for
+the lighter Element, of which it was now going to be an inhabitant; for, by
+observing one of these with my _Microscope_, I found the eyes of it to be
+altogether differing from what they seem’d before, appearing now all over
+pearl’d or knobb’d, like the eyes of Gnats, as is visible in the second
+_Figure_ by A. At length, I saw part of this creature to swim above, and
+part beneath the surface of the water, below which though it would quickly
+plunge it self if I by any means frighted it, and presently re-ascend into
+its former posture; after a little longer expectation, I found that the
+head and body of a Gnat, began to appear and stand cleer above the surface,
+and by degrees it drew out its leggs, first the two formost, then the
+other, at length its whole body perfect and entire appear’d out of the husk
+(which it left in the water) standing on its leggs upon the top of the
+water, and by degrees it began to move, and after flew about the Glass a
+perfect Gnat.
+
+I have been the more particular, and large in the relation of the
+transformation of divers of these little Animals which I observ’d, because
+I have not found that any Authour has observ’d the like, and because the
+thing it self is so strange and heterogeneous from the usual progress of
+other Animals, that I judge it may not onely be pleasant, but very usefull
+and necessary towards the compleating of Natural History.
+
+There is indeed in _Piso_, a very odd History, which this relation may make
+the more probable; and that is in the 2. Chapter of the 4. Book of his
+Natural History of _Brasil_, where he says, _Porro præter tot documenta
+fertilitatis circa vegetabilia & sensitiva marina telluris æmula, accidit &
+illud, quod paucis à Paranambucensi milliaribus, piscatoris uncum citra
+intentionem contingat infigi vadis petrosis, & loco piscis spongia,
+coralla, aliasque arbusculas marinas capi. Inter hæc inusitatæ formæ prodit
+spongiosa arbuscula sesquipedis longitudinis, brevioribus radicibus,
+lapideis nitens vadis, & rupibus infixa, erigiturque in corpus spongiosum
+molle oblongum rotundum turbinatum: intus miris cancellis & alveis
+fabricatum, extus autem tenaci glutine instar Apum propolis undique
+vestitum, ostio satis patulo & profundo in summitate relicto, sicut ex
+altera iconum probe depicta videre licet _(see the third and fourth
+_Figures_ of the 27. _Scheme_.)_ Ita ut Apiarium marinum vere dixeris;
+primo enim intuitu è Mare ad Terram delatum, vermiculis scatebat cæruleis
+parvis, qui mox à calore solis in Muscas, vel Apes potius, easq; exiguas &
+nigras transformebantur, circumvolantesque evanescebant, ita ut de eorum
+mellificatione nihil certi conspici datum fuerit, cum tamen cærosa materia
+propolis Apumque cellæ manifeste apparerent, atque ipsa mellis qualiscunque
+substantia proculdubio urinatoribus patebit, ubi curiosius inquisiverint
+hæc apiaria, eaque in natali solo & salo diversis temporibus penitius
+lustrarint_.
+
+Which History contains things sufficiently strange to be consider’d, as
+whether the husk were a Plant, growing at the bottom of the Sea before, of
+it self, out of whose putrifaction might be generated these strange kind of
+Magots; or whether the seed of certain Bees, sinking to the bottom, might
+there naturally form it self that vegetable hive, and take root; or,
+whether it might not be placed there by some diving Fly; or, whether it
+might not be some peculiar propriety of that Plant, whereby it might ripen
+or form its vegetable juice into an Animal substance; or, whether it may
+not be of the nature of a Sponge, or rather a Sponge of the nature of this,
+according to some of those relations and conjectures I formerly made of
+that body, is a matter very difficult to be determined. But indeed, in this
+description, the Excellent _Piso_ has not been sufficiently particular in
+the setting down the whole process, as it were to be wish’d: There are
+indeed very odd progresses in the production of several kinds of Insects,
+which are not less instructive then pleasant, several of which, the
+diligent _Goedartius_ has carefully observ’d and recorded, but among all
+his Observations, he has none like this, though that of the _Hemerobius_ be
+somewhat of this kind, which is added as an Appendix by _Johannes Mey_.
+
+I have, for my own particular, besides several of those mention’d by him,
+observ’d divers other circumstances, perhaps, not much taken notice of,
+though very common, which do indeed afford us a very _coercive_ argument to
+admire the goodness and providence of the infinitely wise Creator in his
+most excellent contrivances and dispensations. I have observ’d, at several
+times of the Summer, that many of the leaves of divers Plants have been
+spotted, or, as it were scabbed, and looking on the undersides of those of
+them that have been but a little irregular, I have perceiv’d them to be
+sprinkled with divers sorts of little Eggs, which letting alone, I have
+found by degrees to grow bigger, and become little Worms with leggs, but
+still to keep their former places, and those places of the leaves, of their
+own accords, to be grown very protuberant upwards, and very hollow, and
+arched underneath, whereby those young creatures are, as it were, shelter’d
+and housed from external injury; divers leaves I have observ’d to grow and
+swell so farr, as at length perfectly to inclose the Animal, which, by
+other observations I have made, I ghess to contain it, and become, as it
+were a womb to it, so long, till it be fit and prepar’d to be translated
+into another state, at what time, like (what they say of) Vipers, they gnaw
+their way through the womb that bred them; divers of these kinds I have met
+with upon Goosberry leaves, Rose-tree leaves, Willow leaves, and many other
+kinds.
+
+There are often to be found upon Rose-trees and Brier bushes, little red
+tufts, which are certain knobs or excrescencies, growing out from the Rind,
+or barks of those kinds of Plants, they are cover’d with strange kinds of
+threads or red hairs, which feel very soft, and look not unpleasantly. In
+most of these, if it has no hole in it, you shall find certain little
+Worms, which I suppose to be the causes of their production; for when that
+Worm has eat its way through, they, having performed what they were
+design’d by Nature to do, by degrees die and wither away.
+
+Now, the manner of their production, I suppose to be thus, that the Alwise
+Creator has as well implanted in every creature a faculty of knowing what
+place is convenient for the hatching, nutrition, and preservation of their
+Eggs and of-springs whereby they are stimulated and directed to convenient
+places, which become, as ’twere the wombs that perform those offices: As he
+has also suited and adapted a property to those places wherby they grow and
+inclose those seeds, and having inclosed them, provide a convenient
+nourishment for them, but as soon as they have done the office of a womb,
+they die and wither.
+
+The progress of inclosure I have often observ’d in leaves, which in those
+places where those seeds have been cast, have by degrees swell’d and
+inclos’d them, so perfectly round, as not to leave any perceptible passage
+out.
+
+From this same cause, I suppose that Galls, Oak-apples, and several other
+productions of that kind, upon the branches and leaves of Trees, have their
+original, for if you open any of them, when almost ripe, you shall find a
+little Worm in them. Thus, if you open never so many dry Galls, you shall
+find either a hole whereby the Worm has eat its passage out, or if you find
+no passage, you may, by breaking or cutting the Gall, find in the middle of
+it a small cavity, and in it a small body, which does plainly enough yet
+retain a shape, to manifest it once to have been a Worm, though it dy’d by
+a too early separation from the Oak on which it grew, its navel-string, as
+’twere, being broken off from the leaf or branch by which the Globular body
+that invelop’d it, received its nourishment from the Oak.
+
+And indeed, if we consider the great care of the Creator in the
+dispensations of his providences for the propagation and increase of the
+race, not onely of all kind of Animals, but even of Vegetables, we cannot
+chuse but admire and adore him for his Excellencies, but we shall leave off
+to admire the creature, or to wonder at the strange kind of acting in
+several Animals, which seem to favour so much of reason; it seeming to me
+most manifest, that those are but actings according to their structures,
+and such operations as such bodies, so compos’d, must necessarily, when
+there are such and such circumstances concurring, perform: thus, when we
+find Flies swarming, about any piece of flesh that does begin a little to
+ferment; Butterflies about Colworts, and several other leaves, which will
+serve to hatch and nourish their young; Gnats, and several other Flies
+about the Waters, and marishy places, or any other creatures, seeking and
+placing their Seeds in convenient repositories, we may, if we attentively
+consider and examine it, find that there are circumstances sufficient, upon
+the supposals of the excellent contrivance of their machine, to excite and
+force them to act after such or such a manner; those steams that rise from
+these several places may, perhaps, set several parts of these little
+Animals at work, even as in the contrivance of killing a Fox or Wolf with a
+Gun, the moving of a string, is the death of the Animal; for the Beast, by
+moving the flesh that is laid to entrap him, pulls the string which moves
+the trigger, and that lets go the Cock which on the steel strikes certain
+sparks of fire which kindle the powder in the pann, and that presently
+flies into the barrel, where the powder catching fire rarifies and drives
+out the bullet which kills the Animal; in all which actions, there is
+nothing of intention or ratiocination to be ascrib’d either to the Animal
+or Engine, but all to the ingeniousness of the contriver.
+
+But to return to the more immediate consideration of our Gnat: We have in
+it an Instance, not usual or common, of a very strange _amphibious_
+creature, that being a creature that inhabits the Air, does yet produce a
+creature, that for some time lives in the water as a Fish, though afterward
+(which is as strange) it becomes an inhabitant of the Air, like its Sire,
+in the form of a Fly. And this, methinks, does prompt me to propose certain
+conjectures, as Queries, having not yet had sufficient opportunity and
+leisure to answer them my self from my own Experiments or Observations.
+
+And the first is, Whether all those things that we suppose to be bred from
+corruption and putrifaction, may not be rationally suppos’d to have their
+origination as natural as these Gnats, who, ’tis very probable, were first
+dropt into this Water, in the form of Eggs. Those Seeds or Eggs must
+certainly be very small, which so small a creature as a Gnat yields, and
+therefore, we need not wonder that we find not the Eggs themselves, some of
+the younger of them, which I have observ’d, having not exceeded a tenth
+part of the bulk they have afterwards come to; and next, I have observed
+some of those little ones which must have been generated after the Water
+was inclosed in the Bottle, and therefore most probably from Eggs, whereas
+those creatures have been suppos’d to be bred of the corruption of the
+Water, there being not formerly known any probable way how they should be
+generated.
+
+A second is, whether these Eggs are immediately dropt into the Water by the
+Gnats themselves, or, mediately, are brought down by the falling rain; for
+it seems not very improbable, but that those small seeds of Gnats may
+(being, perhaps, of so light a nature, and having so great a proportion of
+surface to so small a bulk of body) be ejected into the Air, and so,
+perhaps, carried for a good while too and fro in it, till by the drops of
+Rain it be wash’d out of it.
+
+A third is, whether multitudes of those other little creatures that are
+found to inhabit the Water for some time, do not, at certain times, take
+wing and fly into the Air, others dive and hide themselves in the Earth,
+and so contribute to the increase both of the one and the other Element.
+
+       *       *       *       *       *
+
+_Postscript._
+
+A good while since the writing of this Description, I was presented by
+Doctor _Peter Ball_, an ingenious Member of the _Royal Society_, with a
+little Paper of Nuts, which he told me was sent him from a Brother of his
+out of the Countrey, from _Mamhead_ in _Devonshire_, some of them were
+loose, having been, as I suppose, broken off, others were still growing
+fast on upon the sides of a stick, which seem’d by the bark, pliableness of
+it, and by certain strings that grew out of it, to be some piece of the
+root of a Tree; they were all of them dry’d, and a little shrivell’d,
+others more round, of a brown colour; their shape was much like a Figg, but
+very much smaller, some being about the bigness of a Bay-berry, others, and
+the biggest, of a Hazel-Nut. Some of these that had no hole in them, I
+carefully opened with my Knife, and found in them a good large round white
+Maggot, almost as bigg as a small Pea, which seem’d shap’d like other
+Maggots, but shorter. I could not find them to move, though I ghess’d them
+to be alive, because upon pricking them with a Pinn, there would issue out
+a great deal of white _mucous_ matter, which seem’d to be from a voluntary
+contraction of their skin; their husk or matrix consisted of three Coats,
+like the barks of Trees, the outermost being more rough and spongie, and
+the thickest, the middlemost more close, hard, white, and thin, the
+innermost very thin, seeming almost like the skin within an Egg’s shell.
+The two outermost had root in the branch or stick, but the innermost had no
+stem or process, but was onely a skin that cover’d the cavity of the Nut.
+All the Nuts that had no holes eaten in them, I found to contain these
+Maggots, but all that had holes, I found empty, the Maggots, it seems,
+having eaten their way through, taken wings and flown away, as this
+following account (which I receiv’d in writing from the same person, as it
+was sent him by his Brother) manifests. _In a moorish black Peaty mould,
+with some small veins of whitish yellow Sands, upon occasion of digging a
+hole two or three foot deep, at the head of a Pond or Pool, to set a Tree
+in, at that depth, were found, about the end of _October 1663._ in those
+very veins of Sand, those Buttons or Nuts, sticking to a little loose
+stick, that is, not belonging to any live Tree, and some of them also free
+by themselves._
+
+_Four or five of which being then open’d, some were found to contain live
+Insects come to perfection, most like to flying _Ants_, if not the same; in
+others, Insects, yet imperfect, having but the head and wings form’d, the
+rest remaining a soft white pulpy substance._
+
+Now, as this furnishes us with one odd History more, very agreeable to what
+I before hinted, so I doubt not, but were men diligent observers, they
+might meet with multitudes of the same kind, both in the Earth and in the
+Water, and in the Air, on Trees, Plants, and other Vegetables, all places
+and things being, as it were, _animarum plena_. And I have often, with
+wonder and pleasure, in the Spring and Summer time, look’d close to, and
+diligently on, common Garden mould, and in a very small parcel of it, found
+such multitudes and diversities of little _reptiles_, some in husks, others
+onely creepers, many wing’d, and ready for the Air; divers husks or
+habitations left behind empty. Now, if the Earth of our cold Climate be so
+fertile of animate bodies, what may we think of the fat Earth of hotter
+Climates? Certainly, the Sun may there, by its activity, cause as great a
+parcel of Earth to fly on wings in the Air, as it does of Water in steams
+and vapours. And what swarms must we suppose to be sent out of those
+plentifull inundations of water which are poured down by the sluces of Rain
+in such vast quantities? So that we need not much wonder at those
+innumerable clouds of Locusts with which _Africa_, and other hot countries
+are so pestred, since in those places are found all the convenient causes
+of their production, namely, genitors, or Parents, concurrent receptacles
+or matrixes, and a sufficient degree of natural heat and moisture.
+
+I was going to annex a little draught of the Figure of those Nuts sent out
+of _Devonshire_, but chancing to examine Mr. _Parkinson_’s Herbal for
+something else, and particularly about Galls and Oak-apples, I found among
+no less then 24. several kinds of excrescencies of the Oak, which I doubt
+not, but upon examination, will be all found to be the _matrixes_ of so
+many several kinds of Insects; I having observ’d many of them my self to be
+so, among 24. several kinds, I say, I found one described and Figur’d
+directly like that which I had by me, the _Scheme_ is there to be seen, the
+description, because but short, I have here adjoin’d _Theatri Botanici
+trib. 16. Chap. 2. There groweth at the roots of old Oaks in the
+Spring-time, and sometimes also in the very heat of Summer, a peculiar kind
+of Mushrom or Excrescence, call’d _Uva Quercina_, swelling out of the
+Earth, many growing one close unto another, of the fashion of a Grape, and
+therefore took the name, the _Oak-Grape_, and is of a Purplish colour on
+the outside, and white within like Milk, and in the end of Summer becometh
+hard and woody._ Whether this be the very same kind, I cannot affirm, but
+both the Picture and Description come very neer to that I have, but that he
+seems not to take notice of the hollowness or Worm, for which ’tis most
+observable. And therefore ’tis very likely, if men did but take notice,
+they might find very many differing Species of these Nuts, _Ovaries_, or
+_Matrixes_, and all of them to have much the same designation and office.
+And I have very lately found several kinds of Excrescencies on Trees and
+Shrubs, which having endured the Winter, upon opening them, I found most of
+them to contain little Worms, but dead, those things that contain’d them
+being wither’d and dry.
+
+       *       *       *       *       *
+
+
+Observ. XLIV. _Of the tufted or Brush-horn’d _Gnat_._
+
+This little creature was one of those multitudes that fill our _English_
+air all the time that warm weather lasts, and is exactly of the shape of
+that I observ’d to be generated and hatch’d out of those little Insects
+that wriggle up and down in Rain-water. But, though many were of this form,
+yet I observ’d others to be of quite other kinds; nor were all of this or
+the other kind generated out of Water Insects; for whereas I observ’d that
+those that proceeded from those Insects were at their full growth, I have
+also found multitudes of the same shape, but much smaller and tenderer
+seeming to be very young ones, creep up and down upon the leaves of Trees,
+and flying up and down in small clusters, in places very remote from water;
+and this Spring, I observ’d one day, when the Wind was very calm, and the
+afternoon very fair, and pretty warm, though it had for a long time been
+very cold weather, and the wind continued still in the East, several small
+swarms of them playing to and fro in little clouds in the Sun, each of
+which were not a tenth part of the bigness of one of these I here have
+delineated, though very much of the same shape, which makes me ghess, that
+each of these swarms might be the of-spring of one onely Gnat, which had
+been hoorded up in some safe repository all this Winter by some provident
+Parent, and were now, by the warmth of the Spring-air, hatch’d into little
+Flies.
+
+And indeed, so various, and seemingly irregular are the generations or
+productions of Insects, that he that shall carefully and diligently observe
+the several methods of Nature therein, will have infinitely cause further
+to admire the wisdom and providence of the Creator; for not onely the same
+kind of creature may be produc’d from several kinds of ways, but the very
+same creature may produce several kinds: For, as divers Watches may be made
+out of several materials, which may yet have all the same appearance, and
+move after the same manner, that is, shew the hour equally true, the one as
+the other, and out of the same kind of matter, like Watches, may be wrought
+differing ways; and, as one and the same Watch may, by being diversly
+agitated, or mov’d, by this or that agent, or after this or that manner,
+produce a quite contrary effect: So may it be with these most curious
+Engines of Insect’s bodies; the All-wise God of Nature, may have so ordered
+and disposed the little _Automatons_, that when nourished, acted, or
+enlivened by this cause, they produce one kind of effect, or animate shape,
+when by another they act quite another way, and another Animal is produc’d.
+So may he so order several materials, as to make them, by several kinds of
+methods, produce similar _Automatons_.
+
+But to come to the Description of this Insect, as it appears through a
+_Microscope_, of which a representation is made in the 28. _Scheme_. Its
+head A, is exceeding small, in proportion to its body, consisting of two
+clusters of pearl’d eyes BB, on each side of its head, whose pearls or
+eye-balls are curiously rang’d like those of other Flies; between these, in
+the forehead of it, there are plac’d upon two small black balls, CC, two
+long jointed horns, tapering towards the top, much resembling the long
+horns of Lobsters, each of whose stems or quills, DD, were brisled or
+brushed with multitudes of small stiff hairs, issuing out every way from
+the several joints, like the strings or sproutings of the herb
+_Horse-tail_, which is oft observ’d to grow among Corn, and for the whole
+shape, it does very much resemble those _brushy Vegetables_; besides these,
+there are two other jointed and brisled horns, or feelers, EE, in the
+forepart of the head, and a _proboscis_, F, underneath, which in some Gnats
+are very long, streight hollow pipes, by which these creatures are able to
+drill and penetrate the skin, and thence, through those pipes suck so much
+bloud as to stuff their bellies so full till they be ready to burst.
+
+This small head, with its appurtenances, is fastned on by a short neck, G,
+to the middle of the _thorax_, which is large, and seems cased with a
+strong black shel, HIK, out of the under part of which, issue six long and
+slender legs, LLLLLL, shap’d just like the legs of Flies, but spun or drawn
+out longer and slenderer, which could not be express’d in the Figure,
+because of their great length; and from the upper part, two oblong, but
+slender transparent wings, MM, shaped somewhat like those of a Fly,
+underneath each of which, as I have observ’d also in divers sorts of Flies,
+and other kinds of Gnats, was placed a small body, N, much resembling a
+drop of some transparent glutinous substance, hardned or cool’d, as it was
+almost ready to fall, for it has a round knob at the end, which by degrees
+grows slenderer into a small stem, and neer the insertion under the wing,
+this stem again grows bigger; these little _Pendulums_, I may so call them,
+the little creature vibrates to and fro very quick when it moves its wings,
+and I have sometimes observ’d it to move them also, whil’st the wing lay
+still, but always their motion seem’d to further the motion of the wing
+ready to follow; of what use they are, as to the moving of the wing, or
+otherwise, I have not now time to examine.
+
+Its belly was large, as it is usually in all Insects, and extended into
+nine lengths or partitions, each of which was cover’d with round armed
+rings or shells; six of which, OPQRST were transparent, and divers kinds of
+_Peristaltick_ motions might be very easily perceiv’d, whil’st the Animal
+was alive, but especially a small cleer white part V, seemed to beat like
+the heart of a larger Animal. The last three divisios, WXY, were cover’d
+with black and opacous shells. To conclude, take this creature altogether,
+and for beauty and curious contrivances, it may be compared with the
+largest Animal upon the Earth. Nor doth the Alwise Creator seem to have
+shewn less care and providence in the fabrick of it, then in those which
+seem most considerable.
+
+       *       *       *       *       *
+
+
+Observ. XLV. _Of the great Belly’d _Gnat_ or female _Gnat_._
+
+The second Gnat, delineated in the twenty ninth _Scheme_, is of a very
+differing shape from the former; but yet of this sort also, I found several
+of the Gnats, that were generated out of the Water Insect: the wings of
+this, were much larger then those of the other, and the belly much bigger,
+shorter and of an other shape; and, from several particulars, I ghest it to
+be the Female Gnat, and the former to be the Male.
+
+The _thorax_ of this, was much like that of the other, having a very strong
+and ridged back-piece, which went also on either side of its leggs; about
+the wings there were several joynted pieces of Armor, which seem’d
+curiously and conveniently contriv’d, for the promoting and strengthning
+the motion of the wings: its head was much differing from the other, being
+much bigger and neater shap’d, and the horns that grew out between his eyes
+on two little balls, were of a very differing shape from the tufts of the
+other Gnat, these having but a few knots or joynts, and each of those but a
+few, and those short and strong, brisles. The formost horns or feelers,
+were like those of the former Gnat.
+
+One of these Gnats I have suffer’d to pierce the skin of my hand, with its
+_proboscis_, and thence to draw out as much blood as to fill its belly as
+full as it could hold, making it appear very red and transparent; and this
+without any further pain, then whilst it was sinking in its _proboscis_, as
+it is also in the stinging of Fleas: a good argument, that these creatures
+do not wound the skin, and suck the blood out of enmity and revenge, but
+for meer necessity, and to satisfy their hunger. By what means this
+creature is able to suck, we shall shew in another place.
