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 
low-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 afterwards 
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 ; 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 
compound blow-pipe, and particularly for obtaining the intense 
light from lime in the focus of a reflector, as proposed by Lieut. 
mond. No accident or inconvenience occurred. On the 
following day, as the gases had not been entirely consumed, it 
Was used on my lecture table before the class. 
It may be thought that unnecessary precaution was taken to 
‘scertain the safety of an apparatus that had come to us with the 
“actions I have already alluded to; but we cannot be too care- 
ul in experiments of danger, especially with new apparatus, and 
when made in this country from description only, and by artists 
hot 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.* 
a eer ere me orem 
* : 4 “ 
An instance occurred under my own observation a few years since, where a 
— was compressing air into a copper globe, made in this vicinity, when it 
urs . : , 
t wounding the operator very severely in the hand and face 
