128 SIR WILLIAM RAMSAY 



passing electric sparks through a mixture of " dephlo- 

 gisticated air " (oxygen) and common air in contact 

 with a solution of caustic potash Cavendish proved that 

 the greater part of the " phlogisticated air " (nitrogen) 

 was identical with the constituent of nitrates. The 

 residue, which was too small to be submitted to further 

 treatment, was " certainly not more than T ^ of the bulk 

 of the phlogisticated air let up into the tube ; so that if 

 there is any part of the phlogisticated air of our atmo- 

 sphere which differs from the rest and cannot be reduced 

 to nitrous acid, we may safely conclude that it is not 

 more than i^th part of the whole." 



In the earliest attempts to isolate the suspected gas 

 by the method of Cavendish, a Rhumkorff coil actuated 

 by five Grove's cells was used. This was later replaced 

 by an alternate current discharge by which an electric 

 flame is produced, as already shown by Mr. Crookes, 

 and the alkaline liquid for absorption was used in the 

 form of a fountain maintained continuously within the 

 globular vessel containing the mixed gases. 1 



Lord Rayleigh having already, in 1892, taken the 

 chemical world into his confidence, it was inevitable 

 that this essentially chemical problem should attract 

 the attention of chemists, but it does not appear that 

 anyone except Professor Ramsay had attempted to 

 attack the question experimentally. 



Ramsay's account of what followed was related in 

 1898 in a lecture given to the Pharmaceutical Society 



1 Trans. Chem. Soc. 1897, p. 184. 



