506 SUMMARY OF CURRENT RESEARCHES RELATING TO 



shown in the region investigated — the results are not adapted for 

 abstraction ; the original should be consulted. The compounds are 

 NigAsa (existing in two modifications), Ni3As2 and NiAs, Good agree- 

 ment was found between the diagram and the results of microscopical 

 examination. 



Latent Heat of Recalescence in Iron and Steel.* — F. K. Bailey 

 has determined the mean specific heats of a number of steels of 

 diifereut carbon content between temperatures varying from 470° C.to 

 860° C, and 20° C, by a calorimetric method. A sphere was heated in 

 an electric resistance furnace with vertical tube, and when at the required 

 temperature dropped into water contained in a calorimeter below. 

 Heating and cooling curves were also taken. From the results obtained 

 were calculated the values of the latent heat of recalescence. 



Binary and Ternary Alloys of Tin, Lead, Bismuth and Cadmium.t — 

 The original plan of this research by A. Stoffel was the investigation 

 of the solidification of a quaternary system, these four metals being 

 chosen as giving the simplest case possible. It was found that the 

 systems containing tin and cadmium showed a transformation in the 

 solid state. This introduced so much complication that the study of 

 the quaternary system was abandoned. The author here gives an 

 account of previous work on the six binary systems together with his 

 own results on these and two of the ternary systems. The tin-cadmium 

 series was examined microscopically, but though good preparations were 

 obtained no conclusions as to constitution could be drawn. The theory 

 of equilibrium of ternary systems is worked out fully. The composition 

 of any ternary alloy may be represented by a point within an equilateral 

 triangle, the lengths of the perpendiculars from this point to the three 

 sides representing the percentage of each metal. Thus the three angular 

 points of the triangle represent the three pure metals. If a perpendicular 

 to the plane of the triangle is erected from each point within it, its length 

 proportionate to the freezing temperature of the alloy whose composition 

 is indicated by the point, the surface obtained by joining the upper 

 ends of these ordinates is the solidification surface. A straight line 

 joining one vertex of the triangle to a point on the side opposite is 

 the projection of a series of alloys containing two of the metals in 

 constant proportion to each other with varying proportions of the third. 

 The temperature concentration diagram of this series may be figured 

 in the way adopted for a binary system, ordinates representing tempera- 

 ture, abscissa the percentage of the varying metal. The liquidus curve 

 is then a section of the solidification surface of the ternary system. By 

 taking cooling curves of a large number of ternary alloys, classified in 

 ,series forming such sections, the author determined the form of the 

 Complete soHdification surfaces of the Sn, Cd, Bi, and the Sn, Cd, Pb 

 systems. In the latter the eutectic point is at 145° C. and the com- 

 position 57 tin, 21 lead, 22 cadmium atomic p.c. The freezing-point 

 of >^ the eutectic of the other system is 103° C, the composition is 'So '2 



* Physical Review, xxiv. (1907) pp. 129-51 (8 figs.)- 



t Zeitschr. Anorg. Chem., liii. (1907) pp. 137-83 (29 figs.). 



