gaseous mixtures , and its application to their analysis. 2 6g 
SECTION I. 
ON THE ACTION OF FINELY DIVIDED PLATINUM ON GASEOUS 
MIXTURES AT COMMON TEMPERATURES. 
I. Mixtures of Hydrogen and Olefiant Gases with Oxygen. 
When to equal volumes of olefiant gas, and an explosive 
mixture (which is to be understood, whenever it is so named, 
as consisting of two volumes of hydrogen and one of oxygen 
gases) one of the platinum balls, recently heated by the 
blow-pipe, and allowed to cool during eight or ten seconds, 
is introduced through mercury, a rapid diminution of volume 
takes place; the whole of the hydrogen and oxygen gases 
is condensed; but the olefiant gas is either not at all, or very 
little acted upon. In a few experiments, when the tube was 
narrow, and the quantity of mixed gases small, the olefiant 
gas escaped combustion entirely ; but, in general, an eighth 
or tenth of it was converted into water and carbonic acid. It 
is difficult, however, to state the precise proportion of any 
gas which, when added to an explosive mixture, renders the 
latter insensible to the action of the balls or sponge ; for 
much depends on their temperature when introduced into the 
gaseous mixture, the diameter of the containing vessel, and 
other circumstances, which, in comparing different gases, 
should be so regulated as to be equal in every case. 
When the proportions of the gases are changed, so that 
the explosive mixture exceeds in volume the olefiant gas, 
there is a more decided action upon the latter, manifested 
by an increased production of carbonic acid. Thus, for ex- 
ample, the explosive mixture being to the olefiant as 2^ to 1, 
