Chemistry and Physics. 511 



dioxide. The emanation must be fairly concentrated at first to 

 produce the mist, which, however, may persist for a month when 

 the concentration of the emanation has been reduced about 200 

 times. — Comptes JRendus, cxlvii, 379. h. l. w. 



4. The Preparation of Argon. — Fischer and Ringe have 

 worked out a new method for producing argon from the air, 

 which can be carried out on a relatively large scale at a moder- 

 ate cost. The novel feature in the process consists in the use of 

 calcium carbide for absorbing oxygen and nitrogen at a single 

 step. This is used in the form of a powdered mixture of 90 per 

 cent of calcium carbide and 10 per cent of calcium chloride 

 heated in an iron vessel to 800° C. The absorption of these gases 

 is complete after sufficient circulation, practically with the forma- 

 tion of calcium oxide, carbon, and calcium cyanamide, accord- 

 ing to the equations 2 + 2CaC 2 = 2CaO + 4C, and N 2 + CaC 2 = 

 CN 2 Ca-fC. The authors prepared eleven liters of atmospheric 

 argon in the course of two days by means of their apparatus, and 

 showed its purity by making determinations of its density. 

 They make the statements that the atmospheric air contains 0*937 

 per cent by volume of " noble gases," the so-called crude argon ; 

 that the density of crude argon is 19*94 compared with oxygen 

 as 16 ; that crude argon itself consists of 99*75 per cent by 

 volume of argon, and 0*25 per cent of a mixture of helium, neon, 

 krypton, and xenon, in which neon with the density 10 predom- 

 inates, so that crude argon is somewhat lighter than pure argon, 

 the density of which is 19*95. — Berichte, xli, 2017. h. l. w. 



5. The Chemical Analysis of Iron ; by Andrew A. Blair. 

 Seventh edition. Pp. xix, 327, 108 figures and 5 tables. Phila- 

 delphia, 1908 (Lippincott & Co.). — This excellent handbook 

 appears in its seventh edition, the first edition having been issued 

 in 1888 (cf. (3), xxvi, 387). The fact that its admirable. charac- 

 ter has been fully recognized by those using it is well shown by 

 the frequent revisions called for. The present edition contains a 

 description of some new analytical processes concerning the 

 separation of vanadium, molybdenum, chromium and nickel in 

 steel ; and further an account of the volumetric method for nickel. 

 The methods for gas analysis have been revised, as also the 

 subject of atomic weights ; the table of factors for the latter 

 have been recalculated from the values for 1908 given by the 

 International Committee. 



6. Decomposition of Water Vapor by Electric Sparks. — It 

 has been suggested that the decomposition of water vapor in the 

 case of thunderstorms may explain certain phenomena in those 

 storms. Messrs. A. Holt and E. Hopkinson conclude from their 

 experiments "that when electric sparks pass through water vapor 

 or carbon dioxide the separation and arrangement of the decom- 

 position products is not an electric phenomenon but results from 

 gaseous diffusion. The hypothesis of electrolysis in liquids is 

 therefore inapplicable."— Phil. Mag., July, 1908, pp. 92-110. 



J. T. 



