Life of Sir Humphry Davy. 577 



He left Paris for Montpelier on the 29th of December, where 

 he remained a month, and worked upon the subject of iodine 

 in the laboratory of M. Berard : from thence he went by way of 

 Turin to Genoa, and then proceeded to Florence, where he experi- 

 mented in the laboratory of the Accademia del Cimento on iodine, 

 but more particularly on the combustion of the diamond. He 

 quitted Florence on the 3d of April, and entered Rome on the 6th ; 

 here he renewed his researches on the combustion of different kinds 

 of charcoal, and transmitted two papers to the Royal Society, the 

 one containing his further experiments on iodine, the other * On 

 the Combustion of the Diamond and other Carbonaceous Sub- 

 stances.' Dr. Paris observes, 



' that the experiments which Davy conducted at Florence and Rome 

 have removed several important errors in regard to the nature of car- 

 bonaceous substances ; and though they may not encourage the labours 

 of those speculative chemists who still hope to exemplify the old proverb 

 carbonem pro thesauro, by manufacturing diamonds out of charcoal, 

 they certainly show that they are less chimerical than those of the wild 

 visionaries who sought to convert the base metals into gold. 1 



On the 8th of May, he arrived at Naples, and visited Vesuvius 

 and the volcanic country around it. He also took great interest in 

 the excavations, at that time going on at Pompeii under Murat, 

 then King of Naples, who placed at his disposal several specimens 

 of art, which Davy received with a view to investigate the chemical 

 composition of the colours used by the ancients. The results of 

 his inquiry were communicated on the 23d of February, 1815, 

 in a paper ' On a Solid Compound of Iodine and Oxygen,' on 

 April 10, and another ' On the Action of Acids on the Salts 

 usually called Hyper-oxymuriates, and on the Gases produced from 

 them,' on May 4. Before he finally quitted Italy, he again spent 

 three weeks at Naples, during which he experimented on iodine 

 and fluorine in the house of Sementini, and paid several visits 

 to the crater of Vesuvius. He returned to England through 

 Germany and Flanders, and arrived in London in April 1815. 



The invention of the SAFETY LAMP, of which Dr. Paris has given 

 a most interesting detail is, as he observes 



* a discovery which, whether considered in relation to its scientific import- 

 ance, or to its great practical value, is one of the most splendid triumphs 

 of human genius. It was the fruit of elaborate experiment and close 

 induction ; chance or accident, which comes in for so large a share of 

 the credit of human inventions, has no claims to prefer upon this occa- 

 sion ; step by step he may be followed throughout the whole progress of 

 his research, and so obviously does the discovery of each new fact 

 spring from those that preceded it, that we never for a moment lose sight 

 of the philosopher, but keep pace with him during the whole of his 

 inquiry.' 



His attention was called to the subject by Dr. Gray (now Lord 

 Bishop of Bristol), then Rector of Bishop Wearmouth, a zealous 

 member of the association which had been formed *for the Prevent 



