192 GREAT MEN OF SCIENCE 



been discovered, amounted In meaning to spirit of salt 

 freed from hydrogen) or 'oxidised spirits of salt' (Lavoisier). 

 He also discovered and studied many new compounds of 

 chlorine, among these the very explosive chloride of nitro- 

 gen. Many other achievements, among them inventions of 

 value to humanity, but which he refused to patent, cannot be 

 mentioned here. 



Davy came from a Norman family,^ which had settled in 

 the south-west of England. His father was a poor wood- 

 carver. He went to school until his fifteenth year, but un- 

 willingly; he wrote later: 'To learn in a natural manner is 

 true pleasure; how evil it is that in most schools it only causes 

 misery.' He then was apprenticed to a surgeon and apothe- 

 cary. When there he studied all kinds of books very ex- 

 tensively in his spare time. He first paid closer attention to 

 geometry and mathematics, and only later to chemistry, 

 but this then occupied his entire attention so that he soon 

 began to develop ideas of his own. He was also fond of 

 writing poetry. The patients whom he had to bandage liked 

 him greatly, and altogether he was all his life praised for his 

 kindness, readiness to help, and general amiability. At the 

 age of nineteen, he entered an institution which had just 

 been founded with the object of mailing use for medical 

 purposes of the various varieties of gas then recently dis- 

 covered. Nothing could have been more advantageous 

 than this position for Davy's activity, for it placed at his 

 disposal a special laboratory for chemical experimxcnt. He 

 devoted special attention to nitrous oxide, which, as well as 

 other gases, he tested thoroughly by breathing it himself, 

 after finding a suitable means of preparing it. He then pub- 

 lished in the year 1 800 a special work on the subject, which 



1 See his brother John Davy's book, Memoirs of Sir Humphrey Davy, 

 London, 1836; also The Scientific Achievements of Sir Humphrey Davy, 

 by J. C. Gregory, London, 1930. Davy was of medium height, had 

 light brown hair and eyes, his head was small at the back, his hair of 

 very fine texture and slightly curly; he had an aquiline nose. 



