ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 393 



■compact and to lose its lamellar structure, these effects being more pro- 

 nounced as the percentage of aluminium increases. With the higher 

 proportions of aluminium a new constituent, exhibiting all the charac- 

 teristics of cementite, is distinguished. The belief that aluminium 

 •causes the separation of graphite in steel is shown to be erroneous. 

 Steel containing 3 p.c. or more of aluminium is brittle. Aluminium also 

 causes some increase in hardness. The aluminium appears to exist in the 

 state of solution in the iron, and when notable quantities of aluminium 

 are present, this solution is incapable of dissolving carbon, even at high 

 temperatures. 



Flat her, D. — Case-hardening. 



[Describes the most modern methods of carrying out this operation.] 



Iron and Steel Mag., ix. (1905) pp. 305-22 (1 fig.) 



Oiracd — Constitution du Cuivre Oxyde. Rev. Metallurgie, ii. (1905). 



pp. 297-8 (5 figs.). 



Special Nickel-Steel Alloys. Iron and Steel Mag., ix. (1905) pp. 256-60. 



■Stead, J. E. — Science in the Iron Foundry. Tom. cit., pp. 322-34. 



