[ 122 ] 



Qn tbe 1Rcw (Baeee— Hrcjon aub Ibelium. 



By G. F. Hardcastle, 

 Assistant in the Chemical Dept. Hudd. Tech. College. 



ARGON. 



DURING the last three or four years, Lord Rayleigh, the 

 well-known physicist, has been engaged in the determina- 

 tion of the densities of various gases. The method he 

 used was the one used by Regnault, viz., weighing the gas con- 

 tained in a large glass globe. Nitrogen was one of the gases whose 

 density he determined. He obtained his nitrogen in the first 

 case by bubbling air through liquid ammonia, and then passing 

 it through a red hot tube. The excess of ammonia was absorbed 

 by acid, and the water by ordinary dessicating agents. He then 

 weighed the nitrogen obtained from air by absorbing the oxygen 

 with red-hot copper. The nitrogen by this latter method was 

 found to be one-thousandth part heavier than that by the former 

 method. He afterwards performed several experiments with nitrogen 

 derived wholly from ammonia and other chemical compounds. 

 This nitrogen he called " chemical " nitrogen, in distinction to 

 " atmospheric " nitrogen, or that derived from air. The results of 

 these experiments showed that atmospheric nitrogen was about '5 

 per cent, heavier than chemical nitrogen. The following figures 

 represent the actual weights in grams of the globe full of gas, which 

 he obtained in these experiments : — 



Atmospheric Nitrogen. Chemical Nitrogen. 



By hot copper - - - - 2'3i03 From nitric oxide - - - 2*3001 



,, hot iron 2"3ioo ,, nitrous oxide - - - 2*2990 



,, ferrous hydrate - - 2'3io2 ,, ammonium nitrite - 2*2987 



These results seemed to suggest that there is in atmospheric 

 nitrogen some other constituent heavier than true nitrogen. Caven- 

 dish had also noticed in his experiments that, after sparking the nitro- 

 gen of the atmosphere with oxygen for a long time, there was a small 

 residue amounting to about i/i2oth of the original nitrogen. He 

 did not examine the matter any further, but stated that if any other 

 body was present than nitrogen, it was not there in greater quantity 



