But the analysis of potash and soda was not sufficient for Davy; he determined to accomplish the synthesis of these substances. For this purpose he collected small quantities of the newly discovered metals, by conducting the electrolysis of potash and soda under experimental conditions such that the metals, as soon as produced, were plunged under the surface of naphtha, a liquid which does not contain oxygen, and which protected them from the action of the surrounding air. A weighed quantity of each metal was then heated in a stream of pure dry oxygen, the products were collected and weighed, and it was found that solutions of these products in water possessed all the properties of aqueous solutions of potash and soda. The new metals were now obtained in larger quantity by Davy, and their properties carefully determined by him; they were named _potassium_ and _sodium_ respectively. They were shown to possess all those properties which were generally accepted as characteristic of metal, except that of being heavy. The new metals were extremely light, lighter than water. For some time it was difficult to convince all chemists that a metal could be a very light substance. We are assured that a friend of Davy, who was shown potassium for the first time, and was asked what kind of substance he supposed it to be, replied, "It is metallic, to be sure;" "and then, balancing it on his finger, he added in a tone of confidence, 'Bless me, how heavy it is!'" Davy argued that since the alkalis, potash and soda, were found to be oxygen compounds of metals, the earths would probably also be found to be metallic oxides. In the year 1808 he succeeded in decomposing the three earths, lime, baryta and strontia, and in obtaining the metals _calcium_, _barium_ and _strontium_, but not in a perfectly pure condition, or in any quantity. He also got evidence of the decomposition of the earths silica, alumina, zirconia and beryllia, by the action of powerful electric currents, but he did not succeed in obtaining the supposed metallic bases of these substances. So far Davy's discoveries had all tended to confirm the generally accepted view which regarded alkalis and earths as metallic oxides. But we found that the outcome of these views was to regard all salts--and among these, of course, common salt--as oxygen compounds.[11] Acids were oxygen compounds, bases were oxygen compounds, and as salts were produced by the union of acids with bases, they, too, must necessarily be oxygen compounds. Berthollet had thrown doubt on the universality of Lavoisier's name "oxygen," _the_ acidifier, but he had not conclusively proved the existence of any acid which did not contain oxygen. The researches of Davy naturally led him to consider the prevalent views regarding acids, bases and salts.