296 Margueritte and Sourdeval on the Formation of Cyanogen. 



2. When the fulminates of silver or of mercury are treated 

 with alkalies, a cyanate is formed, — a formation due to reduction 

 of the nitro-compound under the influence of the affinity of the 

 alkaline cyanides for oxygen. 



3. The explosive properties of the fulminates would be readily 

 explained by the excessive instability of binitro-ethylene. 



4. Although the group binitro-ethylene is hypothetical, the 

 discovery of the analogous bodies, nitroform, €(NG 2 ) 8 H, and 

 triacetonitrile, € 2 (N9 2 ) 3 N, renders its existence by no means 

 impossible ; and its combination with hydrocyanic acid would be 

 perfectly analogous to the combination of the hydracids with the 

 hydrocarbons. 



MM. Margueritte and Sourdeval* have made a series of 

 researches on the formation of cyanogen, and the production of 

 ammonia by means of atmospheric nitrogen. Their experiments 

 have been made on a large scale, and they state — 



1. That baryta, calcined in the presence of carbon and of 

 atmospheric air, readily assimilates nitrogen and carbon, and 

 that this cyanuration of barium is a very simple operation. 



2. At a temperature of 300° C. cyanide of barium is decom- 

 posed by a current of aqueous vapour, and disengages the whole 

 of the nitrogen which it contains under the form of ammonia. 

 The industrial consequences of these two reactions are the ma- 

 nufacture of the cyanides of barium and potassium, of prussian 

 blue, of ammonia, and of nitric acid and nitrates by known 

 methods. 



The authors add that the methods which they adopt for pre- 

 paring baryta yield this base in such quantity that it may be 

 practically used in the manufacture of sugar. 



Von Hauerf has described some seleniates, and has also mo- 

 dified the methods of preparing selenic acid. Selenium is dis- 

 solved in nitric acid, and the selenious acid is converted into 

 selenic acid by fusing with nitrate of soda. The mixture of 

 seleniate and acetate of soda thus obtained is mixed with a solu- 

 tion of nitrate of lime. The seleniate of lime which forms is 

 almost as insoluble as the sulphate. It is treated with oxalate 

 of cadmium, which completely decomposes it : after filtration 

 from the insoluble oxalate of lime, a current of sulphuretted hy- 

 drogen is passed through the solution of seleniate of cadmium. 

 After filtering the precipitate of sulphuret of cadmium, the solu- 

 tion of selenic acid is freed by heating from excess of sulphur- 

 etted hydrogen. 



* Comptes Rendus, June 11, 1860. 



t Sitzungsberichte der K. Academie der Wissenschaflen zu Wien, January 

 I860. 



