XIII. Note on the bearing on the atomic weight of aluminium of the fact that this metal occludes hydrogen

In a recent communication to the Académie des Sciences, it has been pointed out by Dumas that metallic aluminium and magnesium, as well as silver, may contain sensible quantities of occluded gas, that obtained from aluminium being almost pure hydrogen. In a paper on the atomic weight of aluminium read before the Royal Society on the 22nd of April last I gave, among other data, the results of several experiments on the quantity of hydrogen liberated by a known weight of aluminium from a strong solution of sodium hydrate. In examining beforehand the purity of the specially prepared metal used, warned by Dumas’ previous results as to gaseous occlusion by silver, of which due account was taken in the paper, I did not neglect to test in like manner the aluminium, but obtained an entirely negative result. As, however, I heated the metal in a Sprengel vacuum only to the highest temperature which a hard Bohemian glass tube would bear, while M. Dumas says that gas is only given off suddenly “vers le rouge blanc ,” I have since seeing his paper repeated the experiment in a porcelain tube, and at this higher temperature, obtained by means of an excellent gas furnace, with a small remnant of the same material nsed in the atomic weight determinations.