combinations of platinum. ng 
(a) Examination of the gas. 
The gas remaining in the retort made an ignited piece of 
wood glow brighter; that which came over (deducting the 
common air) was of a cubic inch, which diminished to-j^ 
on being transferred to water and agitated. of the un- 
absorbed gas, on being mixed with an equal volume of pure 
hydrogen and fired by an electric spark, diminished to -p^. 
Hence, the unabsorbed portion of gas contained more oxygen 
than could have been furnished from the common air of the 
retort. 
From other experiments, the gas absorbed by water was 
found to be carbonic acid ; it rendered lime water turbid, was 
absorbed by ammonia, and again disengaged by muriatic 
acid. 
(b.) Examination of the fluid. 
The fluid which rose in the neck of the retort reddened 
litmus paper, and resembled the nitrous acid in odour, colour, 
and taste. It acted upon the mercury in contact with the re- 
tort, and when washed out by pure water, the solution did 
not affect the nitrate of barytes, or silver. 
(c. ) The platinum was perfectly reduced, and its particles 
formed a loosely coherent mass, which could not be removed 
until the bulb of the retort was broken. It weighed 9^ grains, 
and suffered no diminution on being again heated to redness 
in a platinum cup. 
Experiment 2. Ten grains of the same powder as that 
used in the first experiment, afforded by its decomposition 91- 
grains of platinum, a little fluid agreeing in its properties 
with that noticed in the former experiment, and of gas, 
which was examined in a different manner from that of Ex- 
periment 1. The gas remaining in the retort, was treated 
MDCCCXX. Q 
