K>4 Scientific Intelligence. 



as tissue paper, celluloid, gutta-percha, and. glass, while the rays 

 induced in the diamond show much greater penetration and pass 

 through substances a lew millimeters thick. It was found that 

 certain diamonds which phosphoresce after exposure to sunlight 

 or magnesium light, produce no action upon the photographic 

 plate when thus phosphorescing, although the light thus produced, 

 as far as could be judged by the eye, was as great as that induced 

 by the radio-active substance. — Chem. JVeios, lxxxvi, '247. h.l.w. 



3. Radio-active Tellurium. — A short time ago, as noticed in the 

 preceding volume of this Journal (p, 303), Marckwald announced 

 that he had separated the radio-active element (polonium) associ- 

 ated with the bismuth derived from the pitchblende of Joachims- 

 thal. This was accomplished by the electrolysis of the bismuth 

 ehloride solutions, or more satisfactorily by placing rods of pure 

 bismuth in such solutions. Marckwald has now fouud that the 

 element thus precipitated corresponds to tellurium as far as its 

 chemical properties have been investigated. To precipitate the 

 tellurium he now adds to the hydrochloric acid solution of bis- 

 muth a few drops of stannous chloride solution, and, after warm- 

 ing for a few hours, filters off the resulting black precipitate. 

 This has been found to be more active than the product obtained 

 by the other method, while the residual bismuth salt is almost 

 inactive. The amount of tellurium found was very small, scarcely 

 amounting to one ten-thousandth of the bismuth salt used. — 

 Berichte, xxxv, 4239. h. l. w. 



4. Action of Hydrochloric Acid upon Aluminum, Chromium, 

 and Ferric Sulphates. — By dissolving the sulphates under con- 

 sideration in strong hydrochloric acid, Recoura. has obtained, 

 upon cooling the solutions, the compounds AlS0 4 01*6H o 0, CrS0 4 

 C1-6H 2 0, and Fe 2 (S0 4 ) 3 'H 2 S0 4 -8H 2 0. The results show" a marked 

 difference in behavior between the ferric salt and the other 

 sulphates. The chromium compound is interesting from the 

 fact that when dissolved in cold water it gives no immediate 

 precipitate with silver nitrate, although the sulphate radical is 

 entirely precipitated at once by means of barium chloride. When 

 the chromium compound is heated for some time at 85° it loses a 

 molecule of water and changes to CrS0 4 Cl # 5H 2 0. This com- 

 pound also gives no immediate precipitate with silver nitrate, and, 

 moreover, in very dilute solution it gives no precipitate with 

 barium chloride. The results indicate that the chromium salt 

 with six molecules of water holds the chlorine atom in a complex 

 radical, while the sulphate group ionizes, and that the loss of a 

 molecule of water puts the sulphate group also into the complex 

 radical. The aluminum compound is considered by the author 

 as analogous to the first chromium salt, although it shows no evi- 

 dence of the existence of a complex radical upon solution in water. 

 — Bulletin, xxvii, 1155. h. l. w. 



5. Alkali-metal Hydrides. — The fact that Moissan had pre- 

 pared a potassium hydride with the formula KH was mentioned 

 in this Journal last year (vol. xiii, p. 240). This author has re- 



