108 Explosion of Hydrogen and Oxygen. 
Having occasion to exhibit the compound blow-pipe in my lec- 
ture on the 16th of May, in addition to my usual method with 
two separate gas holders, andthe double, concentric jet, the cop- 
per globe was charged with the mixed gases, but with a smaller 
proportion of hydrogen, viz. 14 vols. to 1 vol. of oxygen, for the 
purpose of making some comparative experiments. After using 
‘the gases in the separate vessels, I proceeded to operate with the 
new instrument; the jet was ignited and a few experiments 
made with confidence and safety. Having closed the stop cock, 
I removed (as I had often done before) a very short piece from 
the end of the jet for the purpose of obtaining a somewhat larger 
flame, to be directed upon a lump of magnesia. 'The orifice ex- 
posed was now ;,th of an inch in diameter and about 6 inches 
from the end of the Hemming’s tube, being at the extremity of 
a small brass tube bent upwards at an angle of 45°, the same 
which had been used in all the previous experiments. The globe 
was nearly in contact with my person, the jet and Hemming’s 
tube projecting horizontally in front of me from right to left. 
With the right hand the stop cock was opened, and the emission 
of the gases adjusted ; with the left the jet was ignited. The 
slight crackling noise, which all must be familiar with who have 
operated with the compound blow-pipe, occurred several times, 
and the gases were extinguished, but no communication of flame 
or explosion of the gases in the globe took place. 
On again applying a lighted paper to the jet, however, the 
copper globe exploded with tremendous noise and force, shatter- 
ing several glass vessels standing upon the table and shelves i 
the rear, and projecting the torn copper, stop cocks, and tubes, iD 
different directions. My fingers, resting upon the stop cock, were 
bruised ; and the right shoulder severely, by a large fragment of 
the copper, which in its course robbed me of no small part of 
the coat sleeve, and the cuff was entirely carried away. ‘The 
force of the explosion was exerted principally in the direction of ° 
the tube and jet in front of me, or I should not probably have 
escaped with so little injury. ‘The noise and concussion were 
deafening, and my hearing was not perfectly restored for several 
hours. No one, fortunately, of the class was injured ; the usual 
good order and attention were but momentarily interrupted ; the 
lecture was proceeded with, and the remaining experiments pel 
formed. 
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