ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 221 



Iron-cobalt System.* — E. Ruer and K. Kaneko find that the iron- 

 cobalt alloys have a homogeneous polygonal niicrostructure. Alloys in 

 the range 100-30 p.c. iron showed large polygons subdivided into 

 smaller ones, while in the range 20-0 p.c. iron only large polygons, 

 usually showing twinned lamellse, were seen. 



Structure of Zinc-iron Alloys.f — The zinc-iron system has hitherto 

 been investigated only in the range 0-21 p.c. iron. U. Raydt and 

 G. Tammann have now prepared a series of alloys containing 26-97 

 p.c. iron, by melting zinc and iron together, in an atmosphere of 

 hydrogen, under pressures up to 130 atmospheres. The only phases 

 found in the range of composition studied were the compound FeZn 3 

 and a solid solution of zinc in iron having a concentration of 20 p.c. zinc 

 when saturated. Copper sulphate solution, nitric acid in amyl-alcohol, 

 and iodine solution were the etching reagents used ; some specimens 

 were lightly re-polished after etching. 



Iron-copper System. J—R. Ruer and K. Fick, finding that iron and 

 copper are incompletely miscible in the molten state, and yet do not 

 separate into two layers, have made a microscopic examination of a 

 number of melts. The presence of a little carbon causes separation of 

 an alloy of equal weights of iron and copper into two layers, rich in iron 

 and in copper respectively. It is suggested that in pure iron-copper 

 alloys the copper may separate in " submicroscopic " form. The alloys 

 0-8 p.c. copper, and 0-2*5 p.c. iron, were microscopically homogeneous. 



Heat-treatment of Steel. § — I. H. Nead has examined, micro- 

 scopically and otherwise, specimens of steel which had been heat-treated 

 in the form of round bars of sizes ranging from \ in. to If in. diameter. 

 The bars of one series having the composition carbon 0-2, nickel 

 3*5 p.c, were quenched in oil from 1550° F., the bars of the other 

 series, containing carbon 0*1, chromium 0*9, vanadium 0'2 p.c, were 

 quenched in oil from 1650° F. and re-heated to 500° F. The bars \ in. 

 in diameter in both series consisted solely of uniform martensite. The 

 bars If in. in diameter contained some quantity of ferrite, with granular 

 pearlite in the case of the nickel steel and granular troostite in the case 

 of the chromium-vanadium steel. The effect of mass of quenched 

 specimen upon the rate of cooling in oil, and thus upon the niicrostruc- 

 ture, was apparent in the gradual transition, with gradual increase in 

 diameter of bar, from the martensitic to the pearlitic, or to the fcroostitic 

 structure. 



Heat-treatment of Hypo-eutectoid Steel Castings.||— J. II. Hall 

 describes the structure of specimens cut from steel castings containing less 

 than • 9 p.c carbon, heat-treated in various ways. Ingotism is defined 



* Ferrum, xi. (1913) pp. 33-9 (8 photomicrographs.). 



t Zeitschr. Anorg. Chern., lxxxiii. (1913) pp. 257-66 (12 figs.). 



\ Ferrum, xi. (1913) pp. 39-51 (6 photomicrographs.) 



§ Proc. Amer. Soc. for Testing Materials, xiii. (1913) pp. 489-509 (18 photo- 

 micrographs). 



|i Proc. Amer. Soc. for Testing Materials, xiii. (1913) pp. 514-24 (18 photo- 

 micrographs). 



April 15th, 191J+ q 



