7iexv Experiments of M. Dcebereiner. 



287 



change in its appearance, nor had it increased or diminislied 

 in weight. Tiie pha^nonienon then, I presume, was not occa- 

 sioned by any change the metal had undergone. As it was 

 necessary to remove the jilatinum to a greater distance as the 

 gas became jmrer, it aj^peared to indicate that the presence of 

 atmospheric air or oxygen was as essential as the hydrogen : 

 to prove the truth of this idea, a large thin bulb having a hole 

 in its side was blown at the end of a piece of tube ; into which 

 tube hydrogen was conveyed. Tlie platinum was in an at- 

 mosphere of hydrogen, but jt did not become hot ; a fine tube 

 was then introduced into the hole in the bulb, and a stream 

 of common air made to act on the metal; it immediately glowed, 

 and continued to do so as long as both currents were directed 

 towards it, while water was found on the sides of the bulb, 

 which increased as the experiment went on. 



Exp. 2. It seemed to result from this, that the platinum has 

 the curious property of causing oxygen and hydrogen to com- 

 bine at a low heat : I therefore directed a stream of the mixed 

 gases from the gas blowpipe upon a portion of the spongy 

 mass, when it glowed as before and ignited the gases at the 

 jet pipe ; but I found that the metal required to be heated a 

 little before the phaenomenon occurred: as this was notneces- 

 saiy when hydrogen was admitted direct from the retort, the 

 temperature of the atmosphere being sufficient, it favoured the 

 idea that a small quaiUity of caloric was requisite, which quan- 

 tity was carried over from the retort, but which it afterwards 

 lost in the cool vessel. I therefore constructed a small appa- 

 ratus with which I could repeat the experiments under more 

 favourable circumstances. 



Oxygen, or common air. 



Bulb containing 

 platinum. 



Hydrogen, or 

 coal gas. 



Capsule containing water for 

 heating tlie metal. 



Exp. 3. The apparatus was kept full of hydrogen from tlie 

 tube A ; the metal did not glow at any temperature, and the gas 

 was inflanunable as it escaped from the capillary orifice of the 



tube 



