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 chlorine and water.
Faraday first analysed this hydrate, and wrote out an account of its
composition. This account was looked over by Davy, who suggested
the heating of the hydrate under pressure in a sealed glass tube.
This was done. The hydrate fused at a blood-heat, the tube became
filled with a yellow atmosphere, and was afterwards found to contain
two liquid substances. Dr. Paris happened to enter the laboratory
while Faraday was at work. Seeing the oily liquid in his tube, he
rallied the young chemist for his carelessness in employing soiled
vessels. On filing off the end of the tube, its contents exploded
and the oily matter vanished. Early next morning, Dr. Paris
received the following note:--

'Dear Sir,--The oil you noticed yesterday turns out to be
liquid chlorine.

'Yours faithfully,
'M. Faraday.'[2]

The gas had been liquefied by its own pressure. Faraday then tried
compression with a syringe, and succeeded thus in liquefying the gas.