418 Dr. Henry on the Action of [Juhe, 



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 

 luore decided action upon the latter, manifested by an increased 

 production of carbonic acid. Thus, for example, the explosive 

 mixture being to the olefiant as 2-i^ to 1, about one-fourth of the 

 olefiant gas was consumed ; and by increasing the proportion of 

 the explosive mixture, the olefiant gas was still more acted upon. 

 On using oxygen sufficient to saturate both the hydrogen and 

 the olefiant gases, the ball acted much more rapidly ; in several 

 instances it became red hot ; all the hydrogen was consumed ; 

 and the whole of the olefiant gas was changed into water and 

 carbonic acid. In this case the use of the sponge is inadmissi- 

 ble, as it kindles the gases, and occasions their detonation. 



2. Mixtures of Hydrogen and Carhurcttcd Hydrogen Gases with 



Oxygen. 



When carburetted hydrogen, procured from stagnant water, 

 was added to an explosive mixture, in various proportions be- 

 tween equal volumes, and ten of the former to one of the latter, 

 the action of the hydrogen and oxygen on each other took place 

 as usual, on admitting one of the balls. When, reversing the 

 proportion, the explosive mixture wa.5 made to exceed the car- 

 buretted hydrogen, but not more than four or five times, the 

 latter gas was entirely unchanged. AVith a larger proportion of 

 the explosive mixture carbonic acid was always found to have 

 been produced; but still the carburetted hydrogen vi'as very 

 imperfectly consumed, and fully three-fourths of it were gene- 

 rally found to have escaped unburned. 



When, to a mixture of hydrogen and carburetted hydrogen, 

 oxygen enough was added to saturate both gases, the eftect of 

 the sponge was found to vary with the proportion of the simple 

 hydrogen. In several cases, where the hydrogen did not exceed 

 the carburetted hydrogen more than four times, the latter gas 

 remained unchanged ; when in larger proportion, there was a 

 decided action upon the carburetted hydrogen. But it was 

 much more easy to regulate the action of the balls upon such a 

 mixture, so as to act upon the hydrogen and oxygen only, than 



