Page:The empire and the century.djvu/637

 the land can be turned to account remains to be demonstrated. Certain it is, however, that much of the soil is capable of producing the staple commodities for man and beast, and nothing but a lack of enterprise or a little intelligent industry will stand in the way of the whole of the horses, stock, and sheep requisite for internal use being produced in South Africa. The results obtained in the past cannot be taken as any criterion for the future, because the discovery and working of minerals have created markets that were non-existent in the old days. In South Africa mineral wealth is the pioneer that furnishes a reason for, and will more and more supply the means of, establishing industries to support the growing population in the distant future when the mines cease to produce. So great, however, is the proved extent of the gold beds of the Witwatersrand alone, to take one example, that at the present rate of working it would take the best part of one hundred years to see their exhaustion. The conglomerate deposits are proved to continue in a comparatively unbroken easterly and westerly line for a distance of sixty-one and a half miles. They are tilted at an average angle of about 30 degrees from the horizontal.

It is impossible to determine the vertical depth at which it will be profitable to continue mining. Claim licenses are held upon ground in which it would be necessary to sink from 8,000 to 10,000 feet before striking the reefs; and although this depth is greater than any at which successful mining operations have hitherto been carried on in the world, it is reasonable to expect that greater depths will be successfully reached in that region than in any other part of the globe, because the temperature of the earth, so far as tests at present indicate, only rises one degree for every 208 feet sunk, whereas the average in other parts of the world is about one degree for every 65 feet.

Leaving aside problematic depths, however, and assuming a working depth of 4,000 feet vertical, which