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                                                    CONTRIBUTIONS FROM

                                 THE MUSEUM OF HISTORY AND TECHNOLOGY:

                                                               PAPER 8


                                             THE NATURAL PHILOSOPHY OF
                                  WILLIAM GILBERT AND HIS PREDECESSORS

                                                       _W. James King_




                                                      By W. James King

                      THE NATURAL PHILOSOPHY OF
                           WILLIAM GILBERT
                         AND HIS PREDECESSORS

    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.

    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.

    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.

    THE AUTHOR: W. James King is curator of electricity, Museum
    of History and Technology, in the Smithsonian Institution's
    United States National Museum.


The year 1600 saw the publication by an English physician, William
Gilbert, of a book on the loadstone. Entitled _De magnete_,[1] 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.

    [1] William Gilbert, _De magnete, magneticisque corporibus
    et de magno magnete tellure; physiologia nova, plurimis &
    argumentis, & experimentis, demonstrata_, 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.

    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.

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. Koyre considers the Archimedeanization of space as one of the
necessary features of the development of modern astronomy and
physics.[2] A. N. Whitehead and E. Cassirer have turned to measurement
and the quantification of force as marking this transition.[3]
However, the obvious absence[4] of such techniques in _De magnete_
makes it difficult to consider Gilbert as a founder of modern
electricity and magnetism in this sense.

    [2] Alexandre Koyre, _Etudes galileennes_, Paris, 1939.

    [3] Alfred N. Whitehead, _Science and the modern world_, New
    York, 1925, ch. 3; Ernst Cassirer, _Das Erkenntnisproblem_,
    ed. 3, Berlin, 1922, vol. 1, pp. 314-318, 352-359.

    [4] However, see M: pp. 161, 162, 168, 335.

[Illustration: Figure 1.--WILLIAM GILBERT'S BOOK ON THE LOADSTONE,
TITLE PAGE OF THE FIRST EDITION, FROM A COPY IN THE LIBRARY OF
CONGRESS. (_Photo courtesy of the Library of Congress._)]

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.[5] No science can be based upon faulty
observations and certainly much of _De magnete_ 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' _De magnete_ of 1269,[6] and a development of works like
Robert Norman's _The new attractive_,[7] in which the author discussed
how one could show experimentally the declination and inclination of a
magnetized needle, and like William Borough's _Discourse on the
variation of the compass or magnetized needle_,[8] 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 _De havenvinding_.[9]

    [5] For example, William Whewell, _History of the inductive
    sciences_, ed. 3, New York, 1858, vol. 2, pp. 192 and 217;
    Charles Singer, _A short history of science to the nineteenth
    century_, Oxford, 1943, pp. 188 and 343; and A. R. Hall, _The
    scientific revolution_, Boston, 1956, p. 185.

    [6] _Petri Peregrini maricurtenis, de magnete, seu rota
    perpetui motus, libellus_, a reprint of the 1558 Angsburg
    edition in J. G. G. Hellmann, _Rara magnetica_, 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, _Beitraege zur Geschichte der
    Erkenntnis des Erdmagnetismus_, Aarau, 1956, pp. 249-255).

    [7] Hellmann, _ibid._, Robert Norman, _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_. London, 1581. The
    possibility is present that Norman's work was a direct
    stimulus to Gilbert, for Wright's introduction to _De
    magnete_ stated that Gilbert started his study of magnetism
    the year following the publication of Norman's book.

    [8] Hellman, _ibid._, William Borough, _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._ London, 1596.

    [9] Hellman, _ibid._, Simon Stevin, _De havenvinding_,
    Leyden, 1599. It is interesting to note that Wright
    translated Stevin's work into English.

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."[10]

    [10] As Edward Wright was to call him in his introduction.

Gilbert's _De magnete_ 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[11]
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, _Ion_.[12] Such an animistic solution pervaded many of
the later explanations.

    [11] Aristotle, _On the soul_, 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").

    [12] Plato, _Ion_, translated by W. R. M. Lamb, Loeb
    Classical Library, London, 1925, 533 (see also 536).

That a mechanical explanation is also possible was shown by Plato
in his _Timaeus_.[13] 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.

    [13] Plato, _Timaeus_, 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.

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
_De rerum natura_.[14] 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.

    [14] Lucretius, _De rerum natura_, translated by W. H. D.
    Rouse, Loeb Classical Library, London, 1924, bk. VI, lines
    998-1041.

Galen[15] 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.[16] The loadstone is only an
inanimate example of what one finds in nutritive organs in organic
beings.

    [15] Galen, _On the natural faculties_, translated by A. S.
    Brock, Loeb Classical Library, London, 1916, bk. 1 and bk. 3.
    A view similar to this appeared in Plato, _Timaeus_, 81 (see
    footnote 13).

    [16] This same concept was to reappear in the Middle Ages as
    the _inclinatio ad simile_.

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