of the University of Pennsylvania. 71 



sufficiently to again permit the flow of gas, which 

 would then pass off, unburnt, through I. This dif- 

 ficulty is obviated by the use of a second gas-jet, J, 



so placed as to re-light the burner I, upon the re- 

 newed passage of gas, and so minute as not to give 

 out sufficient heat to counterbalance that which is 

 lost from the vessel by radiation, etc., during the 



