54 ESSAYS BIOGRAPHICAL AND CHEMICAL 



of chlorine. But he did not commit himself to the dog- 

 matic assertion that this gas is an element; on the con- 

 trary, he writes : ' In the views that I have ventured to 

 develop, neither oxygen, chlorine, nor fluorine are asserted 

 to be elements ; it is only asserted that, as yet, they have 

 not been decomposed.' It would be well, were all chemists 

 to imitate Davy's caution. 



These views were combated by Gay-Lussac and The- 

 nard; but it would take too much time to follow the 

 contest. Suffice it to say, that Davy came off with flying 

 colours. 



During all these years, honours were being showered on 

 Davy. In 1803, he was made a Fellow of the Royal 

 Society ; in 1807, he was chosen for its secretary, an office 

 which he held until 1812 ; and in the latter year he was 

 knighted. In his private diary, in which he transcribed 

 his inmost thoughts, there is a pleasant little sentence, 

 recording sentiments on the subject of honours: ' A man 

 should be proud of honours, not vain of them.' But 

 besides honours, wealth was also his portion ; for two 

 courses of lectures in Dublin, he was paid no less a sum 

 than 11 70! 



In 1812, his Elements of Chemistry was published. It 

 was dedicated to his wife; for in that year he married 

 Mrs. Apreece. 



In the same year, he nearly lost his sight by experi- 

 menting with chloride of nitrogen, which had recently 

 deprived its discoverer, Dulong, of a finger. In 1813, he 

 established the true nature of fluorine, and demonstrated 

 its analogy with chlorine; and towards the end of the 

 same year, he paid a visit to Paris, conveying with him a 

 portable laboratory, by help of which he proved the simi- 

 larity of iodine to chlorine. That element, which had 

 been discovered about two years previously by Courtois, 

 was supposed by Gay-Lussac to yield an acid identical 



