diff options
Diffstat (limited to '31999-h/31999-h.htm')
| -rw-r--r-- | 31999-h/31999-h.htm | 2777 |
1 files changed, 2777 insertions, 0 deletions
diff --git a/31999-h/31999-h.htm b/31999-h/31999-h.htm new file mode 100644 index 0000000..612d522 --- /dev/null +++ b/31999-h/31999-h.htm @@ -0,0 +1,2777 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml"> + <head> + <meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1" /> + <title> + The Project Gutenberg eBook of The Natural Philosophy of William Gilbert and His Predecessors, by W. James King. + </title> + <style type="text/css"> + + p { margin-top: .75em; + text-align: justify; + margin-bottom: .75em; + } + h1,h2,h3,h4 { + text-align: center; /* all headings centered */ + clear: both; + } + hr { width: 33%; + margin-top: 2em; + margin-bottom: 2em; + margin-left: auto; + margin-right: auto; + clear: both; + } + + body{margin-left: 10%; + margin-right: 10%; + } + + .pagenum { /* uncomment the next line for invisible page numbers */ + /* visibility: hidden; */ + position: absolute; + left: 92%; + font-size: smaller; + text-align: right; + } /* page numbers */ + + .blockquot{margin-left: 5%; margin-right: 10%;} + + .center {text-align: center;} + .smcap {font-variant: small-caps;} + .u {text-decoration: underline;} + + .caption {font-weight: bold;} + + .figcenter {margin: auto; text-align: center;} + + .footnotes {border: dashed 1px;} + .footnote {margin-left: 10%; margin-right: 10%; font-size: 0.9em;} + .footnote .label {position: absolute; right: 84%; text-align: right;} + .fnanchor {vertical-align: super; font-size: .8em; text-decoration: none;} + + .poem {margin-left:10%; margin-right:10%; text-align: left;} + + </style> + </head> +<body> + + +<pre> + +The Project Gutenberg EBook of The Natural Philosophy of William Gilbert +and His Predecessors, by W. James King + +This eBook is for the use of anyone anywhere 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 + + +Title: The Natural Philosophy of William Gilbert and His Predecessors + +Author: W. James King + +Release Date: April 15, 2010 [EBook #31999] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK NATURAL PHILOSOPHY--WILLIAM GILBERT *** + + + + +Produced by Chris Curnow, Joseph Cooper and the Online +Distributed Proofreading Team at https://www.pgdp.net + + + + + + +</pre> + + + +<p><span class='pagenum'><a name="Page_121" id="Page_121">[Pg 121]</a></span></p> + + +<p style='text-align:right;'><big><span class="smcap">Contributions from<br /><br /> + +the Museum of History and Technology:<br /><br /> + +Paper 8<br /><br /><br /></span></big></p> + + +<p style='text-align:right;'><big><span class="smcap">The Natural Philosophy of<br /> +William Gilbert and His Predecessors</span><br /><br /> + +<i>W. James King</i><br /><br /></big></p> + +<hr style="width: 65%;" /> +<p><span class='pagenum'><a name="Page_122" id="Page_122">[Pg 122]</a></span></p> +<p style='text-align:right;'><big>By W. James King</big></p> +<h2>THE NATURAL PHILOSOPHY OF</h2> + +<h1>WILLIAM GILBERT</h1> + +<h2>AND HIS PREDECESSORS</h2> + +<div class="blockquot"><p><big><i>Until several decades ago, the physical sciences were +considered to have had their origins in the 17th century—mechanics +beginning with men like Galileo Galilei and +magnetism with men like the Elizabethan physician and +scientist William Gilbert.<br /><br /> + +Historians of science, however, have traced many of the +17th century's concepts of mechanics back into the Middle +Ages. Here, Gilbert's explanation of the loadstone and +its powers is compared with explanations to be found in +the Middle Ages and earlier.<br /><br /> + +From this comparison it appears that Gilbert can best +be understood by considering him not so much a herald +of the new science as a modifier of the old.</i><br /><br /> + +<span class="smcap">The Author</span>: <i>W. James King is curator of electricity, +Museum of History and Technology, in the Smithsonian +Institution's United States National Museum.</i></big></p></div> + +<p>The year 1600 saw the publication by an English +physician, William Gilbert, of a book on the +loadstone. Entitled <i>De magnete</i>,<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a> it has traditionally +been credited with laying a foundation for the +modern science of electricity and magnetism. The +following essay is an attempt to examine the basis +for such a tradition by determining what Gilbert's +original contributions to these sciences were, and +to make explicit the sense in which he may be considered +as being dependent upon earlier work. In +this manner a more accurate estimate of his position +in the history of science may be made.</p> + +<div class="figcenter" style="width: 700px;"> +<p><span class='pagenum'><a name="Page_123" id="Page_123">[Pg 123]</a></span></p> +<img src="images/title.jpg" width="700" height="1000" alt="William Gilbert's Book on the Loadstone" title="William Gilbert's Book on the Loadstone" /> +<span class="caption">Figure 1.—<span class="smcap">William Gilbert's Book on the Loadstone, Title Page of the First Edition, +from a Copy in the Library of Congress.</span> (<i>Photo courtesy of the Library of Congress.</i>)</span> +</div> + +<p>One criterion as to the book's significance in the +history of science can be applied almost immediately. +A number of historians have pointed to the introduction +of numbers and geometry as marking a +watershed between the modern and the medieval +understanding of nature. Thus A. Koyré considers +the Archimedeanization of space as one of the necessary +features of the development of modern astronomy +and physics.<a name="FNanchor_2_2" id="FNanchor_2_2"></a><a href="#Footnote_2_2" class="fnanchor">[2]</a> +A. N. Whitehead and E. Cassirer have turned to measurement +and the quantification of force as marking this +transition.<a name="FNanchor_3_3" id="FNanchor_3_3"></a><a href="#Footnote_3_3" class="fnanchor">[3]</a> +However, the<span class='pagenum'><a name="Page_124" id="Page_124">[Pg 124]</a></span> +obvious absence<a name="FNanchor_4_4" id="FNanchor_4_4"></a><a href="#Footnote_4_4" class="fnanchor">[4]</a> +of such techniques in <i>De magnete</i> makes it difficult to consider +Gilbert as a founder of modern electricity and magnetism in this +sense.</p> + +<p>There is another sense in which it is possible to +contend that Gilbert's treatise introduced modern +studies in these fields. He has frequently been +credited with the introduction of the inductive +method based upon stubborn facts, in contrast to +the methods and content of medieval Aristotelianism.<a name="FNanchor_5_5" id="FNanchor_5_5"></a><a href="#Footnote_5_5" class="fnanchor">[5]</a> +No science can be based upon faulty observations +and certainly much of <i>De magnete</i> was devoted to the +destruction of the fantastic tales and occult sympathies +of the Romans, the medieval writers, and the +Renaissance. However, let us also remember that +Gilbert added few novel empirical facts of a +fundamental nature to previous observations on the +loadstone. Gilbert's experimental work was in large +part an expansion of Petrus Peregrinus' <i>De magnete</i> +of 1269,<a name="FNanchor_6_6" id="FNanchor_6_6"></a><a href="#Footnote_6_6" class="fnanchor">[6]</a> and a development of works like Robert Norman's +<i>The new attractive</i>,<a name="FNanchor_7_7" id="FNanchor_7_7"></a><a href="#Footnote_7_7" class="fnanchor">[7]</a> in which the author discussed +how one could show experimentally the declination and +inclination of a magnetized needle, and like William +Borough's <i>Discourse on the variation of the compass or +magnetized needle</i>,<a name="FNanchor_8_8" id="FNanchor_8_8"></a><a href="#Footnote_8_8" class="fnanchor">[8]</a> in which the author suggested the +use of magnetic declination and inclination for navigational +purposes but felt too little was known about +it. That other sea-going nations had been considering +using the properties of the magnetic compass to solve +their problems of navigation in the same manner can +be seen from Simon Stevin's <i>De havenvinding</i>.<a name="FNanchor_9_9" id="FNanchor_9_9"></a><a href="#Footnote_9_9" class="fnanchor">[9]</a></p> + +<p>Instead of new experimental information, Gilbert's +major contribution to natural philosophy was that +revealed in the title of his book—a new philosophy +of nature, or physiology, as he called it, after the +early Greeks. Gilbert's attempt to organize the mass +of empirical information and speculation that came +from scholars and artisans, from chart and instrument +makers, made him "the father of the magnetic +Philosophy."<a name="FNanchor_10_10" id="FNanchor_10_10"></a><a href="#Footnote_10_10" class="fnanchor">[10]</a></p> + +<p>Gilbert's <i>De magnete</i> was not the first attempt to +determine the nature of the loadstone and to explain +how it could influence other loadstones or iron. It +is typical of Greek philosophy that one of the first +references we have to the loadstone is not to its +properties but to the problem of how to explain these +properties. Aristotle<a name="FNanchor_11_11" id="FNanchor_11_11"></a><a href="#Footnote_11_11" class="fnanchor">[11]</a> preserved the solution of the +first of the Ionian physiologists: "Thales too ... +seems to suppose that the soul is in a sense the cause +of movement, since he says that a stone has a soul +because it causes movement to iron." Plato turned +to a similar animistic explanation in his dialogue, +<i>Ion</i>.<a name="FNanchor_12_12" id="FNanchor_12_12"></a><a href="#Footnote_12_12" class="fnanchor">[12]</a> Such an animistic solution pervaded many of +the later explanations.</p> + +<p>That a mechanical explanation is also possible was +shown by Plato in his <i>Timaeus</i>.<a name="FNanchor_13_13" id="FNanchor_13_13"></a><a href="#Footnote_13_13" class="fnanchor">[13]</a> He argued that +since a vacuum does not exist, there must be a +plenum throughout all space. Motion of this +plenum can carry objects along with it, and one +could in this manner explain attractions like that due +to amber and the loadstone.</p> + +<p>Another mechanical explanation was based upon +a postulated tendency of atoms to move into a vacuum +rather than upon the latter's non-existence. +Lucretius restated this Epicurean explanation in his +<span class='pagenum'><a name="Page_125" id="Page_125">[Pg 125]</a></span> +<i>De rerum natura</i>.<a name="FNanchor_14_14" id="FNanchor_14_14"></a><a href="#Footnote_14_14" class="fnanchor">[14]</a> Atoms from the loadstone push +away the air and tend to cause a vacuum to form +outside the loadstone. The structure of iron is such +that it, unlike other materials, can be pushed into +this empty space by the thronging atoms of air beyond +it.</p> + +<p>Galen<a name="FNanchor_15_15" id="FNanchor_15_15"></a><a href="#Footnote_15_15" class="fnanchor">[15]</a> +returned to a quasi-animistic solution in his denial of Epicurus' +argument, which he stated somewhat differently from Lucretius. One can +infer that Galen held that all things have, to a greater or lesser +degree, a sympathetic faculty of attracting its specific, or proper, +quality to itself.<a name="FNanchor_16_16" id="FNanchor_16_16"></a><a href="#Footnote_16_16" class="fnanchor">[16]</a> +The loadstone is only an inanimate example of what one finds in +nutritive organs in organic beings.</p> + +<p>One of the few writers whose explanations of the +loadstone Gilbert mentioned with approval is St. +Thomas Aquinas. Although the medieval scholastic +philosophy of St. Thomas seems foreign to our way +of thinking, it formed a background to many of Gilbert's +concepts, as well as to those of his predecessors, +and it will assist our discussion to consider briefly +Thomist philosophy and to make its terminology +explicit at this point.<a name="FNanchor_17_17" id="FNanchor_17_17"></a><a href="#Footnote_17_17" class="fnanchor">[17]</a></p> + +<p>In scholastic philosophy, all beings and substances +are a coalescence of inchoate matter and enacting +form. Form is that which gives being to matter and +which is responsible for the "virtus" or power to cause +change, since matter in itself is inert. Moreover, +forms can be grasped intellectually, whence the +nature of a being or a substance can be known. Any +explanation of phenomena has to be based upon +these innate natures, for only if the nature of a substance +is known can its properties be understood. +Inanimate natures are determined by observation, +abstraction, and induction, or by classification.<a name="FNanchor_18_18" id="FNanchor_18_18"></a><a href="#Footnote_18_18" class="fnanchor">[18]</a></p> + +<p>The nature of a substance is causally prior to its +properties; while the definition of the nature is logically +prior to these properties. Thus, what we call +the theory of a substance is expressed in its definition, +and its properties can be deduced from this +definition.</p> + +<p>The world of St. Thomas is not a static one, but +one of the Aristotelian motions of quantity (change +of size), of quality (alteration), and of place (locomotion). +Another kind of change is that of substance, +called generation and corruption, but this is a mutation, +occurring instantly, rather than a motion, that +requires time. In mutation the essential nature is +replaced by a new substantial form.</p> + +<p>All these changes are motivated by a causal hierarchy +that extends from the First Cause, the "Dator +Formarum," or Creator, to separate intellectual substances +that may be angels or demons, to the celestial +bodies that are the "generantia" of the substantial +forms of the elements and finally to the four prime +qualities (dry and wet, hot and cold) of the substantial +forms. Accidental forms are motivated by the substantial +forms through the instrumentality of the four +prime qualities, which can only act by material +contact.</p> + +<p>The only causal agents in this hierarchy that are +learned through the senses are the tangible qualities. +Usually the prime qualities are not observed directly, +but only other qualities compounded of them. One +of the problems of scholastic philosophy was the +incorporation, into this system of efficient agents, +of other qualities, such as the qualities of gravity +and levity that are responsible for upward and downward +motion.</p> + +<p>Besides the causal hierarchy of forms, the natural +world of St. Thomas existed in a substantial and spatial +hierarchy. All substances whether an element or a +mixture of elements have a place in this hierarchy +by virtue of their nature. If the material were removed +from its proper place, it would tend to return. +In this manner is obtained the natural downward +motion of earth and the natural upward motion +of fire.</p> + +<p>Local motion can also be caused by the "virtus coeli" +generating a new form, or through the qualitative +change of alteration. Since each element and mixture +has its own natural place in the hierarchy of material +substances, and this place is determined by its nature, +changes of nature due to a change of the form can +produce local motion. If before change the substance +is in its natural place, it need not be afterwards, +and if not, would then tend to move to its new +natural place.</p> + +<p>It will be noted that the scholastic explanation of +<span class='pagenum'><a name="Page_126" id="Page_126">[Pg 126]</a></span> +inanimate motion involved the action and passion +of an active external mover and a passive capacity +to be moved. Whence the definition of motion that +Descartes<a name="FNanchor_19_19" id="FNanchor_19_19"></a><a href="#Footnote_19_19" class="fnanchor">[19]</a> was later to deride, "motus est actus +entis in potentia prout quod in potentia."</p> + +<p>We have seen above that the "motor essentialis" +for terrestial change is the "virtus coeli." Thus the +enacting source of all motion and change is the +heavens and the heavenly powers, while the earth +and its inhabitants becomes the focus or passive +recipient of these actions. In this manner the scholastic +restated in philosophical terms the drama of an +earth-centered universe.</p> + +<p>Although change or motion is normally effected +through the above mentioned causal hierarchy, it is +not always necessary that actualization pass from the +First Cause down through each step of the hierarchy +to terminate in the qualities of the individual being. +Some of the steps could be by-passed: for instance +man's body is under the direct influence of the +celestial bodies, his intellect under that of the angels +and his will under God.<a name="FNanchor_20_20" id="FNanchor_20_20"></a><a href="#Footnote_20_20" class="fnanchor">[20]</a> Another example of effects +not produced through the tangible prime qualities +is that of the tide-producing influence of the moon +on the waters of the ocean or the powers of the loadstone +over iron. Such causal relations, where some +members of the normal causal chain have been +circumvented, are called occult.<a name="FNanchor_21_21" id="FNanchor_21_21"></a><a href="#Footnote_21_21" class="fnanchor">[21]</a></p> + +<p>While St. Thomas referred to the loadstone in a +number of places as something whose nature and +occult properties are well known, it was always as +an example or as a tangential reference. One does +not find a systematic treatment of the loadstone in +St. Thomas, but there are enough references to +provide a fairly explicit statement of what he considered +to be the nature of the magnet.</p> + +<p>In one of his earliest writings, St. Thomas argued +that the magnet attracts iron because this is a necessary +consequence of its nature.<a name="FNanchor_22_22" id="FNanchor_22_22"></a><a href="#Footnote_22_22" class="fnanchor">[22]</a></p> + +<div class="blockquot"><p>Respondeo dicendum, quod omnibus rebus naturaliter +insunt quaedam principia, quibus non solum operationes +proprias efficere possunt, sed quibus etiam eas convenientes +fini suo reddant, sive sint actiones quae consequantur rem +aliquam ex natura sui generis, sive consequantur ex natura +speciei, ut magneti competit ferri deorsum ex natura sui +generis, et attrahere ferrum ex natura speciei. Sicut autem +in rebus agentibus ex necessitate naturae sunt principia +actionum ipsae formae, a quibus operationes proprie prodeunt +convenientes fini....</p></div> + +<p>Due to its generic form, the loadstone is subject to natural motion of +place of up and down. However, the "virtus" of its specific form +enabled it to produce another kind of motion—it could draw iron +to itself.</p> + +<p>Normally the "virtus" of a substance is limited to those contact +effects that could be produced by the form operating through the +active qualities of one substance, on the relatively passive qualities +of another. St. Thomas asserted the loadstone to be one of these +minerals, the occult powers of whose form goes beyond those of the +prime qualities.<a name="FNanchor_23_23" id="FNanchor_23_23"></a><a href="#Footnote_23_23" class="fnanchor">[23]</a></p> + +<div class="blockquot"><p>Forma enim elementi non habet aliquam operationem +nisi quae fit per qualitates activas et passivas, quae sunt +dispositiones materiae corporalis. Forma autem corporis +mineralis habet aliquam operationem excedentem qualitates +activas et passivas, quae consequitur speciem ex influentia +corporis coelestis, ut quod magnes attrahit ferrum, et quod +saphirus curat apostema.</p></div> + +<p>That this occult power of the loadstone is a result +of the direct influence of the "virtus coeli" was +<span class='pagenum'><a name="Page_127" id="Page_127">[Pg 127]</a></span> +expounded at greater length in his treatise on the +soul.<a name="FNanchor_24_24" id="FNanchor_24_24"></a><a href="#Footnote_24_24" class="fnanchor">[24]</a></p> + +<div class="blockquot"><p>Quod quidem ex propriis formarum operationibus +perpendi potest. Formae enim elementorum, quae sint +infimae et materiae propinquissime, non habent aliquam +operationem excedentem qualitates activas et passivas, ut +rarum et densum, et aliae huiusmodi, qui videntur esse +materiae dispositiones. Super has autem sunt formae +mistorum quae praeter praedictas operationes, habent +aliquam operationem consequentem speciem, quam fortiuntur +ex corporibus coelestibus; sicut quod magnes attrahit +ferrum non propter calorem aut frigiis, aut aliquid huiusmodi; +sed ex quadam participatione virtutis coelestis. +Super has autem formas sint iterum animae plantarum, +quae habent similitudinem non solum ad ipsa corpora +coelestia, sed ad motores corporum coelestium, inquantum +sunt principia cuiusdam motus, quibusdam seipsa moventibus. +Super has autem ulterius sunt animae brutorum, +quae similitudinem iam habent ad substantiam moventem +coelestia corpora, non solum in operatione qua movent +corpora, sed etiam in hoc quod in seipsis cognoscitivae sunt, +licet brutorum cognitio sit materialium tantum et materialiter....