c 266 3 
XVI. On the action of finely divided Platinum on Gaseous Mix- 
tures, and its Application to their Analysis . By William 
Henry, M. D. F. R. S. 
Read June 17, 1824. 
Several years have elapsed since the President of the Royal 
Society, in the further prosecution of those Researches on 
Flame, which had already led him to the most important 
practical results, discovered some new and curious pheno- 
mena in the combustion of mixed^ gases, by means of fine 
wires of platinum introduced into them at a temperature be- 
low ignition. A wire of this sort being heated much below 
the point of visible redness, and immersed in a mixture of 
coal gas and oxygen gas in due proportions, immediately 
became white hot, and continued to glow until all that was 
inflammable in the mixture was consumed. The wire, re- 
peatedly taken out of the mixture and suffered to cool below 
the point of redness, instantly recovered its temperature on 
being again plunged into the mixed gases. The same phe- 
nomena were produced in mixtures of oxygen with olefiant 
gas, with carbonic oxide, with cyanogen, and with hydrogen; 
and in the last case there was an evident production of water. 
When the wire was very fine, and the gases had been mixed 
in explosive proportions, the heat of the wire became suffi- 
ciently intense to cause them to detonate. In mixtures, which 
were non-explosive from the redundancy of one or other 
gas, the combination of their bases went on silently, and the 
