1874.] ( 119 ) 
PROGEESS: IN. SC LENCE 
MINING. 
STATISTICS of considerable interest in connection with the coal-produce of 
this country have been published during the past quarter. The official returns 
furnished by the twelve Government Inspectors to the Home Office show that 
in 1872 there were 3016 collieries at work in Great Britain. In the previous 
year the number of mines was 3100. But in 1871 the number of coal-miners 
employed reached 418,088, whilst in 1871 the colliers numbered only 
370,881. It appears that during 1872 the amount of coal raised was 
123,393,853 tons, compared with 117,439,251 tons during the preceding year. 
This gives a decrease in the amount of coal raised per man; for whilst the 
average quantity gotten by each miner in 1872 was 295 tons, it amounted to 
316 tons per manin 1871. As to the accidents, we note an increase in their 
number, but a slight decrease in the resulting deaths. Thus, in 1872 there 
occurred 894 separate fatal accidents, resulting in the loss of 1060 lives; in 
1871 there were only 826 similar casualties, but they represented a sacrifice of 
1075 lives. As usual only a small proportion of the deaths could be traced to 
explosions of fire-damp; indeed, out of the ro60 deaths in 1872 only 154 were 
due to such explosions. 
It is not long since we called attention to some investigations on the 
connection between colliery explosions and the state of the weather, under- 
taken by Mr. R. H. Scott, F.R.S., of the Meteorological Office, and Mr. W. 
Galloway, who is now Assistant-Inspector of Mines in Scotland. These 
observers have since extended their researches, and have recently published 
an analysis of the catalogue of accidents which occurred during the year 1871. 
On the whole there were 207 explosions of fire-damp, of which 52 were attended 
with fatal consequences. It is believed that 113 of these explosions, or55 per cent 
may be traced to the low state of the barometer: and that 39, or 1g per cent, 
are referable to a rise of temperature; whilst the remainder are unexplained 
by either of these meteorological causes. The paper contains some valuable 
instructions respecting the method of recording barometric and thermometric 
observations ; these, of course, deserve careful study by the miner, especially 
now that the Coal Mines’ Regulation A& of 1872 requires that ‘after 
dangerous gas has been found in any mine, a barometer and thermometer shall 
be placed above ground in a conspicuous position near the entrance to the 
mine.” With regard to atmospheric pressure, the authors remark that 
if the barometer, after having remained nearly stationary for several days, 
descend half an inch or an inch during the next two or three days, the miner 
may expect to find fire-damp in greater quantity than usual in cavities in the 
roof and in the higher parts of the workings, and it may also appear where it 
had not been previously detected. If the temperature rise to 55° or upwards, the 
ventilating current is likely to be retarded. A sudden fall of the barometer— 
an inch in twenty-four hours or so—or a further fall after it has been unusually 
low for a day or two, points to the possible escape of gas, and calls for in- 
creased ventilating power, especially if the diminution of pressure be coupled 
with a rise of temperature. 
We may observe that Mr. Galloway obtained the first of the prizes offered 
by Mr. Hermon, M.P., for Essays on the Prevention of Colliery Accidents. 
This Essay, which has recently been published in the “‘ Mining Journal,” is 
worthy of attentive study by those who have charge of our coal-mines. 
Coal-cutting machinery received a fair share of attention in the Mechanical 
Section of the British Association at the late Meeting. Mr. Firth, of Leeds, 
well known for his zeal in promoting the use of such machines, read a paper 
“On the Introdu@tion of Working Coal-Cutting Machinery in Mines.” In 
this communication he described in detail his own form of coal-cutter, worked 