+
+       *       *       *       *       *
+
+
+Observ. XLVI. _Of the white featherwing’d _Moth_ or _Tinea Argentea_._
+
+This white long wing’d Moth, which is delineated in the 30. _Scheme_;
+afforded a lovely object both to the naked Eye, and through a _Microscope_:
+to the Eye it appear’d a small Milk-white Fly with four white Wings, the
+two formost somewhat longer then the two hindermost, and the two shorter
+about half an Inch long, each of which four Wings seem’d to consist of two
+small long Feathers, very curiously tufted, or haired on each side, with
+purely white, and exceedingly fine and small Haires, proportion’d to the
+stalks or stems, out of which they grew, much like the tufts of a long
+wing-feather of some Bird, and their stalks or stems were, like those,
+bended backwards and downwards, as may be plainly seen by the draughts of
+them in the Figure.
+
+Observing one of these in my _Microscope_, I found, in the first place,
+that all the Body, Legs, Horns and the Stalks of the Wings, were covered
+over with various kinds of curious white Feathers, which did, with handling
+or touching, easily rubb off and fly about, in so much that looking on my
+Fingers, with which I had handled this Moth, and perceiving on them little
+white specks, I found by my _Microscope_, that they were several of the
+small Feathers of this little creature, that stuck up and down in the
+_rugosities_ of my Skin.
+
+Next, I found that underneath these Feathers, the pretty Insect was covered
+all over with a crusted Shell, like other of those Animals, but with one
+much thinner and tenderer.
+
+Thirdly, I found, as in Birds also is notable, it had differing and
+appropriate kinds of Feathers, that covered several parts of its body.
+
+Fourthly, surveying the parts of its body, with a more accurate and better
+Magnifying _Microscope_, I found that the tufts or haires of its Wings were
+nothing else but a congeries, or thick set cluster of small _vimina_ or
+twiggs, resembling a small twigg of Birch, stript or whitened, with which
+Brushes are usually made, to beat out or brush off the dust from Cloth and
+Hangings. Every one of the twiggs or branches that composed the Brush of
+the Feathers, appeared in this bigger Magnifying Glass (of which EF which
+represents ¹⁄₂₄ part of an Inch, is the scale, as G is of the lesser, which
+is only ⅓) like the figure D. The Feathers also that covered a part of
+his Body, and were interspersed among the brush of his Wings, I found, in
+the bigger Magnifying Glass, of the shape A, consisting of a stalk or stem
+in the middle, and a seeming tuftedness or brushy part on each side. The
+Feathers that cover’d most part of his Body and the stalk of his wings,
+were, in the same _Microscope_, much of the figure B, appearing of the
+shape of a small Feather, and seemed tufted: those which covered the Horns
+and small parts of the Leggs, through the same _Microscope_, appear’d of
+the shape C. Whether the tufts of any or all of these small Feathers,
+consisted of such component particles as the Feathers of Birds, I much
+doubt, because I find that Nature does not alwaies keep, or operate after
+the same method, in smaller and bigger creatures. And of this, we have
+particular Instances in the Wings of several creatures. For whereas, in
+Birds of all kinds, it composes each of the Feathers of which its Wing
+consists, of such an exceeding curious and most admirable and stupendious
+texture, as I else-where shew, in the Observations on a Feather; we find it
+to alter its method quite, in the fabrick of the Wings of these minute
+creatures, composing some of thin extended membranes or skins, such as the
+Wings of Dragon-flys; in others, those skins are all over-grown, or pretty
+thick bestuck, with short brisles, as in Flesh-flies; in others, those
+filmes are covered, both on the upper and under side, with small Feathers,
+plac’d almost like the tyles on a House, and are curiously rang’d and
+adorn’d with most lively colours, as is observable in Butter-flies, and
+several kinds of Moths; In others, instead of their films, Nature has
+provided nothing, but a matter of half a score stalks (if I well remember
+the number; for I have not lately met with any of these flys, and did not,
+when I first observ’d them, take sufficient notice of divers particulars)
+and each of these stalks, with a few single branchings on each side,
+resembling much the branched back-bone of a Herring or the like Fish, or a
+thin hair’d Peacocks feather, the top or the eye being broken off. With a
+few of these on either side (which it was able to shut up or expand at
+pleasure, much like a Fann, or rather like the posture of the feathers in a
+wing, which ly all one under another, when shut, and by the side of each
+other, when expanded) this pretty little grey Moth (for such was the
+creature I observ’d, thus wing’d) could very nimbly, and as it seem’d very
+easily move its _corpuscle_, through the Air, from place to place. Other
+Insects have their wings cas’d, or cover’d over, with certain hollow
+shells, shap’d almost like those hollow Trayes, in which Butchers carry
+meat, whose hollow sides being turn’d downwards, do not only secure their
+folded wings from injury of the earth, in which most of those creatures
+reside, but whilst they fly, serves as a help to sustain and bear them up.
+And these are observable in _Scarabees_ and a multitude of other
+terrestrial _crustaceous_ Insects; in which we may yet further observe a
+particular providence of Nature.
+
+Now in all these kinds of wings, we observe this particular, as a thing
+most worthy remark; that where ever a wing consists of discontinued parts,
+the Pores or _interstitia_ between those parts are very seldom, either much
+bigger, or much smaller, then these which we here find between the
+particles of these brushes, so that it should seem to intimate, that the
+parts of the Air are such, that they will not easily or readily, if at all,
+pass through these Pores, so that they seem to be strainers fine enough to
+hinder the particles of the Air (whether hinder’d by their bulk, or by
+their _agitation_, _circulation_, _rotation_ or _undulation_, I shall not
+here determine) from getting through them, and, by that means, serve the
+Animal as well, if not better, then if they were little films. I say, if
+not better, because I have observ’d that all those creatures, that have
+film’d wings, move them aboundantly quicker and more strongly, such as all
+kind of Flies and _Scarabees_ and Batts, then such as have their wings
+covered with feathers, as Butter-flies and Birds, or twiggs, as Moths,
+which have each of them a much slower motion of their wings; That little
+ruggedness perhaps of their wings helping them somewhat, by taking better
+hold of the parts of the Air, or not suffering them so easily to pass by,
+any other way then one.
+
+But what ever be the reason of it, ’tis most evident, that the smooth
+wing’d Insects, have the strongest Muscles or movent parts of their wings,
+and the other much weaker; and this very Insect, we are now describing, had
+a very small _thorax_ or middle part of his body, if compar’d to the length
+and number of his wings; which therefore, as he mov’d them very slowly, so
+must he move them very weakly. And this last propriety do we find somewhat
+observ’d also in bigger kind of Flying creatures, Birds; so that we see
+that the Wisdom and Providence of the All-wise Creator, is not less shewn
+in these small despicable creatures, Flies and Moths, which we have branded
+with a name of ignominy, calling them Vermine, then in those greater and
+more remarkable animate bodies, Birds.
+
+I cannot here stand to add any thing about the nature of flying, though,
+perhaps, on another occasion, I may say something on that subject, it being
+such as may deserve a much more accurate examination and scrutiny then it
+has hitherto met with; For to me there seems nothing wanting to make a man
+able to fly, but what may be easily enough supply’d from the Mechanicks
+hitherto known, save onely the want of strength, which the Muscles of a man
+seem utterly uncapable of, by reason of their smalness and texture, but how
+even strength also may be mechanically made, and an artificial Muscle so
+contriv’d, that thereby a man shall be able to exert what strength he
+pleases, and to regulate it also to his own mind, I may elsewhere endeavour
+to manifest.
+
+       *       *       *       *       *
+
+
+Observ. XLVII. _Of the _Shepherd Spider_, or long-legg’d _Spider_._
+
+The Carter, Shepherd Spider, or long-legg’d Spider, has, for two
+particularities, very few similar creatures that I have met with, the
+first, which is discoverable onely by the _Microscope_, and is in the first
+and second _Figures_ of the 31. _Scheme_, plainly describ’d, is the curious
+contrivance of his eyes, of which (differing from most other Spiders) he
+has onely two, and those plac’d upon the top of a small pillar or hillock,
+rising out of the middle of the top of its back, or rather the crown of its
+head, for they were fix’d on the very top of this pillar (which is about
+the heighth of one of the transverse Diameters of the eye, and look’d on in
+another posture, appear’d much of the shape, BCD.) The two eyes, BB, were
+placed back to back, with the transparent parts, or the pupils, looking
+towards either side, but somewhat more forward then backwards. C was the
+column or neck on which they stood, and D the crown of the head out of
+which that neck sprung.
+
+These eyes, to appearance, seem’d to be of the very same structure with
+that of larger _binocular_ creatures, seeming to have a very smooth and
+very protuberant _Cornea_, and in the midst of it to have a very black
+pupil, incompassed about with a kind of grey _Iris_, as appears by the
+_Figure_; whether it were able to move these eyes to and fro, I have not
+observ’d, but ’tis not very likely he should, the pillar or neck C, seeming
+to be cover’d and stiffen’d with a crusty shell; but Nature, in
+probability, has supply’d that defect, by making the _Cornea_ so very
+protuberant, and setting it so cleer above the shadowing or obstructing of
+its prospect by the body, that ’tis likely each eye may perceive, though
+not see distinctly, almost a _Hemisphere_, whence having so small and round
+a body plac’d upon such long leggs, it is quickly able so to wind, and turn
+it, as to see any thing distinct. This creature, as do all other Spiders I
+have yet examin’d, does very much differ from most other Insects in the
+Figure of its eyes; for I cannot, with my best _Microscope_, discover its
+eyes to be any ways knobb’d or pearl’d like those of other Insects.
+
+The second Peculiarity which is obvious to the eye, is also very
+remarkable, and that is the prodigious length of its leggs, in proportion
+to its small round body, each legg of this I drew, being above sixteen
+times the length of its whole body, and there are some which have them yet
+longer, and others that seem of the same kind, that have them a great deal
+shorter; the eight leggs are each of them jointed, just like those of a
+Crab, but every of the parts are spun out prodigiously longer in
+proportion; each of these leggs are terminated in a small case or shell,
+shap’d almost like that of a Musle-shell, as is evident in the third
+_Figure_ of the same _Scheme_ (that represents the appearance ot the under
+part or belly of the creature) by the shape of the protuberant _conical_
+body, IIII, &c. These are as ’twere plac’d or fasten’d on to the
+protuberant body of the Insect, which is to be suppos’d very high at M,
+making a kind of blunt cone whereof M is to be suppos’d the _Apex_, about
+which greater cone of the body, the smaller cones of the leggs are plac’d,
+each of them almost reaching to the top in so admirable a manner, as does
+not a little manifest the wisdom of Nature in the contrivance; for these
+long Leavers (as I may so call them) of the legs, having not the advantage
+of a long end on the other side of the _hypomochlion_ or centers on which
+the parts of the leggs move, must necessarily require a vast strength to
+move them, and keep the body ballanc’d and suspended, in so much, that if
+we should suppose a man’s body suspended by such a contrivance, an hundred
+and fifty times the strength of a man would not keep the body from falling
+on the breast. To supply therefore each of these leggs with its proper
+strength, Nature has allow’d to each a large Chest or Cell, in which is
+included a very large and strong Muscle, and thereby this little Animal is
+not onely able to suspend its body upon less then these eight, but to move
+it very swiftly over the tops of grass and leaves.
+
+Nor are these eight leggs so prodigiously long, but the ninth, and tenth,
+which are the two claws, KK, are as short, and serve in steed of a
+_proboscis_, for those seem’d very little longer then his mouth; each of
+them had three parts, but very short, the joints KK, which represented the
+third, being longer then both the other. This creature, seems (which I have
+several times with pleasure observ’d) to throw its body upon the prey,
+insteed of its hands, not unlike a hunting Spider, which leaps like a Cat
+at a Mouse. The whole Fabrick was a very pretty one, and could I have
+dissected it, I doubt not but I should have found as many singularities
+within it as without, perhaps, for the most part, not unlike the parts of a
+Crab, which this little creature does in many things, very much resemble;
+the curiosity of whose contrivance, I have in another place examin’d. I
+omit the description of the horns, AA, of the mouth, LL, which seem’d like
+that of a Crab; the speckledness of his shell, which proceeded from a kind
+of feathers or hairs, and the hairiness of his leggs, his large _thorax_
+and little belly, and the like, they being manifested by the Figure; and
+shall onely take notice that the three parts of the body, namely, the head,
+breast, and belly, are in this creature strangely confus’d, so that ’tis
+difficult to determine which is which, as they are also in a Crab; and
+indeed, this seems to be nothing else, but an Air-crab, being made more
+light and nimble, proportionable to the _medium_ wherein it resides; and as
+Air seems to have but one thousandth part of the body of Water, so does
+this Spider seem not to be a thousandth part of the bulk of a Crab.
+
+       *       *       *       *       *
+
+
+Observ. XLVIII. _Of the hunting _Spider_, and several other sorts of
+_Spiders_._
+
+The hunting Spider is a small grey Spider, prettily bespeck’d with black
+spots all over its body, which the _Microscope_ discovers to be a kind of
+feathers like those on Butterflies wings, or the body of the white Moth I
+lately describ’d. Its gate is very nimble by fits, sometimes running, and
+sometimes leaping, like a Grashopper almost, then standing still, and
+setting it self on its hinder leggs, it will very nimbly turn its body, and
+look round it self every way: It has six very conspicuous eyes, two looking
+directly forwards, plac’d just before; two other, on either side of those,
+looking forward and side-ways; and two other about the middle of the top of
+its back or head, which look backwards and side-wards; these seem’d to be
+the biggest. The surface of them all was very black, sphærical, purely
+polish’d, reflecting a very cleer and distinct Image of all the ambient
+objects, such as a window, a man’s hand, a white Paper, or the like. Some
+other properties of this Spider, observ’d by the most accomplish’d Mr.
+_Evelyn_, in his travels in _Italy_, are most emphatically set forth in the
+History hereunto annexed, which he was pleas’d upon my desire to send me in
+writing.
+
+    Of all the sorts of Insects, there is none has afforded me more
+    divertisements then the _Venatores_, which are a sort of _Lupi_, that
+    have their Denns in the rugged walls, and crevices of our houses; a
+    small brown and delicately spotted kind of Spiders, whose hinder leggs
+    are longer then the rest.
+
+    Such I did frequently observe at _Rome_, which espying a Fly at three
+    or four yards distance, upon the Balcony (where I stood) would not make
+    directly to her, but craul under the Rail, till being arriv’d to the
+    _Antipodes_, it would steal up, seldom missing its aim; but if it
+    chanced to want any thing of being perfectly opposite, would at first
+    peep, immediately slide down again, till taking better notice, it would
+    come the next time exactly upon the Fly’s back: But, if this hapn’d not
+    to be within a competent leap, then would this Insect move so softly,
+    as the very shadow of the Gnomon seem’d not to be more imperceptible,
+    unless the Fly mov’d; and then would the Spider move also in the same
+    proportion, keeping that just time with her motion, as if the same Soul
+    had animated both those little bodies; and whether it were forwards,
+    backwards, or to either side, without at all turning her body, like a
+    well mannag’d Horse: But, if the capricious Fly took wing, and pitch’d
+    upon another place behind our Huntress, then would the Spider whirle
+    its body so nimbly about, as nothing could be imagin’d more swift; by
+    which means, she always kept the head towards her prey, though to
+    appearance, as immovable, as if it had been a Nail driven into the
+    Wood, till by that indiscernable progress (being arriv’d within the
+    sphere of her reach) she made a fatal leap (swift as Lightning) upon
+    the Fly, catching him in the pole, where she never quitted hold till
+    her belly was full, and then carried the remainder home. I have beheld
+    them instructing their young ones, how to hunt, which they would
+    sometimes discipline for not well observing; but, when any of the old
+    ones did (as sometimes) miss a leap, they would run out of the field,
+    and hide them in their crannies, as asham’d, and haply not be seen
+    abroad for four or five hours after; for so long have I watched the
+    nature of this strange Insect, the contemplation of whose so wonderfull
+    sagacity and address has amaz’d me; nor do I find in any chase
+    whatsoever, more cunning and Stratagem observ’d: I have found some of
+    these Spiders in my Garden, when the weather (towards the Spring) is
+    very hot, but they are nothing so eager of hunting as they are in
+    _Italy_.
+
+There are multitudes of other sorts of Spiders, whose eyes, and most other
+parts and properties, are so exceedingly different both from those I have
+describ’d, and from one another, that it would be almost endless, at least
+too long for my present Essay, to describe them, as some with six eyes,
+plac’d in quite another order; others with eight eyes; others with fewer,
+and some with more. They all seem to be creatures of prey, and to feed on
+other small Insects, but their ways of catching them seem very differing:
+the Shepherd Spider by running on his prey; the Hunting Spider by leaping
+on it, other sorts weave Nets, or Cobwebs, whereby they ensnare them,
+Nature having both fitted them with materials and tools, and taught them
+how to work and weave their Nets, and to lie perdue, and to watch
+diligently to run on any Fly, as soon as ever entangled.
+
+Their thread or web seems to be spun out of some viscous kind of excrement,
+lying in their belly, which, though soft when drawn out, is, presently by
+reason of its smallness, hardned and dried by the ambient Air. Examining
+several of which with my _Microscope_, I found them to appear much like
+white Hors-hair, or some such transparent horny substance, and to be of
+very differing magnitudes; some appearing as bigg as a Pigg’s brisle,
+others equal to a Horss-hair; other no bigger then a man’s hair; others yet
+smaller and finer. I observ’d further, that the radiating chords of the web
+were much bigger, and smoother then those that were woven round, which
+seem’d smaller, and all over knotted or pearl’d, with small transparent
+Globules, not unlike small Crystal Beads or seed Pearls, thin strung on a
+Clew of Silk; which, whether they were so spun by the Spider, or by the
+adventitious moisture of a fogg (which I have observ’d to cover all these
+filaments with such Crystalline Beads) I will not now dispute.
+
+These threads were some of them so small, that I could very plainly, with
+the _Microscope_, discover the same consecutions of colours as in a
+_Prisme_, and they seem’d to proceed from the same cause with those colours
+which I have already describ’d in thin plated bodies.
+
+Much resembling a Cobweb, or a confus’d lock of these Cylinders, is a
+certain white substance which, after a fogg, may be observ’d to fly up and
+down the Air; catching several of these, and examining them with my
+_Microscope_, I found them to be much of the same form, looking most like
+to a flake of Worsted prepar’d to be spun, though by what means they should
+be generated, or produc’d, is not easily imagined: they were of the same
+weight, or very little heavier then the Air; and ’tis not unlikely, but
+that those great white clouds, that appear all the Summer time, may be of
+the same substance.
+
+       *       *       *       *       *
+
+
+Observ. XLIX. _Of an _Ant_ or _Pismire_._
+
+This was a creature, more troublesome to be drawn, then any of the rest, for
+I could not, for a good while, think of a way to make it suffer its body to
+ly quiet in a natural posture; but whil’st it was alive, if its feet were
+fetter’d in Wax or Glew, it would so twist and wind its body, that I could
+not any wayes get a good view of it; and if I killed it, its body was so
+little, that I did often spoil the shape of it, before I could throughly
+view it: for this is the nature of these minute Bodies, that as soon,
+almost, as ever their life is destroy’d, their parts immediately shrivel,
+and lose their beauty; and so is it also with small Plants, as I instanced
+before, in the description of Moss. And thence also is the reason of the
+variations in the beards of wild Oats, and in those of Musk-grass seed,
+that their bodies, being exceeding small, those small variations which are
+made in the surfaces of all bodies, almost upon every change of Air,
+especially if the body be porous, do here become sensible, where the whole
+body is so small, that it is almost nothing but surface; for as in
+vegetable substances, I see no great reason to think, that the moisture of
+the Aire (that, sticking to a wreath’d beard, does make it untwist) should
+evaporate, or exhale away, any faster then the moisture of other bodies,
+but rather that the avolation from, or access of moisture to, the surfaces
+of bodies being much the same, those bodies become most sensible of it,
+which have the least proportion of body to their surface. So is it also
+with Animal substances; the dead body of an Ant, or such little creature,
+does almost instantly shrivel and dry, and your object shall be quite
+another thing, before you can half delineate it, which proceeds not from
+the extraordinary exhalation, but from the small proportion of body and
+juices, to the usual drying of bodies in the Air, especially if warm. For
+which inconvenience, where I could not otherwise remove it, I thought of
+this expedient.
+
+I took the creature, I had design’d to delineate, and put it into a drop of
+very well rectified spirit of Wine, this I found would presently dispatch,
+as it were, the Animal, and being taken out of it, and lay’d on a paper,
+the spirit of Wine would immediately fly away, and leave the Animal dry, in
+its natural posture, or at least, in a constitution, that it might easily
+with a pin be plac’d, in what posture you desired to draw it, and the limbs
+would so remain, without either moving, or shriveling. And thus I dealt
+with this Ant, which I have here delineated, which was one of many, of a
+very large kind, that inhabited under the Roots of a Tree, from whence they
+would sally out in great parties, and make most grievous havock of the
+Flowers and Fruits, in the ambient Garden, and return back again very
+expertly, by the same wayes and paths they went.
+
+It was more then half the bigness of an Earwig, of a dark brown, or reddish
+colour, with long legs, on the hinder of which it would stand up, and raise
+its head as high as it could above the ground, that it might stare the
+further about it, just after the same manner as I have also observ’d a
+hunting Spider to do: and putting my finger towards them, they have at
+first all run towards it, till almost at it; and then they would stand
+round about it, at a certain distance, and smell, as it were, and consider
+whether they should any of them venture any further, till one more bold
+then the rest venturing to climb it, all the rest, if I would have suffered
+them, would have immediately followed: many such other seemingly rational
+actions I have observ’d in this little Vermine with much pleasure, which
+would be too long to be here related; those that desire more of them may
+satisfie their curiosity in _Ligons_ History of the _Barbadoes_.
+
+Having insnar’d several of these into a small Box, I made choice of the
+tallest grown among them, and separating it from the rest, I gave it a Gill
+of Brandy, or Spirit of Wine, which after a while e’en knock’d him down
+dead drunk, so that he became moveless, though at first putting in he
+struggled for a pretty while very much, till at last, certain bubbles
+issuing out of its mouth, it ceased to move; this (because I had before
+found them quickly to recover again, if they were taken out presently) I
+suffered to lye above an hour in the Spirit; and after I had taken it out,
+and put its body and legs into a natural posture, remained moveless about
+an hour; but then, upon a sudden, as if it had been awaken out of a drunken
+sleep, it suddenly reviv’d and ran away; being caught, and serv’d as
+before, he for a while continued struggling and striving, till at last
+there issued several bubbles out of its mouth, and then, _tanquam animam
+expirasset_, he remained moveless for a good while; but at length again
+recovering, it was again redipt, and suffered to lye some hours in the
+Spirit; notwithstanding which, after it had layen dry some three or four
+hours, it again recovered life and motion: Which kind of Experiments, if
+prosecuted, which they highly deserve, seem to me of no inconsiderable use
+towards the invention of the _Latent Scheme_, (as the Noble _Verulam_ calls
+it) or the hidden, unknown Texture of Bodies.
