ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 265 



must be in solution before the reaction takes place. The necessity 

 for the presence of water is thus explained. The author deals fully 

 with the reactions occurring during the setting of pozzuolana. 



Different Phases of Matter.* — 0. E. Guillamne gives an account 

 of the experiments of Tammunn, Spring, and others, on the behaviour 

 of metals and other solids when submitted to great pressure. In 

 general, wire -drawn metals are less dense than normal samples. 

 Probably all solids under heavy pressures tend to be converted into an 

 amorphous state, which has no discontinuity with the liquid and gaseous 

 phases. 



Study of Breakages.! — W. Rosenhain discusses the causes of 

 breakages, and insists on the importance of investigating all cases of 

 failure. Segregation, overheating, cold working are dealt with, and 

 details of several instances of failure of steel are given. 



Microstructure and Mechanical Properties of Steel. :j: — The term 

 " tenside " is adopted by A. Jude to express the roughness of the sur- 

 face of a tensile test piece after breaking. The degree of roughness is 

 a reliable index of the coarseness of the structure. Photomicrographs 

 are given, supporting the author's view that, on the whole, there is a 

 decided concurrence of the " tenside," the impact results, and the size 

 of grain. 



&■■ 



Experimental Study of the Thomas Process. § — In the course of a 

 detailed study of the basic Bessemer process, F. Wiist and L. Laval have 

 investigated the metallography of the iron-carbon-phosphorus alloys 

 (containing also silicon, manganese, and sulphur), formed at different 

 stages. The original iron contained cementite, mixed crystals, and a 

 ternary mixed crystals-cementite-phosphide eutectic. As the carbon 

 was eliminated, this ternary eutectic was replaced by a binary mixed 

 crystals-phosphide eutectic. Many photomicrographs, two of which are 

 in colour, are given. 



Solidification of Cast Iron.|| — N. Gutowsky has studied, by means 

 of heating and cooling curves, quenching experiments, and microscopic 

 examination, the processes occurring in the solidification and melting of 

 a commercial cast iron containing 3 '57 p.c. carbon, 1'32 p.c. phos- 

 phorus, 2'05 p.c. silicon. He finds that phosphorus separates as a 

 binary phosphide eutectic. The occurrence of the binary instead of the 

 ternary eutectic required by the theory of ternary alloys, is due to 

 graphite formation. Melting begins with the fusion of the phosphide 

 eutectic at about 980° C. " Solidification of the main body of the 

 cast iron is completed at about 1100° 0., while the high-phosphorus 

 portion finally solidifies at 1)44° C, the solidification point of the binary 

 phosphide eutectic. Graphite formation proceeds throughout the 

 solidification range of the binary eutectic mixed crystals-cementite. 



* Engineering, lxxxvi. (1908) p. 115 (from Rev. Gen. Sci.). 

 t Tom. cit., pp. 340-3 (16 rigs.). See also Electrochem. and Met. Industry, 

 vi. (1908) pp. 459-61. % Tom. cit. p. 772 (8 figs.). 



§ Metallurgie, v. (1908) pp. 431-62, 471-89 (61 figs.). 

 || Tom. cit., pp. 463-70 (27 figs.). 



April 21st, 1909 T 



