ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 299 



METALLOGRAPHY, Etc. 



Fusion Welding Applied to Drop Forgings. — S. W. Miller {The 

 Iron Age, July 31, 1919, 104, No. 5). Oxy-acetylene and electric 

 welds, and their applicability to effective forgings. Effect of high 

 temperatures on physical structure. 



Improved Case-hardening Process. — D. Hanson and J. E. Hurst 

 {The Iron Age, July 17, 1919, 104, No. 3). Slow cooling of nickel- 

 steel gears for automobile and airplane engines prevents flaking and 

 chipping. Practical results. 



Characteristics of Rifle-barrel Steel. — G. F, Butterworth and 

 A. E. Bellis {The Iron Age, July 24, 1919, 104, No. 4). Metal- 

 lography and heat-treatment. Best structure for the best results. Rolled 

 and heat-treated barrels. Factors in erosion. 



Synopsis of Recent Chemical and Metallurgical Literature. — 

 Chemical and Metallurgical Engineering, July 1, 1919, 21, No. 1. 



Metallography of Aluminium Ingot. — Robert J. Anderson 

 {Chemical and Metallurgical Engineering, Sept. 1, 1919, 21, No. 5). Study 

 of the microstructnre of aluminium ingot. Influence of quality of ingot 

 on the resultant castings. " Differential group-etching," a phenomenon 

 noticed in etching aluminium. Tentative explanation of the differential 

 etching. 



Notes on the Influence of Certain Variables associated with the 

 Anneal of Cold-worked Alpha Brass. — Arthur Phillips and George 

 C. Gerner {Chemical and Metallurgical Engineering, June 15, 1919, 

 20, No. 12). Degree of plastic deformation. Temperature and time of 

 anneal. Rate of heating through the ferminative temperature. Size 

 and uniformity of the grains prior to the plastic deformation. Potential 

 possibilities of rolled metal. 



Researches on Bearing Metals. — E. Heyn and 0. Bauer {Metal 

 /nf^us^ry, July 4, 1919, 15, No. 15). Antimony. Lead. Tin. Alloys. 



The Properties of Standard or Sterling Silver, with Notes on its 

 Manufacture. — Ernest A. Smith and Harold Turner {Metal 

 Industry, Oct. 10, 1919, 15, No. 15). 



Season Cracking. — W. H. Hatfield and G. L. Thirkell {Metal 

 Industry, Oct. 10, 1919, 15, No. 15). 



