411 



who fired it to atoms, the report being heard several miles. 

 And if an explosion to a moderate amount should occur, 

 these goafs add their accumulated reservoirs to the general 

 conflagration. For at any explosion the fire-damp suddenly 

 and violently expands to three-and-a-half times its former 

 bulk ; pressing equally on all sides, it drives the gases out 

 of the goafs wherever its influence is exerted, — blows down 

 everything before it, — and expends its force where there is 

 the least pressure, — and usually makes an exit at one or both 

 of the shafts. The state of a colliery in such circumstances 

 was significantly described to me by Mr. Gooddison, (Mr. 

 Charles worth's viewer,) by saying " It was always to keep 

 our gunpowder too damp to take fire." " Yes," said I, 

 " but if it should become dry enough, or if a partial explosion 

 forces your gunpowder out of its magazine, it at once dries 

 and ignites it, and a general conflagration is inevitable." 

 Besides, it is impossible to keep, or know that, the fire-damp 

 in these places always contains less than | of, or more than 

 If of atmospheric air ; or whether it is in an inflammable 

 state or not. In mines thus ventilated, no naked candles 

 should be permitted. 



There is one more source of danger frequently occurring 

 in coal just laid bare, and particularly in the neighbourhood 

 of small faults, that is, from sudden small outbursts of gas, 

 called blowers. The explosion at Killingworth, on the 16th 

 of April, 1845, is an example. These blowers give no notice 

 of their approach, and frequently emit during the night, &c., 

 a very considerable quantity of gas. It is usual, in board- 

 gates, for the men to fire the gas which has thus accumulated ; 

 but in the neighbourhood of goafs, or when the whole 

 ventilation of the pit is not very perfect, it is a dangerous 

 experiment. 



In conclusion, I beg leave to suggest some methods which 

 are calculated to diminish the risk of accident. 

 1. I am firmly convinced that no great improvement can 



