556 SCIENCE PROGRESS 



Conceptions Monistique et Dualistique de l'Univers Stellaire, 

 Scientia, 22, 77, 191 7. 



Miscellaneous. — Becker, L., On the positions of some Pole 

 Stars and a New Determination of the Constant of Aberration, 

 Mem., R.A.S. 62, Pt. II. 191 7. 



Bloch, L., Relativite et Gravitation d'apres les theories 

 recentes, Rev. Gen. des Sciences, 2 8 e Ann. No. 23, 191 7. 



PHYSICS. By James Rice, M.A., University, Liverpool. 



Spectroscopy. — In the Phil. Mag. for October, Mr. Hemsalech 

 describes experiments on the origin of the line spectrum emitted 

 by iron vapour in the explosion region of the air-coal gas 

 flame. The chemical actions which underlie the emission of 

 the cone spectrum of iron have no connection with those 

 underlying the emission of the carbon bands. Nitrogen is 

 one of the determining factors in the emission of the cone 

 spectrum and a hypothesis is advanced based on the assump- 

 tion that a nitride of iron is formed in the explosion region. 

 It is shown that the presence of oxygen in the medium sur- 

 rounding the air-coal gas flame is essential in bringing about 

 the formation of iron nitride. No definite knowledge has been 

 gained whether the spectrum is actually due to the formation 

 of the nitride or to its subsequent decomposition ; but it is 

 possible that the spectrum is the result of the disruptive break- 

 up of the molecules of the iron chloride, oxide, etc., fed into 

 the flame, a break-up which could be brought about or at 

 least facilitated by the existence of a strong chemical affinity 

 between the nitrogen and the metal atom. 



In the same number Prof. Richardson and Lieut. Bazzoni 

 give an account of investigations undertaken for the purpose 

 of detecting and measuring the frequency of the shortest vibra- 

 tions emitted from various gas atoms under electron impacts. 

 Previous investigations by Schumann and Lyman have de- 

 tected ultra-violet radiation as far down as 900 Angstrom units, 

 and recently Lyman (Astrophysical Journal, March 19 16) has 

 published records of work carried on in helium giving definite 

 lines down to about 600 units. The difficulties of working in 

 this region of the spectrum is that not only all radiation in this 

 neighbourhood is absorbed by all solid media (preventing the 

 use of even quartz and fluorite prisms in the spectrograph), 



