124 SUM.MAlIY OF CURRENT KKSKAKCHKS KKLATINC TO 



values. Young's modulus, therefore, tins the same value whether the 

 loading is slow or sudden. 



Annealing of Copper.* — T. Turner and I). M. Levy have deter- 

 mined the dilatation of copper, both hard-drawn and annealed, between 

 0° C. and 600° C. The curves obtained for the two varieties are almost 

 identical, and are nearly straight lines ; the change taking place when 

 hard worked copper is annealed is not accompanied by any alteration of 

 length. Similar determinations were made on wrought iron, steel con- 

 taining * 94 p.c. carbon, and several copper alloys. An extensometer 

 designed by the author was used for measuring the increase of length. 



Magnetisation of Iron and Nickel.f — P. Weiss found the intensity 

 of magnetisation to saturation of pure Swedish iron to be 1731, and that 

 of nickel 407, at the ordinary temperature, the error not exceeding 

 * 5 p.c. Two different methods w T ere employed. 



Equilibrium of the Nickel-bismuth System. :£ — A. Portevin states 

 the results obtained by the application of the method of thermal analysis 

 to cooling curves, but does not give the equilibrium diagram. Micro- 

 scopic examination indicated that equilibrium was reached only for 

 alloys near either end of the series ; complexes of three or four phases 

 were obtained in alloys further removed from the pure metals. 



Annealing-carbon in Cast Iron.§ — G. Charpy divided a quantity of 

 molten cast iron into two portions. One was cooled slowly, giving its 

 carbon as graphite, the other rapidly cooled and subsequently annealed, 

 causing the separation of the carbon as annealing- or temper-carbon. 

 The author then demonstrated the identity of these two forms of 

 carbon : ( ] ) by the chemical reactions of the carbon separated on dis- 

 solving the iron in nitric acid ; (2) by the similarity in progress of 

 decarburisation of the two samples on heating in a current of hydrogen. 



Solubility of Graphite in Iron.|| — G. Charpy prepared a grey cast 

 iron with total carbon :»*75 p.c, graphite 3*34 p.c. and with only traces 

 of impurities, by melting cemented Swedish iron with wood charcoal, and 

 slowly cooling. Small pieces were heated to different temperatures for 

 several hours and quenched. The combined carbon increased steadily 

 from 0*31 p.c in the sample heated at 750° C. to i "47 p.c at 1,150° C. 

 The results of these determinations and of other experiments described 

 by the author lead him to consider that the solubility of graphite in 

 iron decreases regularly with temperature. A probable value for the 

 solubility at 1000° C. is 1 p.c 



Occluded Gases in Steel.f — G. Belloc summarises the results of his 

 extensive investigations, to be fully described later. A steel contain- 

 ing - 12 p.c. carbon was used; the work included determination of 

 (1) the composition of the gas evolved on heating, and variation of 

 composition with temperature ; (2) rate of evolution of gas at different 



* Proc. Roy. Soc, Series A, lxxx. (1907) pp. 1-12 (4 tigs.). 

 t Comptes Rendus, cxlv. (1907) pp. 1155-7. 

 J Tom. cit., pp. 1168-70. § Tom. cit., pp. 1173-4. 



|! Tom. cit., pp. 1277-9. \ Tom. cit., pp. 1280-3. 



