THE GASES OF THE ATMOSPHEKE 131 



Some remarks about the spectrum of the gas follow, 

 and on the 7th August, in reply to Lord Rayleigh, he 

 wrote again as follows : 



" To take the last part of your letter first, I think that joint 

 publication would be the best course, and I am much obliged to 

 you for suggesting it, for I feel that a lucky chance has made me 

 able to get Q in quantity (there are two other Xs, so let us call it 

 Q or Quid ?) 



I have written out my results in a provisional way as far as 

 they go, verified all my calculations, which were only approxi- 

 mate ones, done in the press of work in the laboratory. It 

 may interest you to have a synopsis which will be a sort of 

 record, and put you at home in all I have done." 



The rest of the letter, occupying two sheets, contains 

 an account of his experiments and their results. It 

 winds up as follows : 



" The gas Q is now filled into a critical point tube and to-day 

 I shall see if I can liquefy it. I shall also try sparking it with 

 chlorine and also its action on potassium. That is all I can get 

 through. I shall tell you on Wednesday or Thursday what the 

 results are. Until Oxford therefore." 



The results of the two methods of dealing with atmo- 

 spheric nitrogen, namely sparking with excess of oxygen 

 in the presence of caustic potash as practised by Lord 

 Rayleigh, and contact with hot magnesium in Ramsay's 

 circulating apparatus, were embodied into a joint paper 

 which was communicated to the British Association 

 meeting in August at Oxford. A little later the question 

 arose as to the identity of the gases obtained by the two 

 methods, and this had to be settled. 