</p></div> + +<p>St. Thomas placed the form of the magnet and its +powers in the hierarchy of forms intermediate between +the forms of the inanimate world and the +forms of the organic world with its hierarchy of plant, +animal and rational souls. The form of the loadstone +is then superior to that of iron, which can only act +through its active and passive qualities, but inferior +to the plant soul, that has the powers of growth from +the "virtus coeli." This is similar to Galen's comparison +of the magnet's powers to that of the nutritive +powers of organic bodies.</p> + +<p>In his commentary on Aristotle's <i>Physics</i>, St. Thomas +explained how iron is moved to the magnet. It is +moved by some quality imparted to the iron by +the magnet.<a name="FNanchor_25_25" id="FNanchor_25_25"></a><a href="#Footnote_25_25" class="fnanchor">[25]</a></p> + +<div class="blockquot"><p>Illud ergo trahere dicitur, quod movet alterum ad +seipsum. Movere autem aliquid secundum locum ad +seipsum contingit tripliciter. Uno modo sicut finis movet; +unde et finis dicitur trahere, secundum illud poetate: +"trahit sua quemque voluptas": et hoc modo potest dici quod +locus trahit id, quod naturaliter movetur ad locum. Alio +modo potest dici aliquid trahere, quia movet illud ad +seipsum alterando aliqualiter, ex qua alteratione contingit +quod alteratum moveatur secundum locum: et hoc modo +magnes dicitur trahere ferrum. Sicut enim generans +movet gravia et levia, inquantum dat eis formarum per +quam moventur ad locum, ita et magnes dat aliquam +qualitatem ferro, per quam movetur ad ipsum. Et quod +hoc sit verum patet ex tribus. Primo quidem quia magnes +non trahit ferrum ex quacumque distantia, sed ex propinquo; +si autem ferrum moveretur ad magnetem solum sicut +ad finem, sicut grave ad suum locum, ex qualibet distantia +tenderet ad ipsum. Secundo, quia, si magnes aliis perungatur, +ferrum attrahere non potest; quasi aliis vim +alterativam ipsius impedientibus, aut etiam in contrarium +alterantibus. Tertio, quia ad hoc quod magnes attrahat +ferrum, oportet prius ferrum liniri cum magnete, maxime +si magnes sit parvus; quasi ex magnete aliquam virtutem +ferrum accipiat ut ad eum moveatur. Sic igitur magnes +attrahit ferrum non solum sicut finis, sed etiam sicut movens +et alterans. Tertio modo dicitur aliquid attrahere, quia +movet ad seipsum motu locali tantum. Et sic definitur hic +tractio, prout unum corpus trahit alteram, ita quod trahens +simul moveatur cum eo quod trahitur.</p></div> + +<p>As the "generans" of terrestrial change moves what +is light and heavy to another place by implanting +a new form in a substance, so the magnet moves the +iron by impressing upon it the quality by which it +is moved. By virtue of the new quality, the iron is +not in its natural place and moves accordingly. +St. Thomas proved that the loadstone acts as a +secondary "generans" in three ways: (1) the loadstone +produces an effect not from any distance +but only from a nearby position (showing that this +motion is due to more than place alone), (2) rubbing +the loadstone with garlic acts as if it impedes or +alters the "virtus magnetis," and (3) the iron must +be properly aligned with respect to the loadstone in +order to be moved, especially if the loadstone is small. +Thus the iron is moved by the magnet not only to a +place, but also by changing and altering it: one has +not only the change of locomotion but that of alteration. +Moreover the source of this alteration in the +iron is not the heavens but the loadstone. Accordingly +the loadstone could cause change in another substance +because it could influence the nature of the +other substance.</p> + +<p>About the time that St. Thomas was writing his +letter <i>De operationibus occultis naturae</i> to a certain +knight, Petrus Peregrinus was writing from a military +camp a letter in which he showed how certain relatively +new effects could be produced by the loadstone. +<span class='pagenum'><a name="Page_128" id="Page_128">[Pg 128]</a></span> +He was more interested in what he could do with +the magnet than in explaining these effects. However, +he discussed it at sufficient length for one to find that +his explanation of magnetic phenomena was basically +similar to that of his contemporary, St. Thomas.</p> + +<p>Peregrinus based his discussion of the loadstone +upon its nature and analyzed magnetic phenomena +in terms of the change of alteration. In magnetic +attraction, the nature of the iron is altered by having +a new quality impressed upon it,<a name="FNanchor_26_26" id="FNanchor_26_26"></a><a href="#Footnote_26_26" class="fnanchor">[26]</a> and the loadstone +is the agent that makes the iron the same species as +the stone.<a name="FNanchor_27_27" id="FNanchor_27_27"></a><a href="#Footnote_27_27" class="fnanchor">[27]</a></p> + +<div class="blockquot"><p>... Oportet enim quod illud quod iam conversum est ex +duobus in unum, sit in eadem specie cum agente; quod +non esset, si natura istud impossible eligeret.</p></div> + +<p>This impressed similarity to the agent, Peregrinus +realized, is not a pole of the same polarity but one +opposite to that of the inducing pole. To produce +this effect, the virtue of the stronger agent dominates +the weaker patient and impresses the virtue of the +stronger on the weaker so that they are made similar.<a name="FNanchor_28_28" id="FNanchor_28_28"></a><a href="#Footnote_28_28" class="fnanchor">[28]</a></p> + +<div class="blockquot"><p>... In cuius attractione, lapis fortioris virtutis agens est; +debilioris vero patiens.</p></div> + +<p>A further instance of alteration occurs in the reversal +of polarity of magnetized iron when one brings two +similar poles together. Again, the stronger agent +dominates the weaker patient and the iron is left +with a similarity to the last agent.<a name="FNanchor_29_29" id="FNanchor_29_29"></a><a href="#Footnote_29_29" class="fnanchor">[29]</a></p> + +<div class="blockquot"><p>... Causa huis est impressio ultimi agentis, confundentis et +alterantis virtutem primi.</p></div> + +<p>In this assimilation of the agent to the patient, +another effect is produced: the agent not only desires +to assimilate the patient to itself, but to unite with +it to become one and the same. Speaking of the +motion to come together, he says:<a name="FNanchor_30_30" id="FNanchor_30_30"></a><a href="#Footnote_30_30" class="fnanchor">[30]</a></p> + +<div class="blockquot"><p>Huius autem rei causam per hanc viam fieri existimo: +agens enim intendit suum patiens non solum sibi assimilare, +sed unire, ut ex agente et patiente fiat unum, per numerum. +Et hoc potes experiri in isto lapide mirabili in hunc modum.... +Agens ergo, ut vides experimento, intendit suum paciens +sibi unire; hoc autem fit ratione similitudinis inter ea. +Oportet ergo ... virtute attractionis, fiat una linea, ex +agente et patiente, secundum hunc ordinem ...</p></div> + +<p>The nature of the magnet, as an active cause, tends +to enact, and since it acts in the best manner in which +it is able, it acts so as to preserve the similarities of +opposite poles.<a name="FNanchor_31_31" id="FNanchor_31_31"></a><a href="#Footnote_31_31" class="fnanchor">[31]</a></p> + +<div class="blockquot"><p>Natura autem, que tendet ad esse, agit meliori modo quo +potest, eligit primum ordinem actionis, in quo melius +salvatur idemptitas, quam in secundo ...</p></div> + +<p>Thus unlike poles tend to come together when a +dissected magnet is reassembled.</p> + +<p>Like St. Thomas, Peregrinus argued that the magnet +receives its powers from the heavens. But he further +specified this by declaring that different virtues from +the different parts of the heavens flow into their +counterpart in the loadstone—from the poles of the +heavens the virtue flows into the poles of the magnet,<a name="FNanchor_32_32" id="FNanchor_32_32"></a><a href="#Footnote_32_32" class="fnanchor">[32]</a></p> + +<div class="blockquot"><p>Praeterea cum ferrum, vel lapis, vertatur tarn ad partem +meridionalem quam ad partem septemtrionalem ... +existima cogimur, non solum a partem septemtrionali, +verum etiam a meridionali virtutem influi in polos lapidis, +magis quam a locis minere ... Omnes autem orbes +meridiani in polis mundi concurrent; quare, a polis mundi, +poli magnetis virtutem recipiunt. Et ex hoc apparet +manifeste quod non ad stellam nauticam movetur, cum +ibi non concurrant orbes meridiani, sed in polis; stella enim +nautica, extra orbem meridianum cuiuslibet regionis semper +invenitur, nisi bis, in completa firmanenti revolutione. Ex +hiis ergo manifestum est quod a partibus celi, partes +magnetis virtutem recipiunt.</p></div> + +<p>and similarly for the other parts of the heavens and +the other parts of the loadstone.<a name="FNanchor_33_33" id="FNanchor_33_33"></a><a href="#Footnote_33_33" class="fnanchor">[33]</a></p> + +<div class="blockquot"><p>Ceteras autem partes lapidis merito estimare potes, +influentiam a reliquis celi partibus retinere, ut non sic +solum polos lapidis a polis mundi, sed totum lapidem a toto +celo, recipere influentiam et virtutem, estimes.</p></div> + +<p>Physical proof for such influences was adduced by +Peregrinus from the motions of the loadstone. That +the poles of the loadstone receive their virtue from +the poles of the heavens follows experimentally from +north-south alignment of a loadstone. That not +only the poles but the entire loadstone receives power +from corresponding portions of the heavens follows +from the fact that a spherical loadstone, when +"properly balanced," would follow the motion of +the heavens.<a name="FNanchor_34_34" id="FNanchor_34_34"></a><a href="#Footnote_34_34" class="fnanchor">[34]</a></p> + +<p><span class='pagenum'><a name="Page_129" id="Page_129">[Pg 129]</a></span></p> +<div class="blockquot"><p>Quod tibi tali modo consulo experire: ... Et si tunc +lapis moveatur secundum celi motum, gaudeas te esse +assecutum secretum mirabile; si vero non, imperitie tue, +potiusquam nature, defectus imputetur. In hoc autem +situ, seu modo positionis, virtutes lapidis huius estimo +conservari proprie, et in reliquis sitibus celi virtutem eius +obsecari, seu ebetari, potiusquam conservari puto. Per +hoc autem instrumentum excusaberis ab omni horologio; +nam per ipsum scire poteris Ascensus in quacumque hora +volueris, et omnes alias celi dispositiones, quas querunt +Astrologi.</p></div> + +<p>As the heavens move eternally, so the spherical loadstone +must be a "perpetuum mobile".</p> + +<p>Another of the scholars whose explanation of the +loadstone Gilbert noted with approval was Cardinal +Nicholas of Cusa.<a name="FNanchor_35_35" id="FNanchor_35_35"></a><a href="#Footnote_35_35" class="fnanchor">[35]</a> The latter's references to it were +not as direct as those of St. Thomas, but he did use it +as an image several times to provide a microcosmic +example of the relation of God to his creation. From +this one can infer that he explained the preternatural +motion of the magnet and the iron by impressed +qualities, the heavens being the agent for the loadstone, +and the loadstone, the agent for iron.</p> + +<p>In the <i>Idiota de sapientia</i> the Cardinal used the +image of the magnet and the iron to provide a concrete +instance of his "coincidentia oppositorum," to +illustrate how eternal wisdom, in the Neoplatonic +sense, could, at the same time, be principle or cause of +being, its complement and also its goal.<a name="FNanchor_36_36" id="FNanchor_36_36"></a><a href="#Footnote_36_36" class="fnanchor">[36]</a></p> + +<div class="blockquot"><p>Si igitur in omni desiderio vitae intellectualis attenderes, +a quo est intellectus, per quod movetur et ad quod, in te +comperires dulcedinem sapientiae aeternae illam esse, quae +tibi facit desiderium tuum ita dulce et delectabile, ut in +inerrabili affectu feraris ad eius comprehensionem tanquam +ad immortalitatem vitae tue, quasi ad ferrum et magnetem +attendas. Habet enim ferrum in magnete quoddam sui +effluxus principium; et dum magnes per sui praesentiam +excitat ferrum grave et ponderosum, ferrum mirabili +desiderio fertur etiam supra motum naturae, quo secundum +gravitatem deorsum tendere debet, et sursum movetur +se in suo principio uniendo. Nisi enim in ferro esset +quaedam praegustatio naturalis ipsius magnetis, non +moveretur plus ad magnetem quam ad alium lapidem; et +nisi in lapide esset major inclinatio ad ferrum quam cuprum, +non esset illa attractio. Habet igitur spiritus noster +intellectualis ab aeterna sapientia principium sic intellectualiter +essendi, quod esse est conformius sapientae +quam aliud non intellectuale. Hinc irraditio seu immissio +in sanctam animam est motus desideriosus in excitatione.</p></div> + +<p>By virtue of the principle that flows from the magnet +to the iron—which principle is potentially in the iron, +for the iron already has a foretaste for it—the excited +iron could transcend its gravid nature and be preternaturally +moved to unite with its principle. Reciprocally, +the loadstone has a greater attraction to +the iron than to other things. Just as the power of +attraction comes from the loadstone, so the Deity is +the source of our life. Just as the principle implanted +in the magnet moves the iron against its heavy nature, +so the Deity raises us above our brutish nature so +that we may fulfill our life. As the iron moves to the +loadstone, so we move to the Deity as to the goal +and end of our life.</p> + +<p>In <i>De pace fidei</i>, Cusa<a name="FNanchor_37_37" id="FNanchor_37_37"></a><a href="#Footnote_37_37" class="fnanchor">[37]</a> again used the iron and +magnet as an example of motion contrary to and +transcending nature. He explained this supernatural +motion as being due to the similarity between the +nature of the iron and the magnet, and this in turn +is analogous to the similarity between human spiritual +nature and divine spiritual nature. As the iron can +move upward to the loadstone because both have +similar natures, so man can transcend his own nature +and move towards God when his potential similitude +to God is realized. Another image used by Cusa was +the comparison of Christ to the magnetic needle that +takes its power from the heavens and shows man +his way.<a name="FNanchor_38_38" id="FNanchor_38_38"></a><a href="#Footnote_38_38" class="fnanchor">[38]</a></p> + +<p>The Elizabethan Englishman Robert Norman also +turned to the Deity to explain the wonderful effects +of the loadstone.<a name="FNanchor_39_39" id="FNanchor_39_39"></a><a href="#Footnote_39_39" class="fnanchor">[39]</a></p> + +<div class="blockquot"><p>Now therefore ... divers have whetted their wits, +yea, and dulled them, as I have mine, and yet in the end +have been constrained to fly to the cornerstone: I mean +God: who ... hath given Virtue and power to this Stone +<span class='pagenum'><a name="Page_130" id="Page_130">[Pg 130]</a></span> +... to show one certain point, by his own nature and +appetite ... and by the same vertue, the Needle is turned +upon his own Center, I mean the Center of his Circular +and invisible Vertue ... And surely I am of opinion, +that if this would be found in a Sphericall form, extending +round about the Stone in Great Compass, and the dead body +Stone in the middle therof: Whose center is the center of +his aforesaid Vertue. And this I have partly proved, +and made visible to be seen in the same manner, and God +sparing me life, I will herein make further Experience.</p></div> + +<p>Again, one can infer that the heavens impart a +guiding principle to the iron which acts under the +influence of this Superior Cause.</p> + +<p>One of the points made in St. Thomas' argument +on motion due to the loadstone was that there is a +limit to the "virtus" of the loadstone, but he did not +specify the nature of it. Norman refined the Thomist +concept of a bound by making it spherical in form, +foreshadowing Gilbert's "orbis virtutis."</p> + +<p>Gilbert's philosophy of nature does not move far +from scholastic philosophy, except away from it in +logical consistency. As the concern of Aristotle and +of St. Thomas was to understand being and change +by determining the nature of things, so Gilbert +sought to write a logos of the physis, or nature, of the +loadstone—a physiology.<a name="FNanchor_40_40" id="FNanchor_40_40"></a><a href="#Footnote_40_40" class="fnanchor">[40]</a> This physiology was +not formally arranged into definitions obtained by +induction from experience, but nevertheless there +was the same search for the quiddity of the loadstone. +Once one knew this nature then all the properties +of the loadstone could be understood.</p> + +<p>Gilbert described the nature of the loadstone in the +terms of being that were current with his scholarly +contemporaries. This was the same ontology that +scholasticism had taught for centuries—the doctrine +of form and matter that we have already found in +St. Thomas and Nicholas of Cusa. Thus we find +Richard Hooker<a name="FNanchor_41_41" id="FNanchor_41_41"></a><a href="#Footnote_41_41" class="fnanchor">[41]</a> remarking that form gives being +and that "form in other creatures is a thing proportionable +unto the soul in living creatures." Francis +Bacon,<a name="FNanchor_42_42" id="FNanchor_42_42"></a><a href="#Footnote_42_42" class="fnanchor">[42]</a> in speaking of the relations between causes +and the kinds of philosophy, said: "Physics is the +science that deals with efficient and material causes +while Metaphysics deals with formal and final +causes." John Donne<a name="FNanchor_43_43" id="FNanchor_43_43"></a><a href="#Footnote_43_43" class="fnanchor">[43]</a> expressed the problem of +scholastic philosophy succinctly:</p> + +<div class="poem"><p> +This twilight of two yeares, not past or next,<br /> +<span style="margin-left: 1em;">Some embleme is of me, ...</span><br /> +... of stuffe and forme perplext,<br /> +<span style="margin-left: 1em;">Whose <i>what</i> and <i>where</i>, in disputation is ...</span><br /> +</p></div> + +<p>As we shall see, Gilbert continued in the same tradition, +but his interpretation of form and formal cause +was much more anthropomorphic than that of his +predecessors.</p> + +<p>Gilbert began his <i>De magnete</i> by expounding the +natural history of that portion of the earth with +which we are familiar.<a name="FNanchor_44_44" id="FNanchor_44_44"></a><a href="#Footnote_44_44" class="fnanchor">[44]</a></p> + +<div class="blockquot"><p>Having declared the origin and nature of the loadstone, +we hold it needful first to give the history of iron also ... +before we come to the explication of difficulties connected +with the loadstone ... we shall better understand what +iron is when we shall have developed ... what are the +causes and the matter of metals ...</p></div> + +<p>His treatment of the origin of minerals and rocks +agreed in the main with that of Aristotle,<a name="FNanchor_45_45" id="FNanchor_45_45"></a><a href="#Footnote_45_45" class="fnanchor">[45]</a> but he +departed somewhat from the peripatetic doctrine of +the four elements of fire, air, water, and earth.<a name="FNanchor_46_46" id="FNanchor_46_46"></a><a href="#Footnote_46_46" class="fnanchor">[46]</a> +Instead, he replaced them by a pair of elements.<a name="FNanchor_47_47" id="FNanchor_47_47"></a><a href="#Footnote_47_47" class="fnanchor">[47]</a> +(If the rejection of the four Aristotelian elements were +clearer, one might consider this a part of his rejection +of the geocentric universe but he did not define his +position sufficiently.)<a name="FNanchor_48_48" id="FNanchor_48_48"></a><a href="#Footnote_48_48" class="fnanchor">[48]</a></p> + +<p>According to Gilbert the primary source of matter +is the interior of the earth, where exhalations and +"spiritus" arise from the bowels of the earth and +condense in the earth's veins.