CI1KM1STRY. 



batier: also silicon selenide, SiSe f , which is ob- 

 tained I iy heating crystalline silicon to redness 

 in a current of hydrogen selenide. It has the 

 appearance of a fused hard metallic mass in- 

 capable of volatilization. Water reacts vigorous- 

 ly with it, producing silicic acid, and liberating 

 hydrogen selenide. It emits a very irritating 

 odor of hydrogen selenide. 



Sodium amide, Nll,Na. has been prepared by 

 Mr. .loannis in apparently a purer form than the 

 olive-green fusible, substance that was obtained 

 I iy (iay-Lussac and Thcnard. Mr. Joannis ob- 

 tains it in well-defined colorless crystals from 

 the sodammonium of Weyl, which decomposes 

 spontaneously at the ordinary temperature into 

 hydrogen and sodamide. It is, however, pre- 

 jiared in larger quantities and less time by al- 

 lowing saturated water solutions of sodammo- 

 nium and sodium chloride to react upon each 

 other at the temperature of melting ice. When 

 sodamide is thrown into water a lively action 

 occurs, just as if the crystals had consisted of 

 globules of red-hot metal, with a violent hissing 

 and the evolution of water vapor, but of no 

 other gas. 



11 err Jannasch, in collaboration with Herr 

 Vogtherr, has successfully applied to a large 

 number of minerals a process of decomposing 

 silicates in a special platinum apparatus by 

 strong hydrochloric acid under pressure. In ad- 

 dition to silicates he succeeded in decomposing 

 black amphibole or hornblende, cerite, etc. 

 Chrome-iron ore was perfectly decomposed by 

 hydrochloric acid at about 250 C. 



By adding the special ferments obtained from 

 the wines of Ay, Beaune, Chablis, and Barsac, 

 M. G. Jacquenin has obtained fermented liquors 

 having the special bouquet of the wines in ques- 

 tion from malt and from pure solutions. He 

 has also by a similar process produced cider 

 from barley. 



II. N. Warren's improved process for the 

 manufacture of potassium cyanide depends upon 

 the formation of potassium sulphocyanate, the 

 conversion of that substance into potassium cy- 

 anate, and of that into potassium cyanide. 



Experiments have been made in the labora- 

 tory of Siemens and Halske, in Berlin, in the 

 commercial production of ozone. The original 

 Siemens ozonizing tube consisted of two con- 

 centric glass cylinders, the inner one coated in- 

 teriorly and the outer one exteriorly with metal. 

 These two coatings were supplied with an alter- 

 nating current of high potential, while oxygen 

 was made to traverse the annular space between 

 them. It now appears that only one dielectric is 

 neces-ary, mica, celluloid, porcelain, and the like 

 being available as well as glass, and the ozone 

 tube having either a metal tube within and a 

 metal-coated nonconducting tube without, or a 

 metal tube without, while the inner tube is made 

 of the nonconducting material and lined with 

 metal. Metals not attacked by ozone should l>e 

 used. Cold water flows through the inner tube 

 and nir through the ring si 



Atomic freights. A memoir by the late 

 Pmf. Stas has been left, almost complete, de- 

 scribing the results of several stoichiometrical in- 

 vest igiit ions, particularly respecting silver. The 

 validity of the author's former determination of 

 the atomic weight of silver, by which that of oxy- 



gen would be made 15-96 instead of 10, as the 

 advocates of Front's hypothesis would like to 

 have it, was doubted by Prof. Dumas, on the 

 ground that the silver employed WH- not free 

 from occluded atmospheric gases. Prof. Stas 

 then prepared silver of perfect purity, with which, 

 repeating his experiments, he obtained a result 

 identical with his former one. In addition to 

 this important memoir, Prof. Stas has left the 

 data of a series of twelve separate determina- 

 tions of the stoichiometric relatu u of silver to 

 potassium chloride, the materials for which were 

 the pure silver iust mentioned, and a specimen 

 of potassium chloride prepared with equal care: 

 mm also a third memoir relating to the spectra of 

 several metals which he has obtained in the 

 I in rest state in which they were ever probably 

 seen. 



The atomic weight of copper has been redeter- 

 mined by Dr. T. W. Richards, both by investiga- 

 ting the methods by which the old number (63-3) 

 was obtained, and by a new series of determina- 

 tions, in which corrections for former errors were 

 applied. The final mean value obtained was 

 63-604 (oxygen = 16); the maximum and mini- 

 mum values were 63-609 and 63-6 respectively. 

 If the value of oxygen is taken as 15*96, that of 

 copper becomes 63-44. 



The atomic weight of palladium has been re- 

 determined by H. F. Keller and E. P. Smith, 

 who find as the mean value resulting from their 

 most exact experiments, Pd = 106-914. 



The determination of the atomic weight of 

 lanthanum by Bohuslav Brunner at 138-21 

 (O = 16) is identical with the results obtained 

 by Cleve and Bettendorff. 



Chemical Analysis. What has been hereto- 

 fore called amorphous boron has been shown to 

 be a mixture of that substance with large quanti- 

 ties of impurities, formed by the combination of 

 the boron at the moment of its liberation with a 

 portion of the metal used to replace it, and with 

 the substance of the vessel in which the action 

 is performed. Boron has now been obtained by 

 M. Mcissan in almost perfect purity by the 

 action of metallic magnesium on boric anhy- 

 dride. This reaction had teen previously studied 

 by Prof. Winkler, who employed the magnesium 

 in the quantity calculated to remove all the oxy- 

 gen from its state of combination with the 

 boron. M. Moissan shows that with only one 

 third this quantity of magnesium the yield of 

 free boron is much enhanced, and the impurities 

 are only such as can be removed. Two borides 

 of magnesium may be formed, one of which is 

 dissolved by water with evolution of a mixture 

 of hydrogen and boron hydride, while the other 

 is permanent in the presence of both water and 

 acids. It is this stable boride, which the author 

 has obtained in good crystals, which is so diffi- 

 cult to remove from the substance hitherto con- 

 sidered amorphous boron. 



In the estimation of uusaponifiable matter in 

 fats, Mr. William Mansbridge uses benzoline 

 boiling at 110 F. as a solvent instead of the 

 usual ether. Except in the case of pure wool 

 fat he finds a tolerably close agreement between 

 the results obtained by this process and those 

 arrived at bytitration; hence it is indicated 

 that for practical purposes simple titration. even 

 with unknown greases of low quality, gives a near 



