Chemistry and Physics. 75 



have contained the "element" in question, although v. Lengyel 

 does not mention such a possibility. At all events, the result of 

 the experiment makes it seem possible that the radio-activity of 

 uranium may be due to the same cause as that of radium, and 

 perhaps also of polonium and the others. — JBerichte deittsch. chem. 

 Gesellsch., xxxiii, 1237. . h. l. w. 



2. Mercuric Antimonide, and Stibonium Compounds. — Par- 

 theil and Mannheim have prepared mercuric antimonide, Sb 2 Hg 3 , 

 by passing hydrogen antimonide over finely powdered mercuric 

 chloride which was mixed with sand and fragments of glass. 

 The reaction took place slowly, the white mercuric chloride 

 becoming black. This mercuric compound is interesting because 

 like potassium antimonide it gives stibonium compounds when 

 treated with alkyl iodides. The authors have studied its behavior 

 with ethyl and propyl iodides, heated under pressure. They thus 

 obtained the double salts Sb(C 2 H 5 ) 4 I.HgI 2 and Sb(C 3 H 7 ) 4 I.HgI 2 . 

 By treatment with silver oxide these bodies yielded tetraethyl 

 stibronium hydroxide, Sb(C 2 H 6 ) 4 OH, and the corresponding 

 propyl compound, from which various salts were prepared. — 

 Chem. CentralM., 1900, 1, 1091. h. l. w. 



3. The Atomic Weight of Iron. — This important constant has 

 not been revised since about fifty years ago ; meanwhile analyti- 

 cal methods have been much improved, and the sources of error 

 involved in atomic weight determinations have been more care- 

 fully studied. In view of these facts, Richards and Baxter 

 have made a preliminary series of seven determinations by reduc- 

 ing ferric oxide to metallic iron. Their results show that the 

 previously accepted atomic weight, 56, is somewhat too high and 

 that in all probability the value is very near 55-88. — Zeitschr. 

 anorg. Chem., xxiii, 255. h. l. w. 



4. The Physical Properties of Ccesium. — Eckardt and Graefe 

 have made an elaborate examination of the physical properties of 

 metallic caesium which was prepared by heating pure caesium car- 

 bonate with metallic magnesium in an iron tube in a current of 

 dry hydrogen. The summary of their results is as follows : 



Sp. gr. of liquid Cs at 40° 1-827 



Sp. gr. of liquid Cs at 27° 1-836 



Sp. gr. of solid Cs at 26° 1-886 



Solidifying point of Cs .26-37° 



Conductivity at 27° (Ag=100) 3-63 



Specific heat -04817 



Atomic heat 6-406 



Heat of fusion (for 1 g.) 3*73 cal. 



Contraction upon solidification 2*627 vol. per cent. 



Coefficient of expansion -0003948 



The specific gravity found by the authors corresponds with the 

 value 1*88 previously determined by Setterberg, but it does not 

 agree with the value 2-40003 recently given by Mencke. The 

 latter is probably incorrect, not only in view of the agreement of 



