Davy communicated the results of his inquiries made prior to the summer of 1806 in a paper to the Royal Society, which was made the Bakerian lecture of the year.[F] It is entitled “On some chemical Agencies of Electricity,” and is divided in nine sections and an introduction. In the first section, “On the Changes produced by Electricity in Water,” he set at rest the disputed question as to the origin of the acid and alkaline matter which had been observed to form during the electrolysis of this liquid. By some these substances were supposed to be _generated_ from pure water by the action of electricity; and M. Brugnatelli had even attempted to prove the existence of a body _sui generis_ which he termed the _electric acid_. By a series of convincing experiments Davy showed that the substances were due to the presence of saline matter in the water, derived either from faulty purification, or from the solvent action of the water on the vessels, etc., with which it was in contact. Cruickshank had found that in some cases the acid was nitric acid and the alkali ammonia: these substances were shown by Davy to be due to the presence of dissolved air. When pure water, contained in vessels on which it exerted no solvent action, was “electrised” _in vacuo_, not a trace of either acid or alkali was produced. [F] This lecture, which is one of the events of each session of the Royal Society, owes its origin to Mr. Henry Baker, F.R.S., a learned antiquary and naturalist, who, by his will of July, 1763, bequeathed the sum of £100 to the Society, the interest of which was to be applied “for an oration or discourse to be spoken or read yearly by someone of the Fellows of that Society, on such part of Natural History or Experimental Philosophy, at such time, and in such manner, as the President and Council of the said Society for the time being, shall please to order and appoint.” Baker died in 1774, and the bequest came into operation during the presidency of Sir John Pringle; and Peter Woulfe--one of the last of the English alchemists--was appointed to deliver the lecture, which he did for three successive years.