<a name="FNanchor_49_49" id="FNanchor_49_49"></a><a href="#Footnote_49_49" class="fnanchor">[49]</a> If the condensations, +or humors, are homogeneous, they constitute the +<span class='pagenum'><a name="Page_131" id="Page_131">[Pg 131]</a></span> +"materia prima" of metals.<a name="FNanchor_50_50" id="FNanchor_50_50"></a><a href="#Footnote_50_50" class="fnanchor">[50]</a> From this "materia +prima," various metals may be produced,<a name="FNanchor_51_51" id="FNanchor_51_51"></a><a href="#Footnote_51_51" class="fnanchor">[51]</a> according +to the particular humor and the specificating nature +of the place of condensation.<a name="FNanchor_52_52" id="FNanchor_52_52"></a><a href="#Footnote_52_52" class="fnanchor">[52]</a> The purest condensation +is iron: "In iron is earth in its true and genuine +nature."<a name="FNanchor_53_53" id="FNanchor_53_53"></a><a href="#Footnote_53_53" class="fnanchor">[53]</a> In other metals, we have instead of earth, +"condensed and fixed salts, which are efflorescences +of the earth."<a name="FNanchor_54_54" id="FNanchor_54_54"></a><a href="#Footnote_54_54" class="fnanchor">[54]</a> If the condensed exhalation is +mixed in the vein with foreign earths already present, +it forms ores that must be smelted to free the original +metal from dross by fire.<a name="FNanchor_55_55" id="FNanchor_55_55"></a><a href="#Footnote_55_55" class="fnanchor">[55]</a> If these exhalations should +happen to pass into the open air, instead of being +condensed in the earth, they may return to the earth +in a (meteoric) shower of iron.<a name="FNanchor_56_56" id="FNanchor_56_56"></a><a href="#Footnote_56_56" class="fnanchor">[56]</a></p> + +<p>Gilbert was indeed writing a new physiology, both +in the ancient sense of the word and the modern. +The process of the formation of metals had many +biological overtones, for it was a kind of metallic +epigenesis.<a name="FNanchor_57_57" id="FNanchor_57_57"></a><a href="#Footnote_57_57" class="fnanchor">[57]</a> "Within the globe are hidden the principles +of metals and stones, as at the earth's surface +are hidden the principles of herbs and plants."<a name="FNanchor_58_58" id="FNanchor_58_58"></a><a href="#Footnote_58_58" class="fnanchor">[58]</a> In +all cases, the "spiritus" acts as semen and blood that +inform and feed the proper womb in the generation +of animals.<a name="FNanchor_59_59" id="FNanchor_59_59"></a><a href="#Footnote_59_59" class="fnanchor">[59]</a> "The brother uterine of iron,"<a name="FNanchor_60_60" id="FNanchor_60_60"></a><a href="#Footnote_60_60" class="fnanchor">[60]</a> the +loadstone, is formed in this manner. As the embryo +of a certain species is the result of the specificating +nature of the womb in which the generic seed has +been placed, so the kind of metal is the result of a +certain humor condensing in a particular vein in the +body of the earth.</p> + +<p>Gilbert developed this biological analogy further +by ascribing to metals a process of decay after reaching +maturity. Once these solid materials have been +formed, they will degenerate unless protected, forming +earths of various kinds as a result.<a name="FNanchor_61_61" id="FNanchor_61_61"></a><a href="#Footnote_61_61" class="fnanchor">[61]</a> The "rind of the +earth"<a name="FNanchor_62_62" id="FNanchor_62_62"></a><a href="#Footnote_62_62" class="fnanchor">[62]</a> is produced by this process of growth and +decay. If these earths are soaked with humors, +transparent materials are formed.<a name="FNanchor_63_63" id="FNanchor_63_63"></a><a href="#Footnote_63_63" class="fnanchor">[63]</a></p> + +<p>As we shall see below, the ultimate cause of this +internal and superficial life is the motion of the earth, +which animation is the expression of the magnetic +soul of this sphere.<a name="FNanchor_64_64" id="FNanchor_64_64"></a><a href="#Footnote_64_64" class="fnanchor">[64]</a> As the life of animals results +from the constant working of the heart and arteries,<a name="FNanchor_65_65" id="FNanchor_65_65"></a><a href="#Footnote_65_65" class="fnanchor">[65]</a> +so the daily motion of the earth results in a constant +generation of mineral life within the earth. In contrast +to Aristotle's<a name="FNanchor_66_66" id="FNanchor_66_66"></a><a href="#Footnote_66_66" class="fnanchor">[66]</a> making the motion of the +heavens the cause of continuous change, Gilbert +made that of the earth the remote cause.<a name="FNanchor_67_67" id="FNanchor_67_67"></a><a href="#Footnote_67_67" class="fnanchor">[67]</a> However, +unlike the constant cyclical transmutation of substances +in Aristotle, there is only generation and +decay.</p> + +<p>Gilbert made a number of successive generalizations +in order to arrive at the induction that the form +of the loadstone is a microcosmic "anima" of that +of the earth.<a name="FNanchor_68_68" id="FNanchor_68_68"></a><a href="#Footnote_68_68" class="fnanchor">[68]</a> After comparing the properties of the +loadstone and of iron, his first step in this induction +was that the two materials, found everywhere,<a name="FNanchor_69_69" id="FNanchor_69_69"></a><a href="#Footnote_69_69" class="fnanchor">[69]</a> are +consanguineous:<a name="FNanchor_70_70" id="FNanchor_70_70"></a><a href="#Footnote_70_70" class="fnanchor">[70]</a> "These two associated bodies +possess the true, strict form of one species, though +because of the outwardly different aspect and the +inequality of the selfsame innate potency, they have +hitherto been held to be different ..." Good iron +and good loadstone are more similar than a good and +a poor loadstone, or a good and a poor iron ore.<a name="FNanchor_71_71" id="FNanchor_71_71"></a><a href="#Footnote_71_71" class="fnanchor">[71]</a> +Moreover, they have the same potency,<a name="FNanchor_72_72" id="FNanchor_72_72"></a><a href="#Footnote_72_72" class="fnanchor">[72]</a> for the +innate potency of one can be passed to the other:<a name="FNanchor_73_73" id="FNanchor_73_73"></a><a href="#Footnote_73_73" class="fnanchor">[73]</a> +"The stronger invigorates the weaker, not as if it +imparted of its own substances or parted with aught +<span class='pagenum'><a name="Page_132" id="Page_132">[Pg 132]</a></span> +of its own strength, nor as if it injected into the other +any physical substance; but rather the dormant +power of the one is awakened by the other's without +expenditure." In addition, the potency can be +passed only to the other.<a name="FNanchor_74_74" id="FNanchor_74_74"></a><a href="#Footnote_74_74" class="fnanchor">[74]</a> Finally they both have +the same history:</p> + +<div class="blockquot"><p>We see both the finest magnet and iron ore visited as it +were by the same ills and diseases, acting in the same way +and with the same indications, preserved by the same +remedies and protective measures, and so retaining their +properties ... they are both impaired by the action +of acrid liquids as though by poison<a name="FNanchor_75_75" id="FNanchor_75_75"></a><a href="#Footnote_75_75" class="fnanchor">[75]</a> ... each is saved from +impairment by being kept in the scrapings of the other. +[So] ... form, essence and appearance are one.<a name="FNanchor_76_76" id="FNanchor_76_76"></a><a href="#Footnote_76_76" class="fnanchor">[76]</a></p></div> + +<p>Any difference between the loadstone proper and +the iron proper is due to a difference in the actual +power of the magnetic virtue:<a name="FNanchor_77_77" id="FNanchor_77_77"></a><a href="#Footnote_77_77" class="fnanchor">[77]</a> "Weak loadstones are +those disfigured with dross metallic humors and with +foreign earth admixtures, [hence one may conclude] +they are further removed from the mother earth and +are more degenerate."</p> + +<p>Gilbert's second induction was that they are "true +and intimate parts of the globe,"<a name="FNanchor_78_78" id="FNanchor_78_78"></a><a href="#Footnote_78_78" class="fnanchor">[78]</a> that is, that they +are piece of the "materia prima" of all we see about +us. For they "seem to contain within themselves +the potency of the earth's core and of its inmost +viscera."<a name="FNanchor_79_79" id="FNanchor_79_79"></a><a href="#Footnote_79_79" class="fnanchor">[79]</a> Whence, in Gilbert's philosophy, the +earthy matter of the elements was not passive or +inert<a name="FNanchor_80_80" id="FNanchor_80_80"></a><a href="#Footnote_80_80" class="fnanchor">[80]</a> as it was in Aristotle's, but already had the +magnetic powers of loadstone. Being endowed with +properties, it was, in peripatetic terms, a simple body.</p> + +<p>If these pieces of earth proper, before decay, are +loadstones, then one may pass to the next induction +that the earth itself is a loadstone.<a name="FNanchor_81_81" id="FNanchor_81_81"></a><a href="#Footnote_81_81" class="fnanchor">[81]</a> Conversely, a +terrella has all the properties of the earth:<a name="FNanchor_82_82" id="FNanchor_82_82"></a><a href="#Footnote_82_82" class="fnanchor">[82]</a> "Every +separate fragment of the earth exhibits in indubitable +experiments the whole impetus of magnetic matter; +in its various movements it follows the terrestial globe +and the common principle of motion."<a name="FNanchor_83_83" id="FNanchor_83_83"></a><a href="#Footnote_83_83" class="fnanchor">[83]</a></p> + +<p>The next induction that Gilbert made was that as +the magnet possesses verticity and turns towards +the poles, so the loadstone-earth possesses a verticity +and turns on an axis fixed in direction.<a name="FNanchor_84_84" id="FNanchor_84_84"></a><a href="#Footnote_84_84" class="fnanchor">[84]</a> He could +now discuss the motions of a loadstone in general, in +terms of its nature, just as an Aristotelian discussed the +motion of the elements in terms of their nature.</p> + +<p>But before reaching this point in his argument, +Gilbert digressed to classify the different kinds of +attractions and motions which the elements produce. +In particular, he distinguished electric attraction from +magnetic coition, and pointed out the main features +of electrical attraction. Since the resultant motions +were different, the essential natures of electric and +magnetic substances had to differ.</p> + +<p>Gilbert introduced his treatment of motion by discussing +the attraction of amber. All sufficiently +light solids<a name="FNanchor_85_85" id="FNanchor_85_85"></a><a href="#Footnote_85_85" class="fnanchor">[85]</a> and even liquids,<a name="FNanchor_86_86" id="FNanchor_86_86"></a><a href="#Footnote_86_86" class="fnanchor">[86]</a> but not flame or air<a name="FNanchor_87_87" id="FNanchor_87_87"></a><a href="#Footnote_87_87" class="fnanchor">[87]</a> +are attracted by rubbed amber. Heat from friction,<a name="FNanchor_88_88" id="FNanchor_88_88"></a><a href="#Footnote_88_88" class="fnanchor">[88]</a> +but not from alien sources like the sun<a name="FNanchor_89_89" id="FNanchor_89_89"></a><a href="#Footnote_89_89" class="fnanchor">[89]</a> or the flame,<a name="FNanchor_90_90" id="FNanchor_90_90"></a><a href="#Footnote_90_90" class="fnanchor">[90]</a> +produce this "affection." By the use of a detector +modeled after the magnetic needle, which we would +call an electroscope but which he called a "versorium,"<a name="FNanchor_91_91" id="FNanchor_91_91"></a><a href="#Footnote_91_91" class="fnanchor">[91]</a> +Gilbert was able to extend the list of substances +that attract like amber.<a name="FNanchor_92_92" id="FNanchor_92_92"></a><a href="#Footnote_92_92" class="fnanchor">[92]</a> These Gilbert called +"electricae."<a name="FNanchor_93_93" id="FNanchor_93_93"></a><a href="#Footnote_93_93" class="fnanchor">[93]</a></p> + +<p>Possibly as a result of testing experimentally statements +like that of St. Thomas, on the effect of garlic +on a loadstone, Gilbert discovered that the interposition +of even the slightest material (except a fluid +like olive oil) would screen the attraction of electrics.<a name="FNanchor_94_94" id="FNanchor_94_94"></a><a href="#Footnote_94_94" class="fnanchor">[94]</a> +Hence the attraction is due to a material +cause, and, since it is invisible, it is due to an effluvium.<a name="FNanchor_95_95" id="FNanchor_95_95"></a><a href="#Footnote_95_95" class="fnanchor">[95]</a> +It must be much rarer than air,<a name="FNanchor_96_96" id="FNanchor_96_96"></a><a href="#Footnote_96_96" class="fnanchor">[96]</a> for if its +<span class='pagenum'><a name="Page_133" id="Page_133">[Pg 133]</a></span> +density were that of air or greater, it would repel +rather than attract.<a name="FNanchor_97_97" id="FNanchor_97_97"></a><a href="#Footnote_97_97" class="fnanchor">[97]</a></p> + +<p>The source of the effluvia could be inferred from +the properties of the electrics. Many but not all of +the electrics are transparent, but all are firm and can +be polished.<a name="FNanchor_98_98" id="FNanchor_98_98"></a><a href="#Footnote_98_98" class="fnanchor">[98]</a> Since they retain the appearance and +properties of a fluid in a firm solid mass,<a name="FNanchor_99_99" id="FNanchor_99_99"></a><a href="#Footnote_99_99" class="fnanchor">[99]</a> Gilbert +concluded that they derived their growth mostly +from humors or were concretions of humors.<a name="FNanchor_100_100" id="FNanchor_100_100"></a><a href="#Footnote_100_100" class="fnanchor">[100]</a> By +friction, these humors are released and produce +electrical attraction.<a name="FNanchor_101_101" id="FNanchor_101_101"></a><a href="#Footnote_101_101" class="fnanchor">[101]</a></p> + +<p>This humoric source of the effluvia was substantiated +by Gilbert in a number of ways. Electrics lose +their power of electrical attraction upon being +heated, and this is because the humor has been driven +off.<a name="FNanchor_102_102" id="FNanchor_102_102"></a><a href="#Footnote_102_102" class="fnanchor">[102]</a> Bodies that are about equally constituted of +earth and humor, or that are mostly earth, have +been degraded and do not show electrical attraction.<a name="FNanchor_103_103" id="FNanchor_103_103"></a><a href="#Footnote_103_103" class="fnanchor">[103]</a> +Bodies like pearls and metals, since they are +shiny and so must be made of humors, must also emit +an effluvium upon being rubbed, but it is a thick and +vaporous one without any attractive powers.<a name="FNanchor_104_104" id="FNanchor_104_104"></a><a href="#Footnote_104_104" class="fnanchor">[104]</a> +Damp weather and moist air can weaken or even +prevent electrical attraction, for it impedes the efflux +of the humor at the source and accordingly diminishes +the attraction.<a name="FNanchor_105_105" id="FNanchor_105_105"></a><a href="#Footnote_105_105" class="fnanchor">[105]</a> Charged bodies retain their powers +longer in the sun than in the shade, for in the shade +the effluvia are condensed more, and so obscure +emission.<a name="FNanchor_106_106" id="FNanchor_106_106"></a><a href="#Footnote_106_106" class="fnanchor">[106]</a></p> + +<p>All these examples seemed to justify the hypothesis +that the nature of electrics is such that material +effluvia are emitted when electrics are rubbed, and +that the effluvia are rarer than air. Gilbert realized +that as yet he had not explained electrical attraction, +only that the pull can be screened. The pull must be +explained by contact forces,<a name="FNanchor_107_107" id="FNanchor_107_107"></a><a href="#Footnote_107_107" class="fnanchor">[107]</a> as Aristotle<a name="FNanchor_108_108" id="FNanchor_108_108"></a><a href="#Footnote_108_108" class="fnanchor">[108]</a> and +Aquinas<a name="FNanchor_109_109" id="FNanchor_109_109"></a><a href="#Footnote_109_109" class="fnanchor">[109]</a> had argued. Accordingly, he declared, +the effluvia, or "spiritus,"<a name="FNanchor_110_110" id="FNanchor_110_110"></a><a href="#Footnote_110_110" class="fnanchor">[110]</a> emitted take "hold of +the bodies with which they unite, enfold them, as it +were, in their arms, and bring them into union with +the electrics."<a name="FNanchor_111_111" id="FNanchor_111_111"></a><a href="#Footnote_111_111" class="fnanchor">[111]</a></p> + +<p>It can be seen how this uniting action is effected +if objects floating on water are considered, for solids +can be drawn to solids through the medium of a +fluid.<a name="FNanchor_112_112" id="FNanchor_112_112"></a><a href="#Footnote_112_112" class="fnanchor">[112]</a> A wet body touching another wet body +not only attracts it, but moves it if the other body is +small,<a name="FNanchor_113_113" id="FNanchor_113_113"></a><a href="#Footnote_113_113" class="fnanchor">[113]</a> while wet bodies on the surface of the water +attract other wet bodies. A wet object on the surface +of the water seeks union with another wet object +when the surface of the water rises between both: at +once, "like drops of water, or bubbles on water, they +come together."<a name="FNanchor_114_114" id="FNanchor_114_114"></a><a href="#Footnote_114_114" class="fnanchor">[114]</a> On the other hand, "a dry body +does not move toward a wet, nor a wet to a dry, but +rather they seem to go away from one another."<a name="FNanchor_115_115" id="FNanchor_115_115"></a><a href="#Footnote_115_115" class="fnanchor">[115]</a> +Moreover, a dry body does not move to the dry rim +of the vessel while a wet one runs to a wet rim.<a name="FNanchor_116_116" id="FNanchor_116_116"></a><a href="#Footnote_116_116" class="fnanchor">[116]</a></p> + +<p>By means of the properties of such a fluid, Gilbert +could explain the unordered coming-together that +he called coacervation.<a name="FNanchor_117_117" id="FNanchor_117_117"></a><a href="#Footnote_117_117" class="fnanchor">[117]</a> Different bodies have +different effluvia, and so one has coacervation of +different materials. Thus, in Gilbert's philosophy +air was the earth's effluvium and was responsible for +the unordered motion of objects towards the earth.<a name="FNanchor_118_118" id="FNanchor_118_118"></a><a href="#Footnote_118_118" class="fnanchor">[118]</a></p> + +<p>The analogy between electric attraction and fluids +is a most concrete one, yet lying beneath this image is +a hypothesis that is difficult to fix into a mechanical +system based upon contact forces. This is the assumption +that under the proper conditions bodies tend +to move together in order to participate in a more +<span class='pagenum'><a name="Page_134" id="Page_134">[Pg 134]</a></span> +complete unity.<a name="FNanchor_119_119" id="FNanchor_119_119"></a><a href="#Footnote_119_119" class="fnanchor">[119]</a> The steps in electrical attraction +were described as occurring on two different levels +of abstraction: first one has physical contact through +an effluvium or "spiritus" that connects the two +objects physically. Then, as a result of this contact, +the objects somehow sense<a name="FNanchor_120_120" id="FNanchor_120_120"></a><a href="#Footnote_120_120" class="fnanchor">[120]</a> that a more intimate +harmony is possible, and move accordingly. Gilbert +called the motion that followed contact, attraction. +However, this motion did not connote what we would +call a force:<a name="FNanchor_121_121" id="FNanchor_121_121"></a><a href="#Footnote_121_121" class="fnanchor">[121]</a> it did not correspond directly to a +push or pull, but it followed from what one might +term the apprehension of the possibility of a more +complete participation in a formal unity. The physical +unity due to the "spiritus" was the prelude to a +formal organic unity, so that <i>humor</i> is "rerum omnium +unitore." Gilbert's position can be best seen in +the following:<a name="FNanchor_122_122" id="FNanchor_122_122"></a><a href="#Footnote_122_122" class="fnanchor">[122]</a></p> + +<div class="blockquot"><p>Spiritus igitur egrediens ex corpora, quod ab humore +aut succo aqueo concreverat, corpus attrahendum attingit, +attactum attrahenti unitur; corpus peculiari effluviorum +radio continguum, unum effecit ex duobus: unita confluunt +in conjunctissimam convenientiam, quae attractio vulgo +dicitur. Quae unitas iuxta Pythagorae opinionem rerum +omnium principium est, per cuius participationem unaquaeque +res una dicitur. Quoniam enim nullo actio a +materia potest nisi per contactum, electrica haec non +videntur tangere, sed ut necesse erat demittitur aliquid ab +uno ad aliud, quod proxime tangat, et eius incitationis +principium sit. Corpora omnia uniuntur & quasi ferruminantur +quodammodo humore ... Electrica vero effi via +peculiaria, quae humoris fusi subtilissima sunt materia, +corpuscula allectant. Aër (commune effluvium telluris) +& partes disjunctis unit, & tellus mediante aëre ad se +revocat corpora; aliter quae in superioribus locis essent +corpora, terram non ita avide appelerent.