When an experimental result was obtained by Faraday it was instantly
enlarged by his imagination. I am acquainted with no mind whose
power and suddenness of expansion at the touch of new physical truth
could be ranked with his. Sometimes I have compared the action of
his experiments on his mind to that of highly combustible matter
thrown into a furnace; every fresh entry of fact was accompanied by
the immediate development of light and heat. The light, which was
intellectual, enabled him to see far beyond the boundaries of the
fact itself, and the heat, which was emotional, urged him to the
conquest of this newly-revealed domain. But though the force of his
imagination was enormous, he bridled it like a mighty rider, and
never permitted his intellect to be overthrown.

In virtue of the expansive power which his vivid imagination
conferred upon him, he rose from the smallest beginnings to the
grandest ends. Having heard from Zantedeschi that Bancalari had
established the magnetism of flame, he repeated the experiments and
augmented the results. He passed from flames to gases, examining
and revealing their magnetic and diamagnetic powers; and then he
suddenly rose from his bubbles of oxygen and nitrogen to the
atmospheric envelope of the earth itself, and its relations to the
great question of terrestrial magnetism. The rapidity with which
these ever-augmenting thoughts assumed the form of experiments is
unparalleled. His power in this respect is often best illustrated by
his minor investigations, and, perhaps, by none more strikingly than
by his paper 'On the Diamagnetic Condition of Flame and Gases,'
published as a letter to Mr. Richard Taylor, in the 'Philosophical
Magazine' for December, 1847. After verifying, varying, and
expanding the results of Bancalari, he submitted to examination
heated air-currents, produced by platinum spirals placed in the