October 28, 1920] 



NATURE 



299 



The substances employed included ammonium phos- 

 phate, Bridgemann's black phosphorus, phosphoric 

 acid, and commercial red phosphorus. It was found 

 that the wave-lenfjths of the limits of absorption were 

 different for the various kinds of phosphorus. This 

 is the first time that the chemical state of an element 

 has been found to have an influence on its X-ray 

 spectrum.— M. de Broglie and .\. DauvUlier : The 

 fine structure of the absorption discontinuities in X-ray 

 spectra. A discussion of some phenomena having a 

 bearing on the results described in the preceding paper 

 by .\I. Bergengren. — .A. Dauvilller : The mechanism of 

 the chemical reactions caused by the X-rays. The only 

 mineral substances sensible to the action of the X-ravs 

 are crystals for which I. Langmuir, Born and LandY-, 

 and Debye and Sherrcr have supposed and proved the 

 e.xistence of an ionic structure. All other sensitive 

 substances, colloids, electrolytes, glass, etc., also con- 

 tain ions. The cause of the chemical actions would 

 thus be due to the destruction of the negative ions, 

 which would lose their electrons under the impact of 

 the rapid electrons constituting the corpuscular radia- 

 tion. The violet coloration of alkaline glasses, the 

 photo-electric properties of crystals, and the colour- 

 changes in platinocyanide screens are considered from 

 this point of view.^-H. Copanx and C. Philip* : The 

 heat of oxidation of beryllium. Direct combustion of 

 the metal in compressed oxygen in the calorimetric 

 bomb gave unsatisfactory results ; the combustion of 

 the metal was never complete. The figure required 

 was hence derived indirectly by measuring the heats 

 of solution of the metal and its oxide in dilute hydro- 

 fluoric acid. The heat of oxidation, 151-5 calories, was 

 high, and ranges beryllium with calcium (160 calories), 

 lanthanum (148 calorics), and magnesium (144 



■ ilories).— G. Denigis : The microchemical reactions of 

 ; idium : its differentiation from barium by iodic acid. 

 The usual reagents employed in the microchemical 

 reactions of barium, hvdrofluosilicic, oxalic, and tar- 

 taric acids, tartar emetic, potassium ferrocyanide, and 

 t.Trtrate give identical results with barium and radium 

 s.-dts. .Ammonium cyanurate, ammonium phospho- 

 iiiolybdatc in ammonia solution, and potassium 

 bromate, which are also good reagents for barium, 

 give similar crystals with radium compounds. Iodic 

 .-><id, on the other hand, shows clear differences 

 between the two metals, and reproductions of two 

 niicroscopp-slides are given to prove this. .As showing 

 the delicacy of the microchemical method, it is men- 

 tioned that all experiments on the reactions of radium 

 were carried out with 02 millic'ram of met.nllic 

 ridium added as the bromide.- R. Folic : The Qualita- 

 tive analysis of cyanic acid. — .\. Lumlire and F. Perrin : 

 \ new class of hypnotics : the di.-ilkylhomophthalimides. 

 St.-irtlnr with naphthalene, this is oxidised tophthalonic 



I' id. which reduced bv hvdrio<lic acid leads to homo- 

 hth.-.lir arid. frO.OH).r.H,.rH,.CO.OII. the am- 

 ■onium sflt of which, evaporated to drvness and 



■ ntiv fused, pives the homonhthaliniide. From this 

 l,ilkvl_ <Ierivatives are readilv obtaim-d. l"sed as 



hvpnolics, they oo.ssess the advantages of vrrv .slight 

 toxic power, and are praclI'-.Tllv f'ee from un favour, 

 .nhlr secondary rea'-tioiri.— F. Kerforne : The tectonic 

 "f the .Armoriran massif. 



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