+
+Of what Figure this Creature appear’d through the _Microscope_, the 32.
+_Scheme_ (though not so carefully graven as it ought) will represent to the
+eye, namely, That it had a large head AA, at the upper end of which were
+two protuberant eyes, pearl’d like those of a Fly, but smaller BB; out of
+the Nose, or foremost part, issued two horns CC, of a shape sufficiently
+differing from those of a blew Fly, though indeed they seem to be both the
+same kind of Organ, and to serve for a kind of smelling; beyond these were
+two indented jaws DD, which he open’d side-wayes, and was able to gape them
+asunder very wide; and the ends of them being armed with teeth, which
+meeting went between each other, it was able to grasp and hold a heavy
+body, three or four times the bulk and weight of its own body: It had only
+six legs, shap’d like those of a Fly, which, as I shewed before, is an
+Argument that it is a winged Insect, and though I could not perceive any
+sign of them in the middle part of its body (which seem’d to consist of
+three joints or pieces EFG, out of which sprung two legs), yet ’tis known
+that there are of them that have long wings, and fly up and down in the
+air.
+
+The third and last part of its body III was bigger and larger then the
+other two, unto which it was joyn’d by a very small middle, and had a kind
+of loose shell, or another distinct part of its body H, which seem’d to be
+interpos’d, and to keep the _thorax_ and belly from touching.
+
+The whole body was cas’d over with a very strong armour, and the belly III
+was covered likewise with multitudes of small white shining brisles; the
+legs, horns, head, and middle parts of its body were bestuck with hairs
+also, but smaller and darker.
+
+       *       *       *       *       *
+
+
+Observ. L. _Of the wandring _Mite_._
+
+In _September_ and _October, 1661._ I observ’d in _Oxford_ several of these
+little pretty Creatures to wander to and fro, and often to travel over the
+plains of my Window. And in _September_ and _October, 1663._ I observ’d
+likewise several of these very same Creatures traversing a window at
+_London_, and looking without the window upon the subjacent wall, I found
+whole flocks of the same kind running to and fro among the small groves and
+thickets of green moss, and upon the curiously spreading vegetable blew or
+yellow moss, which is a kind of a Mushrome or Jews-ear.
+
+These Creatures to the naked eye seemed to be a kind of black Mite, but
+much nimbler and stronger then the ordinary Cheese-Mites; but examining
+them in a _Microscope_, I found them to be a very fine crusted or shell’d
+Insect, much like that represented in the first Figure of the three and
+thirtieth _Scheme_, with a protuberant oval shell A, indented or pitted
+with an abundance of small pits, all covered over with little white
+brisles, whose points all directed backwards.
+
+It had eight legs, each of them provided with a very sharp tallon, or claw
+at the end, which this little Animal, in its going, fastned into the pores
+of the body over which it went. Each of these legs were bestuck in every
+joynt of them with multitudes of small hairs, or (if we respect the
+proportion they bore to the bigness of the leg) turnpikes, all pointing
+towards the claws.
+
+The _Thorax_, or middle parts of the body of this Creature, was exceeding
+small, in respect both of the head and belly, it being nothing but that
+part which was covered by the two shells BB, though it seem’d to grow
+thicker underneath: And indeed, if we consider the great variety Nature
+uses in proportioning the three parts of the body, (the _Head_, _Thorax_,
+and _Belly_) we shall not wonder at the small proportion of this _Thorax_,
+nor at the vaster bulk of the belly, for could we exactly anatomise this
+little Creature, and observe the particular designs of each part, we should
+doubtless, as we do in all her more manageable and tractable fabricks, find
+much more reason to admire the excellency of her contrivance and
+workmanship, then to wonder, it was not made otherwise.
+
+The head of this little Insect was shap’d somewhat like a Mite’s, that is,
+it had a long snout, in the manner of a Hogs, with a knobbed ridge running
+along the middle of it, which was bestuck on either side with many small
+brisles, all pointing forward, and two very large pikes or horns, which
+rose from the top of the head, just over each eye, and pointed forward
+also. It had two pretty large black eyes on either side of the head EE,
+from one of which I could see a very bright reflection of the window, which
+made me ghess, that the _Cornea_ of it was smooth, like those of bigger
+Insects. Its motion was pretty quick and strong, it being able very easily
+to tumble a stone or clod four times as big as its whole body.
+
+At the same time and place, and divers times since, I have observed with my
+_Microscope_, another little Insect, which, though I have not annexed the
+picture of, may be worth noting, for its exceeding nimbleness as well as
+smalness; it was as small as a Mite, with a body deep and ridged, almost
+like a Flea; it had eight blood-red legs, not very long, but slender; and
+two horns or feelers before. Its motion was so exceeding quick, that I have
+often lost sight of one I have observed with my naked eye; and though, when
+it was not frighted, I was able to follow the motions of some with my
+_Microscope_; yet if it were never so little startled, it posted away with
+such speed, and turn’d and winded it self so quick, that I should presently
+lose sight of it.
+
+When I first observ’d the former of these Insects, or Mites, I began to
+conjecture, that certainly I had found out the vagabond Parents of those
+Mites we find in Cheeses, Meal, Corn, Seeds, musty Barrels, musty Leather,
+&c. these little Creatures, wandring to and fro every whither, might
+perhaps, as they were invited hither and thither by the musty steams of
+several putrifying bodies, make their invasions upon those new and pleasing
+territories, and there spending the remainder of their life, which might be
+perhaps a day, or thereabouts, in very plentiful and riotous living, might
+leave their offspring behind them, which by the change of the soil and
+Country they now inhabite, might be quite alter’d from the hew of their
+_primogenitors_, and, like _Mores_ translated into Northern _European_
+Climates, after a little time, change both their skin and shape. And this
+seems yet more probable in these Insects, because that the soil or body
+they inhabit, seems to be almost half their parent, for it not only hatches
+and brings those little eggs, or seminal principles, to perfection, but
+seems to augment and nourish them also before they are hatch’d or shaped;
+for it is obvious enough to be observ’d, that the eggs of many other
+Insects, and particularly of Mites, are increas’d in bulk after they are
+laid out of the bodies of the Insects, and plump’d sometimes into many
+times their former bigness, so that the bodies they are laid in being, as
+it were, half their mothers, we shall not wonder that it should have such
+an active power to change their forms. We find by relations how much the
+_Negro_ Women do besmeer the of-spring of the _Spaniard_, bringing forth
+neither white-skinn’d nor black, but tawny hided _Mulattos_.
+
+Now, though I propound this as probable, I have not yet been so farr
+certify’d by Observations as to conclude any thing, either positively or
+negatively, concerning it. Perhaps, some more lucky diligence may please
+the curious Inquirer with the discovery of this, to be a truth, which I now
+conjecture, and may thereby give him a satisfactory account of the cause of
+those creatures, whose original seems yet so obscure, and may give him
+cause to believe, that many other animate beings, that seem also to be the
+mere product of putrifaction, may be innobled with a Pedigree as antient as
+the first creation, and farr exceed the greatest beings in their numerous
+Genealogies. But on the other side, if it should be found that these, or
+any other animate body, have no immediate similar Parent, I have in another
+place set down a conjectural _Hypothesis_ whereby those _Phænomena_ may
+likely enough be solv’d, wherein the infinite wisdom and providence of the
+Creator is no less rare and wonderfull.
+
+       *       *       *       *       *
+
+
+Observ. LI. _Of the _Crab-like_ Insect._
+
+Reading one day in _Septemb._ I chanced to observe a very smal creature
+creep over the Book I was reading, very slowly; having a _Microscope_ by
+me, I observ’d it to be a creature of a very unusual form, and that not
+less notable; such as is describ’d in the second _Figure_ of the 33.
+_Scheme_. It was about the bigness of a large Mite, or somewhat longer, it
+had ten legs, eight of which, AAAA, were topt with very sharp claws, and
+were those upon which he walk’d, seeming shap’d much like those of a Crab,
+which in many other things also this little creature resembled; for the two
+other claws, BB, which were the formost of all the ten, and seem’d to grow
+out of his head, like the horns of other Animals, were exactly form’d in
+the manner of Crabs or Lobsters claws, for they were shap’d and jointed
+much like those represented in the _Scheme_ and the ends of them were
+furnish’d with a pair of claws or pincers, CC, which this little animal did
+open and shut at pleasure: It seem’d to make use of those two horns or
+claws both for feelers and holders; for in its motion it carried these
+aloft extended before, moving them to and fro, just as a man blindfolded
+would do his hands when he is fearfull of running against a wall, and if I
+put a hair to it, it would readily take hold of it with these claws, and
+seem to hold it fast. Now, though these horns seem’d to serve him for two
+uses, namely, for feeling and holding; yet he seem’d neither blind, having
+two small black spots, DD, which by the make of them, and the bright
+reflection from them seem’d to be his eyes, nor did it want other hands,
+having another pair of claws, EE, very neer plac’d to its mouth, and seem’d
+adjoining to it.
+
+The whole body was cased over with armour-shells, as is usuall in all those
+kinds of _crustaceous_ creatures, especially about their bellies, and
+seem’d of three kinds, the head F seem’d cover’d with a kind of scaly
+shell, the _thorax_ with two smooth shells, or Rings, GG, and the belly
+with eight knobb’d ones. I could not certainly find whether it had under
+these last shells any wings, but I suspect the contrary; for I have not
+found any wing’d Insect with eight leggs, two of those leggs being always
+converted into wings, and, for the most part, those that have but six, have
+wings.
+
+This creature, though I could never meet with more then one of them, and so
+could not make so many examinations of it as otherwise I would, I did
+notwithstanding, by reason of the great curiosity that appear’d to me in
+its shape, delineate it, to shew that, in all likelihood, Nature had
+crouded together into this very minute Insect, as many, and as excellent
+contrivances, as into the body of a very large Crab, which exceeds it in
+bulk, perhaps, some Millions of times; for as to all the apparent parts,
+there is a greater rather then a less multiplicity of parts, each legg has
+as many parts, and as many joints as a Crabs, nay, and as many hairs or
+brisles; and the like may be in all the other visible parts; and ’tis very
+likely, that the internal curiosities are not less excellent: It being a
+general rule in Nature’s proceedings, that where she begins to display any
+excellency, if the subject be further search’d into, it will manifest, that
+there is not less curiosity in those parts which our single eye cannot
+reach, then in those which are more obvious.
+
+       *       *       *       *       *
+
+
+Observ. LII. _Of the small Silver-colour’d _Book-worm_._
+
+As among greater Animals there are many that are scaled, both for ornament
+and defence, so are there not wanting such also among the lesser bodies of
+Insects, whereof this little creature gives us an Instance. It is a small
+white Silver-shining Worm or Moth, which I found much conversant among
+Books and Papers, and is suppos’d to be that which corrodes and eats holes
+through the leaves and covers; it appears to the naked eye, a small
+glittering Pearl-colour’d Moth, which upon the removing of Books and Papers
+in the Summer, is often observ’d very nimbly to scud, and pack away to some
+lurking cranney, where it may the better protect itself from any appearing
+dangers. Its head appears bigg and blunt, and its body tapers from it
+towards the tail, smaller and smaller, being shap’d almost like a Carret.
+
+This the _Microscopical_ appearance will more plainly manifest, which
+exhibits, in the third _Figure_ of the 33. _Scheme_, a conical body,
+divided into fourteen several partitions, being the appearance of so many
+several shels, or shields that cover the whole body, every of these shells
+are again cover’d or tiled over with a multitude of thin transparent
+scales, which, from the multiplicity of their reflecting surfaces, make the
+whole Animal appear of a perfect Pearl-colour.
+
+Which, by the way, may hint us the reason of that so much admired
+appearance of those so highly esteem’d bodies, as also of the like in
+mother of Pearl shells, and in multitudes of other shelly Sea-substances;
+for they each of them consisting of an infinite number of very thin shells
+or laminated orbiculations, cause such multitudes of reflections, that the
+compositions of them together with the reflections of others that are so
+thin as to afford colours (of which I elsewhere give the reason) gives a
+very pleasant reflection of light. And that this is the true cause, seems
+likely, first, because all those so appearing bodies are compounded of
+multitudes of plated substances. And next that, by ordering any trasparent
+substance after this manner, the like _Phænomena_ may be produc’d; this
+will be made very obvious by the blowing of Glass into exceeding thin
+shells, and then breaking them into scales, which any lamp-worker will
+presently do; for a good quantity of these scales, laid in a heap together,
+have much the same resemblance of Pearls. Another way, not less instructive
+and pleasant, is a way which I have several times done, which is by working
+and tossing, as ’twere, a parcel of pure crystalline glass whilst it is
+kept glowing hot in the blown flame of a Lamp, for, by that means, that
+purely transparent body will be so divided into an infinite number of
+plates, or small strings, with interpos’d aerial plates and _fibres_, that
+from the multiplicity of the reflections from each of those internal
+surfaces, it may be drawn out into curious Pearl-like or Silver wire, which
+though small, will yet be opacous; the same thing I have done with a
+composition of red _Colophon_ and _Turpentine_, and a little Bee’s Wax, and
+may be done likewise with Birdlime, and such like glutinous and transparent
+bodies: But to return to our description.
+
+The small blunt head of this Insect was furnish’d on either side of it with
+a cluster of eyes, each of which seem’d to contain but a very few, in
+comparison of what I had observ’d the clusters of other Insects to abound
+with; each of these clusters were beset with a row of small brisles, much
+like the _cilia_ or hairs on the eye-lids, and, perhaps, they serv’d for
+the same purpose. It had two long horns before, which were streight, and
+tapering towards the top, curiously ring’d or knobb’d, and brisled much
+like the Marsh Weed, call’d Horse-tail, or Cats-tail, having at each knot a
+fring’d Girdle, as I may so call it, of smaller hairs, and several bigger
+and larger brisles, here and there dispers’d among them: besides these, it
+had two shorter horns, or feelers, which were knotted and fring’d, just as
+the former, but wanted brisles, and were blunt at the ends; the hinder part
+of the creature was terminated with three tails, in every particular
+resembling the two longer horns that grew out of the head: The leggs of it
+were scal’d and hair’d much like the rest, but are not express’d in this
+_Figure_, the Moth being intangled all in Glew, and so the leggs of this
+appear’d not through the Glass which looked perpendicularly upon the back.
+
+This Animal probably feeds upon the Paper and covers of Books, and
+perforates in them several small round holes, finding, perhaps, a
+convenient nourishment in those husks of Hemp and Flax, which have pass’d
+through so many scourings, washings, dressings and dryings, as the parts of
+old Paper must necessarily have suffer’d; the digestive faculty, it seems,
+of these little creatures being able yet further to work upon those
+stubborn parts, and reduce them into another form.
+
+And indeed, when I consider what a heap of Saw-dust or chips this little
+creature (which is one of the teeth of Time) conveys into its intrals, I
+cannot chuse but remember and admire the excellent contrivance of Nature,
+in placing in Animals such a fire, as is continually nourished and supply’d
+by the materials convey’d into the stomach, and _fomented_ by the bellows
+of the lungs; and in so contriving the most admirable fabrick of Animals,
+as to make the very spending and wasting of that fire, to be instrumental
+to the procuring and collecting more materials to augment and cherish it
+self, which indeed seems to be the principal end of all the contrivances
+observable in bruit Animals.
+
+       *       *       *       *       *
+
+
+Observ. LIII. _Of a _Flea_._
+
+The strength and beauty of this small creature, had it no other relation at
+all to man, would deserve a description.
+
+For its strength, the _Microscope_ is able to make no greater discoveries
+of it then the naked eye, but onely the curious contrivance of its leggs
+and joints, for the exerting that strength, is very plainly manifested,
+such as no other creature, I have yet observ’d, has any thing like it; for
+the joints of it are so adapted, that he can, as ’twere, fold them short
+one within another, and suddenly stretch, or spring them out to their whole
+length, that is, of the fore-leggs, the part A, of the 34. _Scheme_, lies
+within B, and B within C, parallel to, or side by side each other; but the
+parts of the two next, lie quite contrary, that is, D without E, and E
+without F, but parallel also; but the parts of the hinder leggs, G, H and
+I, bend one within another, like the parts of a double jointed Ruler, or
+like the foot, legg and thigh of a man; these six leggs he clitches up
+altogether, and when he leaps, springs them all out, and thereby exerts his
+whole strength at once.
+
+But, as for the beauty of it, the _Microscope_ manifests it to be all over
+adorn’d with a curiously polish’d suit of _sable_ Armour, neatly jointed,
+and beset with multitudes of sharp pinns, shap’d almost like Porcupine’s
+Quills, or bright conical Steel-bodkins; the head is on either side
+beautify’d with a quick and round black eye K, behind each of which also
+appears a small cavity, L, in which he seems to move to and fro a certain
+thin film beset with many small transparent hairs, which probably may be
+his ears; in the forepart of his head, between the two fore-leggs, he has
+two small long jointed feelers, or rather smellers, MM, which have four
+joints, and are hairy, like those of several other creatures; between
+these, it has a small _proboscis_, or _probe_, NNO, that seems to consist
+of a tube NN, and a tongue or sucker O, which I have perceiv’d him to slip
+in and out. Besides these, it has also two chaps or biters PP, which are
+somewhat like those of an Ant, but I could not perceive them tooth’d; these
+were shap’d very like the blades of a pair of round top’d Scizers, and were
+opened and shut just after the same manner; with these Instruments does
+this little busie Creature bite and pierce the skin, and suck out the blood
+of an Animal, leaving the skin inflamed with a small round red spot. These
+parts are very difficult to be discovered, because, for the most part, they
+lye covered between the fore-legs. There are many other particulars, which,
+being more obvious, and affording no great matter of information, I shall
+pass by, and refer the Reader to the Figure.
+
+       *       *       *       *       *
+
+
+Observ. LIV. _Of a Louse._
+
+This is a Creature so officious, that ’twill be known to every one at one
+time or other, so busie, and so impudent, that it will be intruding it self
+in every ones company, and so proud and aspiring withall, that it fears not
+to trample on the best, and affects nothing so much as a Crown; feeds and
+lives very high, and that makes it so saucy, as to pull any one by the ears
+that comes in its way, and will never be quiet till it has drawn blood: it
+is troubled at nothing so much as at a man that scratches his head, as
+knowing that man is plotting and contriving some mischief against it, and
+that makes it oftentime sculk into some meaner and lower place, and run
+behind a mans back, though it go very much against the hair; which ill
+conditions of it having made it better known then trusted, would exempt me
+from making any further description of it, did not my faithful _Mercury_,
+my _Microscope_, bring me other information of it. For this has discovered
+to me, by means of a very bright light cast on it, that it is a Creature of
+a very odd shape; it has a head shap’d like that exprest in 35. _Scheme_
+marked with A, which seems almost Conical, but is a little flatted on the
+upper and under sides, at the biggest part of which, on either side behind
+the head (as it were, being the place where other Creatures ears stand) are
+placed its two black shining goggle eyes BB, looking backwards, and fenced
+round with several small _cilia_, or hairs that incompass it, so that it
+seems this Creature has no very good foresight: It does not seem to have
+any eye-lids, and therefore perhaps its eyes were so placed, that it might
+the better cleanse them with its fore-legs; and perhaps this may be the
+reason, why they so much avoid and run from the light behind them, for
+being made to live in the shady and dark recesses of the hair, and thence
+probably their eye having a great aperture, the open and clear light,
+especially that of the Sun, must needs very much offend them; to secure
+these eyes from receiving any injury from the hairs through which it
+passes, it has two horns that grow before it, in the place where one would
+have thought the eyes should be; each of these CC hath four joynts, which
+are fringed, as ’twere, with small brisles, from which to the tip of its
+snout D, the head seems very round and tapering, ending in a very sharp
+nose D, which seems to have a small hole, and to be the passage through
+which he sucks the blood. Now whereas if it be plac’d on its back, with its
+belly upwards, as it is in the 35. _Scheme_, it seems in several Positions
+to have a resemblance of chaps, or jaws, as is represented in the Figure by
+EE, yet in other postures those dark strokes disappear; and having kept
+several of them in a box for two or three dayes, so that for all that time
+they had nothing to feed on, I found, upon letting one creep on my hand,
+that it immediately fell to sucking, and did neither seem to thrust its
+nose very deep into the skin, nor to open any kind of mouth, but I could
+plainly perceive a small current of blood, which came directly from its
+snout, and past into its belly; and about A there seem’d a contrivance,
+somewhat resembling a Pump, pair of Bellows, or Heart, for by a very swift
+_systole_ and _diastole_ the blood seem’d drawn from the nose, and forced
+into the body. It did not seem at all, though I viewed it a good while as
+it was sucking, to thrust more of its nose into the skin then the very
+snout D, nor did it cause the least discernable pain, and yet the blood
+seem’d to run through its head very quick and freely, so that it seems
+there is no part of the skin but the blood is dispers’d into, nay, even
+into the _cuticula_; for had it thrust its whole nose in from D to CC, it
+would not have amounted to the supposed thickness of that _tegument_, the
+length of the nose being not more then a three hundredth part of an inch.
+It has six legs, covered with a very transparent shell, and joynted exactly
+like a Crab’s, or Lobster’s; each leg is divided into six parts by these
+joynts, and those have here and there several small hairs; and at the end
+of each leg it has two claws, very properly adapted for its peculiar use,
+being thereby inabled to walk very securely both on the skin and hair; and
+indeed this contrivance of the feet is very curious, and could not be made
+more commodiously and compendiously, for performing both these requisite
+motions, of walking and climbing up the hair of a mans head, then it is:
+for, by having the lesser claw (a) set so much short of the bigger (b) when
+it walks on the skin the shorter touches not, and then the feet are the
+same with those of a Mite, and several other small Insects, but by means of
+the small joynts of the longer claw it can bend it round, and so with both
+claws take hold of a hair, in the manner represented in the Figure, the
+long transparent Cylinder FFF, being a Man’s hair held by it.
+
+The _Thorax_ seem’d cas’d with another kind of substance then the belly,
+namely, with a thin transparent horny substance, which upon the fasting of
+the Creature did not grow flaccid; through this I could plainly see the
+blood, suck’d from my hand, to be variously distributed, and mov’d to and
+fro; and about G there seem’d a pretty big white substance, which seem’d to
+be moved within its _thorax_; besides, there appear’d very many small
+milk-white vessels, which crost over the breast between the legs, out of
+which, on either side, were many small branchings, these seem’d to be the
+veins and arteries, for that which is analogus to blood in all Insects is
+milk-white.
