When he began these experiments he tells us he knew very little of chemistry. Indeed, he says he had in a manner no idea on the subject before his attention was drawn to it in a course of lectures delivered in the Warrington Academy by Dr Turner of Liverpool. But, as he says, on the whole, this circumstance was no disadvantage to him, as in the situation in which he found himself he was led to devise an apparatus and processes of his own adapted to his peculiar views. If he had been previously accustomed to the usual chemical processes he might not have so easily thought of any other; and without new modes of operation he thinks he should hardly have discovered anything materially new. His means did not permit him to purchase expensive apparatus. Indeed, this very circumstance materially contributed to his success by making his apparatus so simple that his experiments could be readily repeated and their accuracy thereby ensured. His first contribution to Pneumatic Chemistry was published in 1772. It was a small pamphlet on a method of impregnating water with fixed air, which, being immediately translated into French, excited a great degree of attention to the subject, and this was much increased by the publication of his first experimental paper in the _Philosophical Transactions of the Royal Society_. Priestley’s earliest method of impregnating water with carbonic acid consisted in exposing it to the gas above the surface of fermenting wort. This process was no doubt accompanied with many disadvantages and the resulting solution could not have been very palatable. Later on he adopted the method originally employed by Lane in 1709, although apparently in ignorance of Lane’s paper in the _Philosophical Transactions_, of making the gas from chalk and sulphuric acid and leading it directly into the water by means of a flexible tube provided with an intercepting bladder to retain any solid or acid substance projected from the effervescent materials in the generating flask. At about this period increased attention was being paid to the question of the supply of drinking water in the Navy, owing to the publication of Irving’s plan of making fresh water from sea-water by distillation, and Priestley conceived the idea that if some ready means could be devised of impregnating water with carbonic acid on shipboard the solution might be useful as a preventive of sea scurvy. Priestley brought his idea to the knowledge of the Duke of Northumberland, and showed a sample of the impregnated water to Sir George Savile, who introduced him to Lord Sandwich, at that time First Lord of the Admiralty in Lord North’s Administration. The Board of Admiralty thought the matter was of sufficient importance to ask for a report from the College of Physicians, and Priestley was requested to appear before that body in order to explain and illustrate his process. The report from the College was favourable, and in consequence two war-ships were fitted with the apparatus.