Vol. VI, No. 11.] Reactions in presence of Nickel. 597 



INJB.] 



the characteristic vortex rings of phosphuretted hydrogen were 

 observed in abundance. Silver nitrate solution was imme- 

 diately turned black. The gas did not take fire spontaneously on 

 account of its dilution with a large excess of hydrogen. A wash- 

 bottle containing water should be placed between the exit end 

 of the tube containing the mixture and the delivery tube leading 

 to the pneumatic trough in order to arrest the vapours of sub- 

 liming phosphorous pentoxide. The reduction of the pentoxide 

 seems to be indirect. Blank experiments were performed in 

 which P 2 5 and metallic nickel were heated below dull red heat 

 in a current of carbon dioxide. A portion of the P 2 r sublimed 

 and the remaining mass was found to consist of unchanged nickel 

 mixed with glassy particles of fused P S B , nickel phosphide 

 and a little phosphate (details will appear in a separate paper). 

 As phosphates are not reduced by hydrogen (Fresenius, Zeit. 

 fur anal. Chem. 8, 203; Herapath, Pharm. Journ. and Trans. 

 7, 57), the reduction of P 2 6 in presence of nickel seems to be 

 effected by the reduction of the phosphide formed as an inter- 

 mediate compound. 



