182 THE HISTORY OF SCIENCE 



ancients, his investigation of the torpedo fish, and his 

 anticipation of the arc light. 



It seems fitting that Sir Humphry Davy should 

 be popularly remembered for his invention of the 

 miner's safety-lamp. At the beginning of the nine- 

 teenth century the development of the iron industry, 

 the increasing use of the steam engine and of ma- 

 chinery in general led to great activity and enter- 

 prise in the working of the coal mines. Colliery ex- 

 plosions of fire-damp (marsh gas) became alarmingly 

 frequent, especially in the north of England. The 

 mine-owners in some cases sought to suppress the 

 news of fatalities. A society, however, was formed 

 to protect the miners from injury through gas explo- 

 sions, and Davy was asked for advice. On his return 

 from the Continent in 1815 he applied himself en- 

 ergetically to the matter. He visited the mines and 

 analyzed the gas. He found that fire-damp explodes 

 only at high temperature, and that the flame of this 

 explosive mixture will not pass through small aper- 

 tures. A miner's lamp was therefore constructed 

 with wire gauze about the flame to admit air for 

 combustion. The fire-damp entering the gauze 

 burned quietly inside, but could not carry a high 

 enough temperature through the gauze to explode 

 the large quantity outside. To one of the members 

 of the philanthropic society which had appealed to 

 him Davy wrote : " I have never received so much 

 pleasure from the result of any of my chemical la- 

 bours ; for I trust the cause of humanity will gain 

 something by it." 



Davy was elected President of the Royal Society 

 in 1820, and retained that dignity till he felt com- 



