Deflagrating Carburets, Phosphurets, or Cyanides. 305 



so fitted to it by grinding, as to be air-tight. The otherwise open 

 neck of the bell is also closed air-tight by tying about it a caout- 

 chouc bag, of which the lower part has been cut off, while into 

 the neck a stuffing-box has been secured air-tight. Through the 

 last mentioned stuffing-box a second rod passes, terminating within 

 the bell in a kind of forceps, for holding an inverted cone of char- 

 coal, (E.) 



The upper end of this sliding rod is so recurved as to enter 

 some mercury in a capsule, (F.) By these means and the elas- 

 ticity of the caoutchouc bag, this rod has, to the requisite extent, 

 perfect freedom of motion. 



The lower rod descends into a capsule of mercury, (G,) being 

 in consequence, capable of a vertical motion, without breaking 

 contact with the mercury. It is moved by the aid of a lever, 

 (H,) connected with it by a stirrup working upon pivots. 



Of course the capsules may be made to communicate severally 

 with the poles of one or more deflagrators. The substance to be 

 deflagrated is placed upon the charcoal forming the lower elec- 

 trode, being afterwards covered by the bell, as represented in the 

 figure. By means of the valve-cocks and leaden pipes a com- 

 munication is made with a barometer gage ; also with an air- 

 pump, and with a large self-regulating reservoir of hydrogen. 



The air being removed by the pump, a portion of hydrogen is 

 admitted and then withdrawn. This is repeated, and then the 

 bell glass, after as complete exhaustion as the performance of the 

 pump will render practicable, is prepared for the process of de- 

 flagration in vacuo. But, if preferred, evidently hydrogen or 

 any other gas may be introduced from any convenient source by 

 a due communication through flexible leaden pipes and valve- 

 cocks. 



Having described the apparatus, I will give an account of some 

 experiments, made with its assistance, which, if they could have 

 illuminated science as they did my lecture room, would have im- 

 mortalized the operator. But, alas, we may be dazzled, and 

 almost blinded by the light produced by the hydro-oxygen blow- 

 pipe, or voltaic ignition, without being enabled to remove the 

 darkness which hides the mysteries of nature from our intellec- 

 tual vision. 



I hope, nevertheless, that some of the results attained may not 

 be unworthy of attention j and that, as a new mode of employ- 



