1. A new method of determining the atomic 



weight of iodine. Marcel Guichard ; Ann. 

 chim., 6, 279-318 (1916); 7, 5-49 (1917). 



ABSTRACT 



Atomic weight of iodine. — The pentoxide 

 method used involves the preparation of l20g, 

 the decomposition of this anhydrid, and the 

 collection of the iodine by condensation and of 

 the oxygen by combination with pure copper. 

 The mean of five determinations is 126.915. 

 The article gives in voluminous detail the re- 

 finements employed to guard against error. 



Iodine pentoxide; preparation, purification 

 and decomposition with heat. — The results of 

 a thorough study are presented. As it was 

 found impracticable to prepare it by direct 

 combination of 1^ and O,, the method adopted 

 was to oxidize I2 with fuming HlSTOg and 

 subsequently expel free I^ and HNOj by 

 heating to 450°. This was carried out in an 

 evacuated train which is fully described. 



Preparation of pure iodine. — Detailed di- 

 rections are given. 



Occlusion of oxygen hy glass, porcelain and 

 copper was studied in order to determine the 

 best material for the apparatus. 



2. On K. S. magnet steel. K. Honda and S. 



Saito; Physical Review, 16, 495-500, De- 

 cember, 1920. 



ABSTRACT 



K. 8. magnet steel (0 0.^-0.8, Co 30-^0, 

 W 5-9, Cr 1.5-3 per cent). — This remarkable 

 new alloy steel possesses, when tempered, an 

 extremely high coercive force, 226-257 gauss, 

 and a strong residual magnetism, varying from 

 620 to 920 C.G.S. units for different specimens. 

 The effect of repeated shock was to reduce 

 these values by only 6 per cent. The hysteresis 



