Sir Humphry Davy, Bart. 85 



him again in 1820, he was become mild and gentlemanlike." 

 In 1813, ** on my speaking to him of the atomic theory in 

 chemistry, and expressing my belief that the science would 

 ultimately be referred to mathematical laws similar to 

 those which he had so profoundly and successfully esta- 

 blished with respect to the mechanical properties of matter, 

 he treated my idea in a tone bordering on contempt, as if 

 angry that any results in chemistry could even in their 

 future possibilities be compared with his own labours. 

 When I dined with him in 182Q, he discussed the same 

 opinion with acumen and candour, and allowed all the 

 merit of John Dalton." 



From Paris, Sir Humphry proceeded to the South of 

 France by Auvergne, where he examined the extinct vol- 

 canoes of that mountainous country. From thence he 

 went to Montpellier — Nice — Turin and Genoa, where he 

 made some experiments on the torpedo and on iodine. 

 At Florence, he entered upon the study of the nature of the 

 diamond, and of the difterent varieties of carbon. The 

 results of this investigation were published in the Philoso- 

 phical Transactions for 1817; his inference was, that 

 diamond is merely crystallized carbon, as Mr. Tennant 

 had formerly shewn. 



In April he advanced to Rome, where he remained nearly 

 a month, and then passed on to Naples. 



In the course of the same year, he visited Switzerland, 

 and returned to Italy, where he remained till April 

 1815, when he returned to London. In the Philosophical 

 Transactions for that year, three papers from his pen were 

 published, the results of his studies in Italy. In a letter to 

 his mother, he says, — " We have had a very agreeable and 

 instructive journey, and Lady Davy agrees with me, in 

 thinking that England is the only country to live in, how- 

 ever agreeable it may be too see other countries." 



On his return from the continent, he began to investigate 

 the properties of fire damp, for the purpose of determining 

 whether any method could be discovered of preventing the 

 dreadful accidents, which were so often occurring in coal 

 mines at that period. His attention was directed to this 

 subject first, *' in August 1813, in consequence of a letter 

 from the Rev. Dr. Grey." 



