COSMOS, VOL. II - World eBook Library

DISCOVERIES IN THE CELESTIAL SPACES. 717
In order not to sever the links which hold together the general
primitive phenomena of matter in one common bond, I would
here immediately, after my succinct notice of the optical disco-
veries of Huygens, Grimaldi, and Newton, pars to the consideration
of terrestrial magnetism and atmospherJo temperature, as
far as these sciences are included in the century which we have
attempted to describe. The able and important work on magnetic
and electric forces, the Physiologia nova de Maynete, by
William Gilbert, to which I have frequently had occasion to
allude,* appeared in the year 1 600. This writer, whose sagacity
of mind was so highly admired by Galileo, conjectured many
things of which we have now acquired certain knowledge.!
Gilbert regarded terrestrial magnetism and electricity as two
emanations of a single fundamental force pervading all matter,
and he therefore treated of both at once. Such obscure conjectures,
based on analogies of the effect of the Heraclean
magnetic stone on iron, and the attractive force exercised on
dry straws by amber, when animated, as Pliny expresses it, with
a soul by the agency of heat and friction, appertain to all ages
and all races, to the Ionic natural philosophy, no less than to
the science of the Chinese physicists. J According to Gilbert's
idea, the earth itself is a magnet, whilst he considered that
moir, entitled " De Lucis natura et proprietate," (Amstelod., 1662,) for
the knowledge of which I was indebted two years ago, to M. Arago, at
Paris. Brandis treats of this memoir in the new edition of Gehler's plvysikalische
Worterbuch, bd. iv. (1827,) s. 43, and Wilke notices it very
fully, in his Gesch. der Optik, th. i. (1838,) s. 223, 228, and 317.
Isaac Vossius, however, considered the fundamental substance of all
colours (cap. 25, p. 60,) to be sulphur, which forms, according to him, a
component part of all bodies. In Vossii Besponsum ad objecta, Joh.
de Bruyn, Professorls Trajectini, et Petri Petiti 1663, it is said, p. 69
JSTec lumen ullum est absque calore, nee calor ullus absque lumine. Lux
sonus, anima (!) odor, vis magnetica, quamvis incorporea, sunt tamen
aliquid. (De Lucis JST at. cap. 13, p. 29).
* Cosmos, pp. 170, 172, and 656.
f Lord Bacon, whose comprehensive and generally speaking, free
and methodical views, were unfortunately accompanied by very limited
mathematical and physical knowledge, even for the age at which he
lived, was "
very unjust to Gilbert. Bacon showed his inferior aptitude
for physical research, in rejecting the Copernican doctrine which
William Gilbert adopted" (Whewell, Philosophy of tiie Inductive
Sciences, vol. ii. p. 378).
Cosmos, p. 194.