On some Comlmations of Platina. 275 



poiiiided at a red heat in a platina crucible, and afforded 

 7*2 grains of platina ; probably, a little moisturemight have 

 occasioned the slight difference in this experiment. ♦ 



All these experiments very nearly agree : as the second 

 and third aflord the saine results by different methods, 

 ihey appear to merit most confidence. Hence, 100 grains 

 of platinana consibl oF 7-"5 platina 

 *27"5 chlorine 



i 



100 



5. Of I he simple Salts of Platina. 



Scanty as our information is concerning- the salts of pla- 

 tina, it will nevertheless be confined within still narrower 

 limits, when what is erroneous in rhe statements of che- 

 mists is corrected. An acquaintance with the oxides of 

 platina ou^ht surely to precede a knowledge of their com- 

 binations with acids. If what has been staled in the pre- 

 ceding pages is correct, we have as yet no accurate infor- 

 mation relative to the oxides of platina in a pure or sepa- 

 rate state. 



What is supposed to be known concerning the simple 

 salts of platina, is principallv derived from the experiments 

 of Mr. Chcnevix on the subject. He states the composi- 

 tion of a sub-nitrate, an insoluble sulphate, and an insolu- 

 ble muriate of platina. The sub-nitrate of Mr. Chcnevix 

 is said to have been obtained, by precipitating pUuina from 

 its acid solution by lime, redissolving the precipitate in 

 nitric acid, and evaporating to dryness. This experiment 

 1 carefully repeated two or three times, but without wit- 

 nessing similar results. I only procured a minute quantity 

 of a triple compound, as I have already stated. When a 

 solution of platina in nitro-muriatic acid is evaporated to 

 dryness, and afterwards exposed to a pretty elevated tem- 

 perature, the greater j)art of the nitric acid is expelled : by 

 raising the heat still higher, it is entirely driven off, and a 

 compound of chlorine and platina remains, which cannot 

 be decompounded by nitric acid. No nitrate of platina 

 can be produced by the direct agency of nitric acid on this 

 metal ; the nitro-mui:iate or nmriate of platina, cannot be 

 decomposed by nitric acid, nor the muriatic acid separated 

 by nitrate of silver, or by any other method that I am ac- 



* I have since- operated on a iniicli laff^er quantity, .ind obtained almost 

 precisely the same results: 71 grains of platinana, vviiich liad beon drying 

 on a sand-bath for more than a forinif^ht, were dcccni])0!>cd at a red heat 

 in a platinM crucible, atid furniibcd S)S grdim of platjua. 



S 2 quainted 



