ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 787 



Heat-treatment of Steel.* — A. McV\ llliam and E. J. Barnes have 

 carried out tensile tests, and Arnold alternating stress tests on nine acid 

 Bessemer steels, heat-treated in various ways. The carbon content of 

 the steels varied from 0*10-0 '86 p.c. ; the samples were treated in the 

 form of 1 in. round bar. The steels were tested (1) as received ; (2) 

 air-cooled from 050° C. ; (3) slowly cooled after 35 hours at 950° C. ; 

 (4) quenched in water from 850°, 900°, or 950° C, and tempered at 

 400°, 500°, 600°, or 700° C. The very slow cooling of treatment (3) caused 

 the cementite of the pearlite to coalesce into globules ; no pearlite 

 remained in the 0*10 p.c. carbon steel after this treatment. No 

 difference in micro-structure was observed between the steels tempered 

 at 500° C, and those tempered at 700° C. A Bessemer steel, with 

 1 p.c. manganese, consisting entirely of pearlite. contains about 

 0*80 p.c. carbon. 



Ageing of Mild Steel. f — C. E. Stromeyer has further investigated 

 this subject,| ana " finds that brittleness in mild steel is frequently due to 

 excessive percentages of phosphorus and nitrogen, the latter element 

 being particularly dangerous. 



High-tension Steels. § — P. Longmuir gives the results of a large 

 number of tensile and other tests of nickel steels, nickel-chromium 

 steels and chromium-vanadium steels, heat-treated in various ways, and 

 concludes that nickel steels are inferior to either of the two other 

 classes, chromium-vanadium steels giving especially high values. 



Uniform Nomenclature of Iron and Steel. ||—H. M. Howe and 

 A. Sauveur present the second report of the committee appointed to 

 (•(insider this subject. The report includes definitions of the micro- 

 scopical constituents of iron and steel. " Metaral " is suggested as the 

 equivalent of " microscopical constituent." Austenite is a solid solution 

 of carbon, or carbide of iron, in y-iron, stable above the critical range. 

 The authors adhere to the transformation scheme, austenite-martensite- 

 troostite-sorbite-pearlite. 



Binary Alloys.1I — K. Bornemann reviews all the published work on 

 the constitution of binary alloys of metals, and gives a large number of 

 equilibrium diagrams. From a critical comparison of the results 

 obtained by different workers on the copper-zinc system, the author 

 concludes that the compound Cu 2 Zn 3 , melting without decomposition, 

 undoubtedly exists. Another compound, more rich in copper, possibly 

 has the formula CuZn, and decomposes, more rapidly at higher 

 temperatures, into copper and Ou 2 Zn 3 . The copper-aluminium and 

 copper-tin systems are discnssed at some length. These papers collect, 

 in useful form, a large quantity of scattered data. 



* Journ. Irou and Steel lust., lxxix. (1909) pp. 348-82 (12 figs.), 

 t Tom. cit., pp. 404-25 (2 figs.). 

 ; See this Journal, 1907 p. 640. 



§ Joum. Iron and Steel Inst., lxxix. (1909) pp. 383-403 (1 fig.). 

 I| Proc. Int. Assoc, for Testing Materials, No. 10 (1909) 18 pp. 

 % Metallurgie, vi. (1909) pp. 236-53, 296-304, 326-36, 490-500 (93 figs.). 



