 | 1863 - 376 pagina’s
...and that the average annual increase of the eight preceding years amounted to 2£ millions of tons. By combining the known thickness of the various workable...quantity comprised in our coal-bearing strata. Assuming 4000 feet as the greatest depth at which it will ever be possible to carry on mining operations, and... | |
 | 1863 - 404 pagina’s
...increase of the eight preceding years amounted to two millions and three quarters of tons. Let us inquire what will be the duration of our coal-fields if this...quantity comprised in our coal-bearing strata. Assuming four thousand feet as the greatest depth at which it will ever be possible to carry on mining operations,... | |
 | British Association for the Advancement of Science - 1864 - 1112 pagina’s
...Kingdom had reached the enormous total of 8C millions of tons, and that the average annual increase of the eight preceding years amounted to 2$ millions...quantity comprised in our coal-bearing strata. Assuming 4000 feet as the greatest depth at which it will ever be possible to carry on mining operations, and... | |
 | 1864 - 848 pagina’s
...British Association, at the recent Meeting at Newcastle-on-Tyne, spoke as follows on this subject : — " By combining the known thickness of the various workable...greatest depth at which it will ever be possible to cany on mining operations, and rejecting all seams of less than two feet in thickness, the entire available... | |
 | 1865 - 520 pagina’s
...and more especially the geological world — by his recent statement, which was to the effect that " by combining the known thickness of the various workable...quantity comprised in our coal-bearing strata. Assuming four thousand feet as the greatest depth at which it will ever be possible to carry on mining operations,... | |
 | 1865 - 582 pagina’s
...and more especially the geological world — by his recent statement, which was to the effect that " by combining the known thickness of the various workable...an estimate of the total quantity comprised in our ooal-bearing strata. Assuming four thousand feet as the greatest depth at which it will ever be possible... | |
 | Joseph Holdsworth - 1866 - 122 pagina’s
...last twenty years, and has probably increased tenfold since the commencement of the present century. "By combining the known thickness of the various workable...easy to arrive at an estimate of the total quantity combined in our Coal-bearing strata. Assuming 4,000 feet as the greatest depth at which it will ever... | |
 | 1867 - 378 pagina’s
...amounteJ to two and threefourths millions of tons. Let us inquire, then, what' will be the duralion of our coal-fields if this more moderate rate of increase...computing the area of the surface under which they lie, it.is easy to arrive at an estimate of the total quantity comprised in our coal-bearing strata. Assuming... | |
 | 1867 - 498 pagina’s
...tons. " Let us inquire, then, what will be the duration of our coal fields, if this more moderate rale of increase be maintained. By combining the known thickness of the various workable eeams of coal, and computing the area of the surface under which they lie, it is easy to arrive at... | |
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Let us inquire, then, what will be the duration of our coal-fields if this more moderate rate of increase be maintained. By combining the known thickness of the various workable seams of coal, and computing the area of the surface under which they lie,... 