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, pass to the consider- 

 ation of terrestrial magnetism and atmospheric temperature, as 

 far as these sciences are included in the century which we have 

 attempted to describe. The able and important work on mag- 

 netic and electric forces, the Physiologia nova de Magnete, by 

 William Gilbert, to which I have frequently had occasion to 

 allude,* appeared in the year 1600. 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 con- 

 jectures, based on analogies of the effect of the Heraclean 

 magnetic stone on iron, and the attractive force exercised oil 

 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 pliy- 

 sikalisclie Wo'rterbuch, bd. iv. (1827,) s. 43, and Wilke notices it very 

 fully, in his Gescli. der Optilc, 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 Responsum ad objecta, Joh. 

 de Bruyn, Professoris Trajectini, et Petri Petiti 1663, it is said, p. 69 

 Kcc lumen ullurn est absque calore, nee calor ullus absque lumine. Lux 

 sonus, anima ( !) odor, vis magnetica, quamvis incorporea, sunt tamen 

 aliquid. (De Lucis Nat. 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 tfte Inductive 

 Sciences, vol. ii. p. 378). 



J Cosmos, p. 194. 



