It is difficult to determine whether he had any precise idea in again attacking the problem, or any expectation of a definite result. In one of his lectures at the Royal Institution on Electro-Chemical Science, delivered some time subsequently, he said he had a suspicion at that time that potash might turn out to be “phosphorus, or sulphur united to nitrogen”: “For as the volatile alkali was regarded as composed of an extremely light inflammable body--hydrogen--united to nitrogen, I conceived that _phosphorus_ and _sulphur_, much denser bodies, might produce denser alkaline matter; and as there were no _known_ combination of these with _nitrogen_, it was probable that there might be unknown combinations.” Davy once said that “analogy was the fruitful parent of error”; and the whole history of science probably furnishes no more extraordinary instance of perverted analogy, or one more unexpected in its consequences. In another of his lectures he said of the alchemists that “even their _failures_ developed some unsought-for object partaking of the marvellous”--and the statement in this case is even more true of himself. Each phase in the story of this discovery indeed partakes of the marvellous. Sometime during the first fortnight in October, 1807, he obtained his first decisive result; and on the 19th of November he delivered what is generally regarded as the most memorable of all his Bakerian lectures, “On some new Phenomena of chemical Changes produced by Electricity, particularly the Decomposition of the fixed Alkalies, and the Exhibition of the new substances which constitute their bases; and on the general Nature of alkaline Bodies.” Few discoveries of like magnitude have been made and perfected in so short a time, and few memoirs have been more momentous in result than that which Davy put together in a few hours, and in which he announced his results to the world. The whole work was done under conditions of great mental excitement. His cousin Edmund Davy, who at the time acted as his assistant, relates that when he saw the minute globules of the quicksilver-like metal burst through the crust of potash and take fire, his joy knew no bounds; he actually danced about the room in ecstasy, and it was some time before he was sufficiently composed to continue his experiments. The rapidity with which he accumulated results after this first feeling of delirious delight had passed was extraordinary. Before the middle of November he had obtained most of the leading facts. In a letter dated November 13th he tells W. H. Pepys-- “I have decomposed and recomposed the fixed alkalies, and discovered their bases to be two new inflammable substances very like metals; but one of them lighter than ether, and infinitely combustible. So that there are two bodies decomposed, and two new elementary bodies found.”