: [ 2, 3 ] 



In order to judge whether the water contributed 

 to the diminution of this mixture of nitrous and 

 common air, I made the whole procefs feveral 

 times in quickfilver, ufing one third of nitrous, 

 and two thirds of common air, as before. In this 

 cafe the rednefs continued a very long time, and 

 the diminution was not fo great as when the mix- 

 tures had been made in water, there remaining one 

 feventh more than the original quantity of com- 

 mon air. This mixture flood all night upon the 

 quickiilver ; and the next morning I obferved that 

 it was no farther diminished upon the admiffion of 

 water to it, nor by pouring it feveral times through 

 the water, and letting it Hand in water two days. 

 Another mixture, which flood about fix hours on 

 the quickfilver, was diminifhed a little more upon 

 the admiflion of water, but was never lefs than 

 the original quantity of common air, In another 

 cafe, however, in which the mixture flood but a 

 very fhort time in quickfilver, the farther dimi- 

 nution, which took place upon the admiffion of 

 water, was much more confiderable -, fo that the 

 diminution, upon the whole, was very nearly as 

 great as if the procefs had been intirely in water. 

 It is evident from thefe experiments, that the di- 

 minution is in part owing to the abforption by 

 the water; but that when the mixture is kept a 

 long time, in a fituation in which there is no 

 water to abforb any part of it, it acquires a con- 

 flitution, by which it is afterwards incapable of 

 being abforbed by water. 



In order to determine whether the fixed part of 

 common air was depoiited in the diminution of it 



bv 



