worked independently at this subject, in thinking, that a body so
magnetic as oxygen, swathing the earth, and subject to variations of
temperature, diurnal and annual, must affect the manifestations of
terrestrial magnetism.[1] The air that stands upon a single square
foot of the earth's surface is, according to Faraday, equivalent in
magnetic force to 8160 lbs. of crystallized protosulphate of iron.
Such a substance cannot be absolutely neutral as regards the
deportment of the magnetic needle. But Faraday's writings on this
subject are so voluminous, and the theoretic points are so novel and
intricate, that I shall postpone the complete analysis of these
researches to a time when I can lay hold of them more completely
than my other duties allow me to do now.

Footnote to Chapter 12

[1] This persuasion has been greatly strengthened by the recent
perusal of a paper by Mr. Baxendell.


Chapter 13.

Speculations: nature of matter: lines of force

The scientific picture of Faraday would not be complete without a
reference to his speculative writings. On Friday, January 19, 1844,
he opened the weekly evening-meetings of the Royal Institution by a
discourse entitled 'A speculation touching Electric Conduction and
the nature of Matter.' In this discourse he not only attempts the
overthrow of Dalton's Theory of Atoms, but also the subversion of
all ordinary scientific ideas regarding the nature and relations of