OXYGEN. 187 



(B.) IT ACTS ON COMBUSTIBLE BODIES WITH INTENSE ENERGY, 



and this is one of its great characteristic, but not altogether peculiar 

 properties. 



(c.) Generally the temperature must be raised, in order to bring 

 on the action. 



(d.)* A lighted candle burns brilliantly in oxygen gas. If extin- 

 guished, (fire remaining on the wick,) it is instantly relighted with a 

 slight report, and that many times in succession, j- 



Candle in air, in vacuo, and in oxygen gas. Dr. Hare. 



" Let there be two bell glasses, A and B, communicating with 

 each other by a flexible leaden pipe, a cock intervening at C. Sup- 

 pose A, to be placed over a lighted candle on the plate D, which 

 communicates with an air pump plate as represented at E. It will 

 be found that the candle will gradually burn more dimly, and will at 

 last go out, if no supply of fresh air be allowed to enter the contain- 

 ing bell ; if on repeating the experiment, the air be withdrawn by 

 means of the pump, the candle is rapidly extinguished. It is thus 

 demonstrated, that a candle will not burn in vacuo, and that it can 

 burn only for a limited time, in a limited portion of atmospheric air." 



" Let the experiment be repeated with the following change. Let 

 the air be exhausted from both vessels, the cock, C, remaining open, 



* For the experiments under d and /, a common glass bottle answers suf- n 

 ficiently well. 



t A quart of oxygen gas, well managed in a bottle, will relight a candle 

 more than fifty times ; the bottle should be held mouth upwards, and gent- 

 ly inclined each time the candle wick is presented to it ; as the oxygen is 

 consumed or expelled, the bottle must be turned down more and more. A 

 candle in a socket, fixed to a wire, is easily let down into a jar of gas, as rep- 

 resented in the cut. 