</p> + +<p>Electrica effluvia ab aëre multum differunt, & u aër +telluris effluvium est, ita electrica suahabent effluvia & +propria; peculiaribus effluviis suus cuique; est singularis +ad unitatem ductus, motus ad principium, fontem, & +corpus effluvia emittens.</p></div> + +<p>A similar hypothesis will reappear in his explanation +of magnetic attraction.</p> + +<p>Following the tradition of the medieval schoolmen +Gilbert started his examination of the nature of the +loadstone by pointing out the different kinds of +motion due to a magnet. The five kinds (other than +up and down) are:<a name="FNanchor_123_123" id="FNanchor_123_123"></a><a href="#Footnote_123_123" class="fnanchor">[123]</a></p> + +<div class="blockquot"><p>(1) coitio (vulgo attractio, dicta) ad unitatem magneticam +incitatio.</p> + +<p>(2) directio in polos telluris, et telluris in mundi destinatos +terminos verticitas et consistentia.</p> + +<p>(3) variatio, a meridiano deflexio, quem motum nos +depravatum dicimus.</p> + +<p>(4) declinatio, infra horizontem poli magnetici descensus.</p> + +<p>(5) motus circularis, seu revolutio.</p></div> + +<p>Of the five he initially listed, three are not basic +ones. Variation and declination he later explained +as due to irregularities of the surface of the earth, +while direction or verticity is the ordering motion that +precedes coition.<a name="FNanchor_124_124" id="FNanchor_124_124"></a><a href="#Footnote_124_124" class="fnanchor">[124]</a> This leaves only coition and +revolution as the basic motions. How these followed +from "the congregant nature of the loadstone can be +seen when the effusion of forms has been considered."</p> + +<p>Coition (he did not take up revolution at this +point) differed from that due to other attractions. +There are two and only two kinds of bodies that +can attract: electric and magnetic.<a name="FNanchor_125_125" id="FNanchor_125_125"></a><a href="#Footnote_125_125" class="fnanchor">[125]</a> Gilbert refined +his position further by arguing that one does not +even have magnetic attraction<a name="FNanchor_126_126" id="FNanchor_126_126"></a><a href="#Footnote_126_126" class="fnanchor">[126]</a> but instead the +mutual motion to union that he called coition.<a name="FNanchor_127_127" id="FNanchor_127_127"></a><a href="#Footnote_127_127" class="fnanchor">[127]</a> +In electric attraction, one has an action-passion +relation of cause and effect with an external agent +and a passive recipient; while in magnetic coition, +both bodies act and are acted upon, and both move +together.<a name="FNanchor_128_128" id="FNanchor_128_128"></a><a href="#Footnote_128_128" class="fnanchor">[128]</a> Instead of an agent and a patient in +coition,<a name="FNanchor_129_129" id="FNanchor_129_129"></a><a href="#Footnote_129_129" class="fnanchor">[129]</a> one has "conactus." Coition, as the +Latin origin of the term denoted, is always a concerted +action. <a name="FNanchor_130_130" id="FNanchor_130_130"></a><a href="#Footnote_130_130" class="fnanchor">[130]</a> This can be seen from the motions +of two loadstones floating on water.<a name="FNanchor_131_131" id="FNanchor_131_131"></a><a href="#Footnote_131_131" class="fnanchor">[131]</a> The mutual +motion in coition was one of the reasons for Gilbert's +rejection of the perpetual motion machine of Peregrinus.<a name="FNanchor_132_132" id="FNanchor_132_132"></a><a href="#Footnote_132_132" class="fnanchor">[132]</a></p> + +<p>Magnetic coition, unlike electric attraction, cannot +be screened.<a name="FNanchor_133_133" id="FNanchor_133_133"></a><a href="#Footnote_133_133" class="fnanchor">[133]</a> Hence it cannot be corporeal for it +<span class='pagenum'><a name="Page_135" id="Page_135">[Pg 135]</a></span> +travels freely through bodies<a name="FNanchor_134_134" id="FNanchor_134_134"></a><a href="#Footnote_134_134" class="fnanchor">[134]</a> and especially magnetic +bodies;<a name="FNanchor_135_135" id="FNanchor_135_135"></a><a href="#Footnote_135_135" class="fnanchor">[135]</a> one can understand the action of +the armature on this basis.<a name="FNanchor_136_136" id="FNanchor_136_136"></a><a href="#Footnote_136_136" class="fnanchor">[136]</a> Since coition cannot +be prevented by shielding, it must have an immaterial +cause.<a name="FNanchor_137_137" id="FNanchor_137_137"></a><a href="#Footnote_137_137" class="fnanchor">[137]</a></p> + +<p>Yet, unless one has the occult action-at-a-distance, +change must be caused by contact forces. Gilbert +resolved the paradox of combining contact forces +with forces that cannot be shielded, by passing to +a higher level of abstraction for the explanation of +magnetic phenomena: he saw the contact as that of +a form with matter.</p> + +<p>Although Gilbert remarked that the cause of magnetic +phenomena did not fall within any of the categories +of the formal causes of the Aristotelians, he +did not renounce for this reason the medieval tradition. +Actually there are many similarities between +Gilbert's explanation of the loadstone's powers and +that of St. Thomas. Magnetic coition is not due to +any of the generic or specific forms of the Aristotelian +elements, nor is it due to the primary qualities +of any of their elements, nor is it due to the celestial +"generans" of terrestrial change.<a name="FNanchor_138_138" id="FNanchor_138_138"></a><a href="#Footnote_138_138" class="fnanchor">[138]</a></p> + +<div class="blockquot"><p>Relictis aliorum opinionibus de magnetis attractione; +nunc coitionis illius rationem, et motus illius commoventem +naturam docebimus. Cum vero duo sint corporum genera, +quae manifestis sensibus nostris motionibus corpora allicere +videntur, Electrica et Magnetica; Electrica naturalibus ab +humore effluviis; Magnetica formalibus efficientiis, seu +potius primariis vigoribus, incitationes faciunt. Forma +ilia singularis est, et peculiaris, non Peripateticorum causa +formalis, et specifica in mixtis, est secunda forma, non +generantium corporum propagatrix; sed primorum et +praeciporum globorum forma; et partium eorum homogenearum, +non corruptarum, propria entitas et existentia, +quam nos primariam, et radicalem, et astream appellare +possumus formam; non formam primam Aristotelis; sed +singularem illam, quae globum suum proprium tuetur et +disponit. Talis in singulis globis, Sole, lunas et astris, est +una; in terra etiam una, quae vera est ilia potentia magnetica, +quam nos primarium vigorem appellamus. Quare +magnetica natura est telluris propria, eiusque omnibus +verioribus partibus, primaria et stupenda ratione, insita; +haec nec a caelo toto derivatur procreaturve, per sympathiam, +per influentiam, aut occultiores qualitates; nec +peculiari aliquo astro: est enim suus in tellure magneticus +vigor, sicut in sole et luna suae formae; frustulumque; +lunae, lunatice ad eius terminos, et formam componit se; +solarque; ad solem, sicut magnes ad tellurem, et ad alterum +magnetem, secundum naturam sese inclinando et alliciendo. +Differendum igitur de tellure quae magnetica, et magnes; +tum etiam de partibus eius verioribus, quae magneticae +sunt; et quomodo ex coitione difficiuntur.</p></div> + +<p>Instead, he declared it to be due to a form that is +natural and proper to that element that he made the +primary component of the earth.<a name="FNanchor_139_139" id="FNanchor_139_139"></a><a href="#Footnote_139_139" class="fnanchor">[139]</a></p> + +<p>To understand his argument, let us briefly recall +the peripatetic theory of the elements. In this philosophy +of nature each element or simple body is a +combination of a pair of the four primary qualities +that informs inchoate matter. These qualities are the +instruments of the elemental forms and determine +the properties of the element. Thus the element fire +is a compound of the qualities hot and dry, and the +substantial form of fire acts through these qualities. +Similarly for the other elements, earth, water, and +air: their forms determine a proper place for each +element, and a motion to that place natural to each +element.<a name="FNanchor_140_140" id="FNanchor_140_140"></a><a href="#Footnote_140_140" class="fnanchor">[140]</a></p> + +<p>Gilbert had previously declared that the primary +substance of the earth is an element. Since it is an +element, it has a motion natural to it, and this motion +is magnetic coition. As an Aristotelian considered +the substantial form of the element, fire, to act +through the qualities of hot and dry, and to cause +an upward motion; so Gilbert argued that the substantial +form of his element, pure loadstone, acts +through the magnetic qualities and causes magnetic +coition. This motion is due to its primary form, and +is natural to the element earth.<a name="FNanchor_141_141" id="FNanchor_141_141"></a><a href="#Footnote_141_141" class="fnanchor">[141]</a> It is instilled in all +proper and undegenerate parts of the earth,<a name="FNanchor_142_142" id="FNanchor_142_142"></a><a href="#Footnote_142_142" class="fnanchor">[142]</a> but +in no other element.<a name="FNanchor_143_143" id="FNanchor_143_143"></a><a href="#Footnote_143_143" class="fnanchor">[143]</a></p> + +<p>To the medieval philosopher, the "generantia" of +the occult powers of the loadstone are the heavenly +bodies. Gilbert, however, endowed the earth with +these heavenly powers which were placed in the +earth in the beginning<a name="FNanchor_144_144" id="FNanchor_144_144"></a><a href="#Footnote_144_144" class="fnanchor">[144]</a> and caused all magnetic +materials to conform with it both physically and +<span class='pagenum'><a name="Page_136" id="Page_136">[Pg 136]</a></span> +formally.<a name="FNanchor_145_145" id="FNanchor_145_145"></a><a href="#Footnote_145_145" class="fnanchor">[145]</a> Such magnetic powers are the property +of all parts of the earth;<a name="FNanchor_146_146" id="FNanchor_146_146"></a><a href="#Footnote_146_146" class="fnanchor">[146]</a> they give the earth its +rotating motion<a name="FNanchor_147_147" id="FNanchor_147_147"></a><a href="#Footnote_147_147" class="fnanchor">[147]</a> and hold the earth together in +spite of this motion.<a name="FNanchor_148_148" id="FNanchor_148_148"></a><a href="#Footnote_148_148" class="fnanchor">[148]</a></p> + +<p>Indeed, each of the main stellar bodies, sun, moon, +stars, and earth, has such a form or principle unique to +itself that causes its parts not only to conform with +itself but to revolve.<a name="FNanchor_149_149" id="FNanchor_149_149"></a><a href="#Footnote_149_149" class="fnanchor">[149]</a> Thus, if one removes a piece +of the moon from this body, it will tend to align itself +with the moon and then to return to its proper place; +and a fragment of the sun would similarly tend to +return after proper orientation.<a name="FNanchor_150_150" id="FNanchor_150_150"></a><a href="#Footnote_150_150" class="fnanchor">[150]</a> Moreover, there is +a farther-ranging, though weaker, mutual action of +the heavenly bodies so that one has a causal hierarchy +of these specific conforming powers. The form of the +sun is superior to that of the inferior globes and is +responsible for the order and regularity of planetary +orbits.<a name="FNanchor_151_151" id="FNanchor_151_151"></a><a href="#Footnote_151_151" class="fnanchor">[151]</a> In like manner, the moon is responsible for +the tides of the ocean.<a name="FNanchor_152_152" id="FNanchor_152_152"></a><a href="#Footnote_152_152" class="fnanchor">[152]</a></p> + +<p>By virtue of the causal hierarchy of forms, the +loadstone acquires its magnetic powers from the +earth.<a name="FNanchor_153_153" id="FNanchor_153_153"></a><a href="#Footnote_153_153" class="fnanchor">[153]</a> As the earth has its natural parts, so has +the stone.<a name="FNanchor_154_154" id="FNanchor_154_154"></a><a href="#Footnote_154_154" class="fnanchor">[154]</a> Although the geometrical center of a +terrella is the center of the magnetic forces,<a name="FNanchor_155_155" id="FNanchor_155_155"></a><a href="#Footnote_155_155" class="fnanchor">[155]</a> objects +do not tend to move to the center but to its poles,<a name="FNanchor_156_156" id="FNanchor_156_156"></a><a href="#Footnote_156_156" class="fnanchor">[156]</a> +where the magnetic energy is most conspicuous.<a name="FNanchor_157_157" id="FNanchor_157_157"></a><a href="#Footnote_157_157" class="fnanchor">[157]</a> +However, in a sense, the energy is everywhere equal: +the virtue is spread throughout the entire mass of the +loadstone,<a name="FNanchor_158_158" id="FNanchor_158_158"></a><a href="#Footnote_158_158" class="fnanchor">[158]</a> and all the parts direct the forces to the +poles.<a name="FNanchor_159_159" id="FNanchor_159_159"></a><a href="#Footnote_159_159" class="fnanchor">[159]</a> The poles become the "thrones" of the +magnetic powers.<a name="FNanchor_160_160" id="FNanchor_160_160"></a><a href="#Footnote_160_160" class="fnanchor">[160]</a> On the other hand, the directive +force is stronger where coition is weaker and accordingly, +verticity is most prominent at the equator.<a name="FNanchor_161_161" id="FNanchor_161_161"></a><a href="#Footnote_161_161" class="fnanchor">[161]</a></p> + +<p>The strength of a loadstone depends upon its shape +and mass. A bar magnet has greater powers than a +spherical one because it tends to concentrate the +magnetic powers more in the ends.<a name="FNanchor_162_162" id="FNanchor_162_162"></a><a href="#Footnote_162_162" class="fnanchor">[162]</a> For a given +purity and shape, the heavier the loadstone, the +greater its strength.<a name="FNanchor_163_163" id="FNanchor_163_163"></a><a href="#Footnote_163_163" class="fnanchor">[163]</a> A loadstone has a maximum +degree of magnetic force that cannot be increased.<a name="FNanchor_164_164" id="FNanchor_164_164"></a><a href="#Footnote_164_164" class="fnanchor">[164]</a> +However, weaker ones can be strengthened by stronger +ones.<a name="FNanchor_165_165" id="FNanchor_165_165"></a><a href="#Footnote_165_165" class="fnanchor">[165]</a> Similarly, the shape and weight of the iron +determine the magnetic force in coition.<a name="FNanchor_166_166" id="FNanchor_166_166"></a><a href="#Footnote_166_166" class="fnanchor">[166]</a></p> + +<p>The formal forces of a loadstone emanate in all +directions from it,<a name="FNanchor_167_167" id="FNanchor_167_167"></a><a href="#Footnote_167_167" class="fnanchor">[167]</a> but there is a bound to it that +Gilbert called the "orbis virtutis."<a name="FNanchor_168_168" id="FNanchor_168_168"></a><a href="#Footnote_168_168" class="fnanchor">[168]</a> The shape of +this "orbis virtutis" is determined by the shape of the +stone.<a name="FNanchor_169_169" id="FNanchor_169_169"></a><a href="#Footnote_169_169" class="fnanchor">[169]</a> This insensible effusion is analogous to the +spreading of light that reveals its presence only by +opaque bodies.<a name="FNanchor_170_170" id="FNanchor_170_170"></a><a href="#Footnote_170_170" class="fnanchor">[170]</a> Similarly, the magnetic forms are +effused from the stone,<a name="FNanchor_171_171" id="FNanchor_171_171"></a><a href="#Footnote_171_171" class="fnanchor">[171]</a> and can only reveal their +presence by coition with another loadstone or by +"awakening" magnetic bodies within the "orbis +virtutis."<a name="FNanchor_172_172" id="FNanchor_172_172"></a><a href="#Footnote_172_172" class="fnanchor">[172]</a> Unmagnetized iron that comes within +the "orbis virtutis" is altered, and the magnetic virtue +renews a form that is already potentially in the iron.<a name="FNanchor_173_173" id="FNanchor_173_173"></a><a href="#Footnote_173_173" class="fnanchor">[173]</a> +The formal energy is drawn not only from the stone +but from the iron.<a name="FNanchor_174_174" id="FNanchor_174_174"></a><a href="#Footnote_174_174" class="fnanchor">[174]</a> This is not generation, or alteration +in the sense of a new impressed quality, but +alteration in the sense of the entelechy or the activation +of a form potentially present.<a name="FNanchor_175_175" id="FNanchor_175_175"></a><a href="#Footnote_175_175" class="fnanchor">[175]</a> Those bodies +<span class='pagenum'><a name="Page_137" id="Page_137">[Pg 137]</a></span> +magnetized by coming within the "orbis virtutis" +have in turn an efflux of their own.<a name="FNanchor_176_176" id="FNanchor_176_176"></a><a href="#Footnote_176_176" class="fnanchor">[176]</a> Iron can also +receive verticity directly from the earth without the +intervention of an ordinary loadstone.<a name="FNanchor_177_177" id="FNanchor_177_177"></a><a href="#Footnote_177_177" class="fnanchor">[177]</a> Such +verticity can be expelled and annulled by the presence +of another loadstone.<a name="FNanchor_178_178" id="FNanchor_178_178"></a><a href="#Footnote_178_178" class="fnanchor">[178]</a></p> + +<p>Although one does not normally find iron to be +magnetized, a loadstone always has some magnetism. +That two bodies such as iron and loadstone should +have different properties is the result of the loss of a +form by the iron, but this form is still potentially +present in the iron. The iron that has been obtained +from an ore has been deformed,<a name="FNanchor_179_179" id="FNanchor_179_179"></a><a href="#Footnote_179_179" class="fnanchor">[179]</a> for it has been +placed "outside its nature" by the fire.<a name="FNanchor_180_180" id="FNanchor_180_180"></a><a href="#Footnote_180_180" class="fnanchor">[180]</a> The nature +has not been removed, since, once the iron has +cooled, the confused form can be reformed by a loadstone. +<a name="FNanchor_181_181" id="FNanchor_181_181"></a><a href="#Footnote_181_181" class="fnanchor">[181]</a> The latter "awakens" the proper form of +iron.<a name="FNanchor_182_182" id="FNanchor_182_182"></a><a href="#Footnote_182_182" class="fnanchor">[182]</a> After smelting, the magnetized iron may +manifest stronger powers than a loadstone of equal +weight, but this is because the primary matter of the +earth is purer in the iron than in the loadstone.<a name="FNanchor_183_183" id="FNanchor_183_183"></a><a href="#Footnote_183_183" class="fnanchor">[183]</a> +If fire does not deform a loadstone too much, it can +be remagnetized,<a name="FNanchor_184_184" id="FNanchor_184_184"></a><a href="#Footnote_184_184" class="fnanchor">[184]</a> but a burnt loadstone cannot be +reformed.<a name="FNanchor_185_185" id="FNanchor_185_185"></a><a href="#Footnote_185_185" class="fnanchor">[185]</a> Corruption from external causes may +also deform a loadstone or iron so that it can not be +magnetized.<a name="FNanchor_186_186" id="FNanchor_186_186"></a><a href="#Footnote_186_186" class="fnanchor">[186]</a> Bodies mixed with the degenerate +substance of the earth or with aqueous humor spoilt +by contamination with earth, do not show either +electric attraction or magnetic coition.<a name="FNanchor_187_187" id="FNanchor_187_187"></a><a href="#Footnote_187_187" class="fnanchor">[187]</a></p> + +<p>In a manner suggestive of Peregrinus, Gilbert +wrote that, "magnetic bodies seek formal unity."<a name="FNanchor_188_188" id="FNanchor_188_188"></a><a href="#Footnote_188_188" class="fnanchor">[188]</a> +Thus a dissected loadstone not only tends to come +back together, as in the unordered coacervation of +electric attraction, but to restore the organization +it had before dissection.<a name="FNanchor_189_189" id="FNanchor_189_189"></a><a href="#Footnote_189_189" class="fnanchor">[189]</a> Accordingly, opposite +poles appear on the interfaces of the sections, not +"from an opposition" but from "a concordance and +a conformance."<a name="FNanchor_190_190" id="FNanchor_190_190"></a><a href="#Footnote_190_190" class="fnanchor">[190]</a> This ensures that when the +parts are joined together again, they have the same +orientation as before. Gilbert compared this power +of restoring the original loadstone with that of a +plant's vital power under the process of cutting and +grafting; the plant can be revived only when the parts +are in a certain order.<a name="FNanchor_191_191" id="FNanchor_191_191"></a><a href="#Footnote_191_191" class="fnanchor">[191]</a></p> + +<p>A hypothesis similar to that used to explain electric +attraction lay beneath the explanation of magnetic +coition: that bodies brought into contact will move +together. In electric attraction, the contact is material +and due to the "spiritus" from the electric body; +in magnetic coition, it is formal and depends on the +action of a primary form that spreads from a magnetized +body to its limit of effusion, the "orbis virtutis." +If iron is inside the "orbis virtutis," the two bodies "enter +into alliance and are one and the same"<a name="FNanchor_192_192" id="FNanchor_192_192"></a><a href="#Footnote_192_192" class="fnanchor">[192]</a> for within +it "they have absolute continuity, and are joined by +reason of their accordance, albeit the bodies themselves +be separated."