+
+The belly is covered with a transparent substance likewise, but more
+resembling a skin then a shell, for ’tis grain’d all over the belly just
+like the skin in the palms of a man’s hand, and when the belly is empty,
+grows very flaccid and wrinkled; at the upper end of this is placed the
+stomach HH, and perhaps also the white spot II may be the liver or
+_pancreas_, which, by the _peristalick_ motion of the guts, is a little
+mov’d to and fro, not with a _systole_ and _diastole_, but rather with a
+thronging or justling motion. Viewing one of these Creatures, after it had
+fasted two dayes, all the hinder part was lank and flaccid, and the white
+spot II hardly mov’d, most of the white branchings disappear’d, and most
+also of the redness or sucked blood in the guts, the _peristaltick_ motion
+of which was scarce discernable; but upon the suffering it to suck, it
+presently fill’d the skin of the belly, and of the six scolop’d embosments
+on either side, as full as it could be stuft, the stomach and guts were as
+full as they could hold; the _peristaltick_ motion of the gut grew quick,
+and the justling motion of II accordingly; multitudes of milk-white vessels
+seem’d quickly filled, and turgid, which were perhaps the veins and
+arteries and the Creature was so greedy, that though it could not contain
+more, yet it continued sucking as fast as ever, and as fast emptying it
+self behind: the digestion of this Creature must needs be very quick, for
+though I perceiv’d the blood thicker and blacker when suck’d, yet, when in
+the guts, it was of a very lovely ruby colour, and that part of it, which
+was digested into the veins, seemed white; whence it appears, that a
+further digestion of blood may make it milk, at least of a resembling
+colour: What is else observable in the figure of this Creature, may be seen
+by the 35. _Scheme_.
+
+       *       *       *       *       *
+
+
+Observ. LV. _Of _Mites_._
+
+The least of _Reptiles_ I have hitherto met with, is a Mite, a Creature
+whereof there are some so very small, that the sharpest sight, unassisted
+with Glasses, is not able to discern them, though, being white of
+themselves, they move on a black and smooth surface; and the Eggs, out of
+which these Creatures seem to be hatch’d, are yet smaller, those being
+usually not above a four or five hundredth part of a well grown Mite, and
+those well grown Mites not much above one hundredth of an inch in
+thickness; so that according to this reckoning there may be no less then a
+million of well grown Mites contain’d in a cubick inch, and five hundred
+times as many Eggs.
+
+Notwithstanding which minuteness a good _Microscope_ discovers those small
+movable specks to be very prettily shap’d Insects, each of them furnished
+with eight well shap’d and proportion’d legs, which are each of them
+joynted or bendable in eight several places, or joynts, each of which is
+covered, for the most part, with a very transparent shell, and the lower
+end of the shell of each joynt is fringed with several small hairs; the
+contrivance of the joynts seems the very same with that of Crabs and
+Lobsters legs, and like those also, they are each of them terminated with a
+very sharp claw or point; four of these legs are so placed, that they seem
+to draw forwards, the other four are placed in a quite contrary position,
+thereby to keep the body backwards when there is occasion.
+
+[15]The body, as in other larger Insects, consists of three regions or
+parts; the hinder or belly A, seems covered with one intire shell, the
+middle, or chest, seems divided into two shells BC. which running one
+within the other, the Mite is able to shrink in and thrust out as it finds
+occasion, as it can also the snout D. The whole body is pretty transparent,
+so that being look’d on against the light, divers motions within its body
+may be perceived; as also all the parts are much more plainly delineable,
+then in other postures, to the light. The shell, especially that which
+covers the back, is curiously polisht, so that ’tis easie to see, as in a
+_convex_ Looking-glass, or _foliated_ Glass-ball, the picture of all the
+objects round about; up and down, in several parts of its body, it has
+several small long white hairs growing out of its shell, which are often
+longer then the whole body, and are represented too short in the first and
+second Figures; they seem all pretty straight and pliable, save only two
+upon the forepart of its body, which seem to be the horns, as may be seen
+in the Figures; the first whereof is a prospect of a smaller sort of Mites
+(which are usually more plump) as it was _passant_ to and fro; the second
+is the prospect of one fixt on its tail (by means of a little mouth-glew
+rub’d on the object plate) exhibiting the manner of the growing of the
+legs, together with their several joynts.
+
+This Creature is very much diversify’d in shape, colour, and divers other
+properties, according to the nature of the substance out of which it seems
+to be ingendred and nourished, being in one substance more long, in another
+more round, in some more hairy, in others more smooth, in this nimble, in
+that slow, here pale and whiter, there browner, blacker, more transparent,
+&c. I have observed it to be resident almost on all kinds of substances
+that are mouldy, or putrifying, and have seen it very nimbly meshing
+through the thickets of mould, and sometimes to lye _dormant_ underneath
+them; and ’tis not unlikely, but that it may feed on that vegetating
+substance, _spontaneous Vegetables_ seeming a food proper enough for
+_spontaneous Animals_,
+
+But whether indeed this Creature, or any other, be such or not, I cannot
+positively, from any Experiment, or Observation, I have yet made,
+determine. But, as I formerly hinted, it seems probable, that some kind of
+wandring Mite may sow, as ’twere, the first seeds, or lay the first eggs,
+in those places, which Nature has instructed them to know convenient for
+the hatching and nourishing their young; and though perhaps the prime
+Parent might be of a shape very differing from what the offspring, after a
+little while, by reason of the substance they feed on, or the Region (as
+’twere) they inhabite; yet perhaps even one of these alter’d progeny,
+wandering again from its native soil, and lighting on by chance the same
+place from whence its prime Parent came, and there settling, and planting,
+may produce a generation of Mites of the same shapes and properties with
+the first wandring Mite: And from some such accidents as these, I am very
+apt to think, the most sorts of Animals, generally accounted _spontaneous_,
+have their _origination_, and all those various sorts of Mites, that are to
+be met with up and down in divers putrifying substances, may perhaps be all
+of the same kind, and have sprung from one and the same sort of Mites at
+the first.
+
+       *       *       *       *       *
+
+
+Observ. LVI. _Of a small Creature hatch’d on a Vine._
+
+There is, almost all the Spring and Summer time, a certain small, round,
+white Cobweb, as ’twere, about the bigness of a Pea, which sticks very
+close and fast to the stocks of Vines nayl’d against a warm wall: being
+attentively viewed, they seem cover’d, upon the upper side of them, with a
+small husk, not unlike the scale, or shell of a Wood-louse, or Hog-louse, a
+small Insect usually found about rotten wood, which upon touching presently
+rouls it self into the form of a peppercorn: Separating several of these
+from the stock, I found them, with my _Microscope_, to consist of a shell,
+which now seemed more likely to be the husk of one of these Insects: And
+the fur seem’d a kind of cobweb, consisting of abundance of small
+filaments, or sleaves of cobwebs. In the midst of this, if they were not
+hatch’d, and run away before, the time of which hatching was usually about
+the latter end of _June_, or beginning of _July_, I have often found
+abundance of small brown Eggs, such as A and B in the second Figure of the
+36. _Scheme_, much about the bigness of Mites Eggs; and at other times,
+multitudes of small Insects, shaped exactly like that in the third Figure
+marked with X. Its head large, almost half the bigness of its body, which
+is usual in the _fœtus_ of most Creatures. It had two small black eyes
+_aa_, and two small long joynted and brisled horns _bb_. The hinder part of
+its body seem’d to consist of nine scales, and the last ended in a forked
+tayl, much like that of a _Cutio_, or Wood-louse, out of which grew two
+long hairs; they ran to and fro very swiftly, and were much of the bigness
+of a common Mite, but some of them less: The longest of them seem’d not the
+hundredth part of an inch, and the Eggs usually not above half as much.
+They seemed to have six legs, which were not visible in this I have here
+delineated, by reason they were drawn under its body.
+
+If these Minute creatures were _Wood-lice_ (as indeed from their own shape
+and from the frame, the skin, or shell, that grows on them, one may with
+great probability ghess) it affords us an Instance, whereof perhaps there
+are not many like in Nature, and that is, of the prodigious increase of
+these Creatures, after they are hatch’d and run about; for a common
+Wood-louse, of about half an inch long, is no less then a hundred and
+twenty five thousand times bigger then one of these, which though indeed it
+seems very strange, yet I have observed the young ones of some Spiders have
+almost kept the same proportion to their Dam.
+
+This, methinks, if it be so, does in the next place hint a Quæry, which may
+perhaps deserve a little further examination: And that is, Whether there be
+not many of those minute Creatures, such as Mites, and the like, which,
+though they are commonly thought of otherwise, are only the _pully_, or
+young ones, of much bigger Insects, and not the generating, or parent
+_Insect_, that has layd those Eggs; for having many times observ’d those
+Eggs, which usually are found in great abundance where Mites are found, it
+seems something strange, that so small an Animal should have an Egg so big
+in proportion to its body. Though on the other side, I must confess, that
+having kept divers of those Mites inclosed in a box for a good while, I did
+not find them very much augmented beyond their usual bigness.
+
+What the husk and cobweb of this little white substance should be, I cannot
+imagine, unless it be, that the old one, when impregnated with Eggs, should
+there stay, and fix it self on the Vine, and dye, and all the body by
+degrees should rot, save only the husk, and the Eggs in the body: And the
+heat, or fire, as it were, of the approaching Sun-beams should vivifie
+those Relicts of the corrupted Parent, and out of the ashes, as ’twere, (as
+it is fabled of the _Phœnix_) should raise a new _offspring_ for the
+perpetuation of the _Species_. Nor will the cobweb, as it were, in which
+these Eggs are inclos’d, make much against this Conjecture; for we may, by
+those cobwebs that are carried up and down the Air after a Fog (which with
+my _Microscope_ I have discovered to be made up of an infinite company of
+small filaments or threads) learn, that such a texture of body may be
+otherwise made then by the spinning of a Worm.
+
+       *       *       *       *       *
+
+
+Observ. LVII. _Of the _Eels_ in Vinegar._
+
+Of these small Eels, which are to be found in divers sorts of Vinegar, I
+have little to add besides their Picture, which you may find drawn in the
+third Figure of the 25. _Scheme_: That is, they were shaped much like an
+Eel, save only that their nose A, (which was a little more opacous then the
+rest of their body) was a little sharper, and longer, in proportion to
+their body, and the wrigling motion of their body seem’d to be onely
+upwards and downwards, whereas that of Eels is onely side-wayes: They
+seem’d to have a more opacous part about B, which might, perhaps, be their
+Gills; it seeming always the same proportionate distant from their nose,
+from which, to the tip of their tail, C, their body seem’d to taper.
+
+Taking several of these out of their Pond of Vinegar, by the net of a small
+piece of filtring Paper, and laying them on a black smooth Glass plate, I
+found that they could wriggle and winde their body, as much almost as a
+Snake, which made me doubt, whether they were a kind of Eal or Leech.
+
+I shall add no other observations made on this minute Animal, being
+prevented herein by many excellent ones already publish’d by the ingenious,
+Doctor _Power_, among his _Microscopical_ Observations, save onely that a
+quantity of Vinegar repleat with them being included in a small Viol, and
+stop’d very close from the ambient air, all the included Worms in a very
+short time died, as if they had been stifled.
+
+And that their motion seems (contrary to what we may observe in the motion
+of all other Infects) exceeding slow. But the reason of it seems plain, for
+being to move to and fro after that manner which they do, by waving onely,
+or wrigling their body; the tenacity, or glutinousness, and the density or
+resistance of the fluid _medium_ becomes so exceeding sensible to their
+extremely minute bodies, that it is to me indeed a greater wonder that they
+move them so fast as they do, then that they move them no faster. For what
+a vastly greater proportion have they of their superficies to their bulk,
+then Eels or other larger Fishes, and next, the tenacity and density of the
+liquor being much the same to be moved, both by the one and the other, the
+resistance or impediment thence arising to the motions made through it,
+must be almost infinitely greater to the small one then to the great. This
+we find experimentally verify’d in the Air, which though a _medium_ a
+thousand times more rarify’d then the water, the resistance of it to
+motions made through it, is yet so sensible to very minute bodies, that a
+Down-feather (the least of whose parts seem yet bigger then these Eels, and
+many of them almost incomparably bigger, such as the quill and stalk) is
+suspended by it, and carried to and fro as if it had no weight.
+
+       *       *       *       *       *
+
+
+Observ. LVIII. _Of a new Property in the _Air_, and several other
+transparent _Mediums_ nam’d _Inflection_, whereby very many considerable
+_Phænomena_ are attempted to be solv’d, and divers other uses are hinted._
+
+Since the Invention (and perfecting in some measure) of _Telescopes_, it
+has been observ’d by several, that the Sun and Moon neer the Horizon, are
+disfigur’d (losing that exactly-smooth terminating circular limb, which
+they are observ’d to have when situated neerer the Zenith) and are bounded
+with an edge every way (especially upon the right and left sides) ragged
+and indented like a Saw: which inequality of their limbs, I have further
+observ’d, not to remain always the same, but to be continually chang’d by a
+kind of fluctuating motion, not unlike that of the waves of the Sea, so as
+that part of the limb, which was but even now nick’d or indented in, is now
+protuberant, and will presently be sinking again; neither is this all but
+the whole body of the Luminaries, do in the _Telescope_, seem to be
+depress’d and flatted, the upper, and more especially the under side
+appearing neerer to the middle then really they are, and the right and left
+appearing more remote: whence the whole _Area_ seems to be terminated by a
+kind of Oval. It is further observ’d, that the body, for the most part,
+appears red, or of some colour approaching neer unto it, as some kind of
+yellow; and this I have always mark’d, that the more the limb is flatted or
+ovalled, the more red does the body appear, though not always the contrary.
+It is further observable, that both fix’d Stars and Planets, the neerer
+they appear to the Horizon, the more red and dull they look, and the more
+they are observ’d to twinkle; in so much, that I have seen the Dog-starr to
+vibrate so strong and bright a radiation of light, as almost to dazle my
+eyes, and presently, almost to disappear. It is also observable, that those
+bright scintillations neer the Horizon, are not by much so quick and sudden
+in their consecutions of one another, as the nimbler twinklings of Stars
+neerer the Zenith. This is also notable, that the Starrs neer the Horizon,
+are twinkled with several colours; so as sometimes to appear red, sometimes
+more yellow, and sometimes blue, and this when the Starr is a pretty way
+elevated above the Horizon. I have further, very often seen some of the
+small Starrs of the fifth or sixth magnitude, at certain times to disappear
+for a small moment of time, and again appear more conspicuous, and with a
+greater luster. I have several times, with my naked eye, seen many smaller
+Starrs, such as may be call’d of the seventh or eighth magnitude to appear
+for a short space, and then vanish, which, by directing a small _Telescope_
+towards that part they appear’d and disappear’d in; I could presently find
+to be indeed small Starrs so situate, as I had seen them with my naked eye,
+and to appear twinkling like the ordinary visible Stars; nay, in examining
+some very notable parts of the Heaven, with a three foot Tube, me thought I
+now and then, in several parts of the constellation, could perceive little
+twinklings of Starrs, making a very short kind of apparition, and presently
+vanishing, but noting diligently the places where they thus seem’d to play
+at boe-peep, I made use of a very good twelve foot Tube, and with that it
+was not uneasie to see those, and several other degrees of smaller Starrs,
+and some smaller yet, that seem’d again to appear and disappear, and these
+also by giving the same Object-glass a much bigger aperture, I could
+plainly and constantly see appear in their former places; so that I have
+observ’d some twelve several magnitudes of Starrs less then those of the
+six magnitudes commonly recounted in the Globes.
+
+It has been observ’d and confirm’d by the accuratest Observations of the
+best of our modern Astronomers, that all the Luminous bodies appear above
+the Horizon, when they really are below it. So that the Sun and Moon have
+both been seen above the Horizon, whil’st the Moon has been in an Eclipse.
+I shall not here instance in the great refractions, that the tops of high
+mountains, seen at a distance, have been found to have; all which seem to
+argue the Horizontal refraction, much greater then it is hitherto generally
+believ’d.
+
+I have further taken notice, that not onely the Sun, Moon and Starrs, and
+high tops of mountains have suffer’d these kinds of refraction, but Trees,
+and several bright Objects on the ground: I have often taken notice of the
+twinkling of the reflections of the Sun from a Glass-window at a good
+distance, and of a Candle in the night, but that is not so conspicuous, and
+in observing the setting Sun, I have often taken notice of the tremulation
+of the Trees and Bushes, as well as of the edges of the Sun. Divers of
+these _Phænomena_ have been taken notice of by several, who have given
+several reasons of them, but I have not yet met with any altogether
+satisfactory, though some of their conjectures have been partly true, but
+partly also false. Setting my self therfore upon the inquiry of these
+_Phænomena_, I first endeavour’d to be very diligent in taking notice of
+the several particulars and circumstances observable in them; and next, in
+making divers particular Experiments, that might cleer some doubts, and
+serve to determine, confirm, and illustrate the true and adæquate cause of
+each; and upon the whole, I find much reason to think, that the true cause
+of all these _Phænomena_ is from the _inflection_, or _multiplicate
+refraction_ of those Rays of light within the body of the _Atmosphere_, and
+that it does not proceed from a _refraction_ caus’d by any terminating
+_superficies_ of the Air above, nor from any such exactly defin’d
+_superficies_ within the body of the _Atmosphere_.
+
+This Conclusion is grounded upon these two Propositions:
+
+First, that a _medium_, whose parts are unequally _dense_, and mov’d by
+various motions and transpositions as to one another, will produce all
+these visible effects upon the Rays of light, without any other
+_coefficient_ cause.
+
+Secondly, that there is in the Air or _Atmosphere_ such a variety in the
+constituent parts of it, both as to their _density_ and _rarity_, and as to
+their divers mutations and positions one to another.
+
+By _Density_ and _Rarity_, I understand a property of a transparent body,
+that does either more or less refract a Ray of light (coming obliquely upon
+its superficies out of a third _medium_) toward its perpendicular: As I
+call Glass a more dense body then Water, and Water a more rare body then
+Glass, because of the refractions (more or less deflecting towards the
+perpendicular) that are made in them, of a Ray of light out of the Air that
+has the same inclination upon either of their superficies.
+
+So as to the business of Refraction, spirit of Wine is a more _dense_ body
+then Water, it having been found by an accurate Instrument that measures
+the angles of Refractions to Minutes that for the same refracted angle of
+30°.00′. in both those _Mediums_, the angle of incidence in Water was but
+41°.35′. but the angle of the incidence in the trial with spirit of Wine
+was 42°.45′. But as to gravity, Water is a more _dense_ body then spirit of
+Wine, for the proportion of the same Water, to the same very well rectify’d
+spirit of Wine was, as 21. to 19.
+
+So as to Refraction, Water is more Dense then Ice; for I have found by a
+most certain Experiment, which I exhibited before divers illustrious
+Persons of the _Royal Society_, that the Refraction of Water was greater
+then that of Ice, though some considerable Authors have affirm’d the
+contrary, and though the Ice be a very hard, and the Water a very fluid
+body.
+
+That the former of the two preceding Propositions is true, may be
+manifested by several Experiments; As first, if you take any two liquors
+differing from one another in density, but yet such as will readily mix: as
+Salt Water, or Brine, & Fresh; almost any kind of Salt dissolv’d in Water,
+and filtrated, so that it be cleer, spirit of Wine and Water; nay, spirit
+of Wine, and spirit of Wine, one more highly rectify’d then the other, and
+very many other liquors; if (I say) you take any two of these liquors, and
+mixing them in a Glass Viol, against one side of which you have fix’d or
+glued a small round piece of Paper, and shaking them well together (so that
+the parts of them may be somewhat disturb’d and move up and down) you
+endeavour to see that round piece of Paper through the body of the liquors,
+you shall plainly perceive the Figure to wave, and to be indented much
+after the same manner as the limb of the Sun through a _Telescope_ seems to
+be, save onely that the mutations here, are much quicker. And if, in steed
+of this bigger Circle, you take a very small spot, and fasten and view it
+as the former, you will find it to appear much like the twinkling of the
+Starrs, though much quicker: which two _Phænomena_, (for I shall take
+notice of no more at present, though I could instance in multitudes of
+others) must necessarily be caus’d by an _inflection_ of the Rays within
+the terminating superficies of the compounded _medium_, since the surfaces
+of the transparent body through which the Rays pass to the eye, are not at
+all altered or chang’d.
+
+This _inflection_ (if I may so call it) I imagine to be nothing else, but a
+_multiplicate refraction_, caused by the unequal _density_ of the
+constituent parts of the _medium_, whereby the motion, action or progress
+of the Ray of light is hindred from proceeding in a streight line, and
+_inflected_ or _deflected_ by a _curve_. Now, that it is a _curve_ line is
+manifest by this Experiment: I took a Box, such as ADGE, in the first
+_Figure_ of the 37. _Scheme_, whose sides ABCD, and EFGH, were made of two
+smooth flat plates of Glass, then filling it half full with a very strong
+solution of Salt, I filled the other half with very fair fresh water, then
+exposing the opacous side, DHGC, to the Sun, I observ’d both the
+_refraction_ and _inflection_ of the Sun beams, ID & KH, and marking as
+exactly as I could, the points, P, N, O, M, by which the Ray, KH, passed
+through the compounded _medium_, I found them to be in a _curve_ line; for
+the parts of the _medium_ being continually more dense the neerer they were
+to the bottom, the Ray _pf_ was continually more and more deflected
+downwards from the streight line.
+
+This Inflection may be mechanically explained, either by Monsieur _Des
+Cartes_ principles by conceiving the Globuls of the third Element to find
+less and less resistance against that side of them which is downwards, or
+by a way, which I have further explicated in the Inquisition about Colours,
+to be from an obliquation of the pulse of light, whence the under part is
+continually promoted, and consequently refracted towards the perpendicular,
+which cuts the Orbs at right angles. What the particular Figure of the
+_Curve line_, describ’d by this way of light, is, I shall not now stand to
+examine, especially since there may be so many sorts of it as there may be
+varieties of the Positions of the _intermediate_ degrees of _density_ and
+_rarity_ between the bottom and the top of the inflecting Medium.
+
+I could produce many more Examples and Experiments, to illustrate and prove
+this first Proposition, _viz._ that there is such a constitution of some
+bodies as will cause inflection. As not to mention those I have observ’d in
+_Horn_, _Tortoise-Shell_, _transparent Gums_, and _resinous Substances_:
+The _veins_ of Glass, nay, of melted _Crystal_, found, and much complained
+of by Glass-grinders, and others, might sufficiently demonstrate the truth
+of it to any diligent Observator.
+
+But that, I presume, I have by this Example given proof sufficient (_viz.
+ocular demonstration_) to evince, that there is such a modulation, or
+bending of the rayes of light, as I have call’d _inflection_, differing
+both from _reflection_, and _refraction_ (since they are both made in the
+superficies, this only in the middle); and likewise, that this is able or
+sufficient to produce the effects I have ascribed to it.
+
+It remains therefore to shew, that there is such a property in the Air, and
+that it is sufficient to produce all the above mentioned _Phænomena_, and
+therefore may be the principal, if not the only cause of them.
