676 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Corrosion of Bronzes.* — F. G-iolitti and 0. Ceccarelli have shown 

 that the rate of corrosion of bronzes bears a relation to their micro- 

 structure. Bronzes containing less than 10 p.c. tin were annealed at 

 different temperatures, or cooled rapidly or slowly after casting. After 

 microscopical examination, weighed cylinders were immersed in a dilute 

 solution of hydrochloric acid and ferric chloride for a given time, and 

 the loss of weight determined. The conclusions reached may be briefly 

 expressed as follows. 1. Two bronzes of the same composition, but 

 differing in microstructure, as a result of different thermal treatment, 

 may differ widely in their resistance to corrosion. 2. Corrosion is 

 accelerated by the simultaneous presence of the two solid solutions a and 

 (3. 3. The velocity of corrosion increases as the difference of con- 

 centration between nucleus and edge of individual crystals is greater. 

 Thus microscopical examination of a bronze may afford data on which 

 to base a conclusion as to its capacity for resisting corrosion. 



Zinc Amalgams.f — E. Cohen and K. Inouye have worked out a 

 method of determining the solubility of zinc in mercury, which avoids 

 the considerable errors resulting from previous methods. The solubility 

 curve from to 100° C. has been determined, and shows a regularly 

 increasing solubility with rising temperature. 



Copper-arsenic Alloys.J — Gr. D. Bengough and B. P. Hill have 

 studied the mechanical properties of five bars of copper containing " 04 

 to 1*94 p.c. arsenic, in three states : (1) as rolled ; (2) annealed in an 

 oxidizing atmosphere ; (3) annealed in a reducing atmosphere. Bars 

 with less than 1 p.c. arsenic were injured by reducing gases at tempera- 

 tures above 650° C. ; the authors suggest, as a cause, the reduction of 

 arsenious oxide with the sudden formation of gases within the metal 

 and insoluble in it. The constitution of the copper-arsenic alloys was 

 investigated by means of thermal and microscopical examination of 

 thirty-six alloys containing 0*9 to 44 ■ 4 p.c. arsenic. The existence of 

 Cu 3 As and Cu 5 As 2 has been confirmed ; no evidence of the existence of 

 Cu 2 As was found. The authors consider that a true equilibrium dia- 

 gram of the system cannot be constructed by ordinary methods, for the 

 rates of cooling used appeared to be too rapid to allow the change in 

 the solid to complete itself at the critical temperatures, and too slow 

 to allow of constancy of composition. An alkaline solution of copper- 

 ammonium chloride was used for etching some of the alloys. 



Phosphor -bronze.§ — O. F. Hudson and E. F. Law state the 

 conclusions they have reached as to the constitution of the copper-tin- 

 phosphorus alloys, illustrating them by a series of remarkably good 

 photomicrographs. The two compounds Cu 4 Su and Cu 3 P form a binary 

 eutectic, and together with the tin-copper solid solution a give rise to a 

 ternary eutectic containing 81 p.c. copper, 14*2 p.c. tin, 4-8 p.c. phos- 

 phorus. The experimental data on which the authors' conclusions are 



* Gazz. Chim. Ital., xxxix. (WOO) pp. 557-75, through Journ. Soc. Chem. Iud., 

 xxix. (1910) p. 281. 



t Zeitschr. Phys. Chem., lxxi. (1910) pp. 625-35 (2 figs.). 

 X Journ. Inst. Metals, iii. (1910) pp. 34-97 (26 figs.). 

 § Torn, oit., pp. 161-86 (27 figs.). 



