294 EXPERIMENTS AND OBSERVATIONS 



fected, by conducting the experiment in an apparatus some- 

 what on the principle of the instrument invented by Dr Wol- 

 laston, which he named the Cryophorus. In a retort of the 

 capacity of seven cubic inches, fitted with a stop-cock, and ex- 

 hausted, sixty cubic inches of ammoniacal gas were combined 

 with the requisite quantity of muriatic acid gas, each previous- 

 ly carefully dried, — the former by exposure to potash, the lat- 

 ter by exposure to muriate of lime. The stop-cock was then 

 detached from the retort ; the excess of ammoniacal gas was 

 removed by a caoutchouc bottle, and replaced by atmospheric- 

 air ; the salt was pushed down from the neck ; and it was con- 

 nected with another similar retort, the joining of the two be- 

 ing secured by cement. This last retort was also fitted with a 

 stop-cock adapted to a tubulature at its curvature, and heat be- 

 ing applied to it, a little of the included air was allowed to 

 escape. It was then placed in a mixture of muriate of lime and 

 ice, while the other, containing the muriate of ammonia, was pla- 

 ced in warm oil. The heat of this was raised to 420° of Fahrenheit: 

 moisture condensed at the upper part of the neck, when the 

 heat had been raised to 220°, and continued for some time to 

 increase. It then diminished, from the continued application 

 of the heat, carrying it forward into the cold retort, and at the 

 end of the experiment a considerable part of the body of this 

 was encrusted with a thin film of ice. This result, therefore, 

 coincides entirely with what had been before obtained *. 



Another 



* A foreign chemist, who has continued to support the old doctrine of the na- 

 ture of muriatic acid, has observed, (Annals of 'Philosophy, vol. viii. p. 204.) that 

 the water of the muriatic acid gas cannot be supposed to be obtained by the 

 combination of the acid with ammonia, for no neutral ammoniacal salt, he adds, 

 can be obtained free from water, and the water of the acid gas becomes the wa- 

 ter 



