40 Faraday as a Discoverer. 
tion of a magnetic needle round an electric current. Inciden- 
tal to the “ historic sketch” he repeated almost all the experl- — 
ments there referred to; and these, added to his own subsequent — 
experiments on the alloys of steel. He was accustomed in 
after years to present to his friends razors formed from one of 
the alloys then discovered. ; 
During Faraday’s hours of liberty from other duties he took — 
up subjects of inquiry for himself ; and in the spring of 1823, — 
thus self-prompted, he began the examination of a substance — 
which had long been regarded as the chemical element chlorine, — 
in a solid form, but which Sir Humphry Davy, in 1810, had — 
proved to be a hydrate of chlorine, that is, a compound of chlo- — 
rine and water. Faraday first analyzed this hydrate, and — 
te out an account of its composition. This account was — 
looked over by Davy, who suggested the heating of the hydrate 
pucer pressure in a sealed glass tube. This was done. The — 
hydrate fused at a blood-heat, the tube became filled with a 
