On some Combiiiaiions of Platinum. 331 



volumes of a stroiie; aqueous solution of the sulphate, and alco- 

 hol ; and, after agitatins; the mixed fluids, the phial was put 

 aside. Some weeks aftciwards, I found the dark colour of the 

 sulphate had entirely disappeared, a dense black substance had 

 subsided, and the supernatant fluid remained colourless and 

 transparent. On opening the phial, an odour similar to that 

 of ether was perceived, the fluid had a strong acid taste, and 

 afforded a copious precipitate with nitrate of bar\ tesj After the 

 black substance had been well washed and dried, a few prelimi- 

 nary experiments served to show that it was a peculiar coni- 

 pound which had not been noticed. To confirm these results, 

 and procure more of the substance, I repeated the experiment 

 with the sulphate and alcohol. In about two days the fluid as- 

 sumed a darker tint, the black substance began to precipitate in 

 a finely divided state, and in about a week it had all subsided, 

 leaving the fluid colourless and transparent. I afterwards found 

 that the substance in question may be readily obtained by boiling 

 the sulphate and alcohol * together for a few minutes; it sepa- 

 rates in small particles, leaving the supernatant fluid colourless, 

 or with only a slight tinge of yellow. In cases when it is thus 

 procured, a little volatile inflammable fluid, having a peculiar 

 ethereal smell, is also obtained. The substance, after being 

 washed till the water is tasteless and does not affect litmus pa- 

 per, and dried at a temperature of about 250' Fahrenheit, exhi- 

 bits the following properties. 



2. Properties of Ike peculiar Compound. 

 The substance is of a black colour, and in small lumps, which 

 are soft to the touch, and easily reduced to an impal})able pow- 

 der. It readily soils the fingers, or paper. It is destitute of 

 lustre. It is tasteless, and apparently unaffected either by cold 

 or hot water. It has a peculiar ethereal smell that is not easily 

 removed, and probably arises from the presence of a little in- 

 flanmiable matter occasioned by the action of the alcohol. It 

 seems to undergo no change by exposure to the air for some 

 time. When it is gently heated, on a slip of platiiunn or paj^er, 

 a hissing noise or a feeble explosion is produced, and this effect 

 is accompanied bv a flash of red light, and the platinum is re- 

 duced. It is insoluble in nitrous, sulphuric, and phosphoric 

 acids ; but it dissolves slowly in muriatic acid. It is scarcely 

 aO'ected by chlorine, except moisture be present, when a little 

 muriate is gradually formed. When the powder is put into li- 

 (juid ammonia, minute globules of air are evolved from it, and 



• The alcjhol used in tliis experiment may vaiy considerably in its 

 strenjjtii and quimtily, without mateiiiilly iiiTccting the results. Ether may 

 also be employed as a substitute for alcohol. 



T t 2 after 



