178 ANNUAL OF SCIENTIFIC DISCOVERY. 



metallic state, so as to resemble quicksilver. IMany chemists snp- 

 poit this opinion, much evidence on the point having been brought 

 to bear by J\I. Dumas. 



In i)hysical properties the gas acts like a metal, by conducting 

 heat with lac-ility. Dr. Odliiig illustrated this by passing a cur- 

 rent of electricity through two platinum spirals, till the two coils 

 of wire kept at a white heat. Over the one spiral he inverted a 

 jar of common air, and over the other ajar of hydrogeri, and the 

 latter cooled tiie wire so rapidly that it ceased to glow. He said 

 that it was but fair to state that Dr. Tyndal questions wiiether 

 the cooling effect shown in this experiment is due to the rapid 

 conduction of heat by the hydrogen; still, it is the prevalent 

 opinion, that conduction by heat really causes the cooling, and 

 Professor Magnus, of Berlin, has come to the same conclusion. 

 Mr. Graham's experiments also favor the view that hydrogen is a 

 metal. 



Pr. Odling then proved that the condensed hydrogen has a 

 more powerful action upon reducing agents than when in its or- 

 dinary state, by showing its bleaching action upon several colored 

 solutions of chemical reagents. The greatest absorption of h}-- 

 drogen b}' palladium takes place at moderately low temperatures, 

 but a high temperature is necessary for the passage of the gas 

 through the solid metal. He then took a tube of palladium, 

 closed at one end, and connected the other end with the Sprcngel 

 air-pump. A tube of glass was then slipped over the palladium 

 tube, and a stream of hydrogen gas passed between the two, 

 which were then made hot in the njiddle by the flame of a Bun- 

 sen's burner. The hydrogen gas then passed readily through the 

 solid metal, being, it is supposed, liquelied in the pores of the ])al- 

 ladium, and as it evaporated again inside the tube, the Sprcngel 

 pump delivered it inio a glass vessid inverted over a trough of 

 mercury. The hydrogen thus collected was then set on lire by 

 the lecturer, to prove that it was hj'drogen and nothing else. 



Dr. Odling showed that a palladium wire is elongated after 

 being allowed to absorb hydrogen for half an hour; but the re- 

 markable fact is, that when the gas is driven out again l)y heat 

 the wire contracts, not to its origiiuil length, but to k'ss than its 

 oriiJi'inal lenefth. The cause is not known. As a linal illustration 

 of the probable metallic nature of hydrogen, a bar of palladium, 

 charged with the gas, was suspended by a til)re of silk in the 

 lield of an electro-magnet, and was seen to be attracted like iron, 

 thougli not so strongly. The bar had thus acquired a metallic 

 property, not possessed by palladium in its unalloyed state. 



THE METAL HYDROGEN. 



At a late meetino; of the Roval Societv, as we learn from the 

 •' Aihenajuui " of January Kjth, Mr. Graham presented a specimen 

 of palhulium, charged with some 800 or 'JOO times it-^ volume of hy- 

 drogen, by some process which is not described in tli(; above jour- 

 nal, but which, Irom his previous researches, we presume con- 



