114 M. Pauli on Phosphuret of Nitrogen. 



has ceased, the residue is taken out of the retort and again heated, 

 the process being repeated as long as sal-ammoniac distils off. 



The residue presents then the form of a powder, light like 

 magnesia. It is insoluble in water and in fuming nitric acid ; 

 fused with caustic potash, it disengages ammonia, and at a red 

 heat is completely decomposed by sulphuretted hydrogen into sul- 

 phide of phosphorus and ammonia. Fused with zinc, it is decom- 

 posed, ammonia being liberated. It therefore contains hydrogen. 



The analytical data gave niimbers which agree with the theory 

 of its being a mixture of phosphuret of nitrogen, PN'"', and phos- 

 phamide, PN^ H. The formation of the latter would be thus 

 expressed : — 



3NH4C1 + PS5=PN2H4-4HS + 3HC1 + NH4S. 



Rose ascribed to phosphuret of nitrogen prepared by the action 

 of ammonia on terchloride of phosphorus, and which has the 

 same properties as Pauh's compound, the formula PN^. But 

 his analyses gave a small constant quantity of hydrogen, which 

 he however neglected. Gerhardt's analyses led to the formula 

 PN'^ H ; and a recent qualitative analysis of a specimen of this 

 compound, which had been prepared by Liebig and AYohler, was 

 found by Schiflf* to contain hydrogen. 



Freseniusf has observed the occurrence, in the water of the mi- 

 neral spring at AVeilbach, of traces of formic and propionic acids ; 

 and Kraut J found in a spring water, butyric and caproic acids. 

 The water was taken from a brook which arose in a marshy neigh- 

 bourhood ; it contained the usual mineral constituents, and an 

 almost equal quantity of organic substances. A special experi- 

 ment showed that the fresh water contained merely traces of 

 caproic and butyric acids, and that the greater or perhaps entire 

 part was formed by the decomposition of the organic substances. 



According to Wohlcr §, molybdic acid may be at once obtained 

 pure and sublimed by heating native sulphide of molybdenum in 

 pieces in a glass tube through which a stream of atmospheric air 

 is passed until the molybdenum is oxidized. 



A new mode of forming silicon has been made known by 

 St. -Claire Deville|| and Caron in a communication on silicon 

 and its alloys. It consists in taking advantage of the solubility 

 of silicon in zinc. 



An earthen crucible is made red-hot, and a carefully prepared 

 mixture of three parts of silico-fluoride of potassium, one part of 



* Liebig's Annalev, March 1857. 



t Jourualfur Prakiische Chemie, January 1857. 



X Liebig's Annalen, July 1857. § Ibid. December 1856. 



II Comptes Rendtts, August 3, 1857. 



