ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 543 



properties, of cold-drawn steel wire containing 0*08 p.c. carbon, before 

 and after annealing at various temperatures. Tlie so-called fibrous 

 structure is rapidly replaced by a granular structure when the tempera- 

 ture reaches 520° 0. 



Cold Flow of Steel.* — P. Longmuir has studied the structural and 

 other effects of wire-drawing of steel. Both ferrite and pearlite are 

 mobile within the limits of cold flow. Each annealing heals the effect 

 of cold-work, but the crystals do not regain their original size, the 

 structure becoming finer as the wire decreases in diameter. It is 

 doubtful whether cementite, present in high carbon steels, yields at all 

 in drawing. 



Influence of the Metalloids on Cast Iron.f — H. I. Ooe has studied 

 the properties of fifty-four cast irons, containing varying quantities of 

 silicon, sulphur, phosphorus, and manganese, and describes their micro- 

 structure. The crystallization of iron-carbide in the form of thin plates 

 is illustrated by a photomicrograph of a specimen containing 1'6 p.c. 

 silicon, 1*7 p.c. phosphorus, heat-tinted. 



Influence of Sulphur on the Stability of Iron-carbide.J — W. H. 

 Hatfield has made a microscopical and chemical study of the changes 

 occurring in a number of cast irons containing different percentages of 

 sulphur, silicon, and manganese, submitted to different heat-treatments. 

 In etched or unetched sections the cementite, pearlite, and sulphide 

 could not readily be identified at the same time. Sections were there- 

 fore prepared by heat-tinting. When heat-tinting was carried to the 

 correct degree, the cementite carbide became brownish-purple, the 

 pearlite a very pale brown, and the sulphide assumed a pale blue tint. 

 The microstructures are described in detail and illustrated with photo- 

 micrographs. The author concludes that the increased stability at high 

 temperatures conferred upon iron-carbide by the presence of sulphur 

 in the alloy is due to a chemical action, and is not caused by the 

 mechanical action of sulphide films. The effect is probably due to the 

 small percentage of sulphur associated with the carbide crystals. It is 

 suggested that the effect of silicon in neutralizing the action of sulphur 

 may be explained by the formation of a silicon sulphide. 



Crystallization of Metals. §—C. H. Desch describes a method of 

 studying crystal skeletons in metals in three dimensions. Serial sections 

 are photographed and the crystal is reconstructed as a model. The form 

 of a eutectic is generally determined by the crystallizing power of one 

 component, the other serving as a filling material. Illustrations are 

 furnished by the copper-antimony and copper-phosphorus alloys. 



* Journ. Iron and Steel Inst., Ixxxvii. (1913, 1) pp. 93-117 (28 figs.). 

 t Journ. Iron and Steel Inst., Ixxxvii. (1913, 1) pp. 361-81 (10 figs.), 

 t Journ. Iron and Steel Inst., Ixxxvii. (1913, 1) pp. 139-68 (31 figs.). 

 § Proc. Roy. Phil. Soc. Glasgow, xliii. (1911-12) pp. 107-20, through Journ 

 Chem. Soc, civ. (1913) p. 567. 



