of chlorine and carbon, &c. 6 1 
volume, its place being occupied by muriatic acid gas. Hence, 
as muriatic acid gas is known to consist of equal volumes of 
chlorine and hydrogen, combined without condensation, it is 
evident that half the chlorine introduced into the vessel has 
combined with the elements of the fluid, and liberated an equal 
volume of hydrogen ; and as, when the chloride is perfectly 
formed, it condenses no muriatic acid gas, a method, apparently 
free from all fallacy, is thus afforded of ascertaining its nature. 
I have made many experiments on given volumes of 
chlorine and olefiant gases. A clean dry retort was fitted 
with a cap and stop-cock. Its capacity was 25.25 cubic 
inches. Being exhausted by the air-pump, it was filled with 
nitrogen (24.25 cubic inches being required), and being 
again exhausted, 5 cubic inches of olefiant gas, and 10 
cubic inches of chlorine were introduced. It was then set 
aside for half an hour, that the fluid compound might form, 
and afterwards being placed again over a jar of chlorine, 
19.25 cubic inches entered; so that the condensation had 
been as nearly as possible 10 cubic inches, or twice the vo- 
lume of the olefiant gas (barometer 29.1 inches). It was 
now placed for the day (October 18th.) in the rays of the 
sun ; but the weather was not very fine. In the evening the 
solid crystalline substance had formed in abundance, and 
very little fluid remained. When placed over chlorine, not 
the slightest change in volume had been produced. The stop- 
cock was now opened under mercury, and a small portion of 
the metal having entered, it was agitated in the retort, to 
absorb the chlorine ; the neck of the retort was left open 
under the mercury all night, and the whole agitated from 
time to time. Next morning (barometer 29.6} the mercury 
