Safely -lamp Controversy. 69 



It is evident from all that Mr. Stevenson has said in his evi- 

 dence, and from every thing that has been said for him, that his 

 original idea was to burn the fire-damp, or, as he and the Com- 

 mittee choose to call it, hydrogen, from a blower, at a small tube 

 or tubes in a vessel so confined that the whole current of the 

 blower could not be fired from it. This explains every thing ; 

 *' his burning the hydrogen in detached portions," tlie top of 

 his apparatus being ojien to admit air, and his putting his tube- 

 lamp in the current of a blower. 



That he had no notion of the nature of explosive mixtures, or of 

 explosions not passing through small apertures, till long after Sir 

 H. Davy's researciies were published, is certain ; and the best 

 proofs of it are found in experiments upon his early lamps ; for 

 models of these, whenever they will burn in explosive mixtures, 

 instantly communicate explosion. 



Models of his two first pretended safe-lamps, that with the tube 

 of half an inch in diameter and slider, and that with the three 

 tubes of between l-7th and l-8th of an inch diameter, and three 

 inches and a half long, have been made ijy Mr. Newman ; and 

 one of his own original aperture lamps is preserved in the Royal 

 Institution. Any person who will take the trouble to make ex- 

 periments upon these lamps will find that they are exploding and 

 not safe-lamps. They may be made to burn pure fire-damp as 

 gas-light burners, when open at the top ; but in really explosive 

 mixtures they are almost as dangerous as naked lights ; and 

 Mr. Stevenson's own lamp, sold by him in January 1816, com- 

 municales explosion even when the larger apertures in the bot- 

 tom are closed. 



As to the lamp now used in the Killingworth colliery, it is in 

 reality one of the first forms of Sir H. Davy's lamp. Mr. 

 Stevenson does not deny oH the details of the piracy on which 

 the Committee thought proper to question him. 



However the Conmiittee may be deceived, by their want of 

 chemical information, in confounding large apertures with small 

 ones, the powers of long curved tul)es with those of short straight 

 ones in feeding flame, and the difference between tubes of half 

 an inch in diameter with sliders, and systems of tubes of 

 I-lOth of an inch, in arresting explosions; yet upon the ques- 

 tion of dates they have not any excuse of this kind to plead. They 

 quote a letter of Sir H. Davy to the Rev. John Hodgson, of the 

 19th of October, as containing a passage relating to his (Sir II. 's) 

 lamp with apertures .above and below; but omit the passage re- 

 lating to his discovery that explosive mixtures will not fire in 

 small tuljfis; and they refer to Mr. Stevenson's experiments prior 

 to the 21st of October, as if he had been trying experiments on 



E 3 the 



