ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 121 



Thermo-electricity of Nickel.* — H. Pecheux has measured the 

 E.M.F. developed by thermocouples prepared from copper and three 

 specimens of commercial nickel, varying- somewhat in chemical com- 

 position. The notable effect of impurities in the nickel, and of anneal- 

 ing, on the E.M.F. developed is shown. 



Blowholes in Steel Ingots.f — E. von Maltitz discusses the forma- 

 tion and prevention of blowholes. Though the gas found in them 

 consists almost wholly of hydrogen and nitrogen, the gas evolved during 

 solidification contains a large proportion of carbon monoxide, and it 

 appears that the formation of blowholes is largely due to the evolution 

 of carbon monoxide. The solvent power of molten steel for ferrous 

 oxide (the source of the carbon monoxide) increases as the temperature 

 rises, and at the same time the affinity of iron for oxygen increases more 

 rapidly than that of carbon for oxygen. Thus carbon monoxide is 

 given off when highly heated molten steel (containing both ferrous 

 oxide and carbon in solution) is cooled, as by stirring with a steel rod. 

 The liberation of carbon monoxide probably induces the simultaneous 

 liberation of hydrogen and nitrogen. 



Melting- Points of the Iron Group Elements.} — G. K. Burgess 

 has obtained the following values by a new radiation method : — Iron 

 1505° C, cobalt 1464° C, manganese 1207° C, chromium 1489° C, 

 nickel 1485° C. Minute quantities of the metal were placed on an 

 electrically heated platinum strip within a brass tube through which 

 hydrogen was passed. The particles were microscopically observed 

 through a mica window, and the temperature of the platinum strip was 

 taken by a Holborn-Kurlbaum optical pyrometer at the instant when 

 the metal was seen to melt. 



Melting- Points of Palladium and Platinum.§ — G. W. Waidner 

 and G. K. Burgess have selected the values, palladium 1546° G. and 

 platinum 1753° C., from the results given by radiation and other 

 methods. 



Electrolytic Corrosion of Brasses.||— A. T. Lincoln, D. Klein, and 

 P. E. Howe have subjected to electrolytic corrosion in normal solutions 

 of some sodium and ammonium salts a series of copper-zinc alloys 

 representing most of the different solid solutions, annealed at 400° 0. 

 for several weeks. For the alloys of 50 p.c. or more copper the 

 corrosion product (precipitate resulting from corrosion) has practically 

 the same composition as the alloy. For alloys of low copper content 

 the corrosion product is nearly pure zinc. While the amount of corro- 

 sion in sodium chloride decreases with increase in copper content of the 

 brass, in other solutions the reverse was found to be the case. 



* Cornptes Rendus, cxlv. (1907) pp. 591-3. 



t Bull. Amer. Inst. Mining Eng., xvii. (1907) pp. 691-726. 



t Bull. Bureau of Standards, iii. (1907) pp. 345-55 (1 fig.). 



§ Tom. cit., pp. 163-208. 



|| Journ. Phys. Chem., xi. (1907) pp. 501-36 (12 figs.). 



