8i6 THE POPULAR SCIENCE MONTHLY. 



tors waited on him to induce him to study the causes of the numerous 

 explosions of fire-damp which were annually attended with fearful loss 

 of life. He began his investigation by analyzing the gas and ascertain- 

 ing in what proportions its mixture with air renders it most explosive. 

 Having observed that the combustion was not communicated through 

 tubes of small dimensions, he gradually reduced the length of the tubes 

 till he found that a simple metallic gauze, with spaces not exceeding 

 -^^ of an inch square, was sufficient to prevent the burning gas on the 

 one side from igniting the explosive mixture on the other. On this 

 principle he constructed his " safety-lamp." 



At the recent celebration of the centenary of Davy's birth, held at 

 his native town of Penzance, it vras remarked by one of the orators, a 

 colliery proprietor, that but for the discovery of Davy's lamp some of 

 the best seams of coal in England would have remained unworked, or 

 could only have been worked at such cost that none but the rich could 

 afford to use coal. "Davy's lamp," he further said, "is still the best, 

 and if properly constructed, and used in conjunction with efficient ven- 

 tilation, is an infallible guide to the presence of dangerous gases." 



Urged to have his lamp patented, Davy made this noble reply : "My 

 sole object was to serve the cause of humanity ; and if I have succeeded 

 I am amply rewarded in the gratifying reflection of having done so." 

 In 1817 the colliery owners and miners of England presented Davy with 

 a magnificent service of plate worth £2,500. This was bequeathed to 

 the Royal Society by Lady Davy, who directed it to be sold and the 

 proceeds applied to the encouragement of science. 



In 1818 Davy was created a baronet. The same year he again 

 visited the Continent, traveling extensively in Germany, Hungary, and 

 Italy. The possibility of unrolling the Herculanean papyri engaged 

 his attention while in Naples, and he published observations on vol- 

 canic phenomena, and on Oersted's electro-magnetic experiments. He 

 was elected President of the Royal Society in 1820, and held that office 

 for seven years. In 1823 he succeeded in devising a method of pre- 

 venting the corrosion of the copper sheathing on ships' bottoms. 



He now fell into ill health, and but little scientific work was done 

 during the remaining years of his life. Three or four times he visited 

 the Continent, but received little benefit from the change of scene and 

 of climate. He died at Geneva, May 29, 1829, and there, in accordance 

 with his own wishes, was buried. His widow founded a prize in his 

 honor, to be awarded biennially by the Geneva Academy of Sciences 

 for " the most original and important discovery in chemistry." 



