468 On the two-fold Spectra of Oxygen and Nitrogen. [Mar. 21, 



themselves consumed, this external heating and final combustion 

 adding slightly to the light emitted. 



Any unsaturated hydrocarbons which have escaped conversion into 

 acetylene before luminosity commences, and also any methane which 

 may be present on passing into the higher temperatures of the lumin- 

 ous zone, become converted there into acetylene, and at once being 

 decomposed to carbon and hydrogen, increase the area of the light- 

 giving portion of the flame. 



My thanks are due to Mr. F. B. Grundy for the help he has given 

 me in the work entailed by this paper. 



IV. " A possible Explanation of the two-fold Spectra of Oxygen 

 and Nitrogen." By E. C. C. BALY, A.I.C., 1851 Exhibition 

 Scholar in University College, London. Communicated 

 by Professor RAMSAY, F.R.S. Received February 27, 1895. 



(Abstract.) 



The two spectra of oxygen are shown to be of a different nature. 

 They behave differently, and reasons are given for their being in all 

 probability the spectra of different gases. They may either be two 

 spectra produced by different vibrations of the oxygen molecule, or 

 they may be the spectra of two different modifications of oxygen, or 

 the spectra of two distinct gases resulting from a dissociation of 

 oxygen, a combination of which is called oxygen. 



It appeared worth while to undertake experiments with a view of 

 testing the last of these. Oxygen was sparked in an apparatus 

 similar to that used by Professor J. J. Thomson in his experiments 

 on the electrolysis of steam. Hollow platinum electrodes were used, 

 each one of which was connected with a Sprengel mercury pump. In 

 the first experiments, the distance between the electrodes was 35 mm., 

 and the highest pressure compatible with the appearance of the two 

 spectra was made the starting point of the experiments. In these 

 first experiments it was 380 mm. The density of the oxygen before 

 sparking was determined, and taken as a test of its purity. The 

 fractions obtained from the anode and cathode were weighed, and the 

 results are given. They follow the lines of J. J. Thomson's results, 

 inasmuch as with long sparks a lighter fraction was obtained at the 

 cathode, and with short sparks a heavier fraction. The fractions from 

 the anode were not so definite as from the cathode, though the differ- 

 ence was in the right direction. The probable maximum error of 

 weighing was O0001 gram. This meant exactly one in the second 

 decimal place of the density obtained. The general accuracy of 

 the results may be gauged from the densities of unsparked oxygen 

 obtained. 



