266 Lord Rayleigli and Prof. Ramsay. [Jan. 31, 



while for " atmospheric nitrogen " there was found 



By hot copper, 1892 2-3103 



By hot iron, 1893 2'3100 



By ferrous hydrate, 1894. ...... 2'3102 



At the suggestion of Professor Thorpe experiments were subse- 

 quently tried with nitrogen liberated from urea by the action of 

 sodium hypobromite. The hypobromite was prepared from com- 

 mercial materials in the proportions recommended for the analysis 

 of urea. The reaction was well under control, and the gas could 

 be liberated as slowly as desired. 



In the first experiment the gas was submitted to no other treat- 

 ment than slow passage through potash and phosphoric anhydride, 

 but it soon became apparent that the nitrogen was contaminated. 

 The " inert and inodorous " gas attacked vigorously the mercury of 

 the Topler pump, and was described as smelling like a dead rat. As 

 to the weight, it proved to be in excess even of the weight of atmos- 

 pheric nitrogen. 



The corrosion of the mercury and the evil smell were in great 

 degree obviated by passing the gas over hot metals. For the fillings 

 of June 6, 9, and 13 the gas passed through a short length of tube 

 containing copper in the form of fine wire heated by a flat Bunsen 

 burner, then through the furnace over red-hot iron, and back over 

 copper oxide. On June 19 the furnace tubes were omitted, the gas 

 being treated with the red-hot copper only. The mean result, re- 

 duced so as to correspond with those above quoted, is 2 - 2985. 



Without using heat, it has not been found possible to prevent the 

 corrosion of the mercury. Even when no urea is employed, and air 

 simply bubbled through the hypobromite solution is allowed to pass 

 with constant shaking over mercury contained in a JJ tube, the sur- 

 face of the metal was soon fouled. 



Although the results relating to urea nitrogen are interesting for 

 comparison with that obtained from other nitrogen compounds, the 

 original object was not attained on account of the necessity of retain- 

 ing the treatment with hot metals. We have found, however, that 

 nitrogen from ammonium nitrite may be prepared without the em- 

 ployment of hot tubes, whose weight agrees with that above quoted. 

 It is true that the gas smells slightly of ammonia, easily removable 

 by sulphuric acid, and apparently also of oxides of nitrogen. The 

 mean result from three 'fillings is 2*2987. 



It will be seen that, in spite of the slight nitrous smell, there is no 

 appreciable difference in the densities of gas prepared from ammonium 

 nitrite with and without the treatment by hot metals. The result is 

 interesting as showing that the agreement of numbers obtained for 



