Biographical Memoir of' Sir Humphry Davy, 1 1 



We are unable to bestow much time on his mineralogical 

 discoveries, although they are doubtless far from unimportant. 

 In 1805, his analysis of a stone from Devonshire, which had 

 been named wavellite, furnished to this science a new species. 

 It is a combination of pure alumina with water *. 



The same year he published a new method of analyzing stones 

 containing a fixed alkali, by means of the boracic acid -f*. 



He proved more evidently than had been previously done, and 

 contrary to his own conjectures on the subject, that the diamond 

 produces on combustion only pure carbonic acid +. In 1822, 

 he proved that iron and silex are dissolved in the thermal waters 

 of Lucca §. Rock-crystal and other stones often contain in 

 cavities in their interior gases and liquids ; and as these sub- 

 stances must have been inclosed at the time of their formation, 

 a knowledge of their nature was not without interest in the an- 

 cient history of the globe. Mr Davy found them to consist of 

 pure water and pure azotic gas J. 



Much light was likewise thrown on many branches of physics 

 by the observations made in the course of his researches. The 

 nature of the changes of colour produced by heat on the surface 

 of steel ^ ; the formation of mists over the surface of rivers ** ; 

 the application that may be made of liquids formed by the con- 



• An Account of some analytical experiments on a mineral production from, 

 Devonshire, consisting principally of alumina and water. — Rot/. Soc. Lond. 

 28th Feb. 1805 ; Phil. Trans, xcv. p. 155 ; Biblioth. Brit, xxx. p. 303 ; Anru 

 de Chimie, Ix. p. 297. 



f Roy. Soc. Lond. IGth May 1816; PfUl. Trans, xcv. p. 231 ; Annates de 

 Chitnie^ torn. Ix. p. 297. 



$ Some experiments on the combustion of the diamond and other carbona- 

 ceous substances — Roy. Soc. Lond. 23d June 1811 ; Phil. Trans, civ. p. 657 ; 

 Ami. de Chimie et de Physique, i p. 16; Bibl. Britan. voL Ivii. p. 124. 



§ Memoria sopra di un deposito trovato nei Bagni di Lucca. — Atti della 

 Real. Acad. Neapolit. v. ii. p. 9 ; Ann. de Chimie et de Physique, tom. xix. 

 p. 194. 



II On the state of water and aeriform matter in cavities found in certain 

 crystals — Roy. Soc. Lond. 13th June 1822; Phil. Trans, v. cxii. p. 367; Ann, 

 de Chim. et de Phys. tom. xxL p. 132. 



% Ann. of Philosophy, vol. L p. 131 ; Bibl. Brit. voL Iv. p. 157. 



•• Some observations on the formation of mists in particular situations... 

 Roy. Soc. Lond. 25th Feb. 1819 ; Phil. Trans, vol. cix. p. 123; Ann. de Chim. 

 et de Phys. xii. 195. 



