Faraday as a Discoverer HTML version

Chapter 10
Magnetization of light.
But we must quit the man and go on to the discoverer: we shall return for a brief space to
his company by-and-by. Carry your thoughts back to his last experiments, and see him
endeavouring to prove that induction is due to the action of contiguous particles. He
knew that polarized light was a most subtle and delicate investigator of molecular
condition. He used it in 1834 in exploring his electrolytes, and he tried it in 1838 upon his
dielectrics. At that time he coated two opposite faces of a glass cube with tinfoil,
connected one coating with his powerful electric machine and the other with the earth,
and examined by polarized light the condition of the glass when thus subjected to strong
electric influence. He failed to obtain any effect; still he was persuaded an action existed,
and required only suitable means to call it forth.
After his return from Switzerland he was beset by these thoughts; they were more
inspired than logical: but he resorted to magnets and proved his inspiration true. His
dislike of 'doubtful knowledge' and his efforts to liberate his mind from the thraldom of
hypotheses have been already referred to. Still this rebel against theory was incessantly
theorising himself. His principal researches are all connected by an undercurrent of
speculation. Theoretic ideas were the very sap of his intellect--the source from which all
his strength as an experimenter was derived. While once sauntering with him through the
Crystal Palace, at Sydenham, I asked him what directed his attention to the magnetization
of light. It was his theoretic notions. He had certain views regarding the unity and
convertibility of natural forces; certain ideas regarding the vibrations of light and their
relations to the lines of magnetic force; these views and ideas drove him to investigation.
And so it must always be: the great experimentalist must ever be the habitual theorist,
whether or not he gives to his theories formal enunciation.
Faraday, you have been informed, endeavoured to improve the manufacture of glass for
optical purposes. But though he produced a heavy glass of great refractive power, its
value to optics did not repay him for the pains and labour bestowed on it. Now, however,
we reach a result established by means of this same heavy glass, which made ample
amends for all.
In November, 1845, he announced his discovery of the 'Magnetization of Light and the
Illumination of the Lines of Magnetic Force.' This title provoked comment at the time,
and caused misapprehension. He therefore added an explanatory note; but the note left his
meaning as entangled as before. In fact Faraday had notions regarding the magnetization
of light which were peculiar to himself, and untranslatable into the scientific language of
the time. Probably no other philosopher of his day would have employed the phrases just
quoted as appropriate to the discovery announced in 1845. But Faraday was more than a
philosopher; he was a prophet, and often wrought by an inspiration to be understood by
sympathy alone. The prophetic element in his character occasionally coloured, and even
injured, the utterance of the man of science; but subtracting that element, though you