283 LIGHT SCIENCE FOR LEISURE HOURS. 



and intelligence should Jbe exhibited in its use. On 

 this point Professor Tyndall remarks that, unfortu- 

 nately the requisite intelligence is not often possessed 

 nor the requisite caution exercised by the miner, " and 

 the consequence is that, even with the safety-lamp, 

 explosions still occur." And he suggests that it would 

 be well to exhibit to the miner in a series of experi- 

 ments the properties of the valuable instrument which 

 has been devised for his security. " Mere advice will 

 not enforce caution," he says ; " but let the miner have 

 the physical image of what he is to expect clearly and 

 vividly before his mind, and he will find it a restrain- 

 ing and monitory influence long after the effect of 

 cautioning words has passed away." 



A few words on the history of the invention may 

 be acceptable. Early in the present century a series 

 of terrible catastrophes in coal-mines had excited the 

 sympathy of enlightened and humane persons through- 

 out the country. In. the year 1813, a society was 

 formed at Sunderland to prevent accidents in coal- 

 mines, or at least to diminish their frequency, and 

 prizes were offered for the discovery of new methods 

 of lighting and ventilating mines. Dr. "William Reid 

 Clanny, of Bishop wearmouth, presented to this society 

 a lamp which burned without explosion in an atmos- 

 phere heavily loaded with fire-damp; for which in- 

 vention the Society of Arts awarded him a gold medal. 

 The Eev. Dr. Gray called the attention of Sir Humphry 



