878 



SEC. 16. GEOLOGY AND MINING. 



North of England Institute of Mining and Mechanical 

 Engineers. 



3409. Rudiments of Apparatus constructed by Sir Hum- 

 phry Davy during his researches on the Safety Lamp. 



The Royal Institution of Great Britain. 

 Phil. Trans. 1815 to 1817. 



3409 a. Mining Lamp, 



M. Breguct, Paris. 



3410. Specimen of the General Map of the Belgian 

 Mines (a chromo-lithographic sheet, 0'46 m by 0*60, with a MS. 

 or printed note). 



This map, to a scale of 1 : 5000, represents a section of the coal 

 basin comprised between two horizontal planes at the levels of 140 

 and 190 below the sea. It was executed by order of the Public 

 Works Department, and the General Map will be completed in 

 six or seven years. J. van Scherpenzcel Thini, Liege. 



3411. Bidder's Patent Magnetic Lock for Miners' Safety 

 Lamps. S. P. Bidder. 



All previous inventions have failed to prevent the men from opening their 

 lamps with forged keys or other implements, and it is well known that a large 

 proportion of explosions have occurred from this dangerous practice. It is 

 evident that safety can only be secured by rendering the opening of the lamp 

 impossible by any means, short of its destruction, which are available to the 

 colliers. 



This important desideratum is supplied by these lamps, which are secured 

 by a self-locking catch, which comes into action when the bottom of the lamp 

 is screwed home, and it can only be opened by means of a powerful magnet, 

 which is kept in a strong box, under lock and key, in charge of the lamp 

 cleaner. 



Another magnet may be put under the care of a fireman in the pit, 

 whose duty it will be to re-light lamps which have been put out by accident 



