He tried the following substances: oxalic acid, dry; succinic acid; oxalic acid; soap; alcohol; water; carbonate of ammonia; nitrate of potash. He wrote, ‘Pure potash, as dry as it can be made, discharges the negative in a remarkable degree and insulates the positive.’
‘Remarkable Phenomena with Potash. It soon—’ Here the laboratory note ends, but his paper in the ‘Philosophical Transactions’ says—‘fused, became a conductor, and gave brilliant light with the appearance of flame at the negative wire. When it was slightly moistened, to make it a better conductor, the potash began to fuse at both its points of electrisation; there was a violent effusion at its upper or positive surface, while at the lower or negative surface there was no liberation of an elastic fluid, but a formation of small granules resembling quicksilver, which occasionally burst with explosion.’
He then tried carbonate of ammonia, sulphuric acid and water, soap, and the flame of a candle.
The following day carbonate of ammonia and oxalic acid were tried, sulphuric acid, water, and alcohol.
From the 7th to the 16th no experiments were entered in the Laboratory Book; but to the substance that produced the gas and globules he gave the name first of alkaligen; for on the 16th he says, ‘Gas from alkaligen in alcohol;’ also ‘gas from ether and gas from oil of turpentine.’
On the 17th he again experimented on this gas from the alkaligen in ether and turpentine, and says, ‘The gas which had been collected from the globules under oil of turpentine by the action of water burnt in contact with the air. Does it (the matter of the globules) not form gaseous compounds with ether, alcohol, and the oils?’
Then he notes the action of the alkaligen on mercury. ‘Forms with it a solid amalgam, which soon loses its alkaligen in the air.’ ‘This amalgam amalgamates with platina and iron, but soon flies off on exposure to the air.’ ‘Query, Does it amalgamate with phosphorus?’
‘Probably whenever it meets with hydrogen it dissolves in it.’ ‘Probably forms an æriform compound with ether.’
On October 19 he made his famous experiment by which he showed beyond question that potash can give up its oxygen. ‘When potash was introduced into a tube having a platina wire attached to it, so (fig.), and fused into the tube so as to be a conductor—i.e. so as to contain just water enough, though solid—and inserted over mercury, when the platina was made negative, no gas was formed and the mercury became oxydated, and a small quantity of the alkaligen was produced round the platina wire, as was evident from its quick inflammation by the action of water. When the mercury was made the negative, gas was developed in great quantities from the positive wire, and none from the negative mercury, and this gas proved to be pure oxygen—a capital experiment, proving the decomposition of potash.’ ‘A small quantity of alkaligen was produced round the platina wire.’