<a name="FNanchor_193_193" id="FNanchor_193_193"></a><a href="#Footnote_193_193" class="fnanchor">[193]</a></p> + +<p>Gilbert's treatment of coition can be analyzed into +the same two steps as can electric attraction. First +occurs a contact, which in this case is not physical +but formal, and from this initial formal contact +follows movement to a more complete unity. Both +the contact and the movement to unity are described +on the same level of abstraction, instead of on two +different levels as in electric attraction. Again +one does not find any clear-cut concept of force as a +push or pull,<a name="FNanchor_194_194" id="FNanchor_194_194"></a><a href="#Footnote_194_194" class="fnanchor">[194]</a> but instead, a motion to a formal +unity, this time a cooperative motion. The parts of +a magnetic body are in greater harmony when they +are assembled in a certain pattern and so they move +accordingly.</p> + +<p>As to the nature of the primary form itself, Gilbert +agreed with Thales that it is like a soul,<a name="FNanchor_195_195" id="FNanchor_195_195"></a><a href="#Footnote_195_195" class="fnanchor">[195]</a> "for the +power of self-movement seems to betoken a soul."<a name="FNanchor_196_196" id="FNanchor_196_196"></a><a href="#Footnote_196_196" class="fnanchor">[196]</a> +With Galen and St. Thomas he placed the form of +the loadstone superior to that of inanimate matter.<a name="FNanchor_197_197" id="FNanchor_197_197"></a><a href="#Footnote_197_197" class="fnanchor">[197]</a> +In a sense, Gilbert even made it superior to organic +matter, for it is incapable of error.<a name="FNanchor_198_198" id="FNanchor_198_198"></a><a href="#Footnote_198_198" class="fnanchor">[198]</a> Like the soul, +the primary form cannot be fragmented; when a +loadstone is divided, one does not separate the poles +but each part acquires its own poles and an equator. +<span class='pagenum'><a name="Page_138" id="Page_138">[Pg 138]</a></span> +Like the soul, fire does not destroy it.<a name="FNanchor_199_199" id="FNanchor_199_199"></a><a href="#Footnote_199_199" class="fnanchor">[199]</a> Like the +soul of astral bodies, and of the earth itself, it produces +complex but regular motions; the motion of +two loadstones on water offers such an example.<a name="FNanchor_200_200" id="FNanchor_200_200"></a><a href="#Footnote_200_200" class="fnanchor">[200]</a> +Like the soul of a newborn child, whose nature +depends on the configuration of the heavens, the +properties in the newly awakened iron depend upon +its position in the "orbis virtutis."<a name="FNanchor_201_201" id="FNanchor_201_201"></a><a href="#Footnote_201_201" class="fnanchor">[201]</a></p> + +<p>Whence Gilbert declared:</p> + +<div class="blockquot"><p>... the earth's magnetic force and the animate form +of the globes, that are without senses, but without error ... +exert an unending action, quick, definite, constant, directive, +motive, imperant, harmonious through the whole mass of +matter; thereby are the generation and the ultimate decay +of all things on the superficies propagated.<a name="FNanchor_202_202" id="FNanchor_202_202"></a><a href="#Footnote_202_202" class="fnanchor">[202]</a> The +bodies of the globes ... to the end that they might be in +themselves, and in their nature endure, had need of souls +to be conjoined to them, for else there were neither life, +nor prime act, nor movement, nor unition, nor order, nor +coherence, nor <i>conactus</i>, nor <i>sympathia</i>, nor any generation +nor alteration of seasons, and no propagation; but all were +in confusion....<a name="FNanchor_203_203" id="FNanchor_203_203"></a><a href="#Footnote_203_203" class="fnanchor">[203]</a> Wherefore, not with reason, Thales +... declares the loadstone to be animate, a part of the +animate mother earth and her beloved offspring.<a name="FNanchor_204_204" id="FNanchor_204_204"></a><a href="#Footnote_204_204" class="fnanchor">[204]</a></p></div> + +<p>Gilbert ended book 5 of his treatise on the magnet +with a persuasive plea for his magnetic philosophy +of the cosmos, yet his conceptual scheme was not too +successful an induction in the eyes of his contemporaries. +In particular the man from whom the Royal +Society took the inspiration for their motto, "Nullius +in verba," did not value his magnetic philosophy very +highly. Whether Francis Bacon was alluding to +Gilbert when he expounded his parable of the spider +and the ant<a name="FNanchor_205_205" id="FNanchor_205_205"></a><a href="#Footnote_205_205" class="fnanchor">[205]</a> is not explicit, but he certainly had +him in mind when he wrote of the Idols of the Cave +and the Idols of the Theater.<a name="FNanchor_206_206" id="FNanchor_206_206"></a><a href="#Footnote_206_206" class="fnanchor">[206]</a></p> + +<p>Few of the subsequent experimenters and writers +on magnetism turned to Gilbert's work to explain the +effects they discussed. Although both his countrymen +Sir Thomas Browne<a name="FNanchor_207_207" id="FNanchor_207_207"></a><a href="#Footnote_207_207" class="fnanchor">[207]</a> and Robert Boyle<a name="FNanchor_208_208" id="FNanchor_208_208"></a><a href="#Footnote_208_208" class="fnanchor">[208]</a> described +a number of the experiments already described +by Gilbert and even used phrases similar to his in +describing them, they tended to ignore Gilbert and +his explanation of them. Instead, both turned to an +explanation based upon magnetic effluvia or corpuscles. +The only direct continuation of Gilbert's <i>De magnete</i> +was the <i>Philosophia magnetica</i> of Nicolaus Cabeus.<a name="FNanchor_209_209" id="FNanchor_209_209"></a><a href="#Footnote_209_209" class="fnanchor">[209]</a> +The latter sought to bring Gilbert's explanation of +magnetism more directly into the fold of medieval +substantial forms.</p> + +<p>However, Gilbert's efforts towards a magnetic +philosophy did find approval in two of the men that +made the seventeenth century scientific revolution. +While Galileo Galilei<a name="FNanchor_210_210" id="FNanchor_210_210"></a><a href="#Footnote_210_210" class="fnanchor">[210]</a> was critical of Gilbert's +arguments as being unnecessarily loose, he nevertheless +saw in them some support for the Copernican +world-system. Johannes Kepler<a name="FNanchor_211_211" id="FNanchor_211_211"></a><a href="#Footnote_211_211" class="fnanchor">[211]</a> found in Gilbert's +explanation of the loadstone-earth a possible physical +framework for his own investigations on planetary +motions.</p> + +<p>Yet Galileo and Kepler had moved beyond Gilbert's +world of intellectual experience. They were no +longer concerned with determining the nature of +material things in order to explain their qualities. +Instead, they had passed into the realm of the mathematical +relations of kinematics: quantitative law had +replaced qualitative experience of cause and effect. +Gilbert had some intimations of the former, but he +was primarily concerned with explaining magnetism +in terms of substance and attribute. He had to +ascertain the nature of the loadstone and of the earth +in order to explain their properties and their motions. +He even went further and explained the nature of +the form of the loadstone.</p> + +<p>His method of determining the nature of a substance +was a rather primitive one—it was not by a process +of induction and deduction, nor by synthesis and +analysis, nor by "resolutio" and "compositio," but by +the use of analogies. He compared the natural history +of metals and rocks with that of plants, and gave the +two former the same kind of principle as the last. +He determined the nature of the entity behind electric +attraction by finding that such attractions could be +screened, and hence it had to be corporeal. After +comparing this "corporeal" attraction with that of +<span class='pagenum'><a name="Page_139" id="Page_139">[Pg 139]</a></span> +the surface forces of a fluid, he concluded that the +entity was a subtle fluid. He determined the nature +of the entity behind magnetic coition by (incorrectly) +finding that it cannot be screened, and hence the +cause had to be a formal one. Since both stars and +the loadstone can carry out regular motions, and +stars had souls, the form of the loadstone had to be +a soul. The method of analogy was used again in +his comparison of the properties of a magnetized +needle placed over a terrella with the properties of +a compass placed over the earth, whence he concluded +the earth to be a giant loadstone. Since the earth +resembled the other celestial globes, it had to have, +the circular inertia of these globes.<a name="FNanchor_212_212" id="FNanchor_212_212"></a><a href="#Footnote_212_212" class="fnanchor">[212]</a> As for his +magnetic experiments to show physically that the +earth moved, and his unbridled speculations on the +"animae" of the celestial globes, one is inclined to +agree with Bacon's estimate of his magnetic philosophy.</p> + +<p>One might consider Gilbert's book as a Renaissance +recasting of Aristotle's <i>De caelo</i> with the earth +in the role of a heavenly body. So it might well be, +for Gilbert was still concerned with distinguishing +the nature of the heavenly body, earth, that caused +the coitional and revolving motions, from those +natures for which up and down, and coacervation +were the natural motions. Because the natural +motions were different, the natures had to be different, +and these different natures led to a universe and a +concept of space neither of which were Aristotelian. +One no longer had a central reference point for +absolute space; there was no "motor essentialis" +focused upon the earth but one had only the mutual +motion of the heavenly bodies. The natural distinction +between heaven and earth was gone, for the +earth was no longer an inert recipient but a source +of wonder, and so the stage was set for the universe +of Giordano Bruno.<a name="FNanchor_213_213" id="FNanchor_213_213"></a><a href="#Footnote_213_213" class="fnanchor">[213]</a> The Aristotelian philosophy +of nature was used to justify a new cosmology, but +there was no break with the past such as one finds in +Galileo and Kepler. Instead he followed the chimera +of the world organism, as Paracelsus had, and of the +world soul, as Bruno had. Consequently Gilbert's +physiology did not enter into the main stream of +science.</p> + +<p>Yet this is not to deny Gilbert's services to natural +philosophy. Although not all of his experimental +distinction between electric and magnetic forces +has been retained, still, some of it has. His "orbis +virtutis" was to become a field of force, and his class +of electrics, insulators of electricity. His practice +of arming a loadstone was to be of considerable importance +in the period before the invention of the +electromagnet. His limited recognition of the mutual +nature of forces and their quantitative basis in mass +was ultimately to appear in Newton's second and +third laws of motion. In spite of the weaknesses of +the method of analogy, Gilbert's experimental model +of the terrella to interpret the earth's magnetism +was as much a contribution to scientific method as +to the theory of magnetism.</p> + +<p>Consequently, in spite of an explanation of electricity +and magnetism that one would be amused to +find in a textbook today, we can still read his <i>De +magnete</i> with interest and profit. But more important +than his scientific speculations, is the insight he can +give us into a Renaissance philosophy of nature and +its relation to medieval thought. One does not find +in <i>De magnete</i> a prototype of modern physical science +in the same sense one can in the writings of Galileo +and Kepler. Instead one finds here a full-fledged +example of an earlier kind of science, and this is +Gilbert's main value to the historian today.</p> + +<div class="footnotes"> +<h4>FOOTNOTES</h4> +<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> +William Gilbert, <i>De magnete, magneticisque corporibus et de magno +magnete tellure; physiologia nova, plurimis & argumentis, & +experimentis, demonstrata</i>, London, 1600, 240 pp., with an +introduction by Edward Wright. All references to Gilbert in this +article, unless otherwise noted, are to the American translation by P. +Fleury Mottelay, 368 pp., published in New York in 1893, and are +designated by the letter M. However, the Latin text of the 1600 +edition has been quoted wherever I have disagreed with the Mottelay +translation.</p> +<p>A good source of information on Gilbert is Dr. Duane H. D. Roller's +doctoral thesis, written under the direction of Dr. I. B. Cohen of +Harvard University. Dr. Roller, at present Curator of the De Golyer +Collection at the University of Oklahoma, informed me that an expanded +version of his dissertation will shortly appear in book form. +Unfortunately his researches were not known to me until after this +article was completed.</p></div> + +<div class="footnote"><p><a name="Footnote_2_2" id="Footnote_2_2"></a><a href="#FNanchor_2_2"><span class="label">[2]</span></a> +Alexandre Koyré, <i>Études galiléennes</i>, Paris, 1939.</p></div> + +<div class="footnote"><p><a name="Footnote_3_3" id="Footnote_3_3"></a><a href="#FNanchor_3_3"><span class="label">[3]</span></a> +Alfred N. Whitehead, <i>Science and the modern world</i>, New York, +1925, ch. 3; Ernst Cassirer, <i>Das Erkenntnisproblem</i>, ed. 3, +Berlin, 1922, vol. 1, pp. 314-318, 352-359.</p></div> + +<div class="footnote"><p><a name="Footnote_4_4" id="Footnote_4_4"></a><a href="#FNanchor_4_4"><span class="label">[4]</span></a> +However, see M: pp. 161, 162, 168, 335.</p></div> + +<div class="footnote"><p><a name="Footnote_5_5" id="Footnote_5_5"></a><a href="#FNanchor_5_5"><span class="label">[5]</span></a> +For example, William Whewell, <i>History of the inductive +sciences</i>, ed. 3, New York, 1858, vol. 2, pp. 192 and 217; Charles +Singer, <i>A short history of science to the nineteenth century</i>, Oxford, +1943, pp. 188 and 343; and A. R. Hall, <i>The scientific revolution</i>, +Boston, 1956, p. 185.</p></div> + +<div class="footnote"><p><a name="Footnote_6_6" id="Footnote_6_6"></a><a href="#FNanchor_6_6"><span class="label">[6]</span></a> +<i>Petri Peregrini maricurtenis, de magnete, seu rota perpetui motus, +libellus</i>, a reprint of the 1558 Angsburg edition in J. G. G. +Hellmann, <i>Rara magnetica</i>, Berlin, 1898, not paginated. A +number of editions of Peregrinus, work, both ascribed to him +and plagiarized from him, appeared in the 16th century (see +Heinz Balmer, <i>Beiträge zur Geschichte der Erkenntnis des Erdmagnetismus</i>, +Aarau, 1956, pp. 249-255).</p></div> + +<div class="footnote"><p><a name="Footnote_7_7" id="Footnote_7_7"></a><a href="#FNanchor_7_7"><span class="label">[7]</span></a> +Hellmann, <i>ibid.</i>, Robert Norman, <i>The newe attractive, containyng +a short discourse of the magnes or lodestone, and amongest other +his vertues, of a newe discovered secret and subtill propertie, concernyng +the declinyng of the needle, touched therewith under the plaine of the +horizon. Now first founde out by Robert Norman Hydrographer</i>. +London, 1581. The possibility is present that Norman's work +was a direct stimulus to Gilbert, for Wright's introduction to +<i>De magnete</i> stated that Gilbert started his study of magnetism +the year following the publication of Norman's book.</p></div> + +<div class="footnote"><p><a name="Footnote_8_8" id="Footnote_8_8"></a><a href="#FNanchor_8_8"><span class="label">[8]</span></a> +Hellman, <i>ibid.</i>, William Borough, <i>A discourse of the variation +of the compasse, or magneticall needle. Wherein is mathematically +shewed, the manner of the observation, effects, and application thereof, +made by W. B. And is to be annexed to the newe attractive of R. N.</i> +London, 1596.</p></div> + +<div class="footnote"><p><a name="Footnote_9_9" id="Footnote_9_9"></a><a href="#FNanchor_9_9"><span class="label">[9]</span></a> +Hellman, <i>ibid.</i>, Simon Stevin, <i>De havenvinding</i>, Leyden, 1599. +It is interesting to note that Wright translated Stevin's work +into English.</p></div> + +<div class="footnote"><p><a name="Footnote_10_10" id="Footnote_10_10"></a><a href="#FNanchor_10_10"><span class="label">[10]</span></a> +As Edward Wright was to call him in his introduction.</p></div> + +<div class="footnote"><p><a name="Footnote_11_11" id="Footnote_11_11"></a><a href="#FNanchor_11_11"><span class="label">[11]</span></a> +Aristotle, <i>On the soul</i>, translated by W. S. Hett, Loeb +Classical Library, London, 1935, 405a20 (see also 411a8: +"Some think that the soul pervades the whole universe, whence +perhaps came Thales' view that everything is full of gods").</p></div> + +<div class="footnote"><p><a name="Footnote_12_12" id="Footnote_12_12"></a><a href="#FNanchor_12_12"><span class="label">[12]</span></a> +Plato, <i>Ion</i>, translated by W. R. M. Lamb, Loeb Classical +Library, London, 1925, 533 (see also 536).</p></div> + +<div class="footnote"><p><a name="Footnote_13_13" id="Footnote_13_13"></a><a href="#FNanchor_13_13"><span class="label">[13]</span></a> +Plato, <i>Timaeus</i>, translated by R. G. Bury, Loeb Classical +Library, London, 1929, 80. It is difficult to determine which +explanation Plato preferred, for in both cases the speaker may +be only a foil for Plato's opinion rather than an expression +of these opinions.</p></div> + +<div class="footnote"><p><a name="Footnote_14_14" id="Footnote_14_14"></a><a href="#FNanchor_14_14"><span class="label">[14]</span></a> +Lucretius, <i>De rerum natura</i>, translated by W. H. D. Rouse, +Loeb Classical Library, London, 1924, bk. VI, lines 998-1041.</p></div> + +<div class="footnote"><p><a name="Footnote_15_15" id="Footnote_15_15"></a><a href="#FNanchor_15_15"><span class="label">[15]</span></a> +Galen, <i>On the natural faculties</i>, translated by A. S. Brock, +Loeb Classical Library, London, 1916, bk. 1 and bk. 3. A +view similar to this appeared in Plato, <i>Timaeus</i>, 81 (see +<a href="#Footnote_13_13">footnote 13</a>).</p></div> + +<div class="footnote"><p><a name="Footnote_16_16" id="Footnote_16_16"></a><a href="#FNanchor_16_16"><span class="label">[16]</span></a> +This same concept was to reappear in the Middle Ages as +the <i>inclinatio ad simile</i>.</p></div> + +<div class="footnote"><p><a name="Footnote_17_17" id="Footnote_17_17"></a><a href="#FNanchor_17_17"><span class="label">[17]</span></a> +The background for much of the following was derived +from Annaliese Maier, <i>An der Grenze von Scholastik und Naturwissenchaft</i>, +ed 2, Rome, 1952.</p></div> + +<div class="footnote"><p><a name="Footnote_18_18" id="Footnote_18_18"></a><a href="#FNanchor_18_18"><span class="label">[18]</span></a> +St. Thomas' epistemology for the natural inanimate world +was based upon Aristotle's dictum: that which is in the mind +was in the senses first.</p></div> + +<div class="footnote"><p><a name="Footnote_19_19" id="Footnote_19_19"></a><a href="#FNanchor_19_19"><span class="label">[19]</span></a> +René Descartes, <i>Oeuvres</i>, Charles Adam and Paul Tannery, +Paris, 1897-1910, vol. 2, p. 597 (letter to Mersenne, 16 Oct., +1639), and vol. 11 (Le Monde), p. 39. The original definition +can be found in Aristotle, <i>Physics</i>, translated by P. H. +Wickstead and F. M. Cornford, Loeb Classical Library, +London, 1934, 201a10. Aquinas rephrases the definition as +"<i>Motus est actus existentis in potentia secundum quod huius modi.</i>" +See St. Thomas Aquinas, <i>Opera omnia</i>, Antwerp, 1612, vol. 2, +<i>Physicorum Aristotelis expositio</i>, lib. 3, lect. 2, cap. a, p. 29.</p></div> + +<div class="footnote"><p><a name="Footnote_20_20" id="Footnote_20_20"></a><a href="#FNanchor_20_20"><span class="label">[20]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol. 9, <i>Summa +contra gentiles</i>, lib. 3, cap. 92 (Quo modo dicitur aliquis bene +fortunatus et quo modo adjuvatur homo ex superioribus causis), +p. 343.