ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 421 



Metallography, etc. 



Microchemistry of Corrosion.*— S. Whyte and C. H. Desch have 

 made corrosion experiments upon four copper-zinc alloys of a composition, 

 by a method substantially the same as that applied previously to /? 

 alloys, f All the alloys contained about 70 p.c. copper, the remainder 

 being all zinc in one alloy, while the three others contained respectively 

 1 p.c. tin, 1 p.c. lead, and 2 p.c. lead. Corrosion appeared to proceed by 

 dezincification in ail cases ; the loss of copper by corrosion, however, was 

 greater than in the /3 alloys. The film of copper left was intimately 

 mixed with basic salts, which adhered very firmly. Momentary immer- 

 sion in very dilute hydrochloric acid removed the oxychloride, exposing 

 the coppery layer, which was invariably made up of small crystals, mainly 

 exhibiting octahedral angles. In the long-period tests etch-figures were 

 conspicuously developed, cubic forms being frequently observed. The 

 boundary between the brass and the dezincified (copper) layer was 

 always perfectly sharp. In the brass surface, after the copper skin had 

 been detached, the crystal boundaries were visible. The cored structure 

 of an unannealed specimen was strongly developed during corrosion, 

 finally leaving ridges in high relief, whilst the annealed alloys corroded 

 very uniformly. When the adherent layer was detached from the alloys 

 containing lead, each isolated mass of lead was seen surrounded by a 

 ring of copper. The micro-structure of some corroded condenser tubes, 

 which also showed pronounced dezincification, is described. 



Vanadium in Brass.! — R. J. Dunn and 0. F. Hudson have made 

 a thermal and microscopic examination of copper-zinc alloys containing 

 50 to 60 p.c. copper and to 1 - 5 p.c. vanadium. No tendency towards 

 the structural resolution of fi into a and y was observed even after pro- 

 longed annealing. The authors conclude that the usual structure of 

 brasses, containing between 50 and 60 p.c. copper, is not greatly modi- 

 fied by the presence of small quantities of vanadium, and that vanadium 

 to the extent of at least 1 p.c. appears to have no influence on the 

 structural stability of the ft constituent of the copper-zinc alloys. 



Muntz Metal. § — In the course of a study of the properties of 60/40 

 brass after various heat-treatments, J. E. Stead and H. G-. A. Stedman 

 have examined numerous specimens microscopically. Long continued 

 annealing at temperatures below 470° C. had the apparent effect of in- 

 creasing considerably the volume of the a phase at the expense of the /?. 



* Journ. Inst. Metals, xi. (1914, 1) pp. 235-51 (6 figs.), 

 t See this Journal, 1914, pp. 220. 



j Journ. Inst. Metals, xi. (1914, 1) pp. 151-68 (22 figs.). 

 § Journ. Inst. Metals, xi. (1914, 1) pp. 119-50 (38 figs.). 



