270 SUMMARY OF CURRENT RESEARCHES RELATING TO 



carbon absorbed by the iron indicates that industrial cementation proceeds 

 chiefly through the agency of gases. 



Influence of Segregation on the Strength of Mild Steel.* — F. Wiist 

 and H. L. Felser have studied, in a very thorough manner, the segrega- 

 tion in basic Bessemer and open hearth steel containing about 0*07 p.c. 

 carbon. Large and small ingots of each description of steel, weighing 

 respectively 1000 kg. and 250 kg., were sectioned longitudinally, 

 polished, and etched with copper-ammonium chloride ; drillings for 

 analysis were taken from sixty positions in each. Sulphur and phos- 

 phorus were found to segregate most ; carbon, manganese, and copper to 

 a lesser degree. While in the segregated regions the static tensile tests 

 were little worse than those from the lower unsegregated parts, the 

 impact bending tests gave much inferior results. 



Gases in Commercial Steel and Iron.j— P. Goerens describes the 

 method he has used for the extraction of occluded gas from steel. Fine 

 drillings are heated in a vacuum at 900°-950° C. The results of numerous 

 analyses of the gases extracted from basic Bessemer, open-heartb, and 

 other steels, at different stages in their manufacture, are given. 



Grain-size in Iron. J — By heating pieces of steel wire containing 

 • 07 p.c. carbon at different temperatures for various lengths of time, 

 A Joisten has confirmed Stead's statement that the greatest increase 

 of grain-size in low-carbon steel takes place in the neighbourhood of 

 700° C. Curves are given showing the relation of dimensions of grain to 

 length of time of heating at 400°, 500°, 600°, 700°, and 850° C. 



Magnetic Properties of the Modifications of Iron.§ — S. Hilpert 

 questions the separate existence of /?-iron, and also suggests that y-iron 

 may be magnetic at ordinary temperatures. The change in magnetic 

 properties with temperature is continuous, and the thermal phenomena 

 which are regarded as evidence of the existence of allotropic modifica- 

 tions of iron may be due to changes in specific heat accompanying loss of 

 magnetic properties. 



Iron-nickel Meteorite. || — W. Guertler combats the view taken by 

 Fraenkel and Tammann,1f that the iron-nickel alloy of which meteorites 

 are composed is metastable. The peculiar structure of meteorites is 

 held to be due to the extremely slow cooling they have undergone. 



Historical Note on Recalescence.** — W. F. Barrett gives an account 

 of the discovery of the recalescence points in iron and steel. The 

 observation by G. Gore, in 1868, of the momentary elongation of an 

 iron wire during cooling from bright incandescence, led the author to 

 investigate the subject, and in 1873 the afterglow or recalescence was 

 discovered. 



• Metallurgie, vii. (1910) pp. 363-84 (59 figs.). 



t Tom. cit., pp. 384-95 (2 figs.). t Tom. cit., pp. 456-8 (14 figs.) 



§ Zeitschr. Electrochem., xvi. (1910) pp. 390-4, through Journ. Soc. Chem. 

 Jnd., xxix. (1910) p. 760. 



|l Zeitschr. Phys. Chem., lxxiv. (1910) pp. 428-42 (3 figs.), 

 t See this Journal, 1909, p. 785. 

 ** Nature, lxxxv. (1910) pp. 235-6. 



