“Who had most share in developing the chemical history of that body [iodine], must be determined by a review of the papers that have been published upon it, and by an examination of their respective dates. When M. Clement showed Iodine to me, he believed that the hydriodic acid was muriatic acid; and M. Gay Lussac, after his early experiments, made originally with M. Clement, formed the same opinion, and _maintained_ it, when I _first_ stated to him my belief that it was a new and peculiar acid, and that Iodine was a substance analogous in its chemical relations to Chlorine.” Davy left Paris towards the end of December, passing into Auvergne and thence to Montpellier, where he resumed his work on iodine. He then went to Genoa, where he made some experiments on the electricity of the torpedo, and about the middle of March arrived at Florence. In a letter to his brother John he says:-- “I have worked a good deal on iodine and a little on the torpedo. Iodine had been in embryo for two years. I came to Paris; Clement requested me to examine it, and he believed that it was a compound, affording muriatic acid. I worked upon it for some time, and determined that it was a new body, and that it afforded a peculiar acid by combining with hydrogen, and this I mentioned to Gay Lussac, Ampère, and other chemists. The first immediately ‘took the word of the Lord out of the mouth of His servant,’ and treated this subject as he had treated potassium and boron. The paper which I sent to the Royal Society on iodine I wrote with Clement’s approbation and a note published in the ‘Journal de Physique’ will vindicate my priority. I have just got ready for the Royal Society a second paper on this fourth supporter of combustion. “The old theory is nearly abandoned in France. Berthollet, with much candour, has decided in favour of chlorine. I know no chemist but Thenard who upholds it at Paris, and he upholds it feebly, and by this time, probably, has renounced it. “I doubt if the organ of the torpedo is analogous to the pile of Volta. I have not been able to gain any chemical effects by the shock sent through water; but I tried on small and not very active animals. I shall resume the inquiry at Naples, where I hope to be about the middle of May. In my journey I met with no difficulties of any kind, and received every attention from the scientific men of Paris, and the most liberal permission to go where I pleased from the government. “I lived very much with Berthollet, Cuvier, Chaptal, Vauquelin, Humboldt, Morveau, Clement, Chevreul, and Gay Lussac. They were all kind and attentive to me; and, except for Gay Lussac’s last turn of publishing without acknowledgement what he had first learnt from me, I should have had nothing to complain of; but who can control self-love?