Like the soul, fire does not destroy it.''" Like the 

 soul of astral bodies, and of the earth itself, it pro- 

 duces complex hut reuul.ir motions; ttie motion of 

 two loadstones on water oHers such an example."*" 

 Like the soul of a newborn child, whose nature 

 depends on the eonlimiration of the hea\ens, the 

 properties in the newly awakened iron depend upon 

 its position in the "orbis \irtutis."' •'" 



Whence Gilbert declared: 

 . . . the earllis magnelic force and the animate form 

 of the globes, that arc without senses, but without error . . . 

 exert an unending action. (|uick, (Icfuiiic. ci)ns(ani. directive, 

 motive, impcrant, harmonious through the whole mass of 

 matter; thereby are the generation and the ultimate decay 

 of all things en the superficies prcpagated.^"' 1 he 

 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 conactus, nor sympathin, nor any generation 

 nor alteration of seasons, and no propagation; but all were 

 in confusion . . . .^°^ Wherefore, not with reason, Thales 

 . . . declares the loadstone to be animate, a part of the 

 animate mother earth and her beloved offspring. 



(iilbert ended book .S of his treatise on the magnet 

 with a persuasive plea for his magnetic philo.sophy 

 of the cosmos, yet his conceptual scheme was not too 

 successful an induction in the eyes of his contempo- 

 raries. 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 ^' 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.-'"" 



Few of the sub.sequent experimenters and writers 

 on magnetism turned to Gilbert's work to explain the 

 effects they discus.sed. Although both his countrymen 

 Sir Thomas Browne ^' and Robert Boyle ^"^ de- 



"« M: p. 108. 



2MM: p. 110. 



2»i M: p. 216. 



2»2 M: p. 311. 



2«M: pp. 310, 311, 



20* M: p. 312. 



205 Francis Bacon, oj>. cit. (footnott- 42), vol. 1, Novum organum, 

 bk. 1, ch. 95, p. 306. 



2»« Ibid., ch. 54 and ch. 64 (pp. 259 and 267). 



2°' Sir Thomas Browne, Pseudndoxia epidemka, cd. 3, London, 

 1658, bk. 2, ch. 2, 3, 4. 



2"* Robert Boyle, Experiments and notes about the mechanical 

 production oj magnetism, London, 1 676. 



scribed 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 u|)on magnetic effluvia orcor]3Uscles. 

 riie only direct continuation of Gilbert's De magnele 

 was the Philnsophia magnetica of Nicolaus Gabeus."™ 

 The latter sought to bring Gilbert's explanation of 

 magnetism more directly into the fold of medieval 

 substantial forms. 



However, CJilbert's efloris towards a magnetic 

 philosophy did find approval in two of the men that 

 made the .seventeenth century scientific revolution. 

 While Galileo Galilei -"' was critical of Gilbert's 

 arguments as being unneces.sarily loose, he neverthe- 

 less saw in them some support for the Copernican 

 world-system. Johannes Kepler -" found in (iilbert's 

 explanation of the loadstone-earth a possible physical 

 framework for his own investigations on planetary 

 motions. 



Yet Galileo and Kepler had moved beyond (iillx-rt's 

 world of intellectual exi)erience. 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 mathe- 

 matical relations of kinematics: quantitative law had 

 replaced cjualitative experience of cause and efTect. 

 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. 



His method of determining the nature of a sub- 

 stance was a rather primitive one — it was not by a proc- 

 ess 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 detenniiu-d 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 



-™ Nicolaus Cabcaiis, Philosophia magnetica, Fcrarra, 1629. 



2'" Galileo Galilei, Dialogue on the great world systems, in the 

 translation of T. Salusbury, edited and corrected by G. de 

 Santillana, University of Chicago Press, 1953, pp. 409-423. 



2u Cassircr, op. cit. (footnote 3), vol. 1, p. 359-367. 



138 



BULLETIN 218: f:ON rUIlU 1 IONS IROM THE MUSEUM OF HISTORY' .\NU TECHNOLOGY 



