356 On some Comlinaiions of Plaiina. 



chlorine, and have been distinguished by the terms potas'n 

 nuiriate of platina, boda muriate of platina, &c. 



In making the details connected with the brief examina- 

 tion of the new triple compounds I have procured, I shall 

 adopt a similar method of nomenclature. Thus, the triple 

 compounds obtained by the agency of the afkalies on sul- 

 phate of platina, will be denominated potash sulphate of 

 platina, soda sulphate of platina, &c. 



If these names are cumbrous and unphilosophical, they 

 cannot be said, like the preceding ones, to convey false 

 ideas, and they are sufficiently significant to answer the 

 purpose of description. 



8. Of Potash Sulphate of Platina. 

 This compound is obtained by neutralizing an aqueous 

 solution of sulphate of platina with a solution of pure 

 potash, and boiling the whole for a few minutes ; by this 

 means all the platina is precipitated in combination, as a 

 dark brown substance, and the fluid remains colourless. — 

 After being well wa'^hed with distilled water, and dried for 

 some hours at a temperature not exceeding 212^ Fahrenheit^ 

 it exhibits the following properties. 



Physical and Chemical Properties. 

 Its colour is black or very dark brown : it is in small 

 grains, and has somewhat the appearance of gunpowder. 

 It has considerable lusire reseml)ling blende, or pulverized 

 pit coal. — It has a harsh feel. It is tasteless, and insoluble 

 in water. The atmosphere appears to produce no changes 

 on it. It is not affected by boiling nitric acid. Nitro- 

 muriatic acid exerts very little action on it, even at a boiling 

 heat, yet it is readily soluble in boiling muriatic acid. The 

 presence of nitric acid seems entirely to suspend the agency 

 of muriatic acid on it ; for, after a part of it is dissolved in 

 muriatic, the addition of nitric acid prevents any further 

 effect. The muriatic solution when boiled to dryness, and 

 heated, furnishes the insoluble compound of platina and 

 chlorine and muriate of potash. The potash sulpliate of 

 platina is insoluble in boiling sulphuric, pho.sphoric and 

 acetic acids. Ammonia produces no effect on it. When 

 it is boiled in a strong solution of pure potash, no apparent 

 change is produced ; but when the solution is boiled to dry- 

 ness and heated, two distinct compoimds appear to be 

 iurmcd: one similar to the potash muriate of platina of a 

 yellow colour, the other of an olive colour, analogous to the 

 su!)stance obtained .when that body is heated to redness in 

 close vessels. 



It 



