508 SUMMARY OF CUREENT RESEARCHES RELATING TO 



author's diao-ram showino; 22 fields is deduced from the coolin^ curves 

 and microstructnre of 21 alloys. The eight constituents are pure tin, 

 the compound NiSn, and three solid solutions, one of which exists in 

 two, another in three modifications. It is held that a maximum in the 

 liquidus curve does not necessarily correspond with a definite compound. 



Recording Pyrometer.* — S. Wologdine describes a method of 

 recording time-temperature curves on a fixed photographic plate. The 

 temperature is indicated by the horizontal deflection of a galvanometer 

 mirror, while a vertical movement is given to the ray of light by a 

 mirror, which is rotated about a horizontal axis. This rotation is 

 secured by means of an arm in connection with a float in a vessel con- 

 taining water, the level of which fails at a uniform speed. The spot of 

 fight thus passes over equal vertical spaces on the photographic plate in 

 equal intervals of time. 



Alloys of Cobalt and Tin.f — F. Ducelliez claims to have extracted 

 by chemical methods the compound CoSn from several ingots prepared 

 by melting cobalt and tin together. 



Constitution of Alloys of Copper. J — L. Guillet states some general 

 conclusions regarding the binary alloys of copper. A zone of extreme 

 brittleness occurring in each series, corresponds to a single constituent 

 always behaving in the same manner with reagents. 



Boron Steels. § — L. Guillet has examined four steels containing 

 boron • 2-1 • 5, carbon •18-0' 28 p. c, and two with boron 0*15 and 

 0*41 p.c, carbon O'-IT and 0*59 p.c. Maximum stress is raised by 

 boron both in the normal and quenched conditions. The steels are 

 brittle. The normal steels are constituted of a solid solution iron-boron 

 of low boron content, pearlite, and a special constituent occurring as 

 rounded grains, somewhat resembling cementite in its metallographic 

 reactions. It appears to be a boro-carbide of iron of low carbon content. 



Electrical Conductivity of Alloys. |1 — W. Guertler deduces from 

 the results obtained by previous workers the relationship between 

 constitution and temperature coefficient of electrical conductivity. 

 While in nearly all pure metals and in alloys free from mixed crystals 

 the temperature coefficient has about the same value, the presence of 

 mixed crystals in alloys lowers this value. The relation between con- 

 ductivity and its temperature coefficient given by Matthiessen is 

 supported by later results. 



Alloys of Iron with Tin and Gold. If — E. Isaac and G. Tammann 

 give the equilibrium diagrams of these two systems. Iron and tin are 

 not miscible in all proportions in the liquid state. The range in which 

 two layers are formed extends at 1140° C. from 50-89 p.c. tin, and is 



* Rev. de M6tallurgie, iv. (1907) pp. 552-6 (5 figs.). 

 t Comptes Rendus, cxliv. (1907) pp. 1432-4. 

 X Tom. cit., pp. 845-8. 

 § Tom. cit., pp. 1049-50. 



II Zeitschr. Anorg. Chem., liv. (1907) pp. 58-88 (13 figs.). 

 ^ Op. cit., liii. (1907) pp. 281-97 (14 figs.). 



