360 
CHEMICAL PRINCIPLES. 
Oxides 
tiau. 
of pia- position ; but 1 obtained it by decomposing the double muriate 
of the oxide plarinic and ammonia in a small retort, 'The 
double muriate ot the oxidule followed the gaziform pro- 
ducts, and was condensed in the receiver, mixed with mu- 
riate of ammonia, from which I separated it by means of 
water. It inay also be obtained by exposing the double muriate 
of the platinic oxide to nearly a red healj for the double 
muriate of the oxidule is always formed before the platiua is 
reduced. The muriate forms an insoluble powder whose 
colour is composecj of yellow, grey, and green. It suffers no 
alteration from the concentrated acids; neither does the caustic 
alkali detach any ammonia from it. But when heated in a 
retort to a red heat, it is decomposed and yields water, muriatic 
acid, muriate of ammonia, and metallic platina. 
The platineous oxide detonates sharply with burning char- 
coal ; but the muriate of the oxidule remains undecomposed 
by charcoal only, although it will burn briskly if some sugar 
or other substance containing hydrogen be added, exactly as 
we know to be the case with the muriatic acid. 
For determining the proportions of the component parts of 
the platineous oxide I adopted the following method, I made 
some platineous muriate very dry and then decomposed it 
by heat in a crucible of platina nicely weighed. I after- 
wards repeated the same experiment in a retort, in order to * 
ascertain whether the muriate contained any water of combina- 
tion. But it gave out only oxymuriatic gas. Ten grammes 
of the platineous muriate left a residuum of 7,33 gr. of me- 
tallic platina. But we know that oxymuriatic gas is composed of 
100 parts of dry muriatic acid, and of 29, 454 parts of oxigen gas. 
The muriate consists, therefore, of 
Oxidule of platina / r3<^'cal 73,300 _ 79,375 
\ oxygen 6,075 ^ 
Muriatic acid 20,675 
Whence it follows that the oxidule should be composed of 
Platina 92,35 100,000 
Oxygen 7,65 8,287 
(h.) Oxidum Platinicum. I digested 20 grammes of mer- 
cury. 