+
+First, That there is such a property, may be proved from this, that the
+parts of the Air are some of them more condens’d, others more rarified,
+either by the differing heat, or differing pressure it sustains, or by the
+somewhat heterogeneous vapours interspers’d through it. For as the Air is
+more or less rarified, so does it more or less refract a ray of light (that
+comes out of a denser medium) from the perpendicular. This you may find
+true, if you make tryal of this Experiment.
+
+Take a small Glass-bubble, made in the form of that in the second Figure of
+the 37. _Scheme_, and by heating the Glass very hot, and thereby very much
+rarifying the included Air, or, which is better, by rarifying a small
+quantity of water, included in it, into vapours, which will expel the most
+part, if not all the Air, and then sealing up the small neck of it, and
+letting it cool, you may find, if you place it in a convenient Instrument,
+that there will be a manifest difference, as to the refraction.
+
+As if in this second Figure you suppose A to represent a small sight or
+hole, through which the eye looks upon an object, as C, through the
+Glass-bubble B, and the second sight L; all which remain exactly fixt in
+their several places, the object C being so cized and placed, that it may
+just seem to touch the upper and under edge of the hole L: and so all of it
+be seen through the small Glass-ball of rarified Air; then by breaking off
+the small seal’d neck of the Bubble (without at all stirring the sights,
+object, or glass) and admitting the external Air, you will find your self
+unable to see the utmost ends of the object; but the terminating rayes AE
+and AD (which were before refracted to G and F by the rarified Air) will
+proceed almost directly to I and H; which alteration of the rayes (seeing
+there is no other alteration made in the Organ by which the Experiment is
+tryed, save only the admission, or exclusion of the condens’d Air) must
+necessarily be caused by the variation of the _medium_ contain’d in the
+Glass B; the greatest difficulty in the making of which Experiment, is from
+the uneven surfaces of the bubble, which will represent an uneven image of
+the object.
+
+Now, that there is such a difference of the upper and under parts of the
+Air is clear enough evinc’d from the late improvement of the _Torricellian_
+Experiment, which has been tryed at the tops and feet of Mountains; and may
+be further illustrated, and inquired into, by a means, which some whiles
+since I thought of, and us’d, for the finding by what degrees the Air
+passes from such a degree of Density to such a degree of Rarity. And
+another, for the finding what pressure was requisite to make it pass from
+such a degree of Rarefaction to a determinate Density: Which Experiments,
+because they may be useful to illustrate the present Inquiry, I shall
+briefly describe.
+
+[16] I took then a small Glass-pipe AB, about the bigness of a Swans quill,
+and about four foot long, which was very equally drawn, so that, as far as
+I could perceive, no one part was bigger then another: This Tube (being
+open at both ends) I fitted into another small Tube DE, that had a small
+bore just big enough to contain the small Pipe, and this was seal’d up at
+one, and open at the other, end; about which open end I fastned a small
+wooden box C with cement, so that filling the bigger Tube, and part of the
+box, with Quicksilver, I could thrust the smaller Tube into it, till it
+were all covered with the Quicksilver: Having thus done, I fastned my
+bigger Tube against the side of a wall, that it might stand the steadier,
+and plunging the small Tube cleer under the _Mercury_ in the box, I stopt
+the upper end of it very fast with cement, then lifting up the small Tube,
+I drew it up by a small pully, and a string that I had fastned to the top
+of the Room, and found the height of the _Mercurial Cylinder_ to be about
+twenty nine inches.
+
+Then letting down the Tube again, I opened the top, and then thrust down
+the small Tube, till I perceived the Quicksilver to rise within it to a
+mark that I had plac’d just an inch from the top; and immediately clapping
+on a small piece of cement that I had kept warm, I with a hot Iron seal’d
+up the top very fast, then letting it cool (that both the cement might grow
+hard, and more especially, that the Air might come to its temper, natural
+for the Day I try’d the Experiment in) I observ’d diligently, and found the
+included Air to be exactly an Inch.
+
+Here you are to take notice, that after the Air is seal’d up, the top of
+the Tube is not to be elevated above the superficies of the Quicksilver in
+the box, till the surface of that within the Tube be equal to it, for the
+Quicksilver (as I have elsewhere prov’d) being more heterogeneous to the
+Glass then the Air, will not naturally rise up so high within the small
+Pipe, as the superficies of the _Mercury_ in the box, and therefore you are
+to observe, how much below the outward superficies of the _Mercury_ in the
+box, that of the same in the Tube does stand, when the top being open, free
+ingress is admitted to the outward Air.
+
+Having thus done, I permitted the _Cylinder_, or small Pipe, to rise out of
+the box, till I found the surface of the Quicksilver in the Pipe to be two
+inches above that in the box, and found the Air to have expanded it self
+but one sixteenth part of an inch; then drawing up the small pipe, till I
+found the height of the Quicksilver within to be four inches above that
+without, I observed the Air to be expanded only ⅐ of an inch more then it
+was at first, and to take up the room of 1⅐ inch: then I raised the Tube
+till the Cylinder was six inches high, and found the Air to take up 1²⁄₉
+inches of room in the Pipe; then to 8, 10, 12. &c. the expansion of the Air
+that I found to each of which Cylinders are set down in the following
+Table; where the first row signifies the height of the _Mercurial
+Cylinder_; the next, the expansion of the Air; the third, the pressure of
+the _Atmosphere_, or the highest _Cylinder_ of _Mercury_, which was then
+neer thirty inches: The last signifies the force of the Air so expanded,
+which is found by substracting the first row of numbers out of the third;
+for having found, that the outward Air would then keep up the Quicksilver
+to thirty inches, look whatever of that height is wanting must be
+attributed to the Elater of the Air depressing. And therefore having the
+Expansion in the second row, and the height of the subjacent _Cylinder_ of
+_Mercury_ in the first, and the greatest height of the _Cylinder_ of
+_Mercury_, which of it self counterballances the whole pressure of the
+_Atmosphere_; by substracting the numbers of the first row out of the
+numbers of the third, you will have the measure of the _Cylinders_ so
+deprest, and consequently the force of the Air, in the several Expansions,
+registred.
+
+  The height of the     The Expansion   The height of   The strength
+  Cylinder of Mercury,  of the Air.     the Mercury     of the Elater
+  that, together with                   that counter-   of the expanded
+  the Elater of the                     ballanc’d the   Air.
+  included Air,                         Atmosphere.
+  ballanced the
+  pressure of the
+  Atmosphere.
+   ----------            ----------      ----------      ----------
+      00                    01               30              30
+      02                    01¹⁄₁₆           30              28
+      04                    01⅐              30              26
+      06                    01²⁄₉            30              24
+      08                    01⅓              30              22
+      10                    01½              30              20
+      12                    01⅔              30              18
+      14                    01⅚              30              16
+      16                    02²⁄₂₇           30              14
+      18                    02⁴⁄₉            30              12
+      20                    03               30              10
+      22                    03⁷⁄₉            30               8
+      24                    05⁷⁄₁₈           30               6
+      25                    06⅔              30               5
+      26                    08½              30               4
+      26¼                   09½              30               3¾
+      26½                   10¾              30               3½
+      26¾                   13               30               3¼
+      27                    15½              30               3
+
+I had several other Tables of my Observations, and Calculations, which I
+then made; but it being above a twelve month since I made them; and by that
+means having forgot many circumstances and particulars, I was resolved to
+make them over once again, which I did _August_ the second 1661. with the
+very same Tube which I used the year before, when I first made the
+Experiment (for it being a very good one, I had carefully preserv’d it:)
+And after having tryed it over and over again; and being not well satisfied
+of some particulars, I, at last, having put all things in very good order,
+and being as attentive, and observant, as possibly I could, of every
+circumstance requisite to be taken notice of, did register my several
+Observations in this following Table. In the making of which, I did not
+exactly follow the method that I had used at first; but, having lately
+heard of Mr. _Townly_’s _Hypothesis_, I shap’d my course in such sort, as
+would be most convenient for the examination of that _Hypothesis_; the
+event of which you have in the latter part of the last Table.
+
+The other Experiment was, to find what degrees of force were requisite to
+compress, or condense, the Air into such or such a bulk.
+
+The manner of proceeding therein was this: I took a Tube about five foot
+long, one of whose ends was sealed up, and bended in the form of a
+_Syphon_, much like that represented in the fourth Figure of the 37.
+_Scheme_, one side whereof AD, that was open at A, was about fifty inches
+long, the other side BC, shut at B, was not much above seven inches long,
+then placing it exactly perpendicular, I pour’d in a little Quicksilver,
+and found that the Air BC was 6⅞ inches, or very near to seven; then
+pouring in Quicksilver at the longer Tube, I continued filling of it till
+the Air in the shorter part of it was contracted into half the former
+dimensions, and found the height exactly nine and twenty inches; and by
+making several other tryals, in several other degrees of condensation of
+the Air, I found them exactly answer the former _Hypothesis_.
+
+But having (by reason it was a good while since I first made) forgotten
+many particulars, and being much unsatisfied in others, I made the
+Experiment over again, and, from the several tryals, collected the former
+part of the following Table: Where in the row next the left hand 24.
+signifies the dimensions of the Air, sustaining only the pressure of the
+_Atmosphere_, which at that time was equal to a _Cylinder_ of _Mercury_ of
+nine and twenty inches: The next Figure above it (20) was the dimensions of
+the Air induring the first compression, made by a _Cylinder_ of _Mercury_
+5³⁄₁₆ high, to which the pressure of the _Atmosphere_ nine and twenty
+inches being added, the elastick strength of the Air so comprest will be
+found 34³⁄₁₆, &c.
+
+_A Table of the Elastick power of the Air, both Experimentally and
+Hypothetically calculated, according to its various Dimensions._
+
+
+  The dimensions   The height    The Mercurial  The sum or  What they
+  of the included  of the        Cylinder       difference  ought to
+  Air.             Mercurial     added, or      of these    be according
+                   Cylinder      taken from     two         to the
+                   counter-      the former.    Cylinders.  Hypothesis.
+                   pois’d
+                   by the
+                   Atmosphere.
+   ----------      ----------     ----------     ----------  ----------
+       12             29      +     29         =   58          58
+       13             29      +     24¹¹⁄₁₆    =   53¹¹⁄₁₆     53⁷⁄₁₃
+       14             29      +     20³⁄₁₆     =   49³⁄₁₆      49⁵⁄₇
+       16             29      +     14         =   43          43½
+       18             29      +      9⅛        =   38⅛         38⅔
+       20             29      +      5³⁄₁₆     =   34³⁄₁₆      34⅘
+       24             29             0         =   29          29
+       48             29      −     14⅝        =   14⅜         14½
+       96             29      −     22⅛        =    6⅞          7²⁄₈
+      192             29      −     25⅝        =    3⅜         3⅝
+      384             29      −     27²⁄₈      =    1⁶⁄₈       1⁷⁄₁₆
+      576             29      −     27⅞        =    1⅛         1⁵⁄₂₄
+      768             29      −     28⅛        =    0⅞         0[7¼]⁄₈
+      960             29      −     28⅜        =    0⅝         0[5⅘]⁄₈
+     1152             29      −     28⁷⁄₁₆     =    0⁹⁄₁₆      0¹⁰⁄₁₆
+
+From which Experiments, I think, we may safely conclude, that the Elater of
+the Air is reciprocal to its extension, or at least very neer. So that to
+apply it to our present purpose (which was indeed the chief cause of
+inventing these wayes of tryal) we will suppose a _Cylinder_ indefinitely
+extended upwards, [I say a _Cylinder_, not a piece of a _Cone_, because, as
+I may elsewhere shew in the Explication of Gravity, that _triplicate_
+proportion of the shels of a Sphere, to their respective diameters, I
+suppose to be removed in this case by the decrease of the power of Gravity]
+and the pressure of the Air at the bottom of this _Cylinder_ to be strong
+enough to keep up a _Cylinder_ of _Mercury_ of thirty inches: Now because
+by the most accurate tryals of the most illustrious and incomparable Mr.
+_Boyle_, published in his deservedly famous Pneumatick Book, the weight of
+Quicksilver, to that of the Air here below, is found neer about as fourteen
+thousand to one: If we suppose the parts of the _Cylinder_ of the
+_Atmosphere_ to be every where of an equal density, we shall (as he there
+deduces) find it extended to the height of thirty five thousand feet, or
+seven miles: But because by these Experiments we have somewhat confirm’d
+the hypothesis of the reciprocal proportion of the Elaters to the
+Extensions we shall find, that by supposing this _Cylinder_ of the
+_Atmosphere_ divided into a thousand parts, each of which being equivalent
+to thirty five feet, or seven geometrical paces, that is, each of these
+divisions containing as much Air as is suppos’d in a _Cylinder_ neer the
+earth of equal diameter, and thirty five foot high, we shall find the
+lowermost to press against the surface of the Earth with the whole weight
+of the above mentioned thousand parts; the pressure of the bottom of the
+second against the top of the first to be 1000 − 1 = 999. of the third
+against the second to be 1000 − 2 = 998. of the fourth against the third to
+be 1000 − 3 = 997. of the uppermost against the 999. or that next below it,
+to be 1000 − 999 = 1. so that the extension of the lowermost next the
+Earth, will be to the extension of the next below the uppermost, as 1. to
+999. for as the pressure sustained by the 999. is to the pressure sustain’d
+by the first, so is the extension of the first to the extension of the 999.
+so that, from this hypothetical calculation, we shall find the Air to be
+indefinitely extended: For if we suppose the whole thickness of the Air to
+be divided, as I just now instanced, into a thousand parts, and each of
+those under differing Dimensions, or Altitudes, to contain an equall
+quantity of Air, we shall find, that the first _Cylinder_, whose Base is
+supposed to lean on the Earth, will be found to be extended 35³⁵⁄₉₉₉ foot;
+the second equal Division, or _Cylinder_, whose _basis_ is supposed to lean
+on the top of the first, shall have its top extended higher by 35⁷⁰⁄₉₉₈
+the third 35¹⁰⁵⁄₉₉₇ the fourth 35¹⁴⁰⁄₉₉₆ and so onward, each equal
+quantity of Air having its dimensions measured by 35. and some additional
+number exprest alwayes in the manner of a fraction, whose numerator is
+alway the number of the place multipli’d by 35. and whose denominator is
+alwayes the pressure of the _Atmosphere_ sustain’d by that part, so that by
+this means we may easily calculate the height of 999. divisions of those
+1000. divisions, I suppos’d; whereas the uppermost may extend it self more
+then as high again, nay, perhaps indefinitely, or beyond the Moon; for the
+Elaters and Expansions being in reciprocal proportions, since we cannot yet
+find the _plus ultra_, beyond which the Air will not expand it self, we
+cannot determine the height of the Air: for since, as we have shewn, the
+proportion will be alway as the pressure sustain’d by any part is to 35. so
+1000. to the expansion of that part; the multiplication or product
+therefore of the pressure, and expansion, that is, of the two extream
+proportionals, being alwayes equal to the product of the means, or 35000.
+it follows, since that Rectangle or Product may be made up of the
+multiplication of infinite diversities of numbers, that the height of the
+Air is also indefinite; for since (as far as I have yet been able to try)
+the Air seems capable of an indefinite Expansion, the pressure may be
+decreased in _infinitum_, and consequently its expansion upwards indefinite
+also.
+
+There being therefore such a difference of density, and no Experiment yet
+known to prove a _Saltus_, or skipping from one degree of rarity to another
+much differing from it, that is, that an upper part of the Air should so
+much differ from that immediately _subjacent_ to it, as to make a distinct
+superficies, such as we observe between the Air and Water, &c. But it being
+more likely, that there is a continual increase of rarity in the parts of
+the Air, the further they are removed from the surface of the Earth: It
+will hence necessarily follow, that (as in the Experiment of the salt and
+fresh Water) the ray of Light passing obliquely through the Air also, which
+is of very different density, will be continually, and infinitely
+inflected, or bended, from a streight, or direct motion.
+
+This granted, the reason of all the above recited _Phænomena_, concerning
+the appearance of the Celestial Bodies, will very easily be deduced. As,
+
+First, The redness of the Sun, Moon, and Stars, will be found to be caused
+by the inflection of the rays within the _Atmosphere_. That it is not
+really in or near the luminous bodies, will, I suppose, be very easily
+granted, seeing that this redness is observable in several places differing
+in Longitude, to be at the same time different, the setting and rising Sun
+of all parts being for the most part red:
+
+And secondly, That it is not meerly the colour of the Air interpos’d, will,
+I suppose, without much more difficulty be yielded, seeing that we may
+observe a very great _interstitium_ of Air betwixt the Object, and the Eye,
+makes it appear of a dead blew, far enough differing from a red, or yellow.
+
+But thirdly, That it proceeds from the refraction, or inflection, of the
+rays by the _Atmosphere_, this following Experiment will, I suppose,
+sufficiently manifest.
+
+Take a sphærical Crystalline Viol, such as is describ’d in the fifth Figure
+ABCD, and, having fill’d it with pure clear Water, expose it to the Sun
+beams; then taking a piece of very fine _Venice_ Paper, apply it against
+that side of the Globe that is opposite to the Sun, as against the side BC,
+and you shall perceive a bright red Ring to appear, caus’d by the
+refraction of the Rays, AAAA, which is made by the Globe; in which
+Experiment, if the Glass and Water be very cleer, so that there be no Sands
+nor bubbles in the Glass, nor dirt in the Water, you shall not perceive any
+appearance of any other colour. To apply which Experiment, we may imagine
+the _Atmosphere_ to be a great transparent Globe, which being of a
+substance more dense then the other, or (which comes to the same) that has
+its parts more dense towards the middle, the Sun beams that are tangents,
+or next within the tangents of this Globe, will be refracted or inflected
+from their direct passage towards the center of the Globe, whence,
+according to the laws of refractions made in a triangular _Prism_, and the
+generation of colour set down in the description of Muscovi-glass there
+must necessarily appear a red colour in the _transitus_ or passage of those
+tangent Rays. To make this more plain, we will suppose (in the sixth
+_Figure_) ABCD, to represent the Globe of the _Atmosphere_, EFGH to
+represent the opacous Globe of the Earth, lying in the midst of it, neer to
+which, the parts of the Air, sustaining a very great pressure, are thereby
+very much condens’d, from whence those Rays that are by inflection made
+tangents to the Globe of the Earth, and those without them, that pass
+through the more condens’d part of the _Atmosphere_, as suppose between A
+and E, are by reason of the inequality of the _medium_, inflected towards
+the center, whereby there must necessarily be generated a red colour, as is
+more plainly shewn in the former cited place; hence whatsoever opacous
+bodies (as vapours, or the like) shall chance to be elevated into those
+parts, will reflect a red towards the eye; and therefore those evenings and
+mornings appear reddest, that have the most store of vapours and halituous
+substances exhaled to a convenient distance from the Earth; for thereby the
+inflection is made the greater, and thereby the colour also the more
+intense; and several of those exhalations being opacous, reflect several of
+those Rays, which, through an _Homogeneous_ transparent _medium_ would pass
+unseen; and therefore we see, that when there chances to be any clouds
+situated in those Regions they reflect a strong and vivid red. Now, though
+one great cause of the redness may be this inflection, yet I cannot wholly
+exclude the colour of the vapours themselves, which may have something of
+redness in them, they being partly nitrous; and partly fuliginous; both
+which steams tinge the Rays that pass through them, as is made evident by
+looking at bodies through the fumes of _Aqua fortis_ or spirit of _Nitre_
+[as the newly mentioned Illustrious Person has demonstrated] and also
+through the smoak of a Fire or Chimney.
+
+Having therefore made it probable at least, that the morning and evening
+redness may partly proceed from this inflection or refraction of the Rays,
+we shall next shew how the Oval Figure will be likewise easily deduced.
+
+Suppose we therefore, EFGH in the sixth _Figure_ of the 37. _Scheme_, to
+represent the Earth; ABCD, the _Atmosphere_; EI, and EL, two Rays coming
+from the Sun, the one from the upper, the other from the neather Limb,
+these Rays, being by the _Atmosphere_ inflected, appear to the eye at E, as
+if they had come from the points, N and O; and because the Ray L has a
+greater inclination upon the inequality of the _Atmosphere_ then I,
+therefore must it suffer a greater inflection, and consequently be further
+elevated above its true place, then the Ray I, which has a less
+inclination, will be elevated above its true place; whence it will follow,
+that the lower side appearing neerer the upper then really it is, and the
+two _lateral_ sides, _viz._ the right and left side, suffering no sensible
+alteration from the inflection, at least what it does suffer, does rather
+increase the visible Diameter then diminish it, as I shall shew by and by,
+the Figure of the luminous body must necessarily appear somewhat
+_Elliptical_.
+
+This will be more plain, if in the seventh _Figure_ of the 37. _Scheme_ we
+suppose AB to represent the sensible Horizon; CDEF, the body of the Sun
+really below it; GHIK, the same appearing above it, elevated by the
+inflection of the _Atmosphere_: For if, according to the best observation,
+we make the visible Diameter of the Sun to be about three or four and
+thirty minutes, and the Horizontal refraction according to _Ticho_ be
+thereabout, or somewhat more, the lower limb of the Sun E, will be elevated
+to I; but because, by his account, the point C will be elevated but 29.
+minutes, as having not so great an inclination upon the inequality of the
+Air, therefore IG, which will be the apparent refracted perpendicular
+Diameter of the Sun, will be less then CG, which is but 29. minutes, and
+consequently six or seven minutes shorter then the unrefracted apparent
+Diameter. The parts, D and F, will be likewise elevated to H and K, whose
+refraction, by reason of its inclination, will be bigger then that of the
+point C, though less then that of E; therefore will the semidiameter IL, be
+shorter then LG, and consequently the under side of the appearing Sun more
+flat then the upper.
+
+Now, because the Rays from the right and left sides of the Sun, &c. have
+been observ’d by _Ricciolo_ and _Grimaldus_, to appear more distant one
+from another then really they are, though (by very many Observations that I
+have made for that purpose, with a very good _Telescope_, fitted with a
+divided Ruler) I could never perceive any great alteration, yet there being
+really some, it will not be amiss, to shew that this also proceeds from the
+refraction or inflection of the _Atmosphere_; and this will be manifest, if
+we consider the _Atmosphere_ as a transparent Globe, or at least a
+transparent shell, encompassing an opacous Globe, which, being more dense
+then the _medium_ encompassing it, refracts or inflects all the entring
+parallel Rays into a point or focus, so that wheresoever the Observator is
+plac’d within the _Atmosphere_, between the focus and the luminous body,
+the _lateral_ Rays must necessarily be more converg’d towards his eye by
+the refraction or inflection, then they would have been without it; and
+therefore the Horizontal Diameter of the luminous body must necessarily be
+augmented.
+
+This might be more plainly manifest to the eye by the sixth _Figure_; but
+because it would be somwhat tedious, and the thing being obvious enough to
+be imagin’d by any one that attentively considers it, I shall rather omit
+it, and proceed to shew, that the mass of Air neer the surface of the
+Earth, consists, or is made up, of parcels, which do very much differ from
+one another in point of density and rarity; and consequently the Rays of
+light that pass through them will be variously inflected, here one way, and
+there another, according as they pass so or so through those differing
+parts; and those parts being always in motion, either upwards or downwards,
+or to the right or left, or in some way compounded of these, they do by
+this their motion inflect the Rays, now this way, and presently that way.