</p></div> + +<div class="footnote"><p><a name="Footnote_21_21" id="Footnote_21_21"></a><a href="#FNanchor_21_21"><span class="label">[21]</span></a> +St. Thomas Aquinas, op. cit. (<a href="#Footnote_19_19">footnote 19</a>), vol. 17 <i>Opuscula, +De operationibus occultis naturae ad queindam militem ultramontem</i>, +pp. 213-224.</p></div> + +<div class="footnote"><p><a name="Footnote_22_22" id="Footnote_22_22"></a><a href="#FNanchor_22_22"><span class="label">[22]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol 7, <i>Scriptum +in quartum librum sententiarum magistri Petri Lombardi</i>, lib. 4, disq. +33 (De diversis coniugii legibus), art. 1 (Utrum habere plures +uxores sit contra legem naturae), p. 168. The same statement +occurs in one of his most mature works, <i>op. cit.</i> vol. 20, <i>Summa +theologica</i>, pars 3 (supplementum), quaestio 65 (De pluralitate +uxorum in quinque articulos divisa), art. 1 (Utrum habere +plures uxores sit contra legem naturae), p. 107.</p></div> + +<div class="footnote"><p><a name="Footnote_23_23" id="Footnote_23_23"></a><a href="#FNanchor_23_23"><span class="label">[23]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol. 8, <i>Quaestio +unica: de spiritualibus creaturis</i>, art. 2 (Utrum substantia spiritualis +possit uniri corpori), p. 404. See also vol. 9, <i>Summa +contra gentiles</i>, lib. 3, cap. 92 (Quomodo dicitur aliquis bene +fortunatus, et quomodo adjuvatur homo ex superioribus causis), +p. 344; and vol. 17, <i>Opuscula, De operationibus occultis naturae ad +queindam militem ultramontem</i>, pp. 213-214.</p></div> + +<div class="footnote"><p><a name="Footnote_24_24" id="Footnote_24_24"></a><a href="#FNanchor_24_24"><span class="label">[24]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol. 8, <i>Quaestio +unica: de anima</i>, art. 1 (Utrum anima humana possit esse +forma et hoc aliquid), p. 437. See also vol. 8, <i>Quaestio: De +veritate</i>, quaestio 5 (De providentia), art. 10 (Utrum humani +actus a divina providentia gubernentur mediis corporibus +coelestibus), p. 678.</p></div> + +<div class="footnote"><p><a name="Footnote_25_25" id="Footnote_25_25"></a><a href="#FNanchor_25_25"><span class="label">[25]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol. 2, <i>Physicorum +Aristotelis expositio</i>, lib. 7, lect. 3, cap. g (Probatur in +motu locali quod movens et motum oportet esse simul), p. 97 +(quoted in Gilbert, M: p. 104).</p></div> + +<div class="footnote"><p><a name="Footnote_26_26" id="Footnote_26_26"></a><a href="#FNanchor_26_26"><span class="label">[26]</span></a> +Hellmann, <i>op. cit.</i> (<a href="#Footnote_6_6">footnote 6</a>), Peregrinus, pt. 1, ch. 8. +The magnet attracts the iron "secundum naturalem appetitum +lapidis ... sine resistentia." There is no natural resistence +to this motion since it is no longer contrary to the nature of +the iron. The nature of the iron has changed.</p></div> + +<div class="footnote"><p><a name="Footnote_27_27" id="Footnote_27_27"></a><a href="#FNanchor_27_27"><span class="label">[27]</span></a> +<i>Ibid.</i>, pt. 1, ch. 9.</p></div> + +<div class="footnote"><p><a name="Footnote_28_28" id="Footnote_28_28"></a><a href="#FNanchor_28_28"><span class="label">[28]</span></a> +<i>Ibid.</i>, pt. 1, ch. 9.</p></div> + +<div class="footnote"><p><a name="Footnote_29_29" id="Footnote_29_29"></a><a href="#FNanchor_29_29"><span class="label">[29]</span></a> +<i>Ibid.</i>, pt. 1, ch. 8.</p></div> + +<div class="footnote"><p><a name="Footnote_30_30" id="Footnote_30_30"></a><a href="#FNanchor_30_30"><span class="label">[30]</span></a> +<i>Ibid.</i>, pt. 1, ch. 9.</p></div> + +<div class="footnote"><p><a name="Footnote_31_31" id="Footnote_31_31"></a><a href="#FNanchor_31_31"><span class="label">[31]</span></a> +<i>Ibid.</i>, pt. 1, ch. 9. See also <a href="#Footnote_27_27">footnote 27</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_32_32" id="Footnote_32_32"></a><a href="#FNanchor_32_32"><span class="label">[32]</span></a> +<i>Ibid.</i>, pt. 1, ch. 10. See also ch. 4.</p></div> + +<div class="footnote"><p><a name="Footnote_33_33" id="Footnote_33_33"></a><a href="#FNanchor_33_33"><span class="label">[33]</span></a> +<i>Ibid.</i>, pt. 1, ch. 10. See also ch. 4.</p></div> + +<div class="footnote"><p><a name="Footnote_34_34" id="Footnote_34_34"></a><a href="#FNanchor_34_34"><span class="label">[34]</span></a> +<i>Ibid.</i>, pt. 1, ch. 10.</p></div> + +<div class="footnote"><p><a name="Footnote_35_35" id="Footnote_35_35"></a><a href="#FNanchor_35_35"><span class="label">[35]</span></a> +However, he may not always have approved of him. See +M:74; "Overinquisitive theologians, too, seek to light up God's +mysteries and things beyond man's understanding by means +of the loadstone and amber."</p></div> + +<div class="footnote"><p><a name="Footnote_36_36" id="Footnote_36_36"></a><a href="#FNanchor_36_36"><span class="label">[36]</span></a> +Nicholas of Cusa (Nicolaus Cusaneus), <i>Nicolaus von Cues, +Texte seiner philosophischen Schriften</i>, ed. A. Petzelt, Stuttgart, +1949, bk. 1, <i>Idiota de sapientia</i>, p. 306 (quoted in Gilbert, M:104). +It is interesting that Cusa held that the loadstone has an inclination +to iron, as well as the converse!</p></div> + +<div class="footnote"><p><a name="Footnote_37_37" id="Footnote_37_37"></a><a href="#FNanchor_37_37"><span class="label">[37]</span></a> +Cusa, <i>Cusa Schriften</i>, vol. 8, <i>De pace fidei</i>, translated by +L. Mohler, Leipzig, 1943, ch. 12, p. 127.</p></div> + +<div class="footnote"><p><a name="Footnote_38_38" id="Footnote_38_38"></a><a href="#FNanchor_38_38"><span class="label">[38]</span></a> +Cusa, <i>Exercitationes</i>, ch. 7, 563 and 566, quoted in, F. A. +Scharpff, <i>Des Cardinals und Bischofs Nicolaus Von Cusa Wichtigste +Schriften in Deutscher Uebersetzung</i>, Freiburg, 1862, p. 435. See also +Martin Billinger, <i>Das Philosophische in Den Excitationen Des +Nicolaus Von Cues</i>, Heidelberg, 1938, and <i>Cusa Schriften</i> (see +<a href="#Footnote_37_37">footnote 37</a>), vol. 8, p. 209, note 105. Gilbert (M: p. 223) +called the compass "the finger of God."</p></div> + +<div class="footnote"><p><a name="Footnote_39_39" id="Footnote_39_39"></a><a href="#FNanchor_39_39"><span class="label">[39]</span></a> +Hellmann, <i>op. cit.</i> (<a href="#Footnote_6_6">footnote 6</a>), Norman, bk. 1, ch. 8.</p></div> + +<div class="footnote"><p><a name="Footnote_40_40" id="Footnote_40_40"></a><a href="#FNanchor_40_40"><span class="label">[40]</span></a> +M: p. 14.</p></div> + +<div class="footnote"><p><a name="Footnote_41_41" id="Footnote_41_41"></a><a href="#FNanchor_41_41"><span class="label">[41]</span></a> +Richard Hooker. <i>Of the laws of ecclesiastical polity</i>, bk. 1, +ch. 3, sect. 4 (<i>Works</i>, Oxford, Clarendon Press, 1865, vol. 1, +p. 157)</p></div> + +<div class="footnote"><p><a name="Footnote_42_42" id="Footnote_42_42"></a><a href="#FNanchor_42_42"><span class="label">[42]</span></a> +Francis Bacon, <i>De augmentis scientiarum</i>, bk. 3, ch. 4, in <i>Works</i>, +ed. J. Spedding, R. L. Ellis, and D. D. Heath, Boston, n.d. +(1900?), vol. 2, p. 267.</p></div> + +<div class="footnote"><p><a name="Footnote_43_43" id="Footnote_43_43"></a><a href="#FNanchor_43_43"><span class="label">[43]</span></a> +<i>The poems of John Donne</i>, ed. H. J. C. Grierson, London, +Oxford University Press, 1933, p. 175 ("To the Countesse of +Bedford, On New Yeares Day").</p></div> + +<div class="footnote"><p><a name="Footnote_44_44" id="Footnote_44_44"></a><a href="#FNanchor_44_44"><span class="label">[44]</span></a> +M: pp. 33, 34.</p></div> + +<div class="footnote"><p><a name="Footnote_45_45" id="Footnote_45_45"></a><a href="#FNanchor_45_45"><span class="label">[45]</span></a> +M: pp. 34, 35. Aristotle, <i>Works</i>, ed. W. D. Ross, Oxford, +1908—1952, vol. 2, <i>De generatione et corruptione</i>, translated by +H. H. Joachim, 1930, vol. 3, <i>Meteorologica</i>, translated by +E. W. Webster, 1931.</p></div> + +<div class="footnote"><p><a name="Footnote_46_46" id="Footnote_46_46"></a><a href="#FNanchor_46_46"><span class="label">[46]</span></a> +M: pp. 34, 35, 64, 65, 69, 81. Dr. H. Guerlac has kindly +brought to my attention the similarity between the explanation +given in Gilbert and that given in the <i>Meteorologica</i>, bk. 3, ch. 6. +p. 378.</p></div> + +<div class="footnote"><p><a name="Footnote_47_47" id="Footnote_47_47"></a><a href="#FNanchor_47_47"><span class="label">[47]</span></a> +M: p. 83.</p></div> + +<div class="footnote"><p><a name="Footnote_48_48" id="Footnote_48_48"></a><a href="#FNanchor_48_48"><span class="label">[48]</span></a> +A statement of the relation between Aristotle's four elements +and place can be found in Maier, <i>op. cit.</i> (<a href="#Footnote_17_17">footnote 17</a>), +pp. 143-182.</p></div> + +<div class="footnote"><p><a name="Footnote_49_49" id="Footnote_49_49"></a><a href="#FNanchor_49_49"><span class="label">[49]</span></a> +M: pp. 21, 34, 35, 36, 45.</p></div> + +<div class="footnote"><p><a name="Footnote_50_50" id="Footnote_50_50"></a><a href="#FNanchor_50_50"><span class="label">[50]</span></a> +M: pp. 35, 36, 38, 69; see, however, pp. 42-43: "Iron ore, +therefore, as also manufactured iron, is a metal slightly different +from the homogenic telluric body because of the metallic +humor it has imbibed ..."</p></div> + +<div class="footnote"><p><a name="Footnote_51_51" id="Footnote_51_51"></a><a href="#FNanchor_51_51"><span class="label">[51]</span></a> +M: pp. 19, 34, 36, 37, 42, 69.</p></div> + +<div class="footnote"><p><a name="Footnote_52_52" id="Footnote_52_52"></a><a href="#FNanchor_52_52"><span class="label">[52]</span></a> +M: pp. 35, 36, 37, 38.</p></div> + +<div class="footnote"><p><a name="Footnote_53_53" id="Footnote_53_53"></a><a href="#FNanchor_53_53"><span class="label">[53]</span></a> +M: pp. 38, 63, 69, 84; on p. 34 he says that iron is "more +truly the child of the earth than any other metal"; it is the +hardest because of "the strong concretion of the more earthy +substance."</p></div> + +<div class="footnote"><p><a name="Footnote_54_54" id="Footnote_54_54"></a><a href="#FNanchor_54_54"><span class="label">[54]</span></a> +M: pp. 21, 35, 37, 38.</p></div> + +<div class="footnote"><p><a name="Footnote_55_55" id="Footnote_55_55"></a><a href="#FNanchor_55_55"><span class="label">[55]</span></a> +M: pp. 35, 63.</p></div> + +<div class="footnote"><p><a name="Footnote_56_56" id="Footnote_56_56"></a><a href="#FNanchor_56_56"><span class="label">[56]</span></a> +M: pp. 45, 46.</p></div> + +<div class="footnote"><p><a name="Footnote_57_57" id="Footnote_57_57"></a><a href="#FNanchor_57_57"><span class="label">[57]</span></a> +Gilbert's terminology strongly suggests that he was familiar +with alchemical literature, as well as that of medical chemistry. +He has been credited as being highly skilled in chemistry. See +Sir Walter Langdon-Brown, "William Gilbert: his place in +the medical world," <i>Nature</i>, vol. 154, pp. 136-139, 1944.</p></div> + +<div class="footnote"><p><a name="Footnote_58_58" id="Footnote_58_58"></a><a href="#FNanchor_58_58"><span class="label">[58]</span></a> +<i>Ibid.</i>, p. 37.</p></div> + +<div class="footnote"><p><a name="Footnote_59_59" id="Footnote_59_59"></a><a href="#FNanchor_59_59"><span class="label">[59]</span></a> +M: pp. 35, 36, 53, 59. See also Galen, <i>op. cit.</i> (<a href="#Footnote_15_15">footnote 15</a>) bk. 2, ch. 3.</p></div> + +<div class="footnote"><p><a name="Footnote_60_60" id="Footnote_60_60"></a><a href="#FNanchor_60_60"><span class="label">[60]</span></a> +M: pp. 16, 59.</p></div> + +<div class="footnote"><p><a name="Footnote_61_61" id="Footnote_61_61"></a><a href="#FNanchor_61_61"><span class="label">[61]</span></a> +M: pp. 20, 21, 32, 61, 63, 66, 70.</p></div> + +<div class="footnote"><p><a name="Footnote_62_62" id="Footnote_62_62"></a><a href="#FNanchor_62_62"><span class="label">[62]</span></a> +M: p. 59.</p></div> + +<div class="footnote"><p><a name="Footnote_63_63" id="Footnote_63_63"></a><a href="#FNanchor_63_63"><span class="label">[63]</span></a> +M: p. 84.</p></div> + +<div class="footnote"><p><a name="Footnote_64_64" id="Footnote_64_64"></a><a href="#FNanchor_64_64"><span class="label">[64]</span></a> +M: pp. 310, 311, 312.</p></div> + +<div class="footnote"><p><a name="Footnote_65_65" id="Footnote_65_65"></a><a href="#FNanchor_65_65"><span class="label">[65]</span></a> +M: p. 338. A somewhat different opinion, although not +necessarily inconsistent is expressed on p. 66, where he says +the surface is due to the action of the atmosphere, the waters, +and the radiations and other influences of heavenly bodies.</p></div> + +<div class="footnote"><p><a name="Footnote_66_66" id="Footnote_66_66"></a><a href="#FNanchor_66_66"><span class="label">[66]</span></a> +Aristotle, <i>op. cit.</i> (<a href="#Footnote_45_45">footnote 45</a>), <i>De generatione et corruptione</i>, bk. 2, ch. 10.</p></div> + +<div class="footnote"><p><a name="Footnote_67_67" id="Footnote_67_67"></a><a href="#FNanchor_67_67"><span class="label">[67]</span></a> +M: pp. 311, 334, 338.</p></div> + +<div class="footnote"><p><a name="Footnote_68_68" id="Footnote_68_68"></a><a href="#FNanchor_68_68"><span class="label">[68]</span></a> +M: pp. xlvii, 309, 328.</p></div> + +<div class="footnote"><p><a name="Footnote_69_69" id="Footnote_69_69"></a><a href="#FNanchor_69_69"><span class="label">[69]</span></a> +M: pp. 18, 20, 44, 46, 69.</p></div> + +<div class="footnote"><p><a name="Footnote_70_70" id="Footnote_70_70"></a><a href="#FNanchor_70_70"><span class="label">[70]</span></a> +M: pp. 59, 61, 63.</p></div> + +<div class="footnote"><p><a name="Footnote_71_71" id="Footnote_71_71"></a><a href="#FNanchor_71_71"><span class="label">[71]</span></a> +M: pp. 60, 63.</p></div> + +<div class="footnote"><p><a name="Footnote_72_72" id="Footnote_72_72"></a><a href="#FNanchor_72_72"><span class="label">[72]</span></a> +M: p. 110.</p></div> + +<div class="footnote"><p><a name="Footnote_73_73" id="Footnote_73_73"></a><a href="#FNanchor_73_73"><span class="label">[73]</span></a> +M: pp. 60, 61.</p></div> + +<div class="footnote"><p><a name="Footnote_74_74" id="Footnote_74_74"></a><a href="#FNanchor_74_74"><span class="label">[74]</span></a> +M: p. 62.</p></div> + +<div class="footnote"><p><a name="Footnote_75_75" id="Footnote_75_75"></a><a href="#FNanchor_75_75"><span class="label">[75]</span></a> +M: p. 63.</p></div> + +<div class="footnote"><p><a name="Footnote_76_76" id="Footnote_76_76"></a><a href="#FNanchor_76_76"><span class="label">[76]</span></a> +M: p. 60.</p></div> + +<div class="footnote"><p><a name="Footnote_77_77" id="Footnote_77_77"></a><a href="#FNanchor_77_77"><span class="label">[77]</span></a> +M: pp. 19, 21, 43, 53, 61, 63, 184.</p></div> + +<div class="footnote"><p><a name="Footnote_78_78" id="Footnote_78_78"></a><a href="#FNanchor_78_78"><span class="label">[78]</span></a> +M: p. 61.</p></div> + +<div class="footnote"><p><a name="Footnote_79_79" id="Footnote_79_79"></a><a href="#FNanchor_79_79"><span class="label">[79]</span></a> +M: pp. 66, 67.</p></div> + +<div class="footnote"><p><a name="Footnote_80_80" id="Footnote_80_80"></a><a href="#FNanchor_80_80"><span class="label">[80]</span></a> +M: p. 69. Gilbert is confusing Aristotelian matter and an +element. He includes cold and dry, with formless and inert! +See also Maier, <i>op. cit.</i> (<a href="#Footnote_17_17">footnote 17</a>).</p></div> + +<div class="footnote"><p><a name="Footnote_81_81" id="Footnote_81_81"></a><a href="#FNanchor_81_81"><span class="label">[81]</span></a> +M: p. 63; bk. 1, ch. 17.</p></div> + +<div class="footnote"><p><a name="Footnote_82_82" id="Footnote_82_82"></a><a href="#FNanchor_82_82"><span class="label">[82]</span></a> +M: pp. 67, 181-183, 235-240, 281-289, 313-314.</p></div> + +<div class="footnote"><p><a name="Footnote_83_83" id="Footnote_83_83"></a><a href="#FNanchor_83_83"><span class="label">[83]</span></a> +M: p. 71. See also pp. 314 and 331. It is not clear, at +this point, whether he believed a "properly balanced" terrella +would be a <i>perpetuum mobile</i>.</p></div> + +<div class="footnote"><p><a name="Footnote_84_84" id="Footnote_84_84"></a><a href="#FNanchor_84_84"><span class="label">[84]</span></a> +M: pp. 68, 70-71, 97, 129, 179-180, 311, 315, 317-335 +Gilbert implied (M: p. 166), that a terrella does not rotate as +Peregrinus said, due to resistance (M: p. 326), or due to the +mutual nature of coition (M: p. 166); or even to the rotation +of the earth (M: p. 332). However (M: p. 129), he also mentioned +that a terrella would revolve by itself!</p></div> + +<div class="footnote"><p><a name="Footnote_85_85" id="Footnote_85_85"></a><a href="#FNanchor_85_85"><span class="label">[85]</span></a> +M: pp. 78, 82, 84, 86.</p></div> + +<div class="footnote"><p><a name="Footnote_86_86" id="Footnote_86_86"></a><a href="#FNanchor_86_86"><span class="label">[86]</span></a> +M: pp. 78, 89, 91.</p></div> + +<div class="footnote"><p><a name="Footnote_87_87" id="Footnote_87_87"></a><a href="#FNanchor_87_87"><span class="label">[87]</span></a> +M: pp. 89, 95.</p></div> + +<div class="footnote"><p><a name="Footnote_88_88" id="Footnote_88_88"></a><a href="#FNanchor_88_88"><span class="label">[88]</span></a> +M: pp. 83, 86.</p></div> + +<div class="footnote"><p><a name="Footnote_89_89" id="Footnote_89_89"></a><a href="#FNanchor_89_89"><span class="label">[89]</span></a> +M: pp. 81, 86, 87.</p></div> + +<div class="footnote"><p><a name="Footnote_90_90" id="Footnote_90_90"></a><a href="#FNanchor_90_90"><span class="label">[90]</span></a> +M: pp. 80, 81, 86, 87.</p></div> + +<div class="footnote"><p><a name="Footnote_91_91" id="Footnote_91_91"></a><a href="#FNanchor_91_91"><span class="label">[91]</span></a> +M: p. 79.</p></div> + +<div class="footnote"><p><a name="Footnote_92_92" id="Footnote_92_92"></a><a href="#FNanchor_92_92"><span class="label">[92]</span></a> +M: pp. 77-78, 79.</p></div> + +<div class="footnote"><p><a name="Footnote_93_93" id="Footnote_93_93"></a><a href="#FNanchor_93_93"><span class="label">[93]</span></a> +M: p. 78. The definition Gilbert gave of an electric in the +glossary at the beginning of his treatise was not an experimental +one: "Electricae, quae attrahunt eadem ratione ut electrum."</p></div> + +<div class="footnote"><p><a name="Footnote_94_94" id="Footnote_94_94"></a><a href="#FNanchor_94_94"><span class="label">[94]</span></a> +M: pp. 86, 91, 135.</p></div> + +<div class="footnote"><p><a name="Footnote_95_95" id="Footnote_95_95"></a><a href="#FNanchor_95_95"><span class="label">[95]</span></a> +M: pp. 96, 135.</p></div> + +<div class="footnote"><p><a name="Footnote_96_96" id="Footnote_96_96"></a><a href="#FNanchor_96_96"><span class="label">[96]</span></a> +M: p. 89.</p></div> + +<div class="footnote"><p><a name="Footnote_97_97" id="Footnote_97_97"></a><a href="#FNanchor_97_97"><span class="label">[97]</span></a> +M: pp. 90, 92, 95.</p></div> + +<div class="footnote"><p><a name="Footnote_98_98" id="Footnote_98_98"></a><a href="#FNanchor_98_98"><span class="label">[98]</span></a> +M: pp. 83, 84, 85.</p></div> + +<div class="footnote"><p><a name="Footnote_99_99" id="Footnote_99_99"></a><a href="#FNanchor_99_99"><span class="label">[99]</span></a> +M: p. 84.</p></div> + +<div class="footnote"><p><a name="Footnote_100_100" id="Footnote_100_100"></a><a href="#FNanchor_100_100"><span class="label">[100]</span></a> +M: pp. 84, 89. See also Aristotle, <i>op. cit.</i> (<a href="#Footnote_45_45">footnote 45</a>), <i>Meteorologica</i>, bk. 4.</p></div> + +<div class="footnote"><p><a name="Footnote_101_101" id="Footnote_101_101"></a><a href="#FNanchor_101_101"><span class="label">[101]</span></a> +M: p. 90.</p></div> + +<div class="footnote"><p><a name="Footnote_102_102" id="Footnote_102_102"></a><a href="#FNanchor_102_102"><span class="label">[102]</span></a> +M: pp. 84, 85.</p></div> + +<div class="footnote"><p><a name="Footnote_103_103" id="Footnote_103_103"></a><a href="#FNanchor_103_103"><span class="label">[103]</span></a> +M: p. 84.</p></div> + +<div class="footnote"><p><a name="Footnote_104_104" id="Footnote_104_104"></a><a href="#FNanchor_104_104"><span class="label">[104]</span></a> +M: p. 90. See also p. 95.</p></div> + +<div class="footnote"><p><a name="Footnote_105_105" id="Footnote_105_105"></a><a href="#FNanchor_105_105"><span class="label">[105]</span></a> +M: pp. 78, 85-86, 91. (see particularly the heated amber +experiment described on p. 86).