Infra-red and Ultra-violet Absorption of Sulphur Dioxide. 505 



the electric field on the emission at the hot wire, or to an 

 effect which it may produce indirectly by the impact of the 

 ions on the negative electrode. Some experiments which 

 we made led us to conclude that the second of these alterna- 

 tives was the correct one *. In these experiments it appeared 

 that the large currents at high potentials could be cut down 

 by the application of rather small transverse magnetic fields, 

 indicating that the carriers of part of the discharge were 

 negative electrons liberated at the cold electrode. However, 

 further experiments showed that this influence of a magnetic 

 field was not always to be relied on ; so that the results of 

 this test cannot be regarded as decisive. At this stage we 

 were compelled to discontinue the experiments, which were 

 made in the Palmer Laboratory at Princeton University;. 

 At the suggestion of one of us the further investigation 

 •of these phenomena was undertaken by Mr. H. H. Lester, 

 whose results will shortly be published in this journal. 



LXI. The Infra-red and Ultra-violet Absorption of Sidphur 

 Dioxide and their Relation to the Infra-red Spectra of 

 Oxygen and Hydrogen Sulphide. By C. Scott Garrett, 

 B.Sc.-f 



IN a recent paper on the absorption of sulphites and 

 sulphur dioxide, the equilibrium conditions existing in 

 the aqueous solutions of these substances were investigated, 

 and it was intimated that further data on the absorption 

 •of sulphur dioxide would be published separately J. The 

 present paper deals with these data and contains a detailed 

 study of the gaseous absorption of sulphur dioxide, which 

 was undertaken more especially to test the applicability of 

 Baly's theory of the connexion between ultra-violet and 

 infra-red absorption §. This theory, which is based on the 

 energy quantum theory and Bjerrunr's work, has found 

 considerable experimental support in the absorption spectra 

 of benzene and certain other organic compounds, and it was 

 thought probable that it could be put to a more extended 

 test by an investigation of the absorption system of sulphur 



* Phvs. Rev. vol. xxxiv. p. 391 (1912). 

 t Communicated by Prof. E. C. C. Baly, F.R.S. 

 t Trans. Chem. Soc. cvii. p. 1335 (1915). 



§ Phil. Mag. xxvii. p. 632 (1914); xxix. p. 223 (1915); and xxx. 

 2>. 510 (1915). 



