Engineering Wonders of the World
Volume I

320 ENGINEERING WONDERS OF THE WORLD. hardest substance known. South African dia- monds are also used. A drill using chilled shot has been also employed. As regards labour, the cost has been in Australia from 15s. to 40s. per foot of depth, the deeper wells Facts and Figures. Bimerali. It a mile. The being, of course, the most ex- pensive per foot. The deep- est bore is in Queensland, at goes down 5,045 feet, or nearly well which gives the greatest flow is that at Charleville, in the same state. The flow averages over three million gallons per day. It is stated that a flow of one million gallons is sufficient for the stock on eighty thousand acres, but for agricultural purposes about four hundred acres only can be served by this quantity of water. In all, be- tween 1,300 and 1,400 bores have been sunk. From some of the deeper bores the water springs up with great violence. For instance, at Boomi, in New South Wales, the pressure at the surface of High ground Pressures. is 150 lbs. per square inch, and if the casing were carried up sufficiently high, the water would rise to 350 feet above ground level. In many of the wells this characteristic might be made a source of power. In other wells, which are called subartesian, the water, through rising from a great depth, fails to CAMBRIDGE TOWN BORE, NEAR RICHMOND, NORTH QUEENSLAND. Depth 841 feet. Output, 1,500,000 gallons per day. reach the surface, and has to be assisted to that level by pumping. An example of an average Australian arte- sian bore may fitly conclude this article. Tho Rowena bore in New South Wales struck water at a depth of 2,670 feet, and gives a flow of about Financial. 925,000 gallons per day. The water is led in various directions by an aggregate of 41 miles of distributing channels, and waters twenty- one sheep farms covering a total area of 55,405 acres. The total cost of the works came to about £3,374, and the benefit derived by the settlers is estimated at £400 per annum. The annual assessment is well under a Id. per acre, which, assuming that a sheep requires in that country 2| acres, amounts to about 2£d. per sheep per annum. The financial return to the country, taking the cost and the annual benefit as above, amounts to about 11 per cent., leav- ing a small margin for the trifling working expenses. The supply of artesian water for the immense territory which has been described opens up almost infinite possibilities for the future, providing as it will, when judiciously ex- tended, a trustworthy in- surance against the recur- rence of the disastrous droughts of the past, and sensibly affecting the wool markets of the world, and, consequently, the clothing of its people. \Thanlts are due to the Royal Colonial Institute, and to the New South Wales Government Agency, for supplying the Illustrations accompanying this Article.}