</p></div> + +<div class="footnote"><p><a name="Footnote_106_106" id="Footnote_106_106"></a><a href="#FNanchor_106_106"><span class="label">[106]</span></a> +M: p. 87.</p></div> + +<div class="footnote"><p><a name="Footnote_107_107" id="Footnote_107_107"></a><a href="#FNanchor_107_107"><span class="label">[107]</span></a> +M: p. 92.</p></div> + +<div class="footnote"><p><a name="Footnote_108_108" id="Footnote_108_108"></a><a href="#FNanchor_108_108"><span class="label">[108]</span></a> +Aristotle, <i>Physics</i>, translated by P. H. Wicksteed and F. +M. Cornford, Loeb Classical Library, London, 1934, bk. 7, +ch. 1, 242b25.</p></div> + +<div class="footnote"><p><a name="Footnote_109_109" id="Footnote_109_109"></a><a href="#FNanchor_109_109"><span class="label">[109]</span></a> +St. Thomas Aquinas, <i>op. cit.</i> (<a href="#Footnote_19_19">footnote 19</a>), vol. 2, <i>Physicorum +Aristotelis expositio</i>, lib. 7, lect. 2 (In moventibus et motis non potest +procedi in infinitum, sed oportet devenire ad aliquid primum +movens immobile), cap. d, p. 96.</p></div> + +<div class="footnote"><p><a name="Footnote_110_110" id="Footnote_110_110"></a><a href="#FNanchor_110_110"><span class="label">[110]</span></a> +M: p. 94.</p></div> + +<div class="footnote"><p><a name="Footnote_111_111" id="Footnote_111_111"></a><a href="#FNanchor_111_111"><span class="label">[111]</span></a> +M: p. 95.</p></div> + +<div class="footnote"><p><a name="Footnote_112_112" id="Footnote_112_112"></a><a href="#FNanchor_112_112"><span class="label">[112]</span></a> +M: p. 93.</p></div> + +<div class="footnote"><p><a name="Footnote_113_113" id="Footnote_113_113"></a><a href="#FNanchor_113_113"><span class="label">[113]</span></a> +M: pp. 92, 93.</p></div> + +<div class="footnote"><p><a name="Footnote_114_114" id="Footnote_114_114"></a><a href="#FNanchor_114_114"><span class="label">[114]</span></a> +M: p. 93.</p></div> + +<div class="footnote"><p><a name="Footnote_115_115" id="Footnote_115_115"></a><a href="#FNanchor_115_115"><span class="label">[115]</span></a> +M: p. 94.</p></div> + +<div class="footnote"><p><a name="Footnote_116_116" id="Footnote_116_116"></a><a href="#FNanchor_116_116"><span class="label">[116]</span></a> +M: p. 94.</p></div> + +<div class="footnote"><p><a name="Footnote_117_117" id="Footnote_117_117"></a><a href="#FNanchor_117_117"><span class="label">[117]</span></a> +M: p. 97.</p></div> + +<div class="footnote"><p><a name="Footnote_118_118" id="Footnote_118_118"></a><a href="#FNanchor_118_118"><span class="label">[118]</span></a> +M: p. 92 (see also p. 339). Although Gilbert does not make +it explicit, this would solve the medieval problem of gravitation +without resorting to a Ptolemaic universe. In addition, since +coacervation is electric, and electric forces can be screened, +it should have been possible to reduce the downward motion +of a body by screening!</p></div> + +<div class="footnote"><p><a name="Footnote_119_119" id="Footnote_119_119"></a><a href="#FNanchor_119_119"><span class="label">[119]</span></a> +M: pp. 91, 92: "This unity is, according to Pythagoras, the +principle, through participation, in which a thing is said to be +one" (see <a href="#Footnote_30_30">footnotes 30</a> and <a href="#Footnote_122_122">122</a>).</p></div> + +<div class="footnote"><p><a name="Footnote_120_120" id="Footnote_120_120"></a><a href="#FNanchor_120_120"><span class="label">[120]</span></a> +"Sense" is probably too strong a term, and yet the change +following contact is difficult to describe in Gilbert's phraseology +without some such subjective term. See Gilbert's argument on +the soul and organs of a loadstone, M: pp. 309—313.</p></div> + +<div class="footnote"><p><a name="Footnote_121_121" id="Footnote_121_121"></a><a href="#FNanchor_121_121"><span class="label">[121]</span></a> +M: pp. 112, 113.</p></div> + +<div class="footnote"><p><a name="Footnote_122_122" id="Footnote_122_122"></a><a href="#FNanchor_122_122"><span class="label">[122]</span></a> +Gilbert, <i>De magnete</i>, London, 1600, bk. 2, ch. 2, pp. 56-57.</p></div> + +<div class="footnote"><p><a name="Footnote_123_123" id="Footnote_123_123"></a><a href="#FNanchor_123_123"><span class="label">[123]</span></a> +<i>Ibid.</i>, ch. 1, pp. 45-46.</p></div> + +<div class="footnote"><p><a name="Footnote_124_124" id="Footnote_124_124"></a><a href="#FNanchor_124_124"><span class="label">[124]</span></a> +M: pp. 110, 314.</p></div> + +<div class="footnote"><p><a name="Footnote_125_125" id="Footnote_125_125"></a><a href="#FNanchor_125_125"><span class="label">[125]</span></a> +M: pp. 82, 105, 170, 172, 217.</p></div> + +<div class="footnote"><p><a name="Footnote_126_126" id="Footnote_126_126"></a><a href="#FNanchor_126_126"><span class="label">[126]</span></a> +M: p. 98.</p></div> + +<div class="footnote"><p><a name="Footnote_127_127" id="Footnote_127_127"></a><a href="#FNanchor_127_127"><span class="label">[127]</span></a> +M: pp. 100, 112, 113, 143, 148. It need hardly be pointed +out that coitus is not an impersonal term.</p></div> + +<div class="footnote"><p><a name="Footnote_128_128" id="Footnote_128_128"></a><a href="#FNanchor_128_128"><span class="label">[128]</span></a> +M: p. 110.</p></div> + +<div class="footnote"><p><a name="Footnote_129_129" id="Footnote_129_129"></a><a href="#FNanchor_129_129"><span class="label">[129]</span></a> +M: p. 110.</p></div> + +<div class="footnote"><p><a name="Footnote_130_130" id="Footnote_130_130"></a><a href="#FNanchor_130_130"><span class="label">[130]</span></a> +M: pp. 109, 115, 148, 149, 155, 166, 174.</p></div> + +<div class="footnote"><p><a name="Footnote_131_131" id="Footnote_131_131"></a><a href="#FNanchor_131_131"><span class="label">[131]</span></a> +M: pp. 110, 155.</p></div> + +<div class="footnote"><p><a name="Footnote_132_132" id="Footnote_132_132"></a><a href="#FNanchor_132_132"><span class="label">[132]</span></a> +M: pp. 166, 332. See also <a href="#Footnote_84_84">footnote 84</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_133_133" id="Footnote_133_133"></a><a href="#FNanchor_133_133"><span class="label">[133]</span></a> +M: pp. 90, 106, 107, 108, 113, 132, 135, 136, 158. This +is, of course, contrary to modern experience.</p></div> + +<div class="footnote"><p><a name="Footnote_134_134" id="Footnote_134_134"></a><a href="#FNanchor_134_134"><span class="label">[134]</span></a> +M: pp. 106, 107, 108, 114, 134, 136, 140, 162.</p></div> + +<div class="footnote"><p><a name="Footnote_135_135" id="Footnote_135_135"></a><a href="#FNanchor_135_135"><span class="label">[135]</span></a> +M: pp. 106, 109, 114, 159, 162.</p></div> + +<div class="footnote"><p><a name="Footnote_136_136" id="Footnote_136_136"></a><a href="#FNanchor_136_136"><span class="label">[136]</span></a> +M: pp. 137-140.</p></div> + +<div class="footnote"><p><a name="Footnote_137_137" id="Footnote_137_137"></a><a href="#FNanchor_137_137"><span class="label">[137]</span></a> +M: p. 109.</p></div> + +<div class="footnote"><p><a name="Footnote_138_138" id="Footnote_138_138"></a><a href="#FNanchor_138_138"><span class="label">[138]</span></a> +M: p. 105, and Gilbert, <i>De magnete</i>, London, 1600, bk. 2 +ch. 4, p. 65.</p></div> + +<div class="footnote"><p><a name="Footnote_139_139" id="Footnote_139_139"></a><a href="#FNanchor_139_139"><span class="label">[139]</span></a> +M: p. 105.</p></div> + +<div class="footnote"><p><a name="Footnote_140_140" id="Footnote_140_140"></a><a href="#FNanchor_140_140"><span class="label">[140]</span></a> +M: pp. 289, 322.</p></div> + +<div class="footnote"><p><a name="Footnote_141_141" id="Footnote_141_141"></a><a href="#FNanchor_141_141"><span class="label">[141]</span></a> +M: pp. 26, 68, 105, 179, 198, 307, 335, 343. For rotation, see <a href="#Footnote_147_147">footnote 147</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_142_142" id="Footnote_142_142"></a><a href="#FNanchor_142_142"><span class="label">[142]</span></a> +M: pp. 67, 71. That each part is informed with the +properties of the whole is an argument favoring an animistic +explanation of the nature of this form.</p></div> + +<div class="footnote"><p><a name="Footnote_143_143" id="Footnote_143_143"></a><a href="#FNanchor_143_143"><span class="label">[143]</span></a> +M: p. 109.</p></div> + +<div class="footnote"><p><a name="Footnote_144_144" id="Footnote_144_144"></a><a href="#FNanchor_144_144"><span class="label">[144]</span></a> +M: pp. 111, 188.</p></div> + +<div class="footnote"><p><a name="Footnote_145_145" id="Footnote_145_145"></a><a href="#FNanchor_145_145"><span class="label">[145]</span></a> +M: pp. 67, 105, 179, 183.</p></div> + +<div class="footnote"><p><a name="Footnote_146_146" id="Footnote_146_146"></a><a href="#FNanchor_146_146"><span class="label">[146]</span></a> +M: pp. 101, 105, 217.</p></div> + +<div class="footnote"><p><a name="Footnote_147_147" id="Footnote_147_147"></a><a href="#FNanchor_147_147"><span class="label">[147]</span></a> +M: pp. 179, 304, 305, 311, 322, 326, 328, 330-334, 338-343.</p></div> + +<div class="footnote"><p><a name="Footnote_148_148" id="Footnote_148_148"></a><a href="#FNanchor_148_148"><span class="label">[148]</span></a> +M: pp. 142, 179; see also electric attraction, p. 97.</p></div> + +<div class="footnote"><p><a name="Footnote_149_149" id="Footnote_149_149"></a><a href="#FNanchor_149_149"><span class="label">[149]</span></a> +M: pp. 308, 317-343.</p></div> + +<div class="footnote"><p><a name="Footnote_150_150" id="Footnote_150_150"></a><a href="#FNanchor_150_150"><span class="label">[150]</span></a> +M: pp. 106, 340.</p></div> + +<div class="footnote"><p><a name="Footnote_151_151" id="Footnote_151_151"></a><a href="#FNanchor_151_151"><span class="label">[151]</span></a> +M: pp. 308, 309, 311, 330, 333, 344, 347.</p></div> + +<div class="footnote"><p><a name="Footnote_152_152" id="Footnote_152_152"></a><a href="#FNanchor_152_152"><span class="label">[152]</span></a> +M: pp. 136, 334, 345.</p></div> + +<div class="footnote"><p><a name="Footnote_153_153" id="Footnote_153_153"></a><a href="#FNanchor_153_153"><span class="label">[153]</span></a> +M: pp. 184-186, 190, 232. This is not quite the same +argument as that the powers of the loadstone are identical +with those of the earth. See <a href="#Footnote_78_78">footnote 78</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_154_154" id="Footnote_154_154"></a><a href="#FNanchor_154_154"><span class="label">[154]</span></a> +M: pp. 125, 180.</p></div> + +<div class="footnote"><p><a name="Footnote_155_155" id="Footnote_155_155"></a><a href="#FNanchor_155_155"><span class="label">[155]</span></a> +M: p. 151.</p></div> + +<div class="footnote"><p><a name="Footnote_156_156" id="Footnote_156_156"></a><a href="#FNanchor_156_156"><span class="label">[156]</span></a> +M: pp. 121, 150.</p></div> + +<div class="footnote"><p><a name="Footnote_157_157" id="Footnote_157_157"></a><a href="#FNanchor_157_157"><span class="label">[157]</span></a> +M: pp. 115, 151, 165.</p></div> + +<div class="footnote"><p><a name="Footnote_158_158" id="Footnote_158_158"></a><a href="#FNanchor_158_158"><span class="label">[158]</span></a> +M: pp. 106, 118, 151, 191, 205, 221, 243.</p></div> + +<div class="footnote"><p><a name="Footnote_159_159" id="Footnote_159_159"></a><a href="#FNanchor_159_159"><span class="label">[159]</span></a> +M: pp. 116, 117, 119, 131, 183, 188, 221.</p></div> + +<div class="footnote"><p><a name="Footnote_160_160" id="Footnote_160_160"></a><a href="#FNanchor_160_160"><span class="label">[160]</span></a> +M: p. 31.</p></div> + +<div class="footnote"><p><a name="Footnote_161_161" id="Footnote_161_161"></a><a href="#FNanchor_161_161"><span class="label">[161]</span></a> +M: pp. 116, 151, 200.</p></div> + +<div class="footnote"><p><a name="Footnote_162_162" id="Footnote_162_162"></a><a href="#FNanchor_162_162"><span class="label">[162]</span></a> +M: pp. 131, 132, 153-158.</p></div> + +<div class="footnote"><p><a name="Footnote_163_163" id="Footnote_163_163"></a><a href="#FNanchor_163_163"><span class="label">[163]</span></a> +M: pp. 141, 152, 153, 158, 161, 191, 222.</p></div> + +<div class="footnote"><p><a name="Footnote_164_164" id="Footnote_164_164"></a><a href="#FNanchor_164_164"><span class="label">[164]</span></a> +M: p. 146.</p></div> + +<div class="footnote"><p><a name="Footnote_165_165" id="Footnote_165_165"></a><a href="#FNanchor_165_165"><span class="label">[165]</span></a> +M: p. 165.</p></div> + +<div class="footnote"><p><a name="Footnote_166_166" id="Footnote_166_166"></a><a href="#FNanchor_166_166"><span class="label">[166]</span></a> +M: p. 153.</p></div> + +<div class="footnote"><p><a name="Footnote_167_167" id="Footnote_167_167"></a><a href="#FNanchor_167_167"><span class="label">[167]</span></a> +M: pp. 121, 123, 124, 304, 305, 306, 307, 309.</p></div> + +<div class="footnote"><p><a name="Footnote_168_168" id="Footnote_168_168"></a><a href="#FNanchor_168_168"><span class="label">[168]</span></a> +Gilbert defined the <i>orbis virtutis</i> in the glossary at the +beginning of his treatise as, "... totum illud spatium, per +quod quaevis magnetis virtus extenditur." This is the core of +the difference between electric and magnetic forces. The substantial +form of an electric could not be "effused," but was +"imprisoned" in matter (as the Neoplatonic soul in the human +body); while the primary form of a magnet did not require +a material carrier and its effusion was similar to the propagation +of a species in light.</p></div> + +<div class="footnote"><p><a name="Footnote_169_169" id="Footnote_169_169"></a><a href="#FNanchor_169_169"><span class="label">[169]</span></a> +M: pp. 124, 150, 151.</p></div> + +<div class="footnote"><p><a name="Footnote_170_170" id="Footnote_170_170"></a><a href="#FNanchor_170_170"><span class="label">[170]</span></a> +M: pp. 123, 307.</p></div> + +<div class="footnote"><p><a name="Footnote_171_171" id="Footnote_171_171"></a><a href="#FNanchor_171_171"><span class="label">[171]</span></a> +M: pp. 304-307. See also p. 310, where it is stated that +the sun and earth could awaken souls.</p></div> + +<div class="footnote"><p><a name="Footnote_172_172" id="Footnote_172_172"></a><a href="#FNanchor_172_172"><span class="label">[172]</span></a> +M: pp. 101, 110, 112, 123, 148, 149, 304, 305. This +awakening of the iron within the "orbis virtutis" is comparable +(pp. 216, 350) to the birth of a child under the influence of +the stars.</p></div> + +<div class="footnote"><p><a name="Footnote_173_173" id="Footnote_173_173"></a><a href="#FNanchor_173_173"><span class="label">[173]</span></a> +M: pp. 110, 111, 112, 189, 216, 217. See also <a href="#Footnote_36_36">footnote 36</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_174_174" id="Footnote_174_174"></a><a href="#FNanchor_174_174"><span class="label">[174]</span></a> +M: p. 106.</p></div> + +<div class="footnote"><p><a name="Footnote_175_175" id="Footnote_175_175"></a><a href="#FNanchor_175_175"><span class="label">[175]</span></a> +M: pp. 106, 109, 110.</p></div> + +<div class="footnote"><p><a name="Footnote_176_176" id="Footnote_176_176"></a><a href="#FNanchor_176_176"><span class="label">[176]</span></a> +M: pp. 113, 114.</p></div> + +<div class="footnote"><p><a name="Footnote_177_177" id="Footnote_177_177"></a><a href="#FNanchor_177_177"><span class="label">[177]</span></a> +M: pp. 190, 192, 210-216.</p></div> + +<div class="footnote"><p><a name="Footnote_178_178" id="Footnote_178_178"></a><a href="#FNanchor_178_178"><span class="label">[178]</span></a> +M: p. 209.</p></div> + +<div class="footnote"><p><a name="Footnote_179_179" id="Footnote_179_179"></a><a href="#FNanchor_179_179"><span class="label">[179]</span></a> +M: pp. 107, 110, 111.</p></div> + +<div class="footnote"><p><a name="Footnote_180_180" id="Footnote_180_180"></a><a href="#FNanchor_180_180"><span class="label">[180]</span></a> +M: p. 108.</p></div> + +<div class="footnote"><p><a name="Footnote_181_181" id="Footnote_181_181"></a><a href="#FNanchor_181_181"><span class="label">[181]</span></a> +M: pp. 111, 112, 113.</p></div> + +<div class="footnote"><p><a name="Footnote_182_182" id="Footnote_182_182"></a><a href="#FNanchor_182_182"><span class="label">[182]</span></a> +M: pp. 109, 111, 112, 148, 149.</p></div> + +<div class="footnote"><p><a name="Footnote_183_183" id="Footnote_183_183"></a><a href="#FNanchor_183_183"><span class="label">[183]</span></a> +M: pp. 112, 149.</p></div> + +<div class="footnote"><p><a name="Footnote_184_184" id="Footnote_184_184"></a><a href="#FNanchor_184_184"><span class="label">[184]</span></a> +M: pp. 142, 189.</p></div> + +<div class="footnote"><p><a name="Footnote_185_185" id="Footnote_185_185"></a><a href="#FNanchor_185_185"><span class="label">[185]</span></a> +M: p. 190.</p></div> + +<div class="footnote"><p><a name="Footnote_186_186" id="Footnote_186_186"></a><a href="#FNanchor_186_186"><span class="label">[186]</span></a> +M: pp. 85, 105, 113, 143, 226.</p></div> + +<div class="footnote"><p><a name="Footnote_187_187" id="Footnote_187_187"></a><a href="#FNanchor_187_187"><span class="label">[187]</span></a> +M: p. 84.</p></div> + +<div class="footnote"><p><a name="Footnote_188_188" id="Footnote_188_188"></a><a href="#FNanchor_188_188"><span class="label">[188]</span></a> +M: p. 186.</p></div> + +<div class="footnote"><p><a name="Footnote_189_189" id="Footnote_189_189"></a><a href="#FNanchor_189_189"><span class="label">[189]</span></a> +M: pp. 185-188. See also <a href="#Footnote_31_31">footnote 31</a>.</p></div> + +<div class="footnote"><p><a name="Footnote_190_190" id="Footnote_190_190"></a><a href="#FNanchor_190_190"><span class="label">[190]</span></a> +M: pp. 186, 193.</p></div> + +<div class="footnote"><p><a name="Footnote_191_191" id="Footnote_191_191"></a><a href="#FNanchor_191_191"><span class="label">[191]</span></a> +M: pp. 199-200.</p></div> + +<div class="footnote"><p><a name="Footnote_192_192" id="Footnote_192_192"></a><a href="#FNanchor_192_192"><span class="label">[192]</span></a> +M. p. 111.</p></div> + +<div class="footnote"><p><a name="Footnote_193_193" id="Footnote_193_193"></a><a href="#FNanchor_193_193"><span class="label">[193]</span></a> +M: p. 112.</p></div> + +<div class="footnote"><p><a name="Footnote_194_194" id="Footnote_194_194"></a><a href="#FNanchor_194_194"><span class="label">[194]</span></a> +See, however, M: pp. 112, 113.</p></div> + +<div class="footnote"><p><a name="Footnote_195_195" id="Footnote_195_195"></a><a href="#FNanchor_195_195"><span class="label">[195]</span></a> +M: pp. 109, 312.</p></div> + +<div class="footnote"><p><a name="Footnote_196_196" id="Footnote_196_196"></a><a href="#FNanchor_196_196"><span class="label">[196]</span></a> +M: p. 109.</p></div> + +<div class="footnote"><p><a name="Footnote_197_197" id="Footnote_197_197"></a><a href="#FNanchor_197_197"><span class="label">[197]</span></a> +M: p. 309.</p></div> + +<div class="footnote"><p><a name="Footnote_198_198" id="Footnote_198_198"></a><a href="#FNanchor_198_198"><span class="label">[198]</span></a> +M: pp. 311-312.</p></div> + +<div class="footnote"><p><a name="Footnote_199_199" id="Footnote_199_199"></a><a href="#FNanchor_199_199"><span class="label">[199]</span></a> +M: p. 108.</p></div> + +<div class="footnote"><p><a name="Footnote_200_200" id="Footnote_200_200"></a><a href="#FNanchor_200_200"><span class="label">[200]</span></a> +M: p. 110.</p></div> + +<div class="footnote"><p><a name="Footnote_201_201" id="Footnote_201_201"></a><a href="#FNanchor_201_201"><span class="label">[201]</span></a> +M: p. 216.</p></div> + +<div class="footnote"><p><a name="Footnote_202_202" id="Footnote_202_202"></a><a href="#FNanchor_202_202"><span class="label">[202]</span></a> +M: p. 311.</p></div> + +<div class="footnote"><p><a name="Footnote_203_203" id="Footnote_203_203"></a><a href="#FNanchor_203_203"><span class="label">[203]</span></a> +M: pp. 310, 311.</p></div> + +<div class="footnote"><p><a name="Footnote_204_204" id="Footnote_204_204"></a><a href="#FNanchor_204_204"><span class="label">[204]</span></a> +M: p. 312.</p></div> + +<div class="footnote"><p><a name="Footnote_205_205" id="Footnote_205_205"></a><a href="#FNanchor_205_205"><span class="label">[205]</span></a> +Francis Bacon, <i>op. cit.</i> (<a href="#Footnote_42_42">footnote 42</a>), vol. 1, <i>Novum organum</i>, +bk. 1, ch. 95, p. 306.