Letter to the Dublin Societij on tVlieel-carriages. S3 



rlers the deepest and most valuable coal-mines securely accessi- 

 ble to the workmen. If the Romans decreed a civic crown, to 

 the man who saved the life of a single fellow-citizen, what grati- 

 tude is due to him, whose genius has afforded the means of saving 

 hundreds from a horrible death, and their families from hopeless 

 indigence ! I am, dear sir. 



Your very obedient servant, 

 London, July 29, 1816. ANDREW UrR. 



The engraver of the wood-cut of 

 Sir H. Davy's lamp has not been 

 able to represent the decussations of 

 the wire-cloth. KK are the rings 

 by which it is suspended to the belt 

 of the miner ; H is the metal disc 

 at top, to which is attached the 

 short cylinder of wire-cloth G, 

 which embraces closely the longer 

 cylinder FI, rising from the bottom 

 B. D is the wick; C an inclined 

 tube bv which oil is supplied to the 

 body of tlie lamp ; and E is a wire 

 passing up, pretty tightly through a 

 ^mall tube, nearly in the middle of 

 the lamp. This wire is bent at top, 

 so that when it is worked with the 

 hand applied to its lower extremitv, 

 the wick may be readily trimmed 

 without unscrewing the cage. 



Such lamps may now be had at 

 the chemical laboratory of Messrs. 

 Accuui and Garden, for seven shil- 

 lings. 



XXII. A Letter to the Dublin Societij, relative to Experiments 

 on PVIieel-carriages . By Rjch. Lovell EoGEWORTHjEi^. 



To the Committee of Natural Philosophy of the Dublin Society. 



GiiNTLEMEN, — 1 HAVE the houour to return to you a Report 

 I'f the experiments tried by me, under your directions, at the 



F 2 latter 



