Coal: Its Value and Power page 3

It is, however, possible that means may in the future be found of working coal at depths below 4,000 feet. With this possibility in view, the commissioners inquired into the probable contents of the coal-measures at upwards of 4,000 feet beneath the ground. Within the area of known coal-fields they estimated the quantity at 7,320 millions of tons, 5,922 millions of which are between 4,000 and 6,000 feet below the surface, and the remainder, 1,398 millions, at depths of 6,000 to 10,000 feet. Besides this, they estimated that beyond the known coal-fields below and between the Permian and other newer strata, there exist 41,144 millions of tons of coal at more than 4,000 feet from the surface. Of this, 25,841 millions are computed to lie at between 4,000 and 6,000 feet deep, and 15,303 at between 6,000 feet and 10,000 feet. At 6,000 feet below the surface the temperature of the earth is computed to be 1509 Fahrenheit, while at 10,000 feet down it is estimated to be not less than 215p Fahrenheit, or three degrees higher than the temperature of boiling water - a sufficient proof of the impossibility of the strata at that depth ever being approached by man, unless the progress of science should enlarge his powers in a manner at present unknown and impossible. And, indeed, it is not impossible that the heat may be even greater than has here been stated. The deepest mine in Great Britain is that at Rosebridge, where at the latest reports the shaft had already reached 2,376 feet below the surface, and was still being carried lower. There it was found that after a depth of 1,800 feet had been reached, the heat increased at a considerably more rapid rate than the standard of 1° Fahr, for 60 feet of descent. At the bottom of the pit, at the depth indicated, the thermometer already stood at 92°. This, however, may possibly prove to be due to local and special causes.

The result of the inquiry into the contents of the British coal-fields, therefore, showed that there were altogether probably not far short of 200,000 millions of tons within 10,000 feet of the surface, of which 148,460 millions were within 4,000 feet from the surface. As this is all that can reasonably be expected to be available, it would last 1,273 years if the consumption remained at 115 millions of tons a year - the amount estimated by the commission to have been consumed in 1869. It would, however, only last 276 years on the supposition of an annual increase of three millions of tons in the consumption - this being the average increase of the fourteen years preceding that when the commissioners made their estimate. According to another method of calculation, suggested by Mr. Price Williams, it would last 360 years. These are, after all, mere estimates.. How long it will be before the coal-fields of England are practically exhausted, is a matter which science is unable to reveal, and which history alone will be able to tell. One thing, however, follows clearly from the report of the commissioners, and that is the negative conclusion already arrived at by Professor Jevons, that the present rate of increase in the consumption of coal cannot long endure, and that as it diminishes so the material prosperity of the country must suffer.

To this result the commissioners themselves arrived. The concluding words of their report are as follow: -

"It is certain that if the present rate of increase in the consumption of coal "be indefinitely continued even in an approximate degree, the progress towards the exhaustion of our coal will be very rapid.

" In all the foregoing estimates of duration we have, for the sake of simplicity, excluded from view the impossibility of supposing that the production of coal could continue in full operation until the last remnant was used, and then suddenly cease. In reality a period of scarcity and dearness would first be reached. This would diminish consumption and prolong duration; but only by checking the prosperity of the country.

" The absolute exhaustion of coal is a stage which will probably never be reached. In the natural order of events, the best and most accessible coal is that which is the first to be worked, and nearly all the coal which has hitherto been raised in this country has been taken from the most valuable seams, many of which have in consequence suffered great diminution. Yast deposits of excellent and highly available coal still remain; but a preference will continue to be given to the best and the cheapest beds; and as we approach exhaustion the country will by slow degrees lose the advantageous position it now enjoys in regard to its coal supply. Much of the coal included in the returns could never be worked except under conditions of scarcity and high price. A time must even be anticipated when it will be more economical to import part of our coal than to raise the whole of it from our residual coal-beds; and before complete exhaustion is reached, the importation of coal will become the rule and not the exception of our practice. Other countries would undoubtedly be in a position to supply our deficiencies, for North America alone possesses tracts of coal-bearing strata, as yet almost untouched, of seventy times the area of our own. But it may be doubted whether the manufacturing supremacy of this kingdom can be maintained after the importation of coal has become a necessity."

The average thickness of the seams in Belgium is -estimated at sixty feet, and the coal contained in all the seams together in that country amounts to 36,000 millions of tons. The quantity in France, where the thickness is also estimated at sixty feet, is computed at 59,000 millions of tons. In the British Islands the average thickness is taken at thirty-five feet, and the total contents of the coal-beds are estimated at 190,000 millions of tons. The quantity in the British Islands is, therefore, twice as much as that in France and Belgium together. But compared with the contents of the North American coal-beds, those of Europe sink into comparative insignificance. The total quantity contained in the coal- measures of North America is estimated at four millions of millions of tons (4,000,000,000,000), or more than twenty times as much as that contained in the coal- measures of the United Kingdom. But the production of coal in America is on the other hand very small compared with that of Great Britain. The total produce of America for the whole thirty-five years from 1820 to 1855 was no more than was produced by the single coalfield of Northumberland and Durham in the four years from 1851 to 1855. The total amount produced in the United States in 1855 was only 7,600,000 tons, a quantity no greater than was produced in that year by Scotland alone. Great Britain has, in fact, become the great coal- producing country of the world. She raises indeed considerably more than all the other countries of the world put together. In 1866 it was computed that there were 170 millions of tons produced in the whole world. Of that quantity 101,630,544 were raised in the United Kingdom alone. It is clear, however, from these very facts that Britain is using her coal more rapidly than any other nation, and that the more quickly she proceeds in the process of exhausting the contents of her coal- measures, the sooner the day will come when the advantages derived from coal will lie with those countries whose stores are comparatively intact.