July, 1905.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



that the curve between the north and presumed south 

 outcrops is not symmetrical. In fact, the bed of the 

 area has a more or less level bottom, being a series of 

 synclines and anticlines. 



Gold mining is everywhere a highly speculative 

 undertaking, but in the Transvaal great reliance 

 can be placed upon the regularity of the ore deposits. 

 This justifies very heavy preparatory outlays. It is, 

 for instance, estimated that before an ordinary deep- 

 level mine can reach the producing stage the expendi- 

 ture on boring, sinking (say) two shafts, the erection 

 of a mill of 400 to 600 stamp capacity, the connecting 

 of the two shafts, and driving on the reefs to expose a 

 sufficient quantity of ore to keep the mill in operation 

 amounts to something like one million sterling. This, 

 of course, refers to a proposition where the reef 

 lies at a depth of about 3,000 feet, while the area 

 of such a mine would be something like 1,000 claims. 

 When the ore is " brought to grass," as it is termed, 

 a series of scientific processes is brought into play in 

 order to extract the precious metal. The most ap- 

 proved mechanical appliances and chemical methods 

 are drawn upon, and the leaders of the industry are 

 ever on the look-out for improvements, as the nearer 

 perfection is attained — that is, loo per cent, extrac- 

 tion — the more profitable is the result. The various 

 processes are complicated and delicate in the extreme, 

 and as each particle of gold Is mixed with, perhaps, 

 60,000 particles of rubbish, as the Transvaal tonnage 

 averaged in 1903, it can easily be conceived that the 

 slightest miscarriage would be disastrous. 



A great deal of attention has been given within the 

 past 12 months to tube, or flint, mills. Such a mill 

 at the Glen Deep consists of an iron cylinder, 22 feet 

 long and 5 feet in diameter, with hollow trunnions at 

 each end, through which the pulp to be ground passes 

 in at one end and out at the other. The trunnions 

 rest on solid bearings and the cylinder is revolved by a 

 pulley at a speed of 38 revolutions per minute. The 

 cylinder is lined with chilled steel, and inside seven tons 

 of the hardest flint pebbles are placed. The pebbles 

 are about the size of a tennis ball, and the rounder the 

 pebbles the better. One such mill can deal with the 

 coarse product from 20 stamps crushing 10 tons per 

 diem each. It is estimated that the tube mill will 

 enable the mill capacity to be doubled at the cost of 

 ;^2,ooo per 20 stamps, or ;£rio,ooo to ;^i2,ooo per 100 

 stamps, plus the extra cyanide plant and the cost of 

 something less than 40 h.p. per 20 stamps. Many of 

 the leading groups are now erecting these secondary 

 crushers. 



The high altitude of the Rand has rendered the ques- 

 tion of water supply of first importance. The mines 

 relied upon reservoirs for the collection of a sufficient 

 supply during the rainy period to carry on mills and 

 cyanide works throughout the dry season, the Johannes- 

 burg Water Works doing its best to meet the frequent 

 deficiencies. But the Transvaal Government ap- 

 pointed an investigating Commission in 1901, and in 

 May, 1903, a Water Board was established. The 

 undertakings proposed to be acquired were the 

 Johannesburg Water Works, the Vierfontein, Braam- 

 fontein, and Wonderfontein Syndicates. The last- 

 named was, however, omitted, as it was thought that 

 otherwise the irrigation of the I'otchefstroom District 

 might suffer. The Rand Water Board issued 

 ;^3,400,ooo 4 per cent, inscribed stock in March last. 

 The Board supplies towns in bulk. The mines are sup- 

 plied through mains laid along the Rand by the Board 



at the rate of 3s. 6d. per 1,000 gallons, and 3d. less 

 where not less than 300,000 gallons per day are con- 

 sumed. The rate is not cheap for mines, but when it 

 gets much beyond its present daily consumption of 

 two million gallons, a reduction will be possible. The 

 mines, of course, will not draw upon it until their 

 private reserves in dams, &c., are exhausted: The 

 advantage is that no stopping of mills need be feared 

 now, for it is estimated that about 10 million gallons 

 per diem can be obtained from the undertakings 

 acquired. 



From the above survey of the Transvaal gold mining 

 uidustry its magnitude may be g-athered and an idea 

 obtained of one of the most exact industrial organiza- 

 tions of the world. 



South Africac as at 

 Health Resort. 



Those who have visited South Africa, and made any 

 prolonged stay there, can hardly fail to be sensibly 

 impressed with its possibilities as a health resort. 



Medical men when ordering a "change," recognise 

 that the human constitution requires — above all things 

 —to be subjected to the effects of contrast. In recom- 

 mending the South African continent, this desirable end 

 is achieved in the contrasts afforded by a voyage to a 

 distant land, by climate, scenery, and inhabitants; a 

 series, making for a cumulative restorative effect. 



Climates are classified as follows :— (i), Climates of 

 the sea-shore; (2), Mountain climates; (3), Desert 

 climates; (4), Ocean climates. South Africa itself 

 partakes of the first three; and the invigorating in- 

 fluences of the last-named may be enjoyed on the voyage 

 thither. 



(a) The climate of the sea-shore of South Africa is 

 best experienced during the winter months, com- 

 mencing in April and ending in September; during 

 these months (in Natal) the season is dry. The climate 

 is warm, temperate, sub-tropical, sometimes cold; the 

 warmth, often of a hurnid nature, and for that reason 

 is, in consequence, more enervating than the South 

 African continental climates; yet it has its ozonic-tonic 

 properties. The health seeker will derive great benefit 

 from a stay at Durban, Port Elizabeth, or even Cape 

 Town, and at the same time be able to indulge in easy 

 journeys into the interior of the country, where the air 

 is more rarefied by reason of the higher altitude. The 

 best hotels are expensive, but the interests of visitors 

 are well cared for. 



(b) The term " mountain climate " applies to all eleva- 

 tions between 3,000 and 6,000 feet. Ranging between 

 these heights are the steppes of Natal, extending in a 

 series of gradually rising terraces from the sea, and 

 ending in the majestic peaks of the Drakens- 

 berg Mountains, the high veld of the Transvaal, 

 extending to the Magaliesberg Mountains, and the 

 higher tableland, having the township of Middel- 

 berg as a centre, and terminating in the north at the 

 mountains round Lydenburg. Nestling at the feet of 

 these mountains, and scattered about the kopje-dotted 

 veld, are the homes of the Boer farmers. The moun- 

 tain peaks reach as high as 12,000 feet. The climate 

 of the steppes, high veld, and tableland, is never at any 

 season too warm, when living in houses, and is gener- 

 ally dry during the winter months. In winter-time the 



