406 Scientific Intelligence. [Dec. 



remains so, as long as the hydrogen continues to flow upon it. If 

 the stream of gas be strong, it becomes inflamed, particularly if it 

 has already been mixed in the reservoir with some atmospheric air. 

 This experiment is very surprising, and astonishes every beholder, 

 when he is informed, that it is the result of the dynamic reaction of 

 two species of matter, one of which is the lightest and the other the 

 most ponderous of all known bodies. That 1 have already applied 

 this new discovery to the formation of a new apparatus for procuring 

 fire, and of a new lamp ; and that I shall avail myself of it for much 

 more important purposes, you may well suppose beforehand : — more 

 of it in my next. — (Phil. Mag. vol. Ixii, p. 289, from Schweigger's 

 Journal.) 



From the Annales de Chiraie et de Physique, t. xxiv. p. 91, we 

 extract the following additional experiments by M. Doebereiner :— 



I have found that the combustible energy of hydrogen is so much 

 increased by contact with the powder of platina, that it will combine 

 in a few minutes with all the oxygen of a mixture which consisted of 

 99 parts of azote and 1 of oxygen ; an effect which cannot be pro- 

 duced by the strongest electrical sparks. 1 mix, however, for these 

 experiments, the powder of platina with potters' clay, and I moisten 

 this mixture to form it into small balls of the size of a pea; I suffer 

 these balls to dry in the air, and afterwards heat them to redness in an 

 enameller's lamp. A ball of platina of this kind, although weigh- 

 ing only from 2 to 4- or 6 grains, is capable of converting any volume 

 of the detonating gas into water, provided that after each operation 

 it is carefully dried, and it may be employed for the same purpose 

 more than a thousand times. 



The compound gases containing hydrogen, such as ammonia, 

 olefiant gas, carbureted hydrogen, muriatic acid gas, &c. do not 

 combine with oxygen by the intervention of the powder of platina. 



When a jet of hydrogen was directed upon a mixture of powder of 

 platina and nitrate of platina and ammonia, the mixture became red- 

 hot with a crackling noise and the emission of spark*. The same 

 effect occurred with the black powder of platina, which zinc separates 

 from the solution of that metal. This powder is a mixture of oxide 

 and reduced platina. This powder possesses the property of gradu- 

 ally converting alcohol, when oxygen is present, into acetic acid. 



Among the other metals which I have hitherto tried, nickel, pre- 

 pared by decomposing the oxalate, is the only one which has the 

 property of converting a mixture of oxygen and hydrogen into water, 

 and this takes place very slowly. 



II. On the Ignition of Platina by Hydrogen Gas. By Mr. A. Garden. 



(To the Editor of the Annals of Philosophy.) 



DEAR SIR, Oxford-street, Xov. 20, 1823. 



The very curious phaenomenon, recently observed by Doebereiner, 

 that a jet of hydrogen gas when brought into contact with metallic 

 platina at common temperatures, produces a temperature equal to 

 that of ignition, has already been noticed by other chemists, namely, 

 by Messrs. Dulong and Thenard, in France ; and by Faraday and 



