The ascertainment of the proximate gold contents of the Transvaal mining area leads up to the question, How and when is this stupendous wealth to be rendered available? In other words, what is likely to be the gold production in the several years from now on, and how long will this rate of production continue? or what are the chances of the early exhaustion of the mining industry? To take the last item first, it is the growing conviction of Rand mining engineers that the amount of available gold is only limited by the extent to which mining operations can be prosecuted below the surface. Mining engineers had up till recently generally agreed to fix a depth of 8000 feet as the utmost limit to which mechanical appliances and other circumstances will allow them to follow the descent of the reefs, and the available gold yield is calculated on this basis. But there is no finality in this statement of depth, and already, as we have remarked, engineers are calculating for deeper delvings, and 9000 and even 12,000 feet have been spoken of. This latter increase of 4000 feet--from 8000 to 12,000 feet--would alone augment the gold estimate by 50 per cent. For the rest, and retaining the 8000 feet limit estimate as the measure of the exhaustion of the present Rand, this is naturally controlled by the rate of production per year, which itself is dependent on the particular circumstances of the industry during the period in question. The yearly production of gold from now onwards offers no insurmountable obstacle to a fairly exact appreciation. It is merely a rule of three calculation: if in the past, under given circumstances, working results have been as follows; in the future, with the same or like circumstances, the results will be such. Various computations from time to time have been made on these bases, among the most recent being those of Mr. Cooper-Key and Dr. Hatch in 1899, Mr. Goldring and Mr. Bleloch in 1901, and quite recently Messrs. Leggett and Hatch (on 47 miles of the Rand only, and working to depths of 4000 to 7000 feet). Mr. Cooper-Key's forecast, which was made in 1899, was for the output of the three following years, the war not having then been anticipated. The basis of his calculation, like that of Mr. Goldring's, was the number of stamps or the milling power employed. If in 1898, he argued, there were in work on the Central, Eastern, Far Eastern, and Western sections of the Rand 6000 stamps, at the end of 1899 this number would probably be increased by 165, or to a total of 6165; at the end of 1900 the increase made would be 1730 and the total 7895; at the end of 1901 the total would have risen to 9845; and at the end of 1902 to 11,785. On the basis of 1800 tons milled per stamp, of an average value of £2 per ton, and with an average number of stamps of 7000, 9000, and 10,500 in the three years, the output would have been: 1900, £25,200,000; 1901, £32,400,000; and 1902, £37,800,000. Mr. Goldring, who is the Secretary of the