260 PROCEEDINGS OP THE AMERICAN ACADEMY. 



platinic hydrate is brought in contact with acid tungstates or molyb- 

 dates in the nascent state. Phospho-platino-tungstates and similar 

 molybdenum compounds appear also to exist. A solution of 24 : 1 : 2 

 phospho-tungstate of sodium readily dissolves platinic hydrate on boil- 

 ing, and gives an orange-colored solution which after filtration and 

 evaporation deposits ill defined orange crystals. When a solution of 

 ammonic chloride is mixed with the solution obtained as above, a beau- 

 tiful orange crystalline salt is thrown down. In a preliminary notice 

 published in 1877,* I have described the preparation and properties 

 of platiuo-tungstates having respectively the formulas 



10 WO3 . PtO, . 4 NaaO 4- 25 aq ; 10 WO3 . PtOa . 4 K2O + 9 aq. ; 

 10 WO3 . PtO. . 4 (NH,). O + 12 aq. ; 



and of a platino-molybdate with the formula 



10 M0O3 . PtOa . 4 NagO + 29 aq. 



All of these tungstate compounds were obtained by boiling 



10WO3.4Na2O + 23aq. 



•with the soluble form of platinic hydrate. The molybdenum compound 

 was obtained in a similar manner, but I am not now able to state 

 what acid molybdate of sodium was employed. I have not succeeded 

 in obtaining these compounds a second time, and in the long interval 

 of time which has elapsed since the publication of my preliminary 

 notice the notes of description and analyses have been lost. I can 

 only express my conviction that more extended investigations will 

 show that no error has been made, and that the compounds unite as 

 described. I will further remark, that, taking the analyses which I 

 have given in this paper, it may be possible to give simpler formulas 

 for some at least of the salts described. The formulas given represent 

 I believe most accurately the results of the analyses, but as the per- 

 centages of platinum are relatively small the quotients of these per- 

 centages by the atomic mass of platinum are very small divisors. Ou 

 the other hand, the quotients obtained by dividing the i)ercentages of 

 tungstic or molybdic oxide by the molecular masses of tungstic or 

 molybdic oxide are relatively very large, and the ratio between the 

 two quotients in question becomes somewhat uncertain. The com- 

 pounds which I have obtained by the method which I have given of 

 bringing platinic oxide in statu nascenti into contact with the solutions 



* Rerichte rler deutschen chem. Gesellschaft, X. 1384. Am. Journ. of Sci- 

 ence, [3.], XIV. 61. 



