16 Mr. Nicholson on the 



which lead to the formula 



HO, CiaH^N, HO, PO5, 



as is seen by the following : — 



12 eqs. Carbon 900-00 39-44 39-22 



9 ... Hydrogen 112-50 4-93 5'56 



1 ... Nitrogen 177-01 7'75 



2 ... Oxygen 200-00 8-77 



1 ... Phosphoric acid .^ . . 892-28 39-11 38-85 

 1 ... Pyrophosphate of aniline 2281-79 100-00 

 This salt corresponds to the acid pyrophosphate of soda, 

 NaO, HO, PO5, 



analysed by Professor Graham. 



An analogous salt of ammonia is not known, pyrophosphate 

 of ammonia existing only in solution, which, accoi'ding to 

 Graham's experiments, yields on evaporation crystals of the 

 common phosphate of ammonia, with 2 equivalents of the 

 volatile alkali and 1 equivalent of water. 



III. Metapiiosphate of Aniline. 



I obtained this salt by adding a great excess of aniline to a 

 very strong solution of metaphosphoric acid (glacial acid per- 

 fectly pure), or by adding metaphosphoric acid to a solution 

 of aniline in alcohol or aether; in both cases the salt precipi- 

 tates as a gelatinous white mass ; this is to be placed on a 

 filter and well-washed with aether, until the excess of aniline 

 is removed and no smell of this body perceived, pressed and 

 dried over sulphuric acid in vacuo. 



When dry the salt appears as an amorphous white mass, 

 which changes rose-red in the air, becoming glutinous. It is 

 acid to litmus paper, soluble in water, and almost insoluble 

 in alcohol and aether. 



Its solution dissolves metaphosphate of silver, which pro- 

 perty belongs also to metaphosphate of soda ; upon boiling, 

 it changes red, and partly reduces the silver salt. When an 

 aqueous solution is boiled for a long time it is transformed 

 into common phosphate of aniline. 



Analysis. 



When burnt with oxide of copper — 



I. 0-Gfi4 grm. of the substance gave 0*976 grra. of carbonic 

 acid and 0-2fi4 grm. of water. 



II. 0-994 grm. of the substance, precipitated by acetate of 



