Explosion of Hydrogen and Oxygen. 107 



was screwed into the tube, the mixed gases were condensed in 



the globe by a syringe, until on opening the stop cock they is- 

 sued out with considerable velocity. The globe thus charged 

 Was again placed in the open air, with arrangements for igniting 

 the gases as they issued from the jet and for protection, should 

 explosion occur. They were ignited without explosion, and con- 

 tinued to burn quietly. The experiments were repeated with 

 different proportions of the gases and under different pressures, 

 always without explosion. 



The safety of the tube had thus been severely tested, and there 

 was apparently no cause to apprehend accident, so that I saw no 

 objection to exhibit it to my class in connection with the usual 

 illustrations of the properties of hydrogen gas and the compound 

 blow-pipe. Accordingly, two bladders, filled as before, were at- 

 tached to the two ends of the tube, the stop cocks opened, and 

 one bladder being fired, the other did not explode. This latter, 

 by applying a flame to an orifice and exploding it, was afterwai'ds 

 proved to have retained the mixture. 



A few days after this, I exhibited the gases burning at the jet 

 on the copper globe, to several gentlemen who happened to visit 

 the laboratory J and subsequently employed the same apparatus, 

 filled with the mixed gases, before the audience usually attend- 

 ing the lectures at the Cambridge Lyceum. It was used as a 



pipe 



focus 



Drummond. No accident or inconvenience occurred. On the 



as 



was 



It may be thought that unnecessary precaution was taken to 

 ascertain the safety of an apparatus that had come to us with the 

 sanctions I have already alluded to ; but we cannot be too care- 

 ful in experiments of danger, especially with new apparatus, and 

 when made in this country from description only, and by artists 

 not always aware of its applications, or not prepared to put it to 

 the test to which such instruments are usually subjected by the 



best English makers.* 



* An instance occurred under my own observation a few years emce, where a 

 person was compressing air into a copper globe, made in this vicinity, when it 

 burst, wounding the operator very severely in the hand and face. 



