Chapter 2.

Early researches: magnetic rotations: liquefaction of gases:
heavy glass: Charles Anderson: contributions to physics.

Oersted, in 1820, discovered the action of a voltaic current on a
magnetic needle; and immediately afterwards the splendid intellect
of Ampere succeeded in showing that every magnetic phenomenon then
known might be reduced to the mutual action of electric currents.
The subject occupied all men's thoughts: and in this country
Dr. Wollaston sought to convert the deflection of the needle by the
current into a permanent rotation of the needle round the current.
He also hoped to produce the reciprocal effect of causing a current
to rotate round a magnet. In the early part of 1821, Wollaston
attempted to realise this idea in the presence of Sir Humphry Davy
in the laboratory of the Royal Institution.[1] This was well
calculated to attract Faraday's attention to the subject. He read
much about it; and in the months of July, August, and September he
wrote a 'history of the progress of electro-magnetism,' which he
published in Thomson's 'Annals of Philosophy.' Soon afterwards he
took up the subject of 'Magnetic Rotations,' and on the morning of
Christmas-day, 1821, he called his wife to witness, for the first
time, the revolution of a magnetic needle round an electric current.
Incidental to the 'historic sketch,' he repeated almost all the
experiments there referred to; and these, added to his own
subsequent work, made him practical master of all that was then
known regarding the voltaic current. In 1821, he also touched upon
a subject which subsequently received his closer attention--the
vaporization of mercury at common temperatures; and immediately
afterwards conducted, in company with Mr. Stodart, experiments on