On some ComUnatmis of Platind. 273 



expelled, and the platina remains in a pure «tate. When it 

 IS exposed to a red heat in close vessels, chlorine gas is oh- 

 tained and metallic platina. It is scarcely affected by test 

 murialic acid at the common temperature, bat when boiled 

 in this acid, a portion of it is dissolved ; the solution is oF a 

 vellowish-brown colour, and when evaporated to dryness 

 affords a dark-brown substance. This variation of colour 

 is probal)l\' unconnected with anv chemical chaiiiie, and 

 depends merely on its state of aggreii;ation. It is sliiihtly 

 soluble in diluted murialic acid at a boiling heat. Strong 

 nitro-muriatic acid appears to dissolve only a small quantity 

 of it. It seems to be insoluble in nitric, sulphuric, phos- 

 phoric, and acetic acids at all temperatures. Nor is the 

 agency of these acids on it attended bv any thing worthy 

 of notice. When it is boiled in a strong solution of pure 

 potash or soda, a black powder is obtained, which, as I have 

 already stated, furnishes oxygen gas and chlorine by heat. 

 When it is digested in pure ammonia, it is partially dis- 

 solved ; the clear solution, when evaporated to dryness on 

 glass, leaves a very delicate and pretty coating of platina, 

 which on being heated to redness becomes permanent. 

 When platinana is heated with sulphur or phosphorus, sul- 

 phurane and phosphorane, togevher with sulphuret and 

 phosphoret of platina are formed. It is unaffected when 

 heated in chlorine g.is. ft appears to be nearly insoluole 

 in alcohol and ether. When it is beared with red precipi- 

 tate, calomel, oxveen, mercury, and platina are the results. 



The precedno; statements seem to furnish distinct evi- 

 dences of the constitution of this substance; that it is 

 compounded of chlorine and platina. Its direct formation 

 in chlorine gas, the results of its decomposition in close 

 vessels, the products it affords with sulphur and phos- 

 phorus, arc decisive as to this point. Plaiinana appears to 

 be the (m'y combination of chlorine and a metal yet ex- 

 amined, which affords its elements in their simplest known 

 forms by the mere agency of heat out of the contact of air: 

 the combination of gold and chlorine is analogous in this 

 respect. 



Analysis. 

 The composition of platinana cdnld not be accurately 

 determined by synthesis. Its decomposition in the at- 

 mosphere, in close vessels, and bv sulphur, aflords ample 

 means of determining the proportions of its constituent 

 part-* ; and from a comparison of experiments made in each 

 of the<c ways, I shall venture to state its conipo'^ition. In 

 my first exper.mtnts on a compound of this kind, which 



Vol. 40. No. I yi. Ocr. 1 SI 2. S were 



