Immediately on observing this, Priestley, being then, as has been already stated, Watt's near neighbour, communicated to the latter what he had observed; upon which Watt immediately, viz. by a letter dated the 26th of the same month, declared that the inevitable consequence which followed from Priestley's observations was, that water was a substance compounded of oxygen and hydrogen deprived of [Pg307] a quantity of heat which was previously latent in them.[27] The letter containing this inference was communicated immediately by Priestley to Sir Joseph Banks, then President of the Royal Society, to be laid before that body; and it is accordingly printed with its proper date in the 74th volume of the _Philosophical Transactions_. About two months after the date of Mr. Watt's letter just quoted, Lavoisier made experiments on the combustion of oxygen and hydrogen, and read a memoir before the Academy of Sciences in Paris, in which his views of the formation of water by the combination of these gases were developed. This paper, by Lavoisier, was afterwards printed in the Memoirs of the Academy in the year 1784. The experiments are there stated to have been made in the month of June, 1783; and it is stated that Sir Charles Blagden, who was present at the experiments, told Lavoisier that Mr. Cavendish had already burned the same gases in close vessels, and obtained a very sensible quantity of water. On the 15th of January, 1784, the celebrated paper by Cavendish, entitled "Experiments on Air," was read before the Royal Society, and in this paper the composition of water by the union of oxygen and hydrogen is explained. In a controversy which afterwards ensued on the respective [Pg308] claims of Cavendish and Lavoisier to credit for the discovery of the composition of water, Sir Charles Blagden stated that he had told Lavoisier, in June, 1783, more than Lavoisier acknowledged, that he had not only told him that water was produced by the combustion of the gases, but that his information embraced the whole theory of the composition of water. This declaration of Blagden was subsequent in date to January, 1784, and there is no evidence of any explanation of this theory, verbal or otherwise, having been given by Cavendish, or any other person, antecedent to April, 1783.