Chemistry and Physics. 415 



naine in them, and surface combustion. The references to the 

 literature are numerous and satisfactory. h. l. w. 



5. Petroleum, Where and How to Find It; by Anthony 

 Blum. 12mo, pp. 367. Chicago, 1922 (The Modern Mining 

 Books Publishing Company). — This book has been prepared by 

 an operator in the "oil business," who has evidently had much 

 experience in it, for the benefit of those who are or may become 

 interested in this great industry. It is a popular, rather than 

 a scientific, book. It presents many interesting facts and 

 statistics, and gives much practical information and advice in 

 regard to the production of petroleum. h. l. w. 



6. The Heavier Constituents of the Atmosphere. — Sir J. J. 

 Thomson has recently applied his method of positive ray 

 analysis to several problems involving possibly unknown constit- 

 uents of certain gases. For the first case he had been supplied 

 by Professor Dewar with a considerable amount of the residues 

 obtained by evaporating many thousand tons of liquid air. 

 These residues had been absorbed by charcoal and the subsequent 

 evaporation of the gases from the charcoal apparently effected 

 a fractionation so that only components heavier than krypton 

 were retained by the charcoal. 



The positive ray photographs showed the line of xenon very 

 prominently and also lines of at least two heavier constituents 

 corresponding to atomic weights of approximately 163 and 260. 



The author is of the opinion that these lines are due to mole- 

 cules of krypton and xenon, as these numbers are about twice 

 the atomic weights of the respective gases. Experiments were 

 further made to see if these constituents showed any properties 

 analogous to the emanation of radio active substances, but 

 evidence of ionization resulting from such presumed emanation 

 could not be detected. 



Another application by Professor Thomson of his method was 

 to the analysis of the gases obtained from a tube in which 70 mgm. 

 of radium chloride had been sealed, after exhaustion of the air, 

 for a period of thirteen years. The positive ray line for helium 

 was very strong and a faint line corresponding to m/e = 5 

 was also found. This latter he ascribes to a compound of 

 helium and hydrogen. Neon was not detected. 



A third problem was the testing of gases which had stood over 

 radium and also gas lit by deflagrating wires. In these cases 

 quadruply charged atoms of nitrogen were detected and triply 

 charged atoms of oxygen, nitrogen, and carbon. The compound 

 OH 4 invariablv carried a double charge. — Proc. Roy. Soc. 101, 

 290. 1922. f. e. b. 



7. The Corrosion of Iron and Steel. — Careful estimates of the 

 amount of steel and iron structures or materials which are 

 annually rendered unserviceable by rusting place it as high as 



