ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 395 



austenite. This austenite showed distinct twinning. The steel in this 

 state was not magnetic, was not very hard, but could be considerably 

 hardened by mechanical distortion, by re-heating to 400° C, or by 

 immersion in liquid air, all these treatments converting austenite into 

 martensite. 



H. le Chatelier points out the importance of Maurer's production of 

 homogeneous austenite. While two well-known alloys of iron, con- 

 taining respectively 13 p.c. manganese and 25 p.c. nickel are 

 undoubtedly austenitic. it did not seem possible to produce austenite 

 with certainty in steels containing small amounts of these metals. 



Application of Colour Photography in Metallography.* — For 

 developing the structure of metal sections, methods by which the 

 •constituents are differently coloured are in many respects superior to 

 etching methods, which merely bring out the constituents in relief. 

 P. Goerens regrets that heat-tinting is so little used, and describes the 

 production on Lumiere plates of photomicrographs in colour. The 

 coloured photomicrographs of a heat-tinted iron-phosphorus alloy 

 (1*5 p.c. phosphorus), given by the author as reproductions of 

 Lumiere photographs in colour, clearly show the variation in concen- 

 tration of the solid solution. It is advantageous to have the section 

 as richly coloured as possible ; a yellow screen is placed at the diaphragm 

 of the photomicrographic apparatus. The theory of the process, and full 

 directions for working it, are given. 



Baykoff — Crystallisation and Structure of Steel. 



Rev. de Metallurgie, v. (1908) pp. 177-81 (7 figs.) 



Borne mann, K. — Constitution of Nickel Ore. 



[A determination of the equilibrium diagrams of the systems FeS — Ni 3 S 2 

 and FeS— Ni 2 S.] Metallurgie, v. (1908) pp. 61-8 (22 figs.). 



Crowther, J. A. — Fatigue of Metals subjected to Radium Rays. 



Proc. Comb. Phil. Soc., xiv. (1908) pp. 340-50 (3 figs.). 



Gahl, W. — Graphite Separation in Iron-carbon Alloys. 



[A theoretical discussion of the results obtained by Heyn, Goerens, Bene- 

 dicks, Osann, etc.] 



Stahl nun Eisen, xxviii. (1908) pp. 225-9 (5 figs.). 

 Portevin, A.— Alloys of Gold. 



[The second article of the series. See above, Portevin, " Alloys of Silver."] 



Rev. de Mitallurgie, v. (1908) pp. 182-204 (31 figs.). 

 Bevillon, L. — Special Steels at the Automobile Salon. 



Tom. tit., pp. 53-68. 

 Rowland, W. S. — Electrolytic Corrosion of Copper- aluminium Alloys. 



Journ. Phys. Chem., xii. (1908) pp. 180-206 (8 figs.). 



Stoughton, B. — Micro-constituents of Cast Iron. 



Foundry, xxxii. (1908) p. 41. 



Watts, 0. P. — Metals in the Order of their Boiling-points. 



Traits. Aiurr. Electrochem. Soc, xii. (1907) pp. 141-54. 



* Metallurgie, v. (1908) pp. 19-23 (5 figs.). 



