On the Controversy concerning Safe-lamps. 23 



as much as to counterbalance the loss on the small ones, (on 

 Horses and foot-passengers, &c.) by their being made Decimal, 



" Canal Tolls, as well as the Customs and other Taxes to 

 Government are many of them charged in small money, not 

 exactly reducible to Jec/w2«/ Money, yet these tolls and dnties are 

 always p«»/, on pretty cons'tdeiabte quuntUies ; so that the giving 

 up of they raci (07/ oj' a farthing in the whole amount , on either 

 side, so as to Receive in Decimal Money, could not be an object of 

 material consequence ; indeed, whenever the Mites should exceed 

 12, one more Thousandth might be payable, in this and other cases, 

 whicli, in the long-run, would balance the errors. I shall be 

 happv to give any further explanations in my jjower, before leav- 

 ing Town, which I hope will be in the end of the week, Mr. 

 M'Millan now having tlie Index to my last volume of Report, 

 in his press. 



" I am, &:c." 



III. On the Article in our last Number, entitled" Controversy 

 concerning Safe-lamps." By W. P. Kmght, Esq. 



To Mr. Tilloch. 



Sir, — i- PERL'STiD, with a certain degree of surprise, an article 

 in your excellent Magazine, entitled " Controversy concerning 

 Safe-lamps," which you introduce by expressing an opiu'on 

 that "you had conceived that the discoveries of Sir H. Davy 

 and Mr. George Stevenson were made independent of each 

 other." I do not think the question of dates so near to each 

 other of any importance; and I am still inclined to think that 

 Mr, Stevenson began, without knowing what Sir H. Davy was 

 doing, though he probably did hear that he was engaged in the 

 inquiry. 



When I first saw the account of Mr. G. Stevenst)n's lamp in the 

 Philosophical Magazine, I had an idea that it vvas a lan;p which 

 might burn safclv in explosive atmo'^pheres: but having seen the 

 lamp during a journey tliat I made in tiie north of England 

 this^ummer, I was obliged to give iij) this opinion; and since 

 I have read Mr, R. W. Brandling's letter, 1 am convinced that 

 Mr. Stevenson never made any discovery, and that there is uot 

 the slightest analogy between what he attempted and that wliich 

 Sir H. Davy discovered and carried into execution. 



It is said " that Mr. G. Stevenson had conceived an idea that 

 hydrogen gas might be admitted into a lamp so as to be gra- 

 dually consumed." If any thing be meant by this idea, it must 

 bo— that explosive mixtures admitted into a hlntcrn in small 

 B 4 quantities 



