You are right. This metal is perfectly fluid at the temperature of one hundred degrees; at fifty degrees it is solid, but soft and malleable; at thirty-two degrees it is hard and brittle, and its fracture exhibits an appearance of confused crystallization. It is scarcely more than half as heavy as water; its specific gravity being about six when water is reckoned at ten; so that this metal is actually lighter than any known fluid, even than ether. Potassium combines with sulphur and phosphorus, forming sulphurets and phosphurets; it likewise forms alloys with several metals, and amalgamates with mercury. EMILY. But can a sufficient quantity of potassium be obtained, by means of the Voltaic battery, to admit of all its properties and relations to other bodies being satisfactorily ascertained? MRS. B. Not easily; but I must not neglect to inform you that a method of obtaining this metal in considerable quantities has since been discovered. Two eminent French chemists, Thenard and Gay Lussac, stimulated by the triumph which Sir H. Davy had obtained, attempted to separate potassium from its combination with oxygen, by common chemical means, and without the aid of electricity. They caused red hot potash in a state of fusion to filter through iron turnings in an iron tube, heated to whiteness. Their experiment was crowned with the most complete success; more potassium was obtained by this single operation, that could have been collected in many weeks by the most diligent use of the Voltaic battery. EMILY. In this experiment, I suppose, the oxygen quitted its combination with the potassium to unite with the iron turnings? MRS. B. Exactly so; and the potassium was thus obtained in its simple state. From that time it has become a most convenient and powerful instrument of deoxygenation in chemical experiments. This important improvement, engrafted on Sir H. Davy’s previous discoveries, served but to add to his glory, since the facts which he had established, when possessed of only a few atoms of this curious substance, and the accuracy of his analytical statements, were all confirmed when an opportunity occurred of repeating his experiments upon this substance, which can now be obtained in unlimited quantities. CAROLINE. What a satisfaction Sir H. Davy must have felt, when by an effort of genius he succeeded in bringing to light and actually giving existence, to these curious bodies, which without him might perhaps have ever remained concealed from our view! MRS. B. The next substance which Sir H. Davy submitted to the influence of the Voltaic battery was _Soda_, the other fixed alkali, which yielded to the same powers of decomposition; from this alkali too, a metallic substance was obtained, very analogous in its properties to that which had been discovered in potash; Sir H. Davy has called it SODIUM. It is rather heavier than potassium, though considerably lighter than water; it is not so easily fusible as potassium.