</p></div> + +<div class="footnote"><p><a name="Footnote_206_206" id="Footnote_206_206"></a><a href="#FNanchor_206_206"><span class="label">[206]</span></a> +<i>Ibid.</i>, ch. 54 and ch. 64 (pp. 259 and 267).</p></div> + +<div class="footnote"><p><a name="Footnote_207_207" id="Footnote_207_207"></a><a href="#FNanchor_207_207"><span class="label">[207]</span></a> +Sir Thomas Browne, <i>Pseudodoxia epidemica</i>, ed. 3, London, +1658, bk. 2, ch. 2, 3, 4.</p></div> + +<div class="footnote"><p><a name="Footnote_208_208" id="Footnote_208_208"></a><a href="#FNanchor_208_208"><span class="label">[208]</span></a> +Robert Boyle, <i>Experiments and notes about the mechanical +production of magnetism</i>, London, 1676.</p></div> + +<div class="footnote"><p><a name="Footnote_209_209" id="Footnote_209_209"></a><a href="#FNanchor_209_209"><span class="label">[209]</span></a> +Nicolaus Cabeaus, <i>Philosophia magnetica</i>, Ferarra, 1629.</p></div> + +<div class="footnote"><p><a name="Footnote_210_210" id="Footnote_210_210"></a><a href="#FNanchor_210_210"><span class="label">[210]</span></a> +Galileo Galilei, <i>Dialogue on the great world systems</i>, in the +translation of T. Salusbury, edited and corrected by G. de +Santillana, University of Chicago Press, 1953, pp. 409-423.</p></div> + +<div class="footnote"><p><a name="Footnote_211_211" id="Footnote_211_211"></a><a href="#FNanchor_211_211"><span class="label">[211]</span></a> +Cassirer, <i>op. cit.</i> (<a href="#Footnote_3_3">footnote 3</a>), vol. 1, p. 359-367.</p></div> + +<div class="footnote"><p><a name="Footnote_212_212" id="Footnote_212_212"></a><a href="#FNanchor_212_212"><span class="label">[212]</span></a> +Because the earth has the same nature as a celestial globe, +its revolution and circular inertia require no more explanation +than those of any other heavenly body.</p></div> + +<div class="footnote"><p><a name="Footnote_213_213" id="Footnote_213_213"></a><a href="#FNanchor_213_213"><span class="label">[213]</span></a> +One wonders if Bruno might not have been another of the +stimuli for Gilbert. The latter's interest in magnetism began +shortly before Bruno visited England and lectured on his +interpretation of the Copernican theory.</p></div> +</div> + + + + + + + + +<pre> + + + + + +End of the Project Gutenberg EBook of The Natural Philosophy of William +Gilbert and His Predecessors, by W. James King + +*** END OF THIS PROJECT GUTENBERG EBOOK NATURAL PHILOSOPHY--WILLIAM GILBERT *** + +***** This file should be named 31999-h.htm or 31999-h.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/3/1/9/9/31999/ + +Produced by Chris Curnow, Joseph Cooper and the Online +Distributed Proofreading Team at https://www.pgdp.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. Project +Gutenberg is a registered trademark, and may not be used if you +charge for the eBooks, unless you receive specific permission. If you +do not charge anything for copies of this eBook, complying with the +rules is very easy. You may use this eBook for nearly any purpose +such as creation of derivative works, reports, performances and +research. They may be modified and printed and given away--you may do +practically ANYTHING with public domain eBooks. Redistribution is +subject to the trademark license, especially commercial +redistribution. + + + +*** START: FULL LICENSE *** + +THE FULL PROJECT GUTENBERG LICENSE +PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK + +To protect the Project Gutenberg-tm mission of promoting the free +distribution of electronic works, by using or distributing this work +(or any other work associated in any way with the phrase "Project +Gutenberg"), you agree to comply with all the terms of the Full Project +Gutenberg-tm License (available with this file or online at +https://gutenberg.org/license). + + +Section 1. General Terms of Use and Redistributing Project Gutenberg-tm +electronic works + +1.A. By reading or using any part of this Project Gutenberg-tm +electronic work, you indicate that you have read, understand, agree to +and accept all the terms of this license and intellectual property +(trademark/copyright) agreement. If you do not agree to abide by all +the terms of this agreement, you must cease using and return or destroy +all copies of Project Gutenberg-tm electronic works in your possession. +If you paid a fee for obtaining a copy of or access to a Project +Gutenberg-tm electronic work and you do not agree to be bound by the +terms of this agreement, you may obtain a refund from the person or +entity to whom you paid the fee as set forth in paragraph 1.E.8. + +1.B. "Project Gutenberg" is a registered trademark. It may only be +used on or associated in any way with an electronic work by people who +agree to be bound by the terms of this agreement. There are a few +things that you can do with most Project Gutenberg-tm electronic works +even without complying with the full terms of this agreement. See +paragraph 1.C below. There are a lot of things you can do with Project +Gutenberg-tm electronic works if you follow the terms of this agreement +and help preserve free future access to Project Gutenberg-tm electronic +works. See paragraph 1.E below. + +1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" +or PGLAF), owns a compilation copyright in the collection of Project +Gutenberg-tm electronic works. Nearly all the individual works in the +collection are in the public domain in the United States. If an +individual work is in the public domain in the United States and you are +located in the United States, we do not claim a right to prevent you from +copying, distributing, performing, displaying or creating derivative +works based on the work as long as all references to Project Gutenberg +are removed. Of course, we hope that you will support the Project +Gutenberg-tm mission of promoting free access to electronic works by +freely sharing Project Gutenberg-tm works in compliance with the terms of +this agreement for keeping the Project Gutenberg-tm name associated with +the work. You can easily comply with the terms of this agreement by +keeping this work in the same format with its attached full Project +Gutenberg-tm License when you share it without charge with others. + +1.D. The copyright laws of the place where you are located also govern +what you can do with this work. Copyright laws in most countries are in +a constant state of change. If you are outside the United States, check +the laws of your country in addition to the terms of this agreement +before downloading, copying, displaying, performing, distributing or +creating derivative works based on this work or any other Project +Gutenberg-tm work. The Foundation makes no representations concerning +the copyright status of any work in any country outside the United +States. + +1.E. Unless you have removed all references to Project Gutenberg: + +1.E.1. The following sentence, with active links to, or other immediate +access to, the full Project Gutenberg-tm License must appear prominently +whenever any copy of a Project Gutenberg-tm work (any work on which the +phrase "Project Gutenberg" appears, or with which the phrase "Project +Gutenberg" is associated) is accessed, displayed, performed, viewed, +copied or distributed: + +This eBook is for the use of anyone anywhere 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 + +1.E.2. If an individual Project Gutenberg-tm electronic work is derived +from the public domain (does not contain a notice indicating that it is +posted with permission of the copyright holder), the work can be copied +and distributed to anyone in the United States without paying any fees +or charges. If you are redistributing or providing access to a work +with the phrase "Project Gutenberg" associated with or appearing on the +work, you must comply either with the requirements of paragraphs 1.E.1 +through 1.E.7 or obtain permission for the use of the work and the +Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or +1.E.9. + +1.E.3. If an individual Project Gutenberg-tm electronic work is posted +with the permission of the copyright holder, your use and distribution +must comply with both paragraphs 1.E.1 through 1.E.7 and any additional +terms imposed by the copyright holder. Additional terms will be linked +to the Project Gutenberg-tm License for all works posted with the +permission of the copyright holder found at the beginning of this work. + +1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm +License terms from this work, or any files containing a part of this +work or any other work associated with Project Gutenberg-tm. + +1.E.5. Do not copy, display, perform, distribute or redistribute this +electronic work, or any part of this electronic work, without +prominently displaying the sentence set forth in paragraph 1.E.1 with +active links or immediate access to the full terms of the Project +Gutenberg-tm License. + +1.E.6. You may convert to and distribute this work in any binary, +compressed, marked up, nonproprietary or proprietary form, including any +word processing or hypertext form. However, if you provide access to or +distribute copies of a Project Gutenberg-tm work in a format other than +"Plain Vanilla ASCII" or other format used in the official version +posted on the official Project Gutenberg-tm web site (www.gutenberg.org), +you must, at no additional cost, fee or expense to the user, provide a +copy, a means of exporting a copy, or a means of obtaining a copy upon +request, of the work in its original "Plain Vanilla ASCII" or other +form. Any alternate format must include the full Project Gutenberg-tm +License as specified in paragraph 1.E.1. + +1.E.7. Do not charge a fee for access to, viewing, displaying, +performing, copying or distributing any Project Gutenberg-tm works +unless you comply with paragraph 1.E.8 or 1.E.9. + +1.E.8. You may charge a reasonable fee for copies of or providing +access to or distributing Project Gutenberg-tm electronic works provided +that + +- You pay a royalty fee of 20% of the gross profits you derive from + the use of Project Gutenberg-tm works calculated using the method + you already use to calculate your applicable taxes. The fee is + owed to the owner of the Project Gutenberg-tm trademark, but he + has agreed to donate royalties under this paragraph to the + Project Gutenberg Literary Archive Foundation. Royalty payments + must be paid within 60 days following each date on which you + prepare (or are legally required to prepare) your periodic tax + returns. Royalty payments should be clearly marked as such and + sent to the Project Gutenberg Literary Archive Foundation at the + address specified in Section 4, "Information about donations to + the Project Gutenberg Literary Archive Foundation." + +- You provide a full refund of any money paid by a user who notifies + you in writing (or by e-mail) within 30 days of receipt that s/he + does not agree to the terms of the full Project Gutenberg-tm + License. You must require such a user to return or + destroy all copies of the works possessed in a physical medium + and discontinue all use of and all access to other copies of + Project Gutenberg-tm works. + +- You provide, in accordance with paragraph 1.F.3, a full refund of any + money paid for a work or a replacement copy, if a defect in the + electronic work is discovered and reported to you within 90 days + of receipt of the work. + +- You comply with all other terms of this agreement for free + distribution of Project Gutenberg-tm works. + +1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm +electronic work or group of works on different terms than are set +forth in this agreement, you must obtain permission in writing from +both the Project Gutenberg Literary Archive Foundation and Michael +Hart, the owner of the Project Gutenberg-tm trademark. Contact the +Foundation as set forth in Section 3 below. + +1.F. + +1.F.1. Project Gutenberg volunteers and employees expend considerable +effort to identify, do copyright research on, transcribe and proofread +public domain works in creating the Project Gutenberg-tm +collection. Despite these efforts, Project Gutenberg-tm electronic +works, and the medium on which they may be stored, may contain +"Defects," such as, but not limited to, incomplete, inaccurate or +corrupt data, transcription errors, a copyright or other intellectual +property infringement, a defective or damaged disk or other medium, a +computer virus, or computer codes that damage or cannot be read by +your equipment. + +1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right +of Replacement or Refund" described in paragraph 1.F.3, the Project +Gutenberg Literary Archive Foundation, the owner of the Project +Gutenberg-tm trademark, and any other party distributing a Project +Gutenberg-tm electronic work under this agreement, disclaim all +liability to you for damages, costs and expenses, including legal +fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT +LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE +PROVIDED IN PARAGRAPH F3. YOU AGREE THAT THE FOUNDATION, THE +TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE +LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR +INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH +DAMAGE. + +1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a +defect in this electronic work within 90 days of receiving it, you can +receive a refund of the money (if any) you paid for it by sending a +written explanation to the person you received the work from. If you +received the work on a physical medium, you must return the medium with +your written explanation. The person or entity that provided you with +the defective work may elect to provide a replacement copy in lieu of a +refund. If you received the work electronically, the person or entity +providing it to you may choose to give you a second opportunity to +receive the work electronically in lieu of a refund. If the second copy +is also defective, you may demand a refund in writing without further +opportunities to fix the problem. + +1.F.4. Except for the limited right of replacement or refund set forth +in paragraph 1.F.3, this work is provided to you 'AS-IS' WITH NO OTHER +WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO +WARRANTIES OF MERCHANTIBILITY OR FITNESS FOR ANY PURPOSE. + +1.F.5. Some states do not allow disclaimers of certain implied +warranties or the exclusion or limitation of certain types of damages. +If any disclaimer or limitation set forth in this agreement violates the +law of the state applicable to this agreement, the agreement shall be +interpreted to make the maximum disclaimer or limitation permitted by +the applicable state law. The invalidity or unenforceability of any +provision of this agreement shall not void the remaining provisions. + +1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the +trademark owner, any agent or employee of the Foundation, anyone +providing copies of Project Gutenberg-tm electronic works in accordance +with this agreement, and any volunteers associated with the production, +promotion and distribution of Project Gutenberg-tm electronic works, +harmless from all liability, costs and expenses, including legal fees, +that arise directly or indirectly from any of the following which you do +or cause to occur: (a) distribution of this or any Project Gutenberg-tm +work, (b) alteration, modification, or additions or deletions to any +Project Gutenberg-tm work, and (c) any Defect you cause. + + +Section 2. Information about the Mission of Project Gutenberg-tm + +Project Gutenberg-tm is synonymous with the free distribution of +electronic works in formats readable by the widest variety of computers +including obsolete, old, middle-aged and new computers. It exists +because of the efforts of hundreds of volunteers and donations from +people in all walks of life. + +Volunteers and financial support to provide volunteers with the +assistance they need are critical to reaching Project Gutenberg-tm's +goals and ensuring that the Project Gutenberg-tm collection will +remain freely available for generations to come. In 2001, the Project +Gutenberg Literary Archive Foundation was created to provide a secure +and permanent future for Project Gutenberg-tm and future generations. +To learn more about the Project Gutenberg Literary Archive Foundation +and how your efforts and donations can help, see Sections 3 and 4 +and the Foundation web page at https://www.pglaf.org. + + +Section 3. Information about the Project Gutenberg Literary Archive +Foundation + +The Project Gutenberg Literary Archive Foundation is a non profit +501(c)(3) educational corporation organized under the laws of the +state of Mississippi and granted tax exempt status by the Internal +Revenue Service. The Foundation's EIN or federal tax identification +number is 64-6221541. Its 501(c)(3) letter is posted at +https://pglaf.org/fundraising. Contributions to the Project Gutenberg +Literary Archive Foundation are tax deductible to the full extent +permitted by U.S. federal laws and your state's laws. + +The Foundation's principal office is located at 4557 Melan Dr. S. +Fairbanks, AK, 99712., but its volunteers and employees are scattered +throughout numerous locations. Its business office is located at +809 North 1500 West, Salt Lake City, UT 84116, (801) 596-1887, email +business@pglaf.org. Email contact links and up to date contact +information can be found at the Foundation's web site and official +page at https://pglaf.org + +For additional contact information: + Dr. Gregory B. Newby + Chief Executive and Director + gbnewby@pglaf.org + + +Section 4. Information about Donations to the Project Gutenberg +Literary Archive Foundation + +Project Gutenberg-tm depends upon and cannot survive without wide +spread public support and donations to carry out its mission of +increasing the number of public domain and licensed works that can be +freely distributed in machine readable form accessible by the widest +array of equipment including outdated equipment. Many small donations +($1 to $5,000) are particularly important to maintaining tax exempt +status with the IRS. + +The Foundation is committed to complying with the laws regulating +charities and charitable donations in all 50 states of the United +States. Compliance requirements are not uniform and it takes a +considerable effort, much paperwork and many fees to meet and keep up +with these requirements. We do not solicit donations in locations +where we have not received written confirmation of compliance. To +SEND DONATIONS or determine the status of compliance for any +particular state visit https://pglaf.org + +While we cannot and do not solicit contributions from states where we +have not met the solicitation requirements, we know of no prohibition +against accepting unsolicited donations from donors in such states who +approach us with offers to donate. + +International donations are gratefully accepted, but we cannot make +any statements concerning tax treatment of donations received from +outside the United States. U.S. laws alone swamp our small staff. + +Please check the Project Gutenberg Web pages for current donation +methods and addresses. Donations are accepted in a number of other +ways including including checks, online payments and credit card +donations. To donate, please visit: https://pglaf.org/donate + + +Section 5. General Information About Project Gutenberg-tm electronic +works. + +Professor Michael S. Hart was the originator of the Project Gutenberg-tm +concept of a library of electronic works that could be freely shared +with anyone. For thirty years, he produced and distributed Project +Gutenberg-tm eBooks with only a loose network of volunteer support. + + +Project Gutenberg-tm eBooks are often created from several printed +editions, all of which are confirmed as Public Domain in the U.S. +unless a copyright notice is included. Thus, we do not necessarily +keep eBooks in compliance with any particular paper edition. + + +Most people start at our Web site which has the main PG search facility: + + https://www.gutenberg.org + +This Web site includes information about Project Gutenberg-tm, +including how to make donations to the Project Gutenberg Literary +Archive Foundation, how to help produce our new eBooks, and how to +subscribe to our email newsletter to hear about new eBooks. + + +</pre> + +</body> +</html> |