September 27, 1901.] 



SCIENCE. 



485 



voted to it. Pupils who show sufficient 

 ability are encouraged to take up quantita- 

 tive analysis or assaying, this work being 

 done in the afternoons without credit, as 

 these are not regular courses. 



13. ' Notes on the Chlorides of Ruthe- 

 nium' : Jas. Lewis Howe. 



Claus described double chlorids of triva- 

 lent ruthenium of the type 2XCl,Ru'"Cl3, 

 and also those of what he considered to be 

 the tetrachlorid of the type 2XCl,RuCl,. 

 These last Joly showed to be nitroso-chlo- 

 rids of the type 2XCl,RuCl3NO. Antony 

 has recently succeeded in forming a true 

 tetrachlorid, 2KCl,RuCl^, by the solution 

 of potassium ruthenate, K^RuO^ in dilute 

 hydrochloric acid. 



When ruthenium tetroxid, RuO^, is 

 treated in the cold with a strong solution of 

 cesium (or rubidium) chlorid and a few 

 drops of hydrochloric acid, it is gradually 

 convertedin to a salt of a new series, csesium- 

 (or rubidium) oxy-chlor-ruthenate, 2CsCl- 

 RuOjClj, which is instantly decomposed by 

 water. On treatment with strong hydro- 

 chloric acid this is converted into the tetra- 

 chlorid (chlor-ruthenate), 2CsCl,Ru'^Cl^. 

 In most of its reactions it closely resembles 

 the ordinary trichlorid. 



This ordinary trichlorid has the formula 

 2CsCl,Ru'"Cl3,H,0, but numerous other 

 salts exist with varying proportions be- 

 tween the ruthenium trichlorid and the 

 alkaline chlorid. 



When the tetrachlorid is warmed in di- 

 lute acid solution with alcohol, rose prisms 

 are formed of the same formula as the ordi- 

 nary trichlorid, but this salt is very distinct 

 in its properties and may be an aqua-tri- 

 chlorid, 2CsCl,RuOH,Cl3. This gives the 

 tetrachlorid again with strong hydrochloric 

 acid. 



The blue solution produced by the^action 

 of H^S on ruthenium solutions can also be 

 obtained by electrolytic reduction, and is, 

 when concentrated, precipitated by caesium 



chlorid, but the precipitated salt has not 

 yet been obtained in a state of purity. It 

 seems to have the formula 3CsCl,2Ru"Clj,- 

 2IIjO, but is receiving further investiga- 

 tion. 



After treatment with stannous chlorid, 

 ruthenium trichlorid gives a yellow floccu- 

 leut precipitate with caustic potash. This 

 is soluble in hydrochloric acid, from which 

 there crystallize brilliant yellow octaedra, 

 containing tin, ruthenium and chlorin. 

 These are being investigated. 



This paper will be published in the Jour- 

 nal of the American Chemical Society. 



14. ' On the Existence of a New Ele- 

 ment associated with Thorium ' : Chas. 

 Baskerville. 



Pure thorium salts obtained from five 

 sources were repurified and fractioned first 

 by sulphur dioxide and second b}^ variation 

 in the solubility of the citrates. Three evi- 

 dences of the complexity of thorium were 

 offered. 



1. Pure thorium dioxide has a specific 

 gravity of 10.2. This was fractioned, giv- 

 ing oxides having specific gravities of 9.25 

 and 10.53. This corroborates Brauner's 

 work on the hydrolysis of the heptahydrated 

 thorium tetrammonium oxalate. 



2. Thorium dioxide is slightly radio- 

 active. Crookes has recentlj'^ found b}' 

 fractioning pure thorium nitrate that one 

 fraction was three times as active as the 

 other. The author has found the radio- 

 activity to increase with the increase of spe- 

 cific gravity of the oxides. The oxide having 

 the lower specific gravity is inactive. De- 

 scription of methodsof procedure weregiven. 



3d. Pure thorium tetrachloride was pre- 

 pared and the atomic weight of thorium de- 

 termined. 223.25 ± .05 was the value found, 

 which is given tentatively. The generally 

 accepted atomic weight is 232.6. 



These evidences prove the complexity of 

 thorium and from some data already ob- 

 tained the new body appears to have an 



