1812. jET. 34.] SIR HUMPHRY DAVY. 379 



pieces of the alkaline metals introduced here and 

 there. Xow by adding a little water to this volcano 

 I shall be able to inflame it and cause it to burn 

 briskly. . . . 



' Meteors consist of alkaline metals and iron ; the 

 iron burns last if it be burnt at all. 



6 What I conceive is, that there are certain bodies 

 that revolve round our earth a kind of satellites and 

 are the same with respect to our globe that comets 

 are to the sun. Their orbits are ellipses, whose longer 

 diameters, like those of the comets, far exceed their 

 shorter ones. They must move with very great 

 velocity to counteract the attraction of the earth. . . . 



Regarding transmutation of metals he said ' the be- 

 ginning was deceit, the progress falsehood, and the end 

 beggary, said Lemery.' 



' It was supposed till lately that the fixed alkalies 

 were simple bodies, but I have had the good fortune 

 to prove them compounds ; and that pure potash 

 should contain a metal, oxygen, and water is not 

 more probable than that the metals are compounds, 

 yet it not only is probable but it is possible, and in 

 reality is so. ... 



' From the mercurial amalgam and from the quantity 

 of hydrogen given out by metals when exposed to the 

 action of a vigorous voltaic battery, either this 

 hydrogen is combined with the metal or it is one of 

 its constituent parts. . . . 



' If, then, we suppose that hydrogen constitutes a part 

 of all metals, they will be compounds of it and a base. 

 The hydrogen will give them their genuine characters 



