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the flame of the safety lamp, cartridges may only be used in 
stone drifts, shafts, and places where the return air does not go 
into any working places, or when no persons are in the mine. 
By the special rules, if a shot misses fire the place may not 
be examined until the lapse of an hour ; and if, notwithstanding 
adequate ventilation, the issue of gas from the strata is such as 
even to show to the lamp, not actually fire, no shot may be fired 
until the ordinary staff is withdrawn from the pit. Further 
than these rules— unless the use of powder and other explosive 
or inflammable substances be altogether prohibited — it appears 
impossible to go. 
The 46th clause of the Mines Regulation Act, 1872, pro- 
hibiting the use of gunpowder in dangerous seams, has recently 
been supported in an arbitration, conducted by Messrs. Higson 
and Wood, restraining the East Hetton Coal Company from 
using powder in working the Harvey seam on the long wall 
principle. 
In North Staffordshire and Shropshire, Mr. Wynne reports that 
the use of powder in blasting is the fruitful source of explosions 
of fire-damp ; that it shakes the roof and renders it dangerous, 
and, used indiscriminately, tends to the production of small 
coal, and the subsequent breaking- up during railway carriage of 
the large. 
In Yorkshire, Mr. Wardell reports that the Barnsley and 
Silkstone seams should be worked with the safety lamp and 
without powder. 
In Durham, Mr. Bell reports that mechanical ventilation has 
completely demonstrated its superiority to the old furnace ; and 
Mr. Wales reports that nearly all the large collieries in his 
district have large fans at work. 
The use of gunpowder in working pillars ought to be dis- 
couraged, as gas lodges in cavities in the roof, which it is im- 
possible for a " competent person ” to examine, falls of the roof 
constantly occur, and block up the air ways. After a fatal 
accident of this nature in 1876 in the 7 -feet coal at the Moss 
Pit Main, Wigan, the use of powder was replaced with good 
effect by wedges, invented by Messrs. Dingley and Ackers. 
A fatal accident occurred in the same year, while taking out 
pillars at the Westminster Colliery near Wrexham, through fire- 
damp issuing from an old goaf, igniting at the candles used by the 
men ! Naked lights are commonly used in a large number of 
collieries in North Wales ; and the district also has the unenvi- 
able distinction, according to Mr. Hall, of the largest number 
of roof accidents of any in Great Britain. In Scotland, in the 
western district, half the accidents of 1876 were due to this 
cause. In some districts, timbering is done by the men; in 
others, as in Durham, by the officials ; but even there the 
