198 Suggestions arising from 



All the lamps that I have examined have at different times 

 been red hot ; and a workman at the Hcbl)urii colliery showed 

 me a lamp, which, though it had been in use about sixteen hours 

 a-day, for nearly three months, was still in excellent condition: 

 he also said it had been red hot sometimes for several hours 

 together. Wherever workmen, however, are exposed to such 

 liighly explosive mixtures, double gauze lamps should be used, 

 or a lamp in which the circulation of air is diminished by a tin- 

 plate reflector placed in the inside, or a cylinder of glass reaching 

 as high as the double wire, with an aperture in the inside ; or 

 slips of Muscovy glass may be placed within the lamp, and in 

 this way the quantity of fire-damj) consnujed, and consequently 

 of heat produced, may be diminished to any extent. Such lamps 

 likewise may be more easily cleaned than the simple wire-gauze 

 lamp; for the smoke may be wiped ojf in an instant from the 

 tin-plate or glass*. 



If a blower or strong current of fire-damp is to be approached, 

 double gauze lamps, or lamps in which the circulation of air is 

 interrupted by sli^js of metal or glass, should be used ; or, if the 

 single lamp be employed, it should be put into a connnon horn or 

 glass lanthorn, the door of which may be removed or open. 



The wire gauze is impermeable to the flame of all currents of 

 fire-damp, as long as it is not heated above redness ; but if the 

 iron wire be made to burn, as at a strong welding heat, of course 

 it can be no longer safe; and though such a circumstance can 

 perhaps never happen in a colliery, yet it ought to be known and 

 guarded against. And if a workman, having a single lamp, should 

 accidentally meet a blower acting on a current of fresh air, he 

 ought, on finding his lamp becoming hot, to take it out of the 

 point of mixture, or screen it from the current. 



I have had an excellent opportunity of making experiments on 

 a most violent blower, at a mine belonging to J. G. Lambton, esq. 

 some of them in the presence of Mr. Lambton : in most of them 

 Mr. Buddie assisted. This blower is walled off from the mine 

 and carried to the surface, where it is discharged with great 

 force. It is made to pass through a leathern pipe, so as to give 

 a stream, of which the force was felt at about two feet from the 

 a])erture in a strong current of air. The common single working 

 lamps and double gauze lamps were brouglit upon this current, 

 both in the free atmosphere and in a confined air. The gas fired 

 in the lamps in various trials, but did not heat them above dull 

 redness, and when they were brought far into the stream they 

 were finally extinguished. 



* Models of the dilTcieiit moililicntions of tlie wirc-gaiize safety-lamps 

 may be seen at the sliop of Mr. Coxe, brass- founder, in Gateshead, by 

 whom they were made. 



A brass 