+
+This irregular, unequal and unconstant inflection of the Rays of light, is
+the reason why the limb of the _Sun_, _Moon_, _Jupiter_, _Saturn_, _Mars_,
+and _Venus_, appear to wave or dance; and why the body of the Starrs appear
+to tremulate or twinkle, their bodies, by this means, being sometimes
+magnify’d, and sometimes diminished; sometimes elevated, otherwhiles
+depress’d; now thrown to the right hand, and then to the left.
+
+And that there is such a property or unequal distribution of parts, is
+manifest from the various degrees of heat and cold that are found in the
+Air; from whence will follow a differing density and rarity, both as to
+quantity and refraction; and likewise from the vapours that are interpos’d,
+(which, by the way, I imagine, as to refraction or inflection, to do the
+same thing, as if they were rarify’d Air; and that those vapours that
+ascend, are both lighter, and less dense, then the ambient Air which boys
+them up; and that those which descend, are heavier and more dense) The
+first of these may be found true, if you take a good thick piece of Glass,
+and heating it pretty hot in the fire, lay it upon such another piece of
+Glass, or hang it in the open Air by a piece of Wire, then looking upon
+some far distant Object (such as a Steeple or Tree) so as the Rays from
+that Object pass directly over the Glass before they enter your eye, you
+shall find such a tremulation and wavering of the remote Object, as will
+very much offend your eye: The like tremulous motion you may observe to be
+caus’d by the ascending steams of Water, and the like. Now, from the first
+of these it is manifest, that from the rarifaction of the parts of the Air,
+by heat, there is caus’d a differing refraction, and from the ascension of
+the more rarify’d parts of the Air, which are thrust up by the colder, and
+therefore more condens’d and heavie, is caus’d an undulation or wavering of
+the Object; for I think, that there are very few will grant, that Glass, by
+as gentle a heat as may be endur’d by ones hand, should send forth any of
+its parts in steams or vapours, which does not seem to be much wasted by
+that violent fire of the green Glass-house; but, if yet it be doubted, let
+Experiment be further made with that body that is accounted, by Chymists
+and others, the most ponderous and fix’d in the world; for by heating of a
+piece of Gold, and proceeding in the same manner, you may find the same
+effects.
+
+This trembling and shaking of the Rays, is more sensibly caus’d by an
+actual flame, or quick fire, or anything else heated glowing hot; as by a
+Candle, live Coal, red-hot Iron, or a piece of Silver, and the like: the
+same also appears very conspicuous, if you look at an Object betwixt which
+and your eye, the rising smoak of some Chimney is interpos’d; which brings
+into my mind what I had once the opportunity to observe, which was, the Sun
+rising to my eye just over a Chimney that sent forth a copious steam of
+smoak; and taking a short _Telescope_, which I had then by me, I observ’d
+the body of the Sun, though it was but just peep’d above the Horizon, to
+have its underside, not onely flatted, and press’d inward, as it usually is
+when neer the Earth; but to appear more protuberant downwards then if it
+had suffered no refraction at all; and besides all this, the whole body of
+the Sun appear’d to tremble or dance, and the edges or limb to be very
+ragged or indented, undulating or waving, much in the manner of a flag in
+the Wind.
+
+This I have likewise often observ’d in a hot Sunshiny Summer’s day, that
+looking on an Object over a hot stone, or dry hot earth, I have found the
+Object to be undulated or shaken, much after the same manner. And if you
+look upon any remote Object through a _Telescope_ (in a hot Summer’s day
+especially) you shall find it likewise to appear tremulous. And further, if
+there chance to blow any wind, or that the air between you and the Object
+be in a motion or current, whereby the parts of it, both rarify’d and
+condens’d, are swiftly remov’d towards the right or left, if then you
+observe the Horizontal ridge of a Hill far distant, through a very good
+_Telescope_, you shall find it to wave much like the Sea, and those waves
+will appear to pass the same way with the wind.
+
+From which, and many other Experiments, ’tis cleer that the lower Region of
+the Air, especially that part of it which lieth neerest to the Earth, has,
+for the most part, its constituent parcels variously agitated, either by
+heat or winds, by the first of which, some of them are made more rare, and
+so suffer a less refraction; others are interwoven, either with ascending
+or descending vapours; the former of which being more light, and so more
+rarify’d, have likewise a less refraction; the latter being more heavie,
+and consequently more dense, have a greater.
+
+Now, because that heat and cold are equally diffus’d every way; and that
+the further it is spread, the weaker it grows; hence it will follow, that
+the most part of the under Region of the Air will be made up of several
+kinds of _lentes_, some whereof will have the properties of _Convex_,
+others of _Concave_ _glasses_, which, that I may the more intelligibly make
+out, we will suppose in the eighth _Figure_ of the 37. _Scheme_, that A
+represents an ascending vapour, which, by reason of its being somewhat
+_Heterogeneous_ to the ambient Air, is thereby thrust into a kind of
+Globular form, not any where terminated, but gradually finished, that is,
+it is most rarify’d in the middle about A. somewhat more condens’d about
+BB, more then that about CC; yet further, about DD, almost of the same
+density with the ambient Air about EE;, and lastly, inclosed with the more
+dense Air FF, so that from A, to FF, there is a continual increase of
+density. The reason of which will be manifest, if we consider the rising
+vapour to be much warmer then the ambient heavie Air; for by the coldness
+of the ambient Air, the shell EE will be more refrigerated then DD, and
+that then CC, which will be yet more then BB, and that more then A; so that
+from F to A, there is a continual increase of heat, and consequently of
+rarity; from whence it will necessarily follow, that the Rays of light will
+be inflected or refracted in it, in the same manner as they would be in a
+_Concave-glase_; for the Rays _GKI_, _GKI_ will be inflected by _GKH_,
+_GKH_, which will easily follow from what I before explained concerning the
+inflection of the _Atmosphere_.
+
+On the other side, a descending vapour, or any part of the air included by
+an ascending vapour, will exhibit the same effects with a _Convex lens_;
+for, if we suppose, in the former Figure, the quite contrary constitution
+to that last describ’d; that is, the ambient Air FF being hotter then any
+part of that matter within any circle, therefore the coldest part must
+necessarily be A, as being farthest remov’d from the heat, all the
+intermediate spaces will be gradually discriminated by the continuall
+mixture of heat and cold, so that it will be hotter at EE, then DD, in DD
+then CC, in CC then BB, and in BB then A. From which, a like refraction and
+condensation will follow, and consequently a lesser or greater refraction,
+so that every included part will refract more then the including, by which
+means the Rays, GKI, GKI, coming from a Starr, or some remote Object, are
+so inflected, that they will again concurr and meet, in the point M. By the
+interposition therefore of this desending vapour the visible body of the
+Star, or other Object, is very much augmented, as by the former it was
+diminished.
+
+From the quick consecutions of these two, one after another, between the
+Object and your eye, caused by their motion upwards or downwards,
+proceeding from their levity or gravity, or to the right or left,
+proceeding from the wind, a Starr may appear, now bigger, now less, then
+really it would otherwise without them; and this is that property of a
+Starr, which is commonly call’d twinkling, or scintillation.
+
+The reason why a Star will now appear of one colour, now of another, which
+for the most part happens when ’tis neer the Horizon, may very easily be
+deduc’d from its appearing now in the middle of the vapour, other whiles
+neer the edge; for if you look against the body of a Starr with a
+_Telescope_ that has a pretty deep _Convex_ Eye-glass, and so order it,
+that the Star may appear sometimes in one place, and sometimes in another
+of it; you may perceive this or that particular colour to be predominant in
+the apparent Figure of the Starr, according as it is more or less remote
+from the middle of the _Lens_. This I had here further explain’d, but that
+it does more properly belong to another place.
+
+I shall therefore onely add some few Quæries, which the consideration of
+these particulars hinted, and so finish this Section.
+
+And the first I shall propound is, Whether there may not be made an
+artificial transparent body of an exact Globular Figure that shall so
+inflect or refract all the Rays, that, coming from one point, fall upon any
+_Hemisphere_ of it; that every one of them may meet on the opposite side,
+and cross one another exactly in a point; and that it may do the like also
+with all the Rays that, coming from a _lateral_ point, fall upon any other
+_Hemisphere_; for if so, there were to be hoped a perfection of
+_Dioptricks_, and a transmigration into heaven, even whil’st we remain here
+upon earth in the flesh, and a descending or penetrating into the center
+and innermost recesses of the earth, and all earthly bodies; nay, it would
+open not onely a cranney, but a large window (as I may so speak) into the
+Shop of Nature, whereby we might be enabled to see both the tools and
+operators, and the very manner of the operation it self of Nature; this,
+could it be effected, would as farr surpass all other kind of perspectives
+as the vast extent of Heaven does the small point of the Earth, which
+distance it would immediately remove, and unite them, as ’twere, into one,
+at least, that there should appear no more distance between them then the
+length of the Tube, into the ends of which these Glasses should be
+inserted: Now, whether this may not be effected with parcels of Glass of
+several densities, I have sometimes proceeded so farr as to doubt (though
+in truth, as to the general, I have wholly despair’d of it) for I have
+often observ’d in Optical Glasses a very great variety of the parts, which
+are commonly called Veins; nay, some of them round enough (for they are for
+the most part, drawn out into strings) to constitute a kind of _lens_.
+
+This I should further proceed to hope, had any one been so inquisitive as
+to have found out the way of making any transparent body, either more dense
+or more rare, for then it might be possible to compose a Globule that
+should be more dense in the middle of it, then in any other part, and to
+compose the whole bulk, so as that there should be a continual gradual
+transition from one degree of density to another; such as should be found
+requisite for the desired inflection of the _transmigrating_ Rays; but of
+this enough at present, because I may say more of it when I set down my own
+Trials concerning the melioration of _Dioptricks_, where I shall enumerate
+with how many several substances I have made both _Microscopes_, and
+_Telescopes_, and by what and how many, ways: Let such as have leisure and
+opportunity farther consider it.
+
+The next Quæry shall be, whether by the same collection of a more dense
+body then the other, or at least, of the denser part of the other, there
+might not be imagin’d a reason of the apparition of some new fix’d Stars,
+as those in the Swan, _Cassiope’s Charr_, _Serpentarius_, _Piscis_,
+_Cetus_, &c.
+
+Thirdly, Whether it be possible to define the height of the _Atmosphere_
+from this inflection of the Rays, or from the Quicksilver Experiment of the
+rarifaction or extension of the Air.
+
+Fourthly, Whether the disparity between the upper and under Air be not
+sometimes so great, as to make a reflecting superficies; I have had several
+Observations which seem to have proceeded from some such cause, but it
+would be too long to relate and examine them. An Experiment, also somewhat
+analogous to this, I have made with Salt-water and Fresh, which two
+liquors, in most Positions, seem’d the same, and not to be separated by any
+determinate superficies, which separating surface yet in some other
+Positions did plainly appear.
+
+And if so, Whether the reason of the equal bounding or _terminus_ of the
+under parts of the clouds may not proceed from this cause; whether,
+secondly, the Reason of the apparition of many Suns may not be found out,
+by considering how the Rays of the Sun may so be reflected, as to describe
+a pretty true Image of the body, as we find them from any regular
+Superficies. Whether also this may not be found to cause the apparition of
+some of those _Parelii_, of counterfeit Suns, which appear coloured, by
+refracting the Rays so, as to make the body of the Sun appear in quite
+another place then really it is. But of this more elsewhere.
+
+5. Whether the _Phænomena_ of the Clouds may not be made out by this
+diversity of density in the upper and under parts of the Air, by supposing
+the Air above them to be much lighter then they themselves are, and they
+themselves to be yet lighter then that which is subjacent to them, many of
+them seeming to be the same substance with the Cobwebs that fly in the Air
+after a Fog.
+
+Now that such a constitution of the Air and Clouds, if such there be, may
+be sufficient to perform this effect, may be confirm’d by this Experiment.
+
+Make as strong a Solution of Salt as you are able, then filling a Glass of
+some depth half full with it, fill the other half with fresh Water, and
+poyse a little Glass-bubble, so as that it may sink pretty quick in fresh
+Water, which take and put into the aforesaid Glass, and you shall find it
+to sink till it comes towards the middle, where it will remain fixt,
+without moving either upwards or downwards. And by a second Experiment, of
+poising such a bubble in water, whose upper part is warmer, and
+consequently lighter, then the under, which is colder and heavier; the
+manner of which follows in this next Quæry, which is,
+
+6. Whether the rarifaction and condensation of Water be not made after the
+same manner, as those effects are produc’d in the Air by heat; for I once
+pois’d a seal’d up Glass-bubble so exactly, that never so small an addition
+would make it sink, and as small a detraction make it swim, which suffering
+to rest in that Vessel of Water for some time, I alwayes found it about
+noon to be at the bottom of the Water, and at night, and in the morning, at
+the top: Imagining this to proceed from the Rarifaction of the Water,
+caus’d by the heat, I made tryal, and found most true; for I was able at
+any time, either to depress, or raise it, by heat and cold; for if I let
+the Pipe stand for some time in cold water, I could easily raise the Bubble
+from the bottom, whither I had a little afore detruded it, by putting the
+same Pipe into warm Water. And this way I have been able, for a very
+considerable time, to keep a Bubble so poys’d in the Water, as that it
+should remain in the middle, and neither sink, nor swim: For gently heating
+the upper part of the Pipe with a Candle, Coal, or hot Iron, till I
+perceived the Bubble begin to descend, then forbearing, I have observed it
+to descend to such or such a station, and there to remain suspended for
+some hours, till the heat by degrees were quite vanished, when it would
+again ascend to its former place. This I have also often observed naturally
+performed by the heat of the Air, which being able to rarifie the upper
+parts of the Water sooner then the lower, by reason of its immediate
+contact, the heat of the Air has sometimes so slowly increased, that I have
+observed the Bubble to be some hours in passing between the top and bottom.
+
+7. Whether the appearance of the _Pike_ of _Tenerif_, and several other
+high Mountains, at so much greater a distance then seems to agree with
+their respective heights, be not to be attributed to the _Curvature_ of the
+visual Ray, that is made by its passing obliquely through so differingly
+_Dense_ a Medium from the top to the eye very far distant in the Horizon:
+For since we have already, I hope, made it very probable, that there is
+such an _inflection_ of the Rays by the differing density of the parts of
+the Air; and since I have found, by several Experiments made on places
+comparatively not very high, and have yet found the pressure sustain’d by
+those parts of the Air at the top and bottom, and also their differing
+Expansions very considerable: Insomuch that I have found the pressure of
+the _Atmosphere_ lighter at the top of St. _Paul_’s Steeple in _London_
+(which is about two hundred foot high) then at the bottom by a sixtieth or
+fiftieth part, and the expansion at the top greater then that at the bottom
+by neer about so much also; for the _Mercurial Cylinder_ at the bottom was
+about 39. inches, and at the top half an inch lower; the Air also included
+in the Weather-glass, that at the bottom fill’d only 155. spaces, at the
+top fill’d 158. though the heat at the top and bottom was found exactly the
+same with a scal’d _Thermometer_: I think it very rational to suppose, that
+the greatest Curvature of the Rays is made nearest the Earth, and that the
+inflection of the Rays, above 3. or 4. miles upwards, is very
+inconsiderable, and therefore that by this means such calculations of the
+height of Mountains, as are made from the distance they are visible in the
+Horizon, from the supposal that that Ray is a straight Line (that from the
+top of the Mountain is, as ’twere, a Tangent to the Horizon whence it is
+seen) which really is a _Curve_, is very erroneous. Whence, I suppose,
+proceeds the reason of the exceedingly differing Opinions and Assertions of
+several Authors, about the height of several very high Hills.
+
+8. Whether this Inflection of the Air will not very much alter the supposed
+distances of the Planets, which seem to have a very great dependence upon
+the Hypothetical refraction or inflection of the Air, and that refraction
+upon the hypothetical height and density of the Air: For since (as I hope)
+I have here shewn the Air to be quite otherwise then has been hitherto
+suppos’d, by manifesting it to be, both of a vast, at least an uncertain,
+height, and of an unconstant and irregular density; It must necessarily
+follow, that its inflection must be varied accordingly: And therefore we
+may hence learn, upon what sure grounds all the Astronomers hitherto have
+built, who have calculated the distance of the Planets from their
+Horizontal _Parallax_; for since the Refraction and _Parallax_ are so
+nearly ally’d, that the one cannot be known without the other, especially
+by any wayes that have been yet attempted, how uncertain must the
+_Parallax_ be, when the Refraction is unknown? And how easie is it for
+Astronomers to assign what distance they please to the Planets, and defend
+them, when they have such a curious _subterfuge_ as that of Refraction,
+wherein a very little variation will allow them liberty enough to place the
+Celestial Bodies at what distance they please.
+
+If therefore we would come to any certainty in this point, we must go other
+wayes to work; and as I have here examined the height and refractive
+property of the Air by other wayes then are usual, so must we find the
+Parallax of the Planets by wayes not yet practiced; and to this end, I
+cannot imagine any better way, then the Observations of them by two persons
+at very far distant parts of the Earth, that lye as neer as may be under
+the same Meridian, or Degree of longitude, but differing as much in
+latitude, as there can be places conveniently found: These two persons, at
+certain appointed times, should (as near as could be) both at the same
+time, observe the way of the _Moon_, _Mars_, _Venus_, _Jupiter_, and
+_Saturn_, amongst the fixt Stars, with a good large _Telescope_, and making
+little Iconismes, or pictures, of the small fixed Stars, that appear to
+each of them to lye in or near the way of the Center of the Planet, and the
+exact measure of the apparent Diameter; from the comparing of such
+Observations together, we might certainly know the true distance, or
+Parallax, of the Planet. And having any one true Parallax of these Planets,
+we might very easily have the other by their apparent Diameters, which the
+_Telescope_ likewise affords us very accurately. And thence their motions
+might be much better known, and their Theories more exactly regulated. And
+for this purpose I know not any one place more convenient for such an
+Observation to be made in, then in the Island of St. _Helena_, upon the
+Coast of _Africk_, which lyes about sixteen degrees to the Southwards of
+the Line, and is very near, according to the latest Geographical Maps, in
+the same Meridian with _London_; for though they may not perhaps lye
+exactly in the same, yet their Observations, being ordered according to
+what I shall anon shew, it will not be difficult to find the true distance
+of the Planet. But were they both under the same Meridian, it would be much
+better.
+
+And because Observations may be much easier, and more accurately made with
+good _Telescopes_, then with any other Instruments, it will not, I suppose,
+seem impertinent to explain a little what wayes I judge most fit and
+convenient for that particular. Such therefore as shall be the Observators
+for this purpose, should be furnished with the best _Telescopes_ that can
+be had, the longer the better and more exact will their Observations be,
+though they are somewhat the more difficultly manag’d. These should be
+fitted with a _Rete_, or divided Scale, plac’d at such a distance within
+the Eye-glass, that they may be distinctly seen, which should be the
+measures of minutes and seconds; by this Instrument each Observator should,
+at certain prefixt times, observe the Moon, or other Planet, in, or very
+near, the Meridian; and because it may be very difficult to find two
+convenient stations that will happen to be just under the same Meridian,
+they shall, each of them, observe the way of the Planet, both for an hour
+before, and an hour after, it arrive at the Meridian; and by a line, or
+stroke, amongst the small fixed Stars, they shall denote out the way that
+each of them observ’d the Center of the Planet to be mov’d in for those two
+hours: These Observations each of them shall repeat for many dayes
+together, that both it may happen, that both of them may sometimes make
+their Observations together, and that from divers Experiments we may be the
+better assured of what certainty and exactness such kind of Observations
+are like to prove. And because many of the Stars which may happen to come
+within the compass of such an _Iconism_, or Map, may be such as are only
+visible through a good _Telescope_, whose Positions perhaps have not been
+noted, nor their longitudes, or latitudes, any where remarked; therefore
+each Observator should indeavour to insert some fixt Star, whose longitude,
+and latitude, is known; or with his _Telescope_ he shall find the Position
+of some notable _telescopical_ Star, inserted in his Map, to some known
+fixt Star, whose place in the _Zodiack_ is well defin’d.
+
+Having by this means found the true distance of the Moon, and having
+observed well the _apparent Diameter_ of it at that time with a good
+_Telescope_, it is easie enough, by one single Observation of the apparent
+Diameter of the Moon with a good Glass, to determine her distances in any
+other part of her _Orbit_, or _Dragon_, and consequently, some few
+Observations will tell us, whether she be mov’d in an _Ellipsis_, (which,
+by the way, may also be found, even now, though I think we are yet ignorant
+of her true distance) and next (which without such Observations, I think,
+we shall not be sure of) we may know exactly the bigness of that
+_Ellipsis_, or Circle, and her true velocity in each part, and thereby be
+much the better inabled to find out the true cause of all her Motions. And
+though, even now also, we may, by such Observations in one station, as here
+at _London_, observe the _apparent Diameter_ and motion of the Moon in her
+_Dragon_, and consequently be inabled to make a better ghess at the
+_Species_ or kind of Curve, in which she is mov’d, that is, whether it be
+sphærical, or _elliptical_, or neither, and with what proportional
+velocities she is carried in that Curve; yet till her true _Parallax_ be
+known, we cannot determine either.
+
+Next, for the true distance of the Sun, the best way will be, by accurate
+Observations, made in both these forementioned stations, of some convenient
+Eclipse of the Sun, many of which may so happen, as to be seen by both; for
+the _Penumbra_ of the Moon may, if she be sixty Semidiameters distant from
+the Earth, and the Sun above seven thousand, extend to about seventy
+degrees on the Earth, and consequently be seen by Observators as far
+distant as _London_, and St. _Helena_, which are not full sixty nine
+degrees distant. And this would much more accurately, then any way that has
+been yet used, determine the Parallax, and distance, of the Sun; for as for
+the Horizontal Parallax I have already shewn it sufficiently uncertain; nor
+is the way of finding it by the Eclipse of the Moon any other then
+hypothetical; and that by the difference of the true and apparent
+quadrature of the Moon is not less uncertain, witness their Deductions from
+it, who have made use of it; for _Vendeline_ puts that difference to be but
+4′.30″. whence he deduces a vast distance of the Sun, as I have before
+shewn. _Ricciolo_ makes it full 30′.00. but _Reinoldus_, and _Kircher_, no
+less then three degrees. And no wonder, for if we examine the _Theory_, we
+shall find it so complicated with uncertainties.
