/.OOLOGY AND BOTANY, MICROSCOPY, ETC. 41/ 



melts at about 1041° C, but exists in the melts only in equilibrium with 

 an excess of tellurium. TeSn melts at 780° C. Mixed crystals do not 

 occur in either system. 



Gold-tellurium System.* — M. Coste has made a microscopical ex- 

 amination of twenty gold-tellurium alloys, prepared in minute quantities 

 by melting together weighed portions of the two pure metals in sealed 

 vacuous glass or silica tubes. One compound, AuTe 2 , which forms eutec- 

 tics with each of the two metals, was found. The results were confirmed 

 by measurements of E.M.F. of solution. 



Alloys of the Noble Metals.f — W. Geibel has determined the elec- 

 trical conductivity, temperature coefficient, and thermal E.M.F. against 

 platinum, of several series of binary alloys of metals of the platinum 

 group, gold, and silver. The tensile strength of wires was also deter- 

 mined. Complete results are given for the palladium-gold series. 



Physico-chemical Studies of Lead. J — E. Cohen and K. Inouye claim 

 to have proved that the two apparently different kinds of lead crystals, 

 which may be obtained by electrolysis of solutions of lead salts, are not 

 allotropic modifications, but must be regarded as identical. 



Zinc Amalgams.§ — E. Cohen and P. J. H. van Ginneken have 

 found in the 10 p.c. and other zinc amalgams transition points at 42 "9° 

 and 20° C. The equilibrium diagram of the zinc-mercury system, based 

 on these and previous observations, is applied to the explanation of the 

 peculiarities of the Clark standard cell. 



Alloys of Cadmium, Bismuth and Lead.|| — W. E. Barlow has deter- 

 mined the equilibrium diagrams of two binary systems, lead-cadmium 

 and lead-bismuth, and the ternary system, by thermal methods. Super- 

 cooling was avoided by frequent inoculation of the cooling melt with 

 fragments of the solid alloy. The composition of the ternary eutectic 

 is given as 40 '2 p.c. lead, 51*65 p.c. bismuth, 8*15 p.c. cadmium; its 

 freezing-point is 91 "5° C. 



Heat-treatment of Brass. f— G. D. Bengough and O. F. Hudson 

 have studied the effects of heat treatment on rolled and drawn brass con- 

 taining 70 p.c. copper, 30 p.c. zinc. The best combination of strength 

 and ductility was obtained by annealing at temperatures between 600° 

 and 700° C. Length of time of annealing has a marked effect ; a bar 

 of pure brass may be heated for half-an-hour at a temperature a few 

 degrees below the solidus without burning, while a sufficiently long an- 

 nealing at a temperature 100° C. lower may produce burning. Burning 

 is considered to occur if the elongation in the tensile test is lowered. 

 The atmosphere of the annealing furnace, whether oxidizing or reducing, 

 appears to have little effect on the brass. The growth of the crystals 

 upon annealing was studied microscopically. 



* Comptes Reudus, clii. (1911) pp. 859-G2 (3 figs.). 



t Zeitschr. Anorg. Cheni., lxix. (1910) pp. 38-46 (2 figs.). 



X Zeitschr. Phys. Chern., lxxiv. (1910) pp. 202-6 (2 figs.). 



§ Tom. cit., pp. 437-93 (8 figs.). 



|| Journ. Amer. Chem. Soc, xxxii. (1910) pp. 1390-1412 (14 figs.). 



If Journ. Inst. Metals, iv. (1910) pp. 92-127 (28 figs.). 



