“Potasium [_sic_] and sodium are the names by which I have ventured to call the new substances; and whatever changes of theory, with regard to the composition of bodies, may hereafter take place, these terms can scarcely express an error; for they may be considered as implying simply the metals produced from potash and soda. I have consulted with many of the most eminent scientific persons in this country, upon the methods of derivation, and the one I have adopted has been the one most generally approved. It is perhaps more significant than elegant. But it was not possible to found names upon specific properties not common to both; and though a name for the basis of soda might have been borrowed from the Greek, yet an analogous one could not have been applied to that of potash, for the ancients do not seem to have distinguished between the two alkalies.” He thinks there is the greater necessity for avoiding any theoretical views in terms because the time is yet far distant for a complete generalisation of chemical facts, and although the antiphlogistic explanation of the phenomena has been uniformly adopted, the motive for employing it has been rather a sense of its beauty and precision than a conviction of its permanency and truth. “The discovery of the agencies of the gases destroyed the hypothesis of Stahl. The knowledge of the powers and effects of the etherial substances may at a future time possibly act a similar part with regard to the more refined and ingenious hypothesis of Lavoisier; but in the present state of our knowledge, it appears the best approximation that has been made to a perfect logic of chemistry.” Led by analogy, Davy soon convinced himself that the volatile alkali--ammonia--also contained oxygen, and in amount not less than 7 or 8 per cent. It is not necessary to go into detail concerning the experiments on which this erroneous conclusion was founded. Davy was subsequently made aware of his error; but at the time he seemed anxious to overturn--as, indeed, he did in the end, but on other grounds--the Lavoisierian doctrine that oxygen was the principle of acidity, by showing that it was equally the principle of alkalescence. In concluding his paper, he mentions that he has begun experiments on the alkaline earths. “From analogy alone it is reasonable to expect that the alkaline earths are compounds of a similar nature to the fixed alkalies, peculiar highly combustible metallic bases united to oxygen. I have tried some experiments upon barytes and strontites, and they go far towards proving that this must be the case.”