378 THE ROYAL INSTITUTION. [CHAP. VI. 



In this lecture Faraday noted twenty-two experi- 

 ments. 



The next day, April 9, Davy was knighted by the 

 Prince Regent. 



On April 10 Sir Humphry Davy gave his last lec- 

 ture at the Royal Institution ; it was on the Metals. 



' All the volatile metals burn with flame, and all 

 those that are not volatile with sparks. . . . 



'These, with the metals of the alkalies and the 

 alkaline earths which I have had the good fortune to 

 discover, make up the number to about forty.' 



He shewed the mode of obtaining alkaline metals 

 by voltaic decomposition ; and earths by potassium. 



The mode of obtaining the alkaline metals by 

 chemical action alone was shown, but the experiment 

 was not made. A quantity of potassium from com- 

 mon potash by iron was on the table. 



'The combustion of metals is according to their 

 electricity, those containing the most electricity 

 burning with the most energy. All those metals that 

 are positive to others are also more inflammable than 

 those others, and burn more readily. . . . 



' That the metals of the earths and alkalies cannot 

 exist at the surface of our globe we are well assured, 

 but they may exist in the interior, and if so they will 

 offer a very complete and a very probable solution of 

 the phenomena of earthquakes and volcanoes ; and 

 perhaps, considered thus, they may lay the foundation 

 of a new and perfect system of geology. 



' We have here a small volcano formed of clay, &c., 

 in the shape of a mountain, and having two or three 



