228 AXNUAL OF SCIENTIFIC DISCOVERY. 



cient to frighten some ; but in comparison with the ine thousand and 

 odd gallons at Murton it was nothing. 



" There arc pits where, long after coal has been for many years ex- 

 tracted from them, the waters break in and flood the mine. In these 

 instances, again, great enterprise is manifested. In the case of the 

 ' drowned ' colliery at Jarrow, an attempt was made a few years ago 

 to draw off the water and to resume ordinary operations. But the 

 sum of one hundred and ten thousand dollars was spent fruitlessly in 

 this attempt, and it was ultimately abandoned without drawing up a 

 single ton of coal. 



" Whence alt this subterranean water comes is an interesting ques- 

 tion, but scarcely capable of receiving a satisfactory reply. Its amount 

 must be immense to afford nearly ten thousand gallons per minute at 

 one sinking, and probably it is the accumulation of numberless cen- 

 turies of surface-waters which have percolated through the porous 

 strata. It is always threatening, and never materially diminished, as 

 respects its vast aggregate, by any efforts of man ; on the contrary, it 

 is always gaining QU man and filling up his excavations. No less than 

 thirty-six collieries near the river Tyne have been, in mining phrase, 

 * drowned out,' or rendered unworkable by an irresistible irruption of 

 water, after the best main Wallsend seam had been nearly exhausted. 

 These stand in the coal district like closed factories in the cotton towns, 

 with this difference, that the cotton factories may be reopened and 

 busily at work again, while the drowned collieries are probably 

 drowned for all future time." 



Exhaustion of the British Coal Mines. The subject of the possi- 

 ble exhaustion of the British coal mines formed a leading topic of con- 

 sideration in the address of the President of the British Association for 

 1863, Sir W. Armstrong. " If we contemplate," he says, " the rate at 

 which we are expending those seams of coal which yield the best qual- 

 ity of fuel, and can be worked at least expense, we shall find much 

 cause for anxiety. We have already drawn from our choicest mines a 

 far larger quantity of coal than has been raised in all other parts of 

 the world put together, and the time is not remote when we shall have 

 to encounter the disadvantages of increased cost of working and dimin- 

 ished value of produce. The estimates which have been made at vari- 

 ous periods as to the time requisite to produce complete exhaustion of 

 all the accessible coal in the British Islands, are extremely discordant ; 

 but the discrepancies arise, not from any important disagreement as to 

 the available quantity of coal, but from the enormous differences in 

 the rate of consumption, at the various dates when the calculations 

 were made, and from different estimates of the probable increase of 

 consumption in the future. The annual product of the British coal 

 mines has almost trebled within the last twenty years, and has prob- 

 ably increased tenfold since the commencement of the present century ; 

 but as this increase has taken place pending the introduction of steam 

 navigation and railway transit, and under exceptional conditions of 

 manufacturing development, it would be too much to assume that it 

 will continue to advance with equal rapidity. The statistics collected 

 by Mr. Hunt, of the Mining Records Office, show that at the end of 

 1861 the quantity of coal raised in the United Kingdom had reached 

 the enormous total of 86 millions of tons, and that the average annual 



