On some Combinations of Platina. 2C7 



washed with distilled water and dried, it weicrhed e-^a^ths 

 grains. It was of a brown colour. It was exposed to a red 

 heat in a small retort over mercury, but no gas came over. 

 It was now of a blackish colour, and in the form of small 

 grains. It had a strong saline taste resembling muriate of 

 liitie, and deliquesced by exposure to the air for a verv short 

 time. It seemed to be a compound of muriate of liuie and 

 muriate of platina, but I did not examine it minutely. 



I varied these experiments, and occasionally repeated 

 them at different times with similar results. ! also n^ade 

 many other experiments to procure the pure oxides of pla- 

 tina ; but as they were unsuccessful, I shall merely relate 

 fiuch of them as furnish some novelty of result. 



1 heated potassium with platina, in a finely divided state, 

 in a small platina tray ; the poiassiun) entered into vivid 

 ignition, and a yellow insoluble substance was formed, 

 which furnished oxygen gas when heated : but thonsh it 

 had been well washed vi'ith distilled water, it still exhibited 

 distinct traces of the presence of alkali after beinir lieated. 

 The quantity I procured of this substance was too minute 

 to determine its component parts ; it seems to be a com- 

 pound of oxide of platina with potash. It appears very 

 likely that the pure oxide f)f platina might be procured 

 from this substance by particular treatment. 



The potash muriate of plaiina, when heated with finely 

 povvdertd caustic lime, furnishes oxygen gas, muriate of lime, 

 and a black powder v\ hich yields ox\ gen gas by heat, and ap- 

 pears to beal^lack oxide with probably a little inetallic platina. 



The insoluble compound of chlorine and platina, when 

 boiled for some time with a strong solution of caustic soda, 

 affords a black powder, which, when well washed and dried, 

 furnishes oxvgcn gas and chlorine bv heat, and seems to be 

 a mixture of black oxide of platina with that insoluble 

 compound. 



At the suggestion of Professor Rerzelius, I digested some 

 of the insoluble compound of chlorine and platina, in a 

 strong solution of caustic potash, for a considerable lime, 

 at a moderate heat. A black powd?r was obtained ana- 

 logous to that from soda, but it v.-as not a pure oxide; it 

 furnished both oxvucn and chlorine bv heat. This distin- 

 guished chemist has recently made some interc«.ting ex- 

 periments on (he oxides of platina, which I presiuTie will 

 soon be published : he has determined from calculations the 

 proportions of oxygen they contain ; but I believe he has 

 pot obtained these oxides in a state of p>irity. 



Whilst I was engaged m these incjuiries, my friend 



Mr. 