+
+First, From the irregular surface of the Moon, and from several Parallaxes,
+that unless the _Dichotomy_ happen in the _Nonagesimus_ of the _Ecliptick_,
+and that in the Meridian, &c. all which happen so very seldom, that it is
+almost impossible to make them otherwise then uncertainly. Besides, we are
+not yet certain, but that there may be somewhat about the Moon _analogus_
+to the Air about the Earth, which may cause a refraction of the light of
+the Sun, and consequently make a great difference in the apparent
+_dichotomy_ of the Moon. Their way indeed is very rational and ingenious;
+and such as is much to be preferred before the way by the Horizontal
+Parallax, could all the uncertainties be remov’d, and were the true
+distance of the Moon known.
+
+But because we find by the Experiments of _Vendiline_, _Reinoldus_, &c.
+that Observations of this kind are very uncertain also: It were to be
+wisht, that such kind of Observations, made at two very distant stations,
+were promoted. And it is so much the more desirable, because, from what I
+have now shewn of the nature of the Air, it is evident, that the refraction
+may be very much greater then all the Astronomers hitherto have imagined
+it: And consequently, that the distance of the Moon, and other Planets, may
+be much lesse then what they have hitherto made it.
+
+For first, this Inflection, I have here propounded, will allow the shadow
+of the Earth to be much shorter then it can be made by the other
+_Hypothesis_ of refraction, and consequently, the Moon will not suffer an
+Eclipse, unless it comes very much nearer the Earth then the Astronomers
+hitherto have supposed it.
+
+Secondly, There will not in this _Hypothesis_ be any other shadow of the
+Earth, such as _Kepler_ supposes, and calls the _Penumbra_, which is the
+shadow of the refracting _Atmosphere_; for the bending of the Rays being
+altogether caus’d by _Inflection_, as I have already shewn, all that part
+which is ascribed by _Kepler_, and others after him, to the _Penumbra_, or
+dark part, which is without the _umbra terræ_, does clear vanish; for in
+this _Hypothesis_ there is no refracting surface of the Air, and
+consequently there can be no shadows, such as appear in the ninth Figure of
+the 37. _Scheme_, where let ABCD represent the Earth, and EFGH the
+_Atmosphere_, which according to _Keplers_ supposition, is like a Sphære of
+Water terminated with an exact surface EFGH, let the lines MF, LB, ID, KH,
+represent the Rays of the Sun; ’tis manifest, that all the Rayes between
+LB, and ID, will be reflected by the surface of the Earth BAD, and
+consequently, the conical space BOD would be dark and obscure; but, say the
+followers of _Kepler_, the Rays between MF, and LB, and between ID, and KH,
+falling on the _Atmosphere_, are refracted, both at their ingress and
+egress out of the _Atmosphere_, nearer towards the Axis of the sphærical
+shadow CO, and consequently, inlighten a great part of that former dark
+Cone, and shorten, and contract, its top to N. And because of this
+Reflection of these Rays, say they, there is superinduc’d another shell of
+a dark Cone FPH, whose Apex P is yet further distant from the Earth: By
+this _Penumbra_, say they, the Moon is Eclipsed, for it alwayes passes
+between the lines 12, and 34.
+
+To which I say, That if the Air be such, as I have newly shewn it to be,
+and consequently cause such an inflection of the Rays that fall into it,
+those dark _Penumbra’s_ FYZQ, HXVT, and ORPS, will all vanish. For if we
+suppose the Air indefinitely extended, and to be no where bounded with a
+determinate refracting surface, as I have shewn it uncapable of having,
+from the nature of it; it will follow, that the Moon will no where be
+totally obscured, but when it is below the Apex N, of the dark blunt Cone
+of the Earth’s shadow: Now, from the supposition, that the Sun is distant
+about seven thousand Diameters, the point N, according to calculation,
+being not above twenty five terrestrial Semidiameters from the Center of
+the Earth: It follows, that whensoever the Moon eclipsed is totally
+darkned, without affording any kind of light, it must be within twenty five
+Semidiameters of the Earth, and consequently much lower then any
+Astronomers have hitherto put it.
+
+This will seem much more consonant to the rest of the secundary Planets;
+for the highest of _Jupiter’s_ Moons is between twenty and thirty _Jovial
+Semidiameters_ distant from the Center of _Jupiter_; and the Moons of
+_Saturn_ much about the same number of _Saturnial Semidiameters_ from the
+Center of that Planet.
+
+But these are but conjectures also, and must be determin’d by such kind of
+Observations as I have newly mention’d.
+
+Nor will it be difficult, by this _Hypothesis_, to salve all the
+appearances of Eclipses of the Moon, for in this _Hypothesis_ also, there
+will be on each side of the shadow of the Earth, a _Penumbra_, not caus’d
+by the Refraction of the Air, as in the _Hypothesis_ of _Kepler_; but by
+the faint inlightning of it by the Sun: For if, in the sixth Figure, we
+suppose ESQ, and GSR, to be the Rays that terminate the shadow from either
+side of the Earth; ESQ coming from the upper limb of the Sun, and GSR from
+the under; it will follow, that the shadow of the Earth, within those Rays,
+that is, the Cone GSE, will be totally dark. But the Sun being not a point,
+but a large _area_ of light, there will be a secondary dark Cone of shadow
+EPG, which will be caus’d by the earth’s hindring part of the Rays of the
+Sun from falling on the parts GPR, and EPQ, of which halved shadow, or
+_Penumbra_, that part will appear brightest which lyes nearest the
+terminating Rayes GP, and EP, and those darker that lye nearest to GS, and
+ES: when therefore the Moon appears quite dark in the middle of the
+Eclipse, she must be below S, that is, between S and F; when she appears
+lighter near the middle of the Eclipse, she must pass some where between RQ
+and S; and when she is alike light through the whole Eclipse, she must pass
+between RQ, and P.
+
+       *       *       *       *       *
+
+
+Observ. LIX. _Of multitudes of small _Stars_ discoverable by the
+_Telescope_._
+
+Having, in the last Observation, premis’d some particulars observable in
+the _medium_, through which we must look upon _Cœlestial_ Objects, I shall
+here add one Observation of the Bodies themselves; and for a _specimen_ I
+have made choice of the _Pleiades_, or seven Stars, commonly so called
+(though in our time and Climate there appear no more then six to the naked
+eye) and this I did the rather, because the deservedly famous _Galileo_,
+having publisht a Picture of this _Asterisme_, was able, it seems, with his
+Glass to discover no more then thirty six, whereas with a pretty good
+twelve foot _Telescope_, by which I drew this 38 _Iconism_, I could very
+plainly discover seventy eight, placed in the order they are ranged in the
+Figure, and of as many differing Magnitudes as the _Asterisks_, wherewith
+they are Marked, do specifie; there being no less then fourteen several
+Magnitudes of those Stars, which are compris’d within the draught, the
+biggest whereof is not accounted greater then one of the third Magnitude;
+and indeed that account is much too big, if it be compared with other Stars
+of the third Magnitude, especially by the help of a _Telescope_; for then
+by it may be perceiv’d, that its splendor, to the naked eye, may be
+somewhat augmented by the three little Stars immediately above it, which
+are near adjoyning to it. The _Telescope_ also discovers a great variety,
+even in the bigness of those, commonly reckon’d, of the first, second,
+third, fourth, fifth, and sixth Magnitude; so that should they be
+distinguish’d thereby, those six Magnitudes would, at least, afford no less
+then thrice that number of Magnitudes, plainly enough distinguishable by
+their Magnitude, and brightness; so that a good twelve foot Glass would
+afford us no less then twenty five several Magnitudes. Nor are these all,
+but a longer Glass does yet further, both more nicely distinguish the
+Magnitudes of those already noted, and also discover several other of
+smaller Magnitudes, not discernable by the twelve foot Glass: Thus have I
+been able, with a good thirty six foot Glass, to discover many more Stars
+in the _Pleiades_ then are here delineated, and those of three or four
+distinct Magnitudes less then any of those spots of the fourteenth
+Magnitude. And by the twinkling of divers other places of this _Asterisme_,
+when the Sky was very clear, I am apt to think, that with longer Glasses,
+or such as would bear a bigger _aperture_, there might be discovered
+multitudes of other small Stars, yet inconspicuous. And indeed, for the
+discovery of small Stars, the bigger the _aperture_ be, the better adapted
+is the Glass; for though perhaps it does make the several specks more
+radiant, and glaring, yet by that means, uniting more Rays very near to one
+point, it does make many of those radiant points conspicuous, which, by
+putting on a less _aperture_, may be found to vanish; and therefore, both
+for the discovery of the fixt Star, and for finding the _Satellites_ of
+_Jupiter_, before it be out of the day, or twilight, I alwayes leave the
+Object-glass as clear without any _aperture_ as I can, and have thereby
+been able to discover the _Satellites_ a long while before; I was able to
+discern them, when the smaller _apertures_ were put on; and at other times,
+to see multitudes of other smaller Stars, which a smaller _aperture_ makes
+to disappear.
+
+In that notable _Asterism_ also of the Sword of _Orion_, where the
+ingenious Monsieur _Hugens van Zulichem_ has discovered only three little
+Stars in a cluster, I have with a thirty six foot Glass, without any
+_aperture_ (the breadth of the Glass being about some three inches and a
+half) discover’d five, and the twinkling of divers others up and down in
+divers parts of that small milky Cloud.
+
+So that ’tis not unlikely, but that the meliorating of _Telescopes_ will
+afford as great a variety of new Discoveries in the Heavens, as better
+_Microscopes_ would among small terrestrial Bodies, and both would give us
+infinite cause, more and more to admire the omnipotence of the Creator.
+
+       *       *       *       *       *
+
+
+Observ. LX. _Of the _Moon_._
+
+Having a pretty large corner of the Plate for the seven Starrs, void, for
+the filling it up, I have added one small _Specimen_ of the appearance of
+the parts of the Moon, by describing a small spot of it, which, though
+taken notice of, both by the Excellent _Hevelius_, and called _Mons
+Olympus_ (though I think somewhat improperly, being rather a vale) and
+represented by the Figure X. of the 38. _Scheme_, and also by the Learn’d
+_Ricciolus_, who calls it _Hipparchus_, and describes it by the Figure Y,
+yet how far short both of them come of the truth, may be somewhat perceiv’d
+by the draught, which I have here added of it, in the Figure Z, (which I
+drew by a thirty foot Glass, in _October_ 1664. just before the Moon was
+half inlightned) but much better by the Reader’s diligently observing it
+himself, at a convenient time, with a Glass of that length, and much better
+yet with one of threescore foot long, for through these it appears a very
+spacious Vale, incompassed with a ridge of Hills, not very high in
+comparison of many other in the Moon, nor yet very steep. The Vale it self
+ABCD, is much of the figure of a Pear, and from several appearances of it,
+seems to be some very fruitful place, that is, to have its surface all
+covered over with some kinds of vegetable substances; for in all positions
+of the light on it, it seems to give a much fainter reflection then the
+more barren tops of the incompassing Hills, and those a much fainter then
+divers other cragged, chalky, or rocky Mountains of the Moon. So that I am
+not unapt to think, that the Vale may have Vegetables _analogus_ to our
+Grass, Shrubs, and Trees; and most of these incompassing Hills may be
+covered with so thin a vegetable Coat, as we may observe the Hills with us
+to be, such as the short Sheep pasture which covers the Hills of
+_Salisbury_ Plains.
+
+Up and down in several parts of this place here describ’d (as there are
+multitudes in other places all over the surface of the Moon) may be
+perceived several kinds of pits, which are shap’d almost like a dish, some
+bigger, some less, some shallower, some deeper, that is, they seem to be a
+hollow _Hemisphere_, incompassed with a round rising bank, as if the
+substance in the middle had been digg’d up, and thrown on either side.
+These seem to me to have been the effects of some motions within the body
+of the Moon, _analogus_ to our Earthquakes, by the eruption of which, as it
+has thrown up a brim, or ridge, round about, higher then the Ambient
+surface of the Moon, so has it left a hole, or depression, in the middle,
+proportionably lower; divers places resembling some of these, I have
+observ’d here in _England_, on the tops of some Hills, which might have
+been caus’d by some Earthquake in the younger dayes of the world. But that
+which does most incline me to this belief, is, first, the generality and
+diversity of the Magnitude of these pits all over the body of the Moon.
+Next, the two experimental wayes, by which I have made a representation of
+them.
+
+The first was with a very soft and well temper’d mixture of Tobacco-pipe
+clay and Water, into which, if I let fall any heavy body, as a Bullet, it
+would throw up the mixture round the place, which for a while would make a
+representation, not unlike these of the Moon; but considering the state and
+condition of the Moon, there seems not any probability to imagine, that it
+should proceed from any cause _analogus_ to this; for it would be difficult
+to imagine whence those bodies should come; and next, how the substance of
+the Moon should be so soft; but if a Bubble be blown under the surface of
+it, and suffer’d to rise, and break; or if a Bullet, or other body, sunk in
+it, be pull’d out from it, these departing bodies leave an impression on
+the surface of the mixture, exactly like these of the Moon, save that these
+also quickly subside and vanish. But the second, and most notable,
+representation was, what I observ’d in a pot of boyling Alabaster, for
+there that powder being by the eruption of vapours reduc’d to a kind of
+fluid consistence, if, whil’st it boyls, it be gently remov’d besides the
+fire, the Alabaster presently ceasing to boyl, the whole surface,
+especially that where some of the last Bubbles have risen, will appear all
+over covered with small pits, exactly shap’d like these of the Moon, and by
+holding a lighted Candle in a large dark Room, in divers positions to this
+surface, you may exactly represent all the _Phænomena_ of these pits in the
+Moon, according as they are more or less inlightned by the Sun.
+
+And that there may have been in the Moon some such motion as this, which
+may have made these pits, will seem the more probable, if we suppose it
+like our Earth, for the Earthquakes here with us seem to proceed from some
+such cause, as the boyling of the pot of Alabaster, there seeming to be
+generated in the Earth from some subterraneous fires, or heat, great
+quantities of vapours, that is, of expanded aerial substances, which not
+presently finding a passage through the ambient parts of the Earth, do, as
+they are increased by the supplying and generating principles, and thereby
+(having not sufficient room to expand themselves) extreamly condens’d, at
+last overpower, with their _elastick_ properties, the resistence of the
+incompassing Earth, and lifting it up, or cleaving it, and so shattering of
+the parts of the Earth above it, do at length, where they find the parts of
+the Earth above them more loose, make their way upwards, and carrying a
+great part of the Earth before them, not only raise a small brim round
+about the place, out of which they break, but for the most part
+considerable high Hills and Mountains, and when they break from under the
+Sea, divers times, mountainous Islands; this seems confirm’d by the
+_Vulcans_ in several places of the Earth, the mouths of which, for the most
+part, are incompassed with a Hill of a considerable height, and the tops of
+those Hills, or Mountains, are usually shap’d very much like these pits, or
+dishes, of the Moon: Instances of this we have in the descriptions of
+_Ætna_ in _Sicily_, of _Hecla_ in _Iceland_, of _Tenerif_ in the
+_Canaries_, of the several _Vulcans_ in _New-Spain_, describ’d by _Gage_,
+and more especially in the eruption of late years in one of the _Canary_
+Islands. In all of which there is not only a considerable high Hill raised
+about the mouth of the _Vulcan_, but, like the spots of the Moon, the top
+of those Hills are like a dish, or bason. And indeed, if one attentively
+consider the nature of the thing, one may find sufficient reason to judge,
+that it cannot be otherwise; for these eruptions, whether of fire, or
+smoak, alwayes raising great quantities of Earth before them, must
+necessarily, by the fall of those parts on either side, raise very
+considerable heaps.
+
+Now, both from the figures of them, and from several other circumstances;
+these pits in the Moon seem to have been generated much after the same
+manner that the holes in Alabaster, and the _Vulcans_ of the Earth are
+made. For first, it is not improbable, but that the substance of the Moon
+may be very much like that of our Earth, that is, may consist of an earthy,
+sandy, or rocky substance, in several of its superficial parts, which parts
+being agitated, undermin’d, or heav’d up, by eruptions of vapours, may
+naturally be thrown into the same kind of figured holes, as the small dust,
+or powder of Alabaster. Next, it is not improbable, but that there may be
+generated, within the body of the Moon, divers such kind of internal fires
+and heats, as may produce such Exhalations; for since we can plainly enough
+discover with a _Telescope_, that there are multitudes of such kind of
+eruptions in the body of the Sun it self, which is accounted the most noble
+Ætherial body, certainly we need not be much scandaliz’d at such kind of
+alterations, or corruptions, in the body of this lower and less
+considerable part of the universe, the Moon, which is only secundary, or
+attendant, on the bigger, and more considerable body of the Earth. Thirdly,
+’tis not unlikely, but that supposing such a sandy or mouldring substance
+to be there found, and supposing also a possibility of the generation of
+the internal _elastical_ body (whether you will call it air or vapours)
+’tis not unlikely, I say, but that there is in the Moon a principle of
+gravitation, such as in the Earth. And to make this probable, I think, we
+need no better Argument, then the roundness, or globular Figure of the body
+of the Moon it self, which we may perceive very plainly by the _Telescope_,
+to be (bating the small inequality of the Hills and Vales in it, which are
+all of them likewise shap’d, or levelled, as it were, to answer to the
+center of the Moons body) perfectly of a Sphærical figure, that is, all the
+parts of it are so rang’d (bating the comparatively small ruggedness of the
+Hills and Dales) that the outmost bounds of them are equally distant from
+the Center of the Moon, and consequently, it is exceedingly probable also,
+that they are equidistant from the Center of gravitation; and indeed, the
+figure of the superficial parts of the Moon are so exactly shap’d,
+according as they should be, supposing it had a gravitating principle as
+the Earth has, that even the figure of those parts themselves is of
+sufficient efficacy to make the gravitation, and the other two suppositions
+probable: so that the other suppositions may be rather prov’d by this
+considerable Circumstance, or Observation, then this suppos’d Explication
+can by them; for he that shall attentively observe with an excellent
+_Telescope_, how all the Circumstances, notable in the shape of the
+superficial parts, are, as it were, exactly adapted to suit with such a
+principle, will, if he well considers the usual method of Nature in its
+other proceedings, find abundant argument to believe it to have really
+there also such a principle; for I could never observe, among all the
+mountainous or prominent parts of the Moon (whereof there is a huge
+variety) that any one part of it was plac’d in such a manner, that if there
+should be a gravitating, or attracting principle in the body of the Moon,
+it would make that part to fall, or be mov’d out of its visible posture.
+Next, the shape and position of the parts is such, that they all seem put
+into those very shapes they are in by a gravitating power: For first, there
+are but very few clifts, or very steep declivities in the ascent of these
+Mountains; for besides those Mountains, which are by _Hevelius_ call’d the
+_Apennine_ Mountains, and some other, which seem to border on the Seas of
+the Moon, and those only upon one side, as is common also in those Hills
+that are here on the Earth; there are very few that seem to have very steep
+ascents, but, for the most part, they are made very round, and much
+resemble the make of the Hills and Mountains also of the Earth; this may be
+partly perceived by the Hills incompassing this Vale, which I have here
+describ’d; and as on the Earth also, the middlemost of these Hills seems
+the highest, so is it obvious also, through a good _Telescope_, in those of
+the Moon; the Vales also in many are much shap’d like those of the Earth,
+and I am apt to think, that could we look upon the Earth from the Moon,
+with a good _Telescope_, we might easily enough perceive its surface to be
+very much like that of the Moon.
+
+Now whereas in this small draught, (as there would be multitudes if the
+whole Moon were drawn after this manner) there are several little
+Ebullitions, or Dishes, even in the Vales themselves, and in the
+incompassing Hills also; this will, from this supposition, (which I have, I
+think, upon very good reason taken) be exceeding easily explicable; for, as
+I have several times also observ’d, in the surface of Alabaster so ordered,
+as I before describ’d, so may the later eruptions of vapours be even in the
+middle, or on the edges of the former; and other succeeding these also in
+time may be in the middle or edges of these, &c. of which there are
+Instances enough in divers parts of the body of the Moon, and by a boyling
+pot of Alabaster will be sufficiently exemplifi’d.
+
+To conclude therefore, it being very probable, that the Moon has a
+principle of gravitation, it affords an excellent distinguishing Instance
+in the search after the cause of gravitation, or attraction, to hint, that
+it does not depend upon the diurnal or turbinated motion of the Earth, as
+some have somewhat inconsiderately supposed and affirmed it to do; for if
+the Moon has an attractive principle, whereby it is not only shap’d round,
+but does firmly contain and hold all its parts united, though many of them
+seem as loose as the sand on the Earth, and that the Moon is not mov’d
+about its Center; then certainly the turbination cannot be the cause of the
+attraction of the Earth, and therefore some other principle must be thought
+of, that will agree with all the secundary as well as primary Planets. But
+this, I confess, is but a probability, and not a demonstration, which (from
+any Observation yet made) it seems hardly capable of, though how successful
+future indeavours (promoted by the meliorating of Glasses, and observing
+particular circumstances) may be in this, or any other, kind, must be with
+patience expected.
+
+       *       *       *       *       *
+
+
+_FINIS._
+
+       *       *       *       *       *
+
+
+THE TABLE.
+
+Observat. 1. Of the point of a Needle.
+
+_A Description of it: what other Bodies have the sharpest points: of the
+ruggedness of polisht Metal. A description of a printed point. Of very
+small writing, and the use of it for secret intelligence: the cause of the
+coursness of printed lines and points._
+
+Observ. 2. Of the Edge of a Razor.
+
+_A description of it: the causes of its roughness: of the roughness of very
+well polisht Optick Glasses._.
+
+Obser. 3. Of fine Lawn.
+
+_A description of it: A silken Flax mention’d, an attempt to explicate the
+_Phænomena_ of it, with a conjecture at the cause of the gloss of Silk._
+
+Observ. 4. Of Tabby.
+
+_A short description of it. A conjecture about the reason why Silk is so
+susceptible of vivid colours: and why Flax and Hair is not. A conjecture,
+that it may perhaps be possible to spin a kind of artificial Silk, out of
+some glutinous substance that may equalize natural Silk._
+
+Observ. 5. Of water’d Silks.
+
+_The great unaccurateness of artificial works. A description of a piece of
+water’d Silk; an Explication of the cause of the _Phænomena_: the way by
+which that operation is perform’d: some other _Phænomena_ mention’d
+depending on the same cause._
+
+Observ. 6. Of Glass Canes.
+
+_The exceeding smallness of some of these Bodies. By what means the
+hollowness of these small pipes was discover’d: several _Phænomena_ of it
+mention’d. An attempt to explicate them from the congruity and incongruity
+of Bodies: what those proprieties are. A hypothetical explication of
+fluidity: of the fluidity of the air, and several other _Phænomena_ of it:
+of congruity & incongruity; illustrated with several Experiments: what
+effects may be ascrib’d to these properties: an explication of the
+roundness of the surface of fluid Bodies: how the ingress of fluid bodies
+into a small hole of an heterogeneous body is hindred by incongruity; a
+multitude of _Phænomena_ explicable hereby. Several Quæries propounded; 1.
