lOS 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, and the double, concentric jet, the cop- 

 per globe was charged with the mixed gases, but with a smaller 

 proportion of hydrogen, viz. 1^ 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 y ^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 in 

 the rear, and projecting the torn copper, stop cocks, and tubes, in 

 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 



and 



formed. 



