Properties of Spongy Platina. 
323 
gravity of platina, to = 16, a cubic inch will weigh 4608 
grains, then — 
1 cubic inch platina precipitated by zinc contains 96.768 
cubic inches oxygen. 
1 cubic inch platina precipitated by sugar contains 172.800 
cubic inches oxygen. 
1 cubic inch platina, process E. Davy 253.440 
When we find the 253 cubic inches of oxygen condensed 
in a cubic inch of platina occupy only a space of 0,25 of a 
cubic inch, it is evident that this platina exercises a conden- 
sing power on it equal to a pressure of rather more than 1000 
atmospheres. 
The ethiops of platina obtained by treating the deutoxide 
of platina, or the combination of this deutoxide with soda, by 
diluted formic acid, reacts in so energetic a manner on alco- 
hol, that this becomes ignited at the moment of contact; its 
inflaming powers are therefore superior to those of the platina 
of Davy; but it does not contain as much oxygen as this 
latter, for ten grains placed in contact with formic acid, af- 
forded only 0.80 cubic inches of carbonic acid. The inflam- 
ing power with which the ethiops of platina is so eminently 
endowed, does not therefore solely depend on the proportion 
of oxygen it may contain, but has some connection with the 
particular form of the molecules of the platina ; those of the 
first are not pulverulent and amorphous, but in a state of ex- 
tremely fine laminae. 
If the ethiops treated with hydrogen be placed in contact 
with atmospheric air, it again absorbs oxygen, if during its 
action on the hydrogen it has undergone no change in the 
aggregation of its molecules, and the quantity thus absorbed 
will be nearly that as shown by the above calculation, it is 
capable of absorbing and condensing. 
When the ethiops prepared by any of the above-mentioned 
processes is digested in tolerably concentrated hydrochloric 
acid, this soon assumes a yellow brown colour, and the mole- 
cules of platina unite in a mass which however has but little 
cohesion. When both are examined, the first will be found 
