^4 ON NtTROGEN ANl> AMMONIA. 



The circumstances, that the ammonia cease? to be producefl 

 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 pro- 

 cess. But till the weights of the substances concerned and 

 produced in these operations are compared, no correct de- 

 Kitrocpn pro- cision on the question can be made. 



TIM" ihcfreez- The experiments of Dr. Priestley upon the production of 

 ingot water, 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 aud inverted over 

 mercury while hot, was converted into ice, and thawed 

 in 16 successive operations; gas was produced, but after 

 the first three or four times of freezing, there was no nota- 

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

 about j^o of a cubical inch was obtained, which proved to 

 be common air. 



A"bout four cubical inches of water from melted snow 

 %vere converted into ice, and thawed four successive times 

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

 lourth process the volume of the gas equalled about ^V of 

 the volume of the water. It proved to contain about y^- 

 Kitrous gas oxigen, -/g hidrogen. and VV nitrogen. 



tell hidrr^on ' ^^''' I'*^"'^'*" observed the fact, that, when nitrous gas and 



keptincoti. sulplmretted hidrogen are kept in contact for some time, 



TDish rnw:]\. ^'^'^''^ '^ * S^'^'^^ diminution of volume ; and that the nitroud 



gas becomes converted into nitrous oxide, and that sulphur 



IS deposited, which has an ammoniacal smell. I repeated 



this experiment several times in 1800 with similar results, 



a,)d I found, that the diminution of tlie volume of the 



gasscs, when they were mixed in equal proportions, was to 



Rrasonings on rather le<;s than {-, which seemed to be nitrous oxide. 



In reasoning upon this phenomenon, I saw grounds for a 

 minute investigation of it. Sulphuretved hidrogen, as apr 

 I«ars from experiments which 1 have stated on a former 



