536 SUMMARY OF CURRENT RESEARCHES. 



other abrasive, which produce a series of scratches. These scratches 

 become liner and finer as the polishing proceeds, finer abrading materials 

 being used until ultimately the marks are invisible. The formation of 

 scratches on the metallic surface sets up internal stresses, so that the 

 skin of the metal is in a different molecular condition from the interior 

 of the mass. A strained surface film may thus result, which upon 

 etching gives deceptive appearances not at all representing the structure 

 of the mass. The authors state that by exercising care in polishing, these 

 deceptive conditions may be almost entirely avoided. 



Special Constituent Obtained by Quenching Aluminium Bronze.* 

 P. Breuil has obtained some remarkable results when studying the effect 

 of quenching on an aluminium bronze known as " Fortior." This alloy 

 melts between 1010° and 1030° C, and shows a critical point between 

 690° and 730° C. Normally it is made up of large grains of copper or a 

 copper-aluminium compound imbedded in a eutectic. By quenching at 

 650° C. and higher temperatures a constituent having a microstructure 

 resembling that of martensite is obtained. The appearance of this 

 martensitic constituent coincides with an increase in the elastic limit, 

 maximum stress, and Brinell hardness number. Quenched at 850° C. the 

 alloy is made up wholly of this constituent. 



Anderson, W. C, & Lean, G. — Properties of the Aluminium-Tin Alloys. 



Proc Roy. Soc, lxxii., No. 482, pp. 277-81 (2 Jigs, and 1 pi. of photomicros.) 



Bdffet, E. P. — Equipment and Work of Metallographical Laboratories in Germany. 



American Machinist, xxviii. (1905) pp. 348-9 (7 figs.). 



Gold8Chmidt, H. — Effect of Vanadium and Titanium on Steel. 



Electrochem. and Metallurgical Industry, iii. (1905) pp. 168-70. 



Gradenwitz, A. —Methods of making Tests on Metals. 



[The machines devised by Guillery for determining hardness by the Brinell 

 method, and for testing metals by impact on notched bars, are described.] 

 Iron and Steel Mag., ix. (1905) pp. 528-33 (4 figs.). 



Gumlich, E. — Versuche mit Heuslerschen ferromagnetischen Mangan-Aluminium- 



Kupfer Legierungen. Electrotech. Zeitschr., ix. (1905) pp. 203-7 (7 figs.). 



Impact Testing of Notched Bars. Engineer, xcix. (1905) pp. 249-50 (9 figs.). 



Kryloff, de — Balance electro-magnetique pour l'essai des proprietes desaciers 

 et des fers. Rev. Metallurgie, ii. (1905) pp. 425-40 (11 figs.). 



M a lett e, J. — Special Steels. Rev. Technique, xxvi. (1905) pp. 147-50. 



Mahler, P. — Experiences surla resistance eleotrique de l'acier. 



Rev. Metallurgie, ii. (1905) pp. 345-7. 



Comptes Rendcis, cxl. (1905) pp. 587-90. 



