180 Prof. Daniell and Dr. Miller on the 



The liquid from the zincode cell was carefully neutralized 

 with nitric acid, and then gave a copious yellow precipitate 

 with nitrate of silver, soluble in nitric acid, and in ammonia, 

 the well-known characters of the tribasic phosphate of silver 

 (3AgO, P2O5). The solution in the platinode cell had be- 

 come much more alkaline than at first, but when neutralized 

 with nitric acid, gave a similar yellow precipitate with nitrate 

 of silver. There could be no doubt therefore that tritoxy- 

 phosphion (or the radicle of the tritohydrate of phosphoric 

 acid) had travelled to the zincode. The experiment was more 

 than once repeated with unvarying results. 



[h.) A solution o^ tribasic phosphate of soda (SNaO, P2O5) 

 (sub-phosphate) was substituted in the same arrangement for 

 the rhombic phosphate, and, after the action of the battery, on 

 neutralizing the liquid in the zincode cell, a similar copious 

 yellow^ precipitate was obtained from nitrate of silver. 



(c.) To complete the series of tribasic phosphates in which 

 different bases are substituted for each other, a solution of the 



NaO 

 phosphate of soda^ ammonia and*mater I NH4 0[P2 05 1 (mi- 



(NaO ^ \ 



NH4O P2OJ 

 HO J / 



crocosmic salt), was subjected in the same manner to electro- 

 lysis, the zincode cell being charged with solution of soda ; 

 the solution in the zincode cell became acid to the test of lit- 

 mus, and produced an abundant yellow precipitate in solution 

 of nitrate of silver ; proving that it was the tribasic acid which 

 had travelled as before. 



(f/.) A similar arrangement was made with a solution of rZ/- 

 ias?V 7?^os/?Aa^e (pyrophosphate) of soda (2NaO, Pg O5). Hy- 

 drogen and oxygen in equivalent proportions were respectively 

 given out at the platinode and zincode, and the process was 

 carried on to the same extent as before. The solution at the 

 zincode after electrolysis was neutralized by nitric acid. When 

 tested with solution of nitrate of silver, a copious white preci- 

 pitate was formed, indicating that in this case deutoxyphosphion 

 (or the radicle of the deuto-hydrate of phosphoric acid) had 

 been transferred to the zincode. 



{e.) A solution of monobasic phosphate (NaO, P^ O5) (me- 

 taphosphate) was subjected to electrolysis under the same cir- 

 cumstances. The solution in the zincode cell was now found 

 to be strongly acid instead of alkaline ; when added to a solu- 

 tion of albumen it immediately coagulated it; and with nitrate 

 of silver and nitrate of baryta it produced the characteristic 

 gelatinous white precipitates, which are distinctive of the mo- 

 nobasic phosphates of those bases. 



It was thus fully established by these experiments, and con- 



