ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 827 



Malleable Castings.* — I). M. Levy explains the changes occurring 

 during the annealing of white cast-iron in the production of malleable 

 castings, by the ore-annealing process and by the black-heart process, in 

 the light of the equilibrium diagram of the iroti-carbon system. The 

 influence of silicon, manganese 5 and sulphur is considered. 



Magnetic Properties of Nickel Steels.j — E. Colver-Glauert and 

 S. Hilpert have determined the magnetic properties of three steels 

 containing respectively 5 • 9, 24-3, and 32*9 p.c. nickel, (V37, 0*24, and 

 0"30 p.c. carbon. The measurements were made at room temperature, 

 after the specimens had been quencbed, or slowly cooled, from various 

 temperatures, or had been cooled to temperatures ranging down to 

 — 180°C. The authors conclude that there is no connexion between 

 magnetic properties and microstructure. The microstructures of com- 

 mercial nickel steels are stated to be practically the same as those of 

 meteoric iron. No evidence of the non-magnetic character of y-iron — 

 if y-iron exists — was obtained. 



Chromium Steels.J — A. Portevin has cooled two steels containing 

 0'12 p.c. carbon, and 13 and 17 p.c. chromium respectively, extremely 

 slowly from 1300° C. The steels were then found to consist of ferrite 

 with interspersed carbide. The martensitic structure obtained by 

 moderately slow cooling from 1100° C. is accordingly regarded as charac- 

 terizing a metastable state. 



Nickel Steels. § — A. McWilliam and E. J. Barnes have studied a 

 series of eight steels containing 3 p.c. nickel, manganese less than ' 2 p c, 

 the carbon increasing from 0"06 to 0'91 p.c. Tensile and alternating 

 stress tests were made after various heat-treatments, as in former investi- 

 gations by the same authors. Heating and cooling curves were taken, 

 and the heat-treated specimens were microscopically examined. The 

 pearlite composition lies between 0*74 and 0"91 p.c. carbon. 



Influence of Vanadium on Iron and Steel. ||— A. McWilliam and 

 E. J. Barnes have made tensile and alternating stress tests of seven 

 steels containing about ■ 2 p.c. vanadium, carbon varying from ■ 09 

 to 1*32 p.c, after different heat-treatments. The microstructure was 

 studied and heating and cooling curves were taken. 



W. H. Hatfieldll has prepared five cast irons containing to ■ 65 p.c. 

 vanadium. A chemical and microscopical investigation indicated that 

 vanadium tended to maintain the carbon in the combined state. 



Troostite.** — An investigation of the properties of tempered steel 

 has led A. McCance to conclude that (1) troostite consists essentially of 

 a-iron which is in the amorphous condition, or which has not yet attained 

 its crystalline state of ferrite ; (2) troostite contains carbon in suspension, 

 and not in solution, as carbide of iron. 



* Foundry Trade Journal, xiii. (1911) pp. 321-5 (1 fig.). 



+ Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 375-411 (35 figs.). 



j Comptes Rendus, cliii. (1911) pp. 6-1-6 (2 figs.). 



§ Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 269-93 (18 figs.). 



|| Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 294-317 (16 figs.). 



H Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 318-31 (20 figs.). 



** Proc. Inst. Mech. Eng., 1910, pp. 1661-98 (21 figs.). 



