22 On some new Electrochemical Researches 



of a new quantity of potash, again gained the power of 

 producing ammonia in two or three successive operations ; 

 and when any mixture had ceased to give ammonia, the 

 power was not restored by cooling it in contact with air. 



Ammonia was produced in a case in which more than 

 200 cubical inches of gas had passed over from the action 

 of water upon a mixture, and when the last portions only 

 were preserved in contact with it during the cooling. In 

 a comparative trial it was however found, that considerably 

 more ammonia was produced, when a mixture was cooled 

 in contact with the atmosphere, than when it was cooled 

 in contact with the gas developed in the operation. 



I shall not attempt to draw any conclusions from these 

 processes. It would appear from some experiments of 

 M. Berthoilet, that nitrogen adheres very strongly to char- 

 coal*. The circumstances that the ammonia ceases to be 

 produced after a certain number of operations, and that the 

 quantity is much greater when free nitrogen is present, 

 are perhaps against the idea that nitrogen is composed in 

 the process. But till the weights of the substances conr 

 cerned and produced in these operations are compared, no, 

 correct decision on the question can be made. 



The experiments of Dr. Priestley upon the production of 

 nitrogen, during the freezing of water, induced that philo- 

 sopher to conceive, either that water was capable of being 

 converted into nitrogen, or that it contained much more 

 nitrogen than is usually suspected. 



I have made some repetitions of his processes. A quan- 

 tity of water, (about a cubical inch and a quarter,) that 

 had been produced from snow, boiled and inverted over 

 mercury whilst hot, was converted into ice, and thawed in 

 16 successive operations ; gas was produced, hut after the 

 first three or four times of freezing there was no notable 

 increase of the volume. At the end of the experiment, 

 about -5^5- of a cubical inch was obtained, which proved tcj 

 be common air. 



About four cubical inches of water from melted snow 

 were converted into ice and thawed, four successive times, 

 in a conical vessel of wrought iron. At the end of the 

 fourth process, the volume of gas equalled about -^l- of the 

 volume of the water. It proved to contain about T } ^ oxy- 

 gen, -jSjj- hydrogen, and T ^ nitrogen. 



Mr. Kirwan observed the fact, that when nitrous gas 

 and sulphuretted hydrogen are kept in contact for some 



Mem. tf Arcueil, torn. ii. page 485. 



time^ 



