154? Prof. Dobereiner’s Account of some Properties of 
monia, leaves a suboxide of platina, containing only ^th per cent, 
of oxygen, and that suboxide has the property of being reduced 
with detonation into the metallic state, if brought in contact with 
a small portion of alcohol. It is some time since I have shewn, 
in the Annalen der Pliysik^ that this detonating platina disposes 
the alcohol to attract oxygen, by which it is converted into a 
mixture of acetic acid and water. I have since found the same 
property in the oxide of sulphuret of platina, which is obtained 
by exposing the dry sulphuret of platina for several weeks to the 
influence of the atmosphere. In this remarkable change, 1 atom 
of alcohol (r= 4?6) attracts 4? atoms of oxygen (=: 4? x 8 — 32), and 
forms thus 1 atom of acetic acid (== 51) and 3 atoms of water 
(=3x9 =S7). The relative quantity of water and acetic acid is 
here exactly the same as in crystallised acetate of lead {Saccha- 
rum saturni) and in the subacetate of copper. In the acetate of 
soda the quantity of the water is double that of either of these 
salts. 
During the last v/inter, I tried a number of experiments rela- 
tive to the action of the two preparations of platina upon several 
expansible bodies, of which the following are the most remark- 
able. 
The suboxide of platina and the oxide of the sulphuret of 
platina do not absorb either oxygen or carbonic acid gas, but 
they absorb whatever combustible gas is brought into contact 
with them. One hundred grains of the suboxide of platina ab- 
sorb from 15 to 20 cubic inches of hydrogen gas ; and during 
this process, so great a quantity of heat is developed, that the 
metallic substance becomes red-hot, and the hydrogen gas de- 
tonates, if previously mixed with atmospheric air, or with oxy- 
gen gas. 
The platina thus charged with hydrogen greedily absorbs a 
portion of oxygen, as much as will suffice for the formation of 
water ; if brought in contact with less than the portion of atmo- 
spheric air required for this purpose, the hydrogen combines 
with part of the azote, and forms ammonia. During this process 
the platina is perfectly reduced to a metallic state, and loses the 
property of decomposing alcohol ; but it retains that of dispos- 
ing a mixture of oxygen and hydi’ogen to combine and form 
water, which is attended with an incandescence of the platina, if 
