ARTICLE VL 



Upon a new Compound of the Deuto-CMoride of Platinum, Nitric Oxide, and 

 Chloro-hydric Acid. By Henry D. Rogers, Professor of Geology in the Uni- 

 versity of Pennsylvania, and Martin H. Boye, Graduate of the University of 

 Copenhagen. Read November 1, 1839. 



1. When platinum is dissolved in an excess of nitro-muriatic acid, and the 

 solution is slowly evaporated, a yellow powder may sometimes be seen gradu- 

 ally to collect. The nature and properties of this substance we propose to 

 describe in the following paper. 



Mode of Preparation. 



2. The method by which we succeeded in obtaining the compound referred 

 to in quantities sufficient for the investigation of its properties and composition 

 is as follows : — A solution of chloride of platinum, procured in the ordinary 

 way, is evaporated, at a rather low temperature, in a porcelain capsule, nearly 

 to dryness. When it has reached this point, aqua regea, freshly prepared from 

 concentrated hydro-chloric and nitric acids, containing an excess of the former, 

 is added in small portions, the mixture being continually stirred with a glass 

 rod. Nitric oxide gas is given off in thick fumes, and the mixture, which is 

 now perfectly liquid, is allowed again to evaporate for some time, during which, 

 chlorine gas is evolved in numerous small bubbles. It is then transferred to a 

 glass vessel and cold water added drop by drop, the whole being continually 

 stirred while it is cooling. If these steps be properly performed, a yellow pow- 



