256 SUMMARY OF CURRENT RESEARHES RELATING TO 



Rolling Figures in a Rail Section.— R. Loebe * has examined a 

 ■section of an old steel rail, in which a singular pattern was developed by 

 a long etching with hydrochloric acid. Standing in relief above the 

 dark-etched surface were two lighter-coloured bands, about 1 • 5 mm. 

 wide, running approximately parallel to each other and to the edge of 

 the section. The microstructure indicated that these bands were almost 

 carbonless iron. The conclusion is drawn that two concentric wrought 

 iron tubes had been placed in tlie centre of the ingot mould before the 

 rail ingot was cast ; the tubes became incorporated with the ingot, but 

 retained their identity throughout the subsequent heating and rolling, 

 in which their form was distorted until in section it roughly resembled 

 the outline of the rail section. 



A. V. Dormus,t discussing Loebe's article, describes experiments 

 carried out fifteen years ago, in which concentric rings of wrought iron 

 were placed in ingot moulds before casting. 



System Manganous Oxide-Silica. + — F. Doerinckel has investigated 

 this system in the range 20-60 molecular p.c. silica. Cooling curves of 

 the fused mixtures were taken, but the conclusions are drawn chiefly 

 from the microscopical examination of thin sections in ordinary and in 

 polarized light. The crystalline constituents observed are manganosite 

 MnO, tephroite Mn2Si04, and rhodonite MnSiOg. 



Injury caused by Cold-working.§ — 0. Bauer and E. Wetzel have 

 investigated some tyres of tenders which failed through the cracking 

 and flaking off of the wearing surface. The microstructure of the de- 

 fective parts, and their greater hardness hs shown by hardness measure- 

 ments, indicated that the tyres had been severely cold worked at the 

 wearing surface, probably in use. The cold-working is held to be the 

 cause of failure. 



Effects of Pressure on Metals. || — G. Spezia has subjected to a pres- 

 sure of HOOO atmospheres for one month, fine powder of silver, copper, 

 and a mixture of silver and copper. The compact masses formed could 

 be cut and polished, but microscopical examination showed that welding 

 or alloying had not occurred. The author doubts the accuracy of con- 

 clusions arrived at by Spring and by Kahlbaum, as to certain other 

 effects of hydrostatic pressure on metals. 



Abnold, J. 0. — Fourth Recalescence in Steel. 



Bit. Zeitschr. MetallograpUe, i. (1911) pp. 192-205 (13 figs.). 



BouDouARD, 0. — Electrical Resistance of Special Steels. 



Comptes Rimdus, cliii. (1911) pp. 1475-8. 

 Burgess, C. F., & J. Aston. — Electric Resistivity of Iron Alloys, 



[A table showing the relative resistivity of forty-three alloys of electrolytic 

 iron vfith chromium, nickel, silicon, and other elements is given.] 



Met. and Chem. Eng., ix. (1911) p. 539. 



* Stahlund Eisen, xxxi. (1911) pp. 792-4 (6 figs.), 

 t Stahlund Eisen, xxxi. (1911) p. 1187 (2 figs.). 

 t Metallurgie, viii. (1911) pp. 201-9 (12 figs.). 

 § Stahl und Eisen, xxxi. (1911) pp. 226-9 (7 figs.). 



II Atti R. Accad. Sci. Torino, xlv., through Journ. Soc. Chem. Ind., xxx. (1911) 

 p. 550. 



