heir 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[205]
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.[206]

[199] M: p. 108.

[200] M: p. 110.

[201] M: p. 216.

[202] M: p. 311.

[203] M: pp. 310, 311.

[204] M: p. 312.

[205] Francis Bacon, _op. cit._ (footnote 42), vol. 1,
_Novum organum_, bk. 1, ch. 95, p. 306.

[206] _Ibid._, ch. 54 and ch. 64 (pp. 259 and 267).

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[207] and Robert Boyle[208] 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 _De magnete_ was the _Philosophia
magnetica_ of Nicolaus Cabeus.[209] The latter sought to bring
Gilbert's explanation of magnetism more directly into the fold of
medieval substantial forms.

[207] Sir Thomas Browne, _Pseudodoxia epidemica_, ed. 3,
London, 1658, bk. 2, ch. 2, 3, 4.

[208] Robert Boyle, _Experiments and notes about the
mechanical production of magnetism_, London, 1676.

[209] Nicolaus Cabeaus, _Philosophia magnetica_, Ferarra,
1629.

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[210] was critical of
Gilbert's arguments as being unnecessarily loose, he nevertheless saw
in them some support for the Copernican world-system. Johannes
Kepler[211] found in Gilbert's explanation of the loadstone-earth a
possible physical framework for his own investigations on planetary
motions.

[210] 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.

[211] Cassirer, _op. cit._ (footnote 3), vol. 1, p. 359-367.

Yet Galileo and Kepler had moved beyond Gilbert's world of
intellectual experience. They were no