+Concerning the propagation of light through differing mediums. 2.
+Concerning Gravity. 3. Concerning the roundness of the Sun, Moon, and
+Planets. 4. Concerning the roundness of Fruits, Stones, and divers
+artificial Bodies. His Highness Prince _Rupert’s_ way of making Shot. Of
+the roundness of Hail. Of the grain of _Kettering_ Stone, and of the Sparks
+of fire. 5. Concerning springiness and tenacity. 6. Concerning the original
+of Fountains; several Histories and Experiments relating thereto. 7.
+Concerning the dissolution of Bodies in Liquors. 8. Concerning the
+universality of this Principle: what method was taken in making and
+applying experiments. The explication of filtration, and several other
+_Phænomena_; such as the motion of Bodies on the surface of Liquors;
+several Experiments mention’d to this purpose. Of the height to which the
+water may rise in these Pipes; and a conjecture about the juices of
+Vegetables, & the use of their pores. A further explication of Congruity:
+And an attempt of solving the _Phænomena_ of the strange Experiment of the
+suspension of the _Mercury_ at a much greater height then thirty inches.
+The efficacy of immediate contact, and the reason of it._
+
+Observ. 7. Of Glass drops.
+
+_Several Experiments made with these small Bodies. The manner of the
+breaking and flawing of them, explicated by Figures. What other bodies will
+be flawed much in the same manner: some other tryals, and a description of
+the Drops themselves: some conjectures at the cause of the _Phænomena_,
+indeavoured to be made probable by several Arguments and Experiments. An
+Experiment of the expansion of Water by heat, and shrinking by cold: the
+like Proprieties suppos’d in Glass drops, and what effects proceed from
+them: the seven Propositions on which the conjectures are grounded.
+Experiments to shew, that bodies expand by heat. The manner of making
+_Thermometers_, and the Instrument for _graduating_ them. The manner of
+_graduating_ them, and their use: Other Experiments to prove the expansion
+of bodies by heat. Four experimental Arguments to prove the expansion of
+Glass by heat: further prov’d by the Experiment of boyling Alabaster; which
+is explicated. An explication of the contracting of heated Glass upon
+cooling. An explication how the parts of the Glass become bent by sudden
+cold, and how kept from extricating themselves by the contignation of the
+Glass drop; which is further explicated by another Experiment made with a
+hollow Glass ball: the reason of the flying asunder of the parts further
+explicated: that ’tis probable these bodies may have many flaws, though not
+visible, and why: how a gradual heating and cooling does put the parts of
+Glass, and other hardned bodies, into a looser texture._
+
+Observ. 8. Of Fiery Sparks.
+
+_The occasion and manner of making this Experiment: divers Observations set
+down in order to the finding out the reasons: some conjectures concerning
+it, which are endeavoured to be explicated and confirm’d by several
+Experiments and Reasons: the _Hypothesis_ a little further explicated. Some
+Observations about the Globular Figure: and an Experiment of reducing the
+filings of Tin or Lead to exactly round Globules._
+
+Observ. 9. Of Fantastical Colours.
+
+_The texture of _Muscovy_ Glass; its Figures: what other Bodies are like
+it: that it exhibits several colours, and how: several Observations and
+Experiments about those colours: the reason why on this occasion the nature
+of colours is inquir’d into. A conjecture at the reason of these colours
+explicated by several Experiments and Reasons: First, by continual cleaving
+the Body till it become colour’d. Secondly, by producing all kinds of
+colours with two flat Plates of Glass. Thirdly, by blowing Glass so thin in
+the Lamp, till it produce the same effect. Fourthly, by doing the same with
+Bubbles of divers other transparent Bodies: the reasons of the colours on
+nealed Steel, where by the way the causes of the hardning and tempering of
+Steel, endeavour’d to be shewn and explicated by several Reasons and
+Experiments: the reason of the colours on Lead, Brass, Copper, Silver, &c.
+other Instances of such colour’d bodies in animal substances: several other
+distinguishing Observations. _Des Cartes Hypothesis_ of Colours examin’d.
+An _Hypothesis_ for the explication of light by motion, indeavoured to be
+explicated and determined by several Reasons and Experiments: three
+distinguishing Properties of the motion of light. The distinguishing
+Properties of a trasparent _Medium_ [that there seems to be no Experiment
+that proves the Instantaneous motion of light] the manner of the
+propagation of light through them. Of the _homogeniety_ and _heterogeniety_
+of transparent _Mediums_, and what effects they cause on the Rayes of
+light, explicated by a Figure: an Examination of the refraction of the Rays
+by a plain Surface, which causes Colours. An Examination of the like
+effects produced by a spherical Surface: the use that may be made of these
+Experiments, for the examination of several _Hypotheses_ of Colours. _Des
+Cartes Hypothesis_ examin’d. Some Difficulties taken notice of in it. What
+seems most likely to be the cause of colour: that propriety is indeavoured
+to be shewn in a Glass ball: that the reflection is not necessary to
+produce Colours nor a double refraction: the _Hypothesis_ further examined,
+both in the _pellucid Medium_ and in the Eye. The definitions of Colours;
+and a further explication and examination of the Proprieties of _laminated_
+Bodies; by what means they conduce to the production of Colours._
+
+Observ. 10. Of Metalline Colours.
+
+_That all Colours seem to be caus’d by refraction. An _Hypothesis_
+consonant hereunto, explicated by Figures. How several Experiments, of the
+sudden changing of Colours by Chymical Liquors may be hereby explicated:
+how many wayes such Chymical Liquors may alter the colours of Bodies.
+Objections made against this _Hypothesis_ of two colours only, indeavoured
+to be answer’d, by several Reasons and Experiments. The reason why some
+Colours are capable of being diluted, others not: what those are: that
+probably the particles of most metalline Colours are transparent; for this
+several Arguments and Observations are recited: how Colours become
+incapable of diluting, explicated by a Similitude. An Instrument, by which
+one and the same coloured Liquor at once exhibited all the degrees of
+colours between the palest yellow and deepest red: as likewise another that
+exhibited all varieties of blues: several Experiments try’d with these
+Boxes. An Objection drawn from the nature of Painters colours answered:
+that diluting and whitening a colour are different operations; as are
+deepening and blackening: why some may be diluted by grinding, and some
+other by being tempered with Oyl: several Experiments for the explicating
+of some former Assertions: why Painters are forced to make use of many
+colours: what those colours are: and how mixt. The conclusion, that most
+coloured Bodies seem to consist of transparent particles: that all colours
+dissoluble in Liquors are capable of diluting: some of mixing, what a
+strange variety may thereby be produc’d._
+
+Observ. 11. Of the Figures of Sand.
+
+_Of the substances and shapes of common and other Sands: a description of a
+very small Shell._
+
+Observ. 12. Of Gravel in Urine.
+
+_A description of such Gravel, and some tryals made with it, and
+conjectures at its cause._
+
+Obser. 13. Of Diamonds in Flints.
+
+_A description and examination of some of them, explicated further by
+Cornish Diamonds: several Observations about reflection and refraction:
+and some deductions therefrom; as an explication of whiteness; that the Air
+has a stronger reflection then Water. How several Bodies may be made
+transparent: an explication of the _Phænomena_ of _Oculus Mundi_. Of the
+regular Geometrical Figures of several Bodies: an hypothetical explication
+mentioned: the method of prosecuting this inquiry._
+
+Observ. 14. Of frozen Figure.
+
+_The Figures of hoar Frost, and the Vortices on windows: several
+Observations on the branched Figures of Urine: the Figures of _Regulus
+Martis stellatus_, and of Fern. Of the Figures of Snow. Of frozen water._
+
+Observ. 15. Of Kettering-Stone.
+
+_A description of the Figure of the Particles, and of the Pores, and of the
+Contexture. Several Observations and Considerations thereupon: some
+Conjectures about the _medium_ and propagation of light, and the
+constitution of fluid and transparent Bodies. Several Experiments to prove
+the porousness of Marble, and some other Stones. An account of some
+Experiments to this purpose made on an _Oculus Mundi_: some other
+Considerations and Experiments about the porousness of Bodies: some other
+Considerations about the propagation of light and refraction._
+
+Observ. 16. Of Charcoal.
+
+_Of two sort of Pores to be found in all Woods and Vegetables; the shape of
+them; the number, thickness, manner and use of these Pores. An explication
+of the _Phænomena_ of Coals. The manner of charring Wood, or any other
+body. What part of Wood is combustible. An _Hypothesis_ of fire explicated
+in twelve particulars, wherein the Action of the Air, as a _Menstruum_ in
+the dissolution of all sulphureous bodies, is very particularly explicated,
+and some other Considerations about the Air proposed: the examination of a
+piece of _Lignum fossile_ sent from _Rome_, and some Conclusions thence
+deduc’d._
+
+Observ. 17. Of Wood, and other Bodies, petrified.
+
+_Several Observations of divers kinds of these substances. A more
+particular examination and explication of one very notable piece of
+petrified Wood; and some Conjectures about the cause of those productions:
+several Observations made on other petrified Bodies, as shells, &c. And
+some probable Conclusions thence deduc’d, about the original cause of those
+Bodies._
+
+Observ. 18. Of the Pores of Cork, and other Bodies.
+
+_Several Observations and Considerations about the nature of Cork: the
+number of Pores in a cubical Inch, and several considerations about Pores.
+Several Experiments and Observations about the nature of Cork: the Texture
+and Pores of the Pith of an Elder, and several other Trees: of the Stalks
+of Burdocks, Teasels, Daisies, Carret, Fennel, Ferne, Reeds, &c. of the
+frothy texture of the Pith of a Feather: some Conjectures about the
+probability of values in these Pores. Argued also from the _Phænomena_ of
+sensible and humble Plant: some Observations on which are inserted._
+
+Observ. 19. Of a Vegetable growing on blighted Leaves.
+
+_Several Observations and Examinations made of them: several Considerations
+about spontaneous generation arising from the putrefaction of Bodies._
+
+Observ. 20. Of Blew Mould and Mushromes.
+
+_The description of several kinds of Moulds. The method of proceeding in
+natural Inquiries. Several Considerations about the nature of Mould and
+Mushromes. 1. That they may be produc’d without seed. 2. That they seem to
+have none. 3. That Salts, &c. are shap’d into as curious figures without a
+seed. 4. Of a kind of Mushrome growing in a Candle: A more particular
+explication of this last sort of Mushromes. 5. Of the figure and manner of
+the production of petrified Iceicles: several deductions from these
+Considerations, about the nature of the vegetation of Mould and Mushromes._
+
+Observ. 21. Of Moss.
+
+_The description of several sorts of Mosses; upon this occasion several
+Conjectures, about the manner of the production of these kinds of Bodies,
+are hinted, and some of them explicated by a Similitude taken from a piece
+of Clock-work, The vast difference of the bigness of vegetable Bodies; and
+the probability that the least may comprehend as curious contrivances as
+the greatest. Of multitudes of other Moulds, Mosses, and Mushromes, and
+other vegetating Principles, in Water, Wood, _&c.
+
+Observ. 22. Of Sponges, and other fibrous Bodies.
+
+_Several Observations and Conjectures about the making of these Bodies, and
+several Histories out of Authors. Scarce any other Body hath such a
+texture; the fibrous texture of Leather, Spunk, &c. (which are there
+describ’d) come nearest to it That upon tryal with a piece of Spunge and
+Oyl the necessity of respiration could not be alter’d._
+
+Observ. 23. Of the Form of Sea-weed.
+
+_From the curiously shap’d Surface of this Sea-weed, and some others, is
+conjectured the possibility of multitudes of the like._
+
+Observ. 24. Of the Surfaces of some Leaves.
+
+_The description, 1. Of the bald Surfaces of Leaves. 2. Of the downy
+Surfaces of several others. 3. Of the gummous exsudation, or small
+transparent Pearls, discovered with a _Microscope_ in several others. An
+Instance of all which is afforded in a Rosemary Leaf._
+
+Observ. 25. Of the stinging Points of a Nettle.
+
+_A description of the Needles and several other contrivances in the leaf of
+a Nettle: how the stinging pain is created: upon this several
+considerations about poysoning Darts are set down. An Experiment of killing
+Effs, and Fishes with Salt. Some conjectures at the efficacy of Baths; the
+use that may be made of injecting into the Veins. A very remarkable History
+out of _Bellonius_; and some Considerations about staining and dying of
+Bodies._
+
+Observ. 26. Of Cowage.
+
+_The description of it out of _Parkinson_: an Experiment made of it: a
+description, and some conjectures at the cause of the _Phænomena_._
+
+Observ. 27. Of the Beard of a wild Oat.
+
+_The description of its shape and properties: the manner of making a
+_Hygroscope_ with it; and a Conjecture at the causes of these motions, and
+of the motions of the Muscles._
+
+Observ. 28. Of the Seeds of _Venice_ Looking-glass.
+
+_The description of them._
+
+Obser. 29. Of the Seeds of Time.
+
+_A description of them. A digression about Natures method._
+
+Observ. 30. Of Poppy Seeds.
+
+_The description and use of them._
+
+Observ. 31. Of Purslane Seeds.
+
+_A description of these and many other Seeds._
+
+Observ. 32. Of Hair.
+
+_The description of several sorts of Hair; their Figures and Textures: the
+reason of their colours, A description of the texture of the skin, and of
+Spunk and Sponges: by what passages and pores of the skin transpiration
+seems to be made. Experiments to prove the porousness of the skin of
+Vegetables._
+
+Observ. 33. Of the Scales of a Soale.
+
+_A description of their beauteous form._
+
+Observ. 34. Of the Sting of a Bee.
+
+_A description of its shape, mechanisme, and use._
+
+Observ. 35. Of Feathers.
+
+_A description of the shape and curious contexture of Feathers: and some
+conjectures thereupon._
+
+Obser. 36. Of Peacocks Feathers.
+
+_A description of their curious form and proprieties; with a conjecture at
+the cause of their variable colours._
+
+Obser. 37. Of the Feet of Flyes, and other Insects.
+
+_A description of their figure, parts, and use; and some considerations
+thereupon._
+
+Obser. 38. Of the Wings of Flyes.
+
+_After what manner and how swiftly the wings of Insects move. A description
+of the Pendulums under the wings, and their motion; the shape and structure
+of the parts of the wing._
+
+Obser. 39. Of the Head of a Fly.
+
+_1. All the face of a Drone-fly is nothing almost but eyes. 2. Those are of
+two magnitudes. 3. They are Hemispheres, and very reflective and smooth. 4.
+Some directed towards every quarter. 5. How the fly cleanses them. 6. Their
+number. 7. Their order: divers particulars observ’d in the dissecting a
+head. That these are very probably the eyes of the Creature; argued from
+several Observations and Experiments, that Crabs, Lobsters, Shrimps, seem
+to be water Insects, and to be framed much like Air Insects. Several
+Considerations about their manner of vision._
+
+Obser. 40. Of the Teeth of a Snail.
+
+_A brief description of it._
+
+Observ. 41. Of the Eggs of Silk-worms.
+
+_Several Observables about the Eggs of Insects._
+
+Observ. 42. Of a blue Fly.
+
+_A description of its outward and inward parts. Its hardiness to indure
+freezing, and sleeping in Spirit of wine._
+
+Observ. 43. Of a water Insect.
+
+_A description of its shape, transparency, motion, both internal and
+progressive, and transformation. A History somewhat _Analogus_ cited out of
+_Piso_. Several Observations about the various wayes of the generations of
+Insects: by what means they act so seemingly wisely and prudently. Several
+Quæries propounded. Postscript, containing a relation of another very odd
+way of the generation of Insects. An Observation about the fertility of the
+Earth of our Climate in producing Insects, and of divers other wayes of
+their generation._
+
+Observ. 44. Of the tufted Gnat.
+
+_Several Observables about Insects, and a more particular description the
+parts of this Gnat._
+
+Ob. 45. Of the great belly’d Gnat.
+
+_A short description of it._
+
+Obser. 46. Of a white Moth.
+
+_A description of the feathers and wings of this, and several other
+Insects. Divers Considerations about the wings, and the flying of Insects
+and Birds._
+
+Obs. 47. Of the Shepherd Spider.
+
+_A description of its Eyes: and the sockets of its long legs: and a
+Conjecture of the mechanical reason of its fabrick; together with a
+supposition, that ’tis not unlikely, but Spiders may have the make of their
+inward parts exactly like a Crab, which may be call’d a water Spider._
+
+Obser. 48. Of the hunting Spider.
+
+_A short description of it; to which is annext an excellent History of it,
+made by Mr. _Evelyn_. Some further Observations on other Spiders, and their
+Webs, together with an examination of a white Substance flying up and down
+in the Air after a Fog._
+
+Obser. 49. Of an Ant.
+
+_That all small Bodies, both Vegetable and Animal, do quickly dry and
+wither. The best remedy I found to hinder it, and to make the Animal lye
+still to be observ’d. Several particulars related of the actions of this
+Creature and a short description of its parts._
+
+Obs. 50. Of the wandring Mite.
+
+_A description of this Creature, and of another very small one, which
+usually bore it company. A Conjecture at the original of Mites._
+
+Observ. 51. Of a Crab-like Insect.
+
+_A brief description of it._
+
+Observ. 52. Of a Book-worm.
+
+_A description of it; where by the way is inserted a digression,
+experimentally explicating the _Phænomena_ of Pearl. A consideration of its
+digestive faculty._
+
+Observ. 53. Of a Flea.
+
+_A short description of it._
+
+Observ. 54. Of a Louse.
+
+_A description of its parts, and some notable circumstances._
+
+Observ. 55. Of Mites.
+
+_The exceeding smalness of some Mites, and their Eggs. A description of the
+Mites of Cheese: and an intimation of the variety of forms in other Mites,
+with a Conjecture at the reason._
+
+Ob. 56. Of small Vine-Mites.
+
+_A description of them; a ghess at their original; their exceeding smalness
+compar’d with that of a Wood-louse, from which they may be suppos’d to
+come._
+
+Observ. 57. Of Vinegar-worms.
+
+_A description of them, with some considerations on their motions._
+
+Obs. 58. Of the Inflection of the Rays of Light in the Air.
+
+_A short rehearsal of several _Phænomena_. An attempt to explicate them:
+the supposition founded on two Propositions, both which are indeavoured to
+be made out by several Experiments, What density and rarity is in respect
+of refraction: the refraction of Spirit of Wine compared with that of
+common Water: the refraction of Ice. An Experiment of making an Undulation
+of the Rays by the mixing of Liquors of differing density. The explication
+of _inflection_, mechanically and hypothetically: what Bodies have such an
+inflection. Several Experiments to shew that the Air has this propriety;
+that it proceeds from the differing density of the Air: that the upper and
+under part of the Air are of differing density: some Experiments to prove
+this. A Table of the strength of the spring of the Air, answering to each
+degree of extension; when first made, and when repeated. Another Experiment
+of compressing the Air. A Table of the strength of the Air, answering to
+each compression and expansion; from which the height of the Air may be
+suppos’d indefinite; to what degree the Air is rarifi’d at any distance
+above the Surface of the Earth: how, from this, Inflection is inferr’d; and
+several _Phænomena_ explain’d. That the Air near the Earth is compos’d of
+parts of differing density; made probable by several Experiments and
+Observations; how this propriety produces the effects of the waving and
+dancing of Bodies; and of the twinkling of the Stars. Several _Phænomena_
+explicated. Some Quæries added._
+
+1. _Whether this Principle may not be made use of, for perfecting Optick
+Glasses? What might be hoped from it if it were to be done?_
+
+2. _Whether from this Principle the apparition of some new Stars may not be
+explicated?_
+
+3. _Whether the height of the Air may be defin’d by it?_
+
+4. _Whether there may not sometimes be so great a disparity of density
+between the upper and under parts of the Air, as to make a reflecting
+Surface?_
+
+5. _Whether, if so, this will not explicate the _Phænomena_ of the Clouds.
+An Experiment to this purpose?_
+
+7. _Whether the Rayes from the top of Mountains are not bended into
+Curve-lines by inflection? An Argument for it, taken from an Experiment
+made on St. _Paul_’s Steeple._
+
+8. _Whether the distance of the Planets will not be more difficult to be
+found? What wayes are most likely to rectifie the distance of the Moon: the
+way of fitting _Telescopes_ for such Observations. How to make the
+Observations, and how from them to find the true distance of the Moon at
+any time. How the distance of the Sun may be found by two Observators. The
+way by the Dichotomy of the Moon uncertain. That the distance of the Moon
+may be less then it has been hitherto suppos’d. _Kepler_’s Supposition not
+so probable: the explication of the _Phænomena_ by another _Hypothesis_._
+
+Observ. 59. Of the fixt Stars.
+
+_Of the multitudes of Stars discoverable by the _Telescope_, and the
+variety of their magnitudes: 78. Stars distinguisht in the _Pleiades_: that
+there are degrees of bigness even in the Stars accounted of the same
+magnitude: the longer the Glasses are, and the bigger apertures they will
+indure, the more fit they are for these discoveries: that ’tis probable,
+longer Glasses would yet make greater discoveries. 5. Stars discover’d in
+the _Galaxie_ of _Orion_’s Sword._
+
+Observ. 60. Of the Moon.
+
+_A description of a Vale in the Moon; what call’d by _Hevelius_ and
+_Ricciolus_, and how describ’d by them: with what substances the hills of
+the Moon may be cover’d. A description of the pits of the Moon, and a
+conjecture at their cause: two Experiments that make it probable, that of
+the surface of boyl’d Alabaster dust seeming the most likely to be
+resembled by eruptions of vapours out of the body of the Moon: that
+Earthquakes seem to be generated much the same way, and their effects seem
+very similar. An Argument that there may be such variations in the Moon,
+because greater have been observ’d in the Sun: because the substance of the
+Moon and Earth seem much alike: and because ’tis probable the Moon has a
+gravitating principle: this is argued from several particulars. The reason
+why several pits are one within another. The use that may be made of this
+Instance of a gravity in the Moon._
+
+       *       *       *       *       *
+
+
+[1] _Schem._ 2. _Fig._ 1.
+
+[2] Diop. ch. 10. § 9.
+
+[3] _Schem._ 2. _Fig._ 2.
+
+[4] _Schem._ 1.* _Fig._ 3.
+
+[5] _Schem._ 3. _Fig._ 1.
+
+[6] _Schem._ 3. _Fig._ 2.
+
+[7] _Schem._ 4.
+
+[8] _Schem._ 4. _Fig._ 1.
+
+[9] _Schem._ 6. _Fig._ 3.
+
+[10] _Schem._ 6. _Fig._ 3.
+
+[11] _Schem._ 8. _Fig._ 1.
+
+[12] _Schem._ 8. _Fig._ 2.
+
+[13] _Schem._ 9. _Fig._ 1.
+
+    [14] See _Schem._ 11. _Fig._ 2.
+
+[15] _Fig._ 1. _Schem._ 36.
+
+[16] _Fig._ 3.
+
+
+
+
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