NATURAL PHILOSOPHY. 177 



MR. Graham's experiments with hydrogen. 



At the February meeting of the Royal Institution in London, Dr. 

 Odling delivered a lecture upon the new discoveries made by Mr. 

 Graham, F.R.S., respecting the properties of hydrogen, tending 

 to prove that hydrogen is a metal having a boiling-point much 

 below the temperature of the air. The lecturer took a tube closed 

 at one end with a single thickness of well-moistened calico, and 

 showed that when the tube was half filled with water, and its 

 lower end just dipped below the surface of some water in a glass 

 vessel, the water in the tube would not run out, because the wet 

 calico was, practically speaking, air-tight. Air could only enter 

 the tube, by dissolving in the water upon the calico, and then 

 evaporating on the other side, — a very slow operation. Ammo- 

 nia being a gas much more soluble in water than common air, a 

 jar of it was inverted over the wet calico ; it was quickly dissolfed 

 in the water, and evaporated on the other side, so as to push 

 down the column of water in tbe tube. In the same way gases 

 are believed to pass through India-rubber, and colloid septa, by 

 first dissolving in the material of the diaphragm, then passing 

 through it as a condensed volatile liquid, and finally evaporating 

 on the other side. 



M. Deville, a French chemist, jDroved that hydrogen gas would 

 pass through red-hot solid platinum. Mr. Graham took up the 

 discovery of M. Deville, and, by other experiments made, gained 

 fresh information respecting these phenomena. He showed that 

 platinum absorbed a certain quantity of hydrogen before the 

 transmission began, as is the case with India-rubber. Next he 

 tried palladium, and discovered that this metal will absorb or oc- 

 clude about 1,000 times its own volume of hydrogen gas, the 

 greatest amount taken up in the actual experiments being 980 

 times the bulk of the palladium. One volume of water will dis- 

 solve 800 times its volume of ammonia, the water being then in- 

 creased in bulk by one-half, — that is to say, that two centimetres 

 of water, after absorbing 800 times their volume of ammonia, 

 will have increased to three cubic centimetres. Palladium does 

 not increase in bulk to anything like the foregoing extent when it 

 absorbs hydrogen ; it only enlarges to one-twentieth or one- 

 twenty-first of its former volume, after taking up 900 times its 

 bulk of the gas, in which operation the hydrogen is reduced to 

 one-nineteenth thousand of its former volu,me. 



The enormous mechanical pressure necessary to compress hy- 

 drogen to this extent would equal that at the base of a column 

 of mercury three times as high as Mont Blanc, supposing hydro- 

 gen, at such a pressure, still to obey the laws of gases, and to 

 possess all the properties of a gas. The weight of hydrogen, 

 thus absorbed, is from eight-tenths to nine-tenths that of the palla- 

 dium. Mercury can be boiled into an invisible gas, and analogy 

 seems to point out that hydrogen, at all temperatures yet pro- 

 duced by man, is similarly the vapor or gas of a metal, and that, 

 by a suliicicncy of pressure or cold, it may bo reduced to a liquid 



