828 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Internal Structure of Pearlitic Steel.* — M. Oknoff has applied 

 the histological method of cutting serial sections to the investigation 

 of the structure of steel in space. Pearlitic specimens containing 0* 1, 

 0*7, and 1*7 p.c carhon, were examined by successively grinding thin 

 layers off the surface, a marked field being photographed at each stage. 

 The continuity of the pearlite grains was thus established, and their solid 

 form determined. 



Crystallization of Steel. f — E. F. Lange describes some masses of 

 perfectly developed " pine-tree " crystals found in the cavity of the 

 sinking-head of a large steel casting. Some of the masses of the crystals 

 pendent from the upper portion of the cavity were as much as 15 in. in 

 length. 



Influence of Impurities on the Corrosion of Iron.} — J. W. Cobb 

 finds that pure iron is electro-positive to most of its impurities, such 

 as phosphide, sulphide, carbide, oxide, and silicate of iron, and carbon 

 (graphite). Sulphide and silicate of manganese are electrically non- 

 conducting. Microscopic examination of iron in contact with particles 

 of impurities, in a corroding solution, showed that the iron went into 

 solution around the particles, though certain rapidly appearing corrosion 

 centres were not visibly related to impurities. Manganese silicate on 

 iron was found to be inactive. 



Changes in Properties of Metals upon Working § — G. Tammann 

 further develops the view that the strengthening of metals by cold- 

 working results from the splitting up of the crystals into smaller 

 elementary crystals. Alloys of two metals of about the same strength 

 are considerably stronger than either of the pure metals, since the 

 crystallites of which the alloys are composed are smaller than those of 

 which the pure metals are constituted. 



Metallic Fog in Fused Salts.|| — B,. Lorenz, G. v. Hevesy, and 

 E. Wolff, show that when lead is heated under fused lead chloride to 

 600° C, the darkening of the lead chloride is due to solution of lead in 

 it. The lead settles out as a black " fog " on cooling. The authors de- 

 scribe a titration method for the estimation of the lead dissolved in the 

 molten chloride, and have determined the solubility between 500° and 

 700° C. 



Crystallization of Cast Metals.^f — C. H. Desch describes the pro- 

 cess of solidification of a molten metal by the formation of crystallites. 



Andstrom, V. — Rusting of Iron. 



Zeitschr. Anorg. Chem., lxix. (1910) pp. 10-21 (3 figs.). 



Baak, N. — Alloys of Molybdenum with Nickel, of Manganese with Thallium, 

 and of Calcium with Magnesium, Thallium, Lead, Copper, and Silver. 



[The equilibrium diagrams of the binary systems have been determined by 

 thermal and microscopical methods.] 



Zeitschr. Anorg. Chem., lxx. (1911) pp. 352-94 (13 figs.). 



* Metallurgie, viii. (1911) pp. 138-9 (35 figs.). 

 t Engineering, xci. (1911) p. 706. 



X Journ. Iron and Steel Inst., lxxxiii. (1911) pp. 170-95 (14 figs.). 

 § Nachrichten Kgl. Ges. Wiss. Gottingen, 1911, pp. 181-96 (2 figs.). 

 || Zeitschr. Phys. Chem., lxxvi. (1911) pp. 732-42 (5 figs.). 

 « Foundry Trade Journal, xiii. (1911) pp. 530-1. 



