54 M. Pouillct o7i the Electricity of Elastic Fluids. 



and uncertain. It is the same when the flame passes to the 

 interior of the spire, and in the direction of its own axis. 

 Therefore, around the apparent flame of the hydrogen there 

 is a sort of atmosphere more than 10 millemetres in thickness, 

 which is always charged with vitreous electricity. Since vi- 

 treous electricity is developed in the phenomenon of combus- 

 tion, it follows that there must be some part which has resi- 

 nous electricity, which we shall now try to discover. As it 

 does not appear in any points outside of the flame, we must 

 try to penetrate into the interior, avoiding as much as possible 

 the exterior outline, which always gives vitreous electricity. 

 To do this, it is sufficient to take a spire of a small diameter, 

 and to place it in the middle of the flame in such a manner, 

 that it is enveloped on all sides ; in this way, indeed, the 

 condenser is charged again, but the flame now gives it re- 

 sinous electricity. Thus both the inside and outside of the 

 flame are in opposite electrical states ; the outside is always 

 vitreous, and the inside always resinous. It follows from this 

 that there is a layer of the flame where the electricity is no- 

 thing, and, indeed, if we plunge the spire in such a manner 

 that it penetrates nearly one-half into the bright part of the 

 flame, all electrical indications disappear. Here then is a very 

 striking analogy between the combustion of hydrogen and that 

 of charcoal. Certainly, in all the thickness of this exterior at- 

 mosphere, where we find vitreous electricity, the combination is 

 not made, for the hydrogen cannot arrive there. It is necessary, 

 then, that this electricity which we observe is an electricity 

 communicated, and from whence can it come, if not from the 

 combustion itself, or rather of the oxygen which is predomi- 

 nant on the outside, and which envelopes, in some measure, 

 all the jet of hydrogen ? 



It follows, then, that this oxygen which is combined, disen- 

 gages vitreous electricity, which communicatesitself to the neigh- 

 bouring strata of air, raised to a sufficiently high temperature 

 to perform the office of a conducting body ; and, in like man- 

 ner, in the interior of the flame, it is the hydrogen which is in 

 the greatest proportion ; and since we find the resinous electri- 

 city, it must be disengaged from the hydrogen which burns, and 

 which it communicates to the excess of hydrogen which is not 



