RECENT ADVANCES IN SCIENCE 291 



surface combustion diaphragms, and the like. In the Proc. 

 Phys. Soc. London (June) Prof. Fleming describes an instru- 

 ment which will project on a screen or photograph on a plate 

 such curves as hysteresis curves, characteristic curves of 

 wireless detectors or rectifiers, or resonance curves, in process 

 of delineation. 



There are also a number of papers bearing on the structure 

 of the atom, and on formulae, meant to summarise spectroscopic 

 series, which are extensions of the Rydberg-Ritz type of formula. 



Two important mathematical-physical papers in the Proc. 

 Roy. Soc. should be mentioned : one, by Prof. Hicks, in the 

 April number, deals with the orbits of a charged particle in 

 motion round a nucleus which is both electrified and magnetised; 

 the other, by Lord Rayleigh, in the May number, is concerned 

 with the application of the third order of approximation to deep 

 water waves, progressive or stationary. 



INORGANIC CHEMISTRY. By C. Scott Garrett, B.Sc, University 

 Liverpool. 



Elements. — The long-drawn-out controversy which has raged 

 around the conditions under which active nitrogen is formed 

 has at length been settled. The main point under dispute 

 was the presence of a trace of oxygen in the nitrogen, as an 

 essential condition for the formation of the active modification. 

 After some collaboration and a mutual exchange of apparatus 

 by the opposing sides, it was found that neither view in itself 

 was entirely correct. In the last paper on the subject {Proc. 

 Roy. Soc. A. 91, 303, 1915) Strutt, the original discoverer of 

 the new modification, reviews the whole controversy. A little 

 active nitrogen can be produced by the passage of the dis- 

 charge in absolutely pure nitrogen, but the addition of a small 

 quantity, not only of oxygen, but of almost any other foreign 

 gas, enormously increases the yield of the active modification. 

 Thus hydrogen sulphide, water vapour, carbon dioxide, carbon 

 monoxide, acetylene, ethylene, methane, oxygen, mercury 

 vapour, chlorine and hydrogen are effective to a degree roughly 

 diminishing from left to right. With methane 1 part in 30,000 

 parts of nitrogen, was found to have an influence, but the 

 maximum effect is obtained when the ratio is about 1 to 1,000. 

 The inert gases, argon and helium, are, not altogether un- 

 expectedly, without effect. As an explanation of the pheno- 



