7. To decompose fluoric acid gas, and to ascertain the source of the hydrogen which it gives by the operation of potassium. 8. To make various experiments on the amalgamation of ammonia, using different amalgams of mercury and different modes of excluding water. 9. To endeavour to bring the ὑδὼρ theory to a test of producing oxygen from water without hydrogen. 10. To decompose muriate of soda and litharge and other bodies that contain no water by electricity, and to see what happens. In the early part of 1810 the experiments were chiefly on the action of potassium on sulphur and phosphorus. From analogy oxygen had been considered as the acidifying principle of the muriatic acid, or spirit of salt. It was thought to combine with more oxygen, and then was called oxygenated muriatic acid, although its powers as an acid were weakened and it became more volatile and bleached. Davy sent two papers to the Royal Society, on this subject. The first was on July 12, ‘Researches on Oxymuriatic Acid and the Elements of Muriatic Acid; with Experiments on Sulphur and Phosphorus,’ and the second, on November 15, was the ‘Bakerian Lecture on Some of the Combinations of Oxymuriatic Gas and Oxygen, and on the Chemical Relations of these Principles to Inflammable Bodies.’ In the first paper he says, ‘Scheele considered oxymuriatic acid as more simple than muriatic acid, and that it became muriatic acid by union with phlogiston. Berthollet said it contained oxygen. The vivid combustion of many bodies in this gas has favoured the presumption that it contained oxygen very loosely combined, and ready to exert its utmost power of affinity; but it is mere presumption, since heat and light result also from the intense agency of any other combination without the presence of oxygen.’ On July 3 he wrote, ‘Equal parts of oxymuriatic acid and hydrogene, both dried, were detonated. There was a diminution equal to about 1/12, and muriatic gas was formed; and this was over mercury, and some of the oxymuriatic acid burnt the mercury, and there was an excess of 1/4 hydrogene. Equal parts of oxymuriatic acid and sulphuretted hydrogene, diminution about 1/12. Muriatic gas formed; sulphuretted hydrogene apparently in excess.’ A most important experiment had been made on September 21, 1809, on the resistance of oxymuriatic acid to galvanic decomposition; and as long previously as April 19, 1808, he had decomposed muriatic acid with a battery of 520 pair of plates.[39] The experiments which were detailed in the Bakerian lecture read during the absence of Davy on November 15, were made in July and August. On August 30, after entering things wanted, he wrote in the Laboratory Book: