Chemistry and Physics. 153 



was slowly absorbed, reaching a limit of 15 per cent absorbed 

 in 10 or 12 hours; a brilliant greenish fluorescence being pro- 

 duced, whose spectrum showed the lines of argon, hydrocarbon 

 and mercury. Helium under these conditions showed a charac- 

 teristic fluorescence of an orange color at the end of 11 hours, 

 the absorbed gas being about 8 per cent. In its spectrum were 

 seen the lines of helium, mercury and hydrocarbons. After 

 17 hours, 13*7 per cent of the helium was absorbed and after 39 

 hours 16 per cent, yielding a solid polymerized volatile resin, as do 

 argon and nitrogen. When bisulphide of carbon was used in 

 place of benzene, nitrogen was rapidly absorbed, argon and 

 helium more slowly, with a faint luminosity. After 175 hours 54 

 per cent of argon was absorbed, and after 192 hours 55*5 per 

 cent of helium; this latter -being increased to 68*4 per cent after 

 210 hours. The result is a carbonaceous mass mixed with sulphur 

 and combined with the absorbed gas, recalling the sulphocyan- 

 ides. On heating this substance in a vacuum to a red heat, a 

 considerable volume of gas was obtained, which after removal of 

 the regenerated carbon disulphide and a trace of carbon monox- 

 ide, gave, when subjected to the action of the electric discharge 

 in presence of benzene, the characteristic reactions of helium. 

 The residual unabsorbed gas behaved similarly. From the iden- 

 tical behavior of the initial gas, of the gas absorbed by carbon di- 

 sulphide and then regenerated and of the residual gas, the infer- 

 ence is strong in favor of the homogeneity of helium. — G. i?., 

 cxxiv, 113, January, 1897. g. e. b, 



6. Further Note on the Influence of a Magnetic Field on 

 Radiation Frequency ; by Oliver Lodge, assisted by Benjamin 

 Davies. Read June 3, 1897, beiore the Royal Society.* 



Referring to a former communication of mine, on the subject 

 of Zeeman's discovery, printed on page 513 of the ''Proceedings 

 of the Royal Society" for February 11 this year, vol. lx, No. 

 367, I wish to add an observation to those previously recorded, 

 as I have recently acquired a concave Rowland grating (3^ x 1-J 

 inch ruled surface, 14,438 lines to inch, 10 feet radius of curva- 

 ture, being the one used by Mr. George Higgs), of which the spectra 

 of the first and third orders on one side are very satisfactory. 



It is said on page 513, "If the focussing is sharp enough to 

 show a narrow, dark reversal line down the middle of each sodium 

 line, that dark line completely disappears when the magnet is 

 excited." With the greater optical power now available, the dark 

 reversal line is often by no means narrow, and though in some 

 positions of the flame it does still tend to disappear or become 

 less manifest when the flame is subjected to a concentrated mag- 

 netic field, the reason of its partial disappearance is that it is par- 

 tially reversed again — i. e., that a third bright line, as it were, 

 makes its appearance in the midst of the dark line, giving a triple 

 appearance to each sodium line. 



More completely stated, the phenomena are as follows : After 



* From an advance proof sent by the author. 



