106 Explosion of Hydrogen and Oxygen. 



in length, to increase the cooling surface ; and bladders, contain- 



ing hydrogen and oxygen gases in the proportions that compose 



3 



water, were attached to the two extremities. The stop cocks 

 being opened, the gases were forced from one bladder into the 

 other several times through the leaden tubes and that of Hem- 

 ming's interposed, thus ensuring their mixture both in the blad- 

 ders and tubes. The apparatus was now placed in the open air 

 and an arrangement made which allowed me to explode one of 

 the bladders and observe the effect without danger. The one 

 bladder alone exploded. This experiment was repeated many 

 times, shortening the leaden tubes each time, until they were en- 

 tirely removed, and bladders were attached directly to the Hem- 

 ming's tube. One of them was then exploded, but the flame 

 was arrested as completely as in the previous trials. 



Having repeated the experiment with the Safety Tube alone 

 several times, and uniformly finding it impossible to explode both 

 bladders, I now did not hesitate to hold the tube in my hand, and 

 to apply a flame to one bladder ; this was repeated severed times, 

 and in no instance was explosion communicated from the one 

 bladder to the other. Mr. Hemming is stated to have operated 

 before the members of the British Association with the bladder 

 under his arm ; and Dr. Hare in his letter to Dr. Dalton,* states 

 that he has employed the mixed gases with safety, more than an 

 hundred times, allowing them to explode as far into the tube of 

 efflux as where the contrivance in questionf was interposed, 

 without explosion extending beyond it. 



The safety of the tube having been so thoroughly tested with 



the bladders, I now substituted for one of them a strong globe 



12 inches in diameter, made of 22 oz. copper; this, as well as 

 the bladder was filled with the mixed gases. The apparatus was 

 placed out of doors, and, with the necessary precautions as to per- 

 sonal safety, the mixture in the bladder was fired, but that in the 

 copper globe did not explode. The same result always occurred 

 in repeating this, and in no trial could I cause the flame to trav- 

 erse the Hemraing's tube. 



My next experiments were made without the bladder. A 

 small jet, having an orifice of about ^-^ of an inch diameter, 



* Amer Jour. Vol. xxxiii, p, 19G. 



i Dr. Hare alludes to some improvement he has made in Hemming's tube, but 

 has not informed us in what it consists. 



