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but a liberal deduction for lost time during the last winter it leaves £2,000 as profit on the workings. A great many contrivances have been adopted to crush up this cement, but all of them have hitherto proved failures. Mr Jackson, the engineer and superintendent of the company, states that he finds it most advantageous to blast it into small blocks, so that it can be broken up with hammers and picks by manual labour, small enough for the water from the nozzle to pulverise it before sending it down to the elevator. There are three elevators at work in this claim. No. 1 is lifting 66ft., the jet being 3Jin. in diameter, and the hydraulic head 445 ft. The water is supplied from a pipe 15in. in diameter and 1,740 ft. in length. No. 2is lifting 62ft. sin., having a jet of 3Jin. in diameter under a hydraulic head of 400-sft., the supply-pipe being 15in. in diameter and 1,580 ft. in length. No. 3is lifting 42ft., having a jet of 2fin. in diameter under a hydraulic head of 354 ft., the supply-pipe being 15in. in diameter and 1,333 ft. in length. The sluicing nozzle for these elevators is 4in. in diameter, under a hydraulic head of 400-sft., and the water is supplied from a pipe llin. in diameter and 1,580 ft. in length. As the whole of these measurements have been accurately made by the superintendent, the ratio of power to carry on hydraulic operations can be fairly ascertained. There is, however, one element which enters largely into the calculation which is not supplied: that is, the diameter of the throat-piece ; but if it is assumed that the throat-piece is in proportion to the head and jet, the following will show the ratio of each elevator : — No. 1 Elevator : Jet 3Jin., supply-pipe 15in. and 1,740 feet in length, head 445 ft. The discharge from a jet under a 445 ft. head = about 9-35 cubic feet per second, which is equal to a velocity of 7'6ft. per second in the supply-pipe. The loss in head due to this velocity and length of pipe is equal to 24ft.—namely, H = —» — where P = perimeter of the pipe, I — the length, c = a co-efficient given by Mr. J. T. Fanning, v = the velocity, a = the area, and g = the acceleration of gravity—all in feet. Therefore, the hydrostatic head = 445 — 24 = 421 ft., and a 3Jin. nozzle under this head will discharge equal to 9-1 cubic feet per second. The sluicing nozzle being 4in. in diameter under a hydraulic head of 445 ft., and the supplypipe being 11 inches in diameter and 1,580 ft. in length, the loss in head due to the velocity of the water, the diameter and length of pipe, would be on same basis as formerly = 218 ft. Therefore, the hydrostatic head = 400-5 — 218 = 182-sft., and the discharge from a 4in. nozzle under this head is equal to 9-07 cubic feet of water per second. We have therefore, in No. 1 Elevator, 9-1 cubic feet, under a hydrostatic head of 421 ft., working the elevator, where there is 18-17 cubic feet of water to lift, exclusive of any material, 66ft. high. The ratio of the power, therefore, required to work this elevator = m * m = 3-18. As this sluicing-nozzle is common to all the elevators, the ratio of the No. 2 elevator would be as follows: Jet, 3Jin.,; head, 400-sft.; pipe 15in. in diameter; and length, 1,580 ft. The discharge from the jet under a head of 400-sft. = 8-88 cubic feet per second, which is equal to a velocity in the pipe of 7-23 ft. per second. The loss of head in the supply-pipe due to this velocity = 20-Bft., therefore the hydrostatic head = 400-5 — 20-8 = 379-7 ft., and the discharge from the jet under this head = 8-64 cubic feet per second; therefore the ratio of the power required = 8-64x379-7 Q no 17-71 X 62-41 - &UA - No. 3 elevator : Jet, 2fin.; supply-pipe, 15in.; length, 1,333 ft.; head, 354 ft. The discharge from the jet under a head of 354 ft. = 5-43 cubic feet per second, which causes a velocity in the pipe 4-43 ft. per second, and this velocity in the length of the pipe is equal to a loss of 7ft. of the head. Therefore the hydrostatic head = 354 — 7 = 347 ft., and the discharge from the jet under this head 5 - 38x347 = 5-38 cubic feet per second. The ratio of power used is equal to -~,,,,; = 3-14. The respective ratios are therefore as follows :— No. 1 elevator ... .. ... ... ... 3-18) No. 2 „ ... ... ... ... ... 3-021 mean, 3-11. No. 3 „ ... ... ... ... ... 3-14) This means that the mean of the ratio of power used to work effectively these elevators is 3-11 times the actual power required to lift the water, exclusive of the w r eight of material. However, the weight of the material lifted forms only a small factor in the weight in proportion to the water. Suppose, for example, that the quantity of water lifted by the No. 3 elevator be taken—namely, 14-45 cubic feet per second, this is equal to 9331b.; whereas the weight of the material lifted in the same period of time would not be more than 601b. The friction of the shingle and stones going up the elevating-pipe would, however, be considerable, the velocity being about 12ft. per second. In comparing these elevators with those at work elsewhere, they will bear a favourable comparison. In blasting the cement, Mr. Jackson found that roburite is the most economical explosive, it being considerably cheaper than dynamite and nearly the same strength. This explosive is said to consist of chlorinated dinitro-benzol mixed with ammonia-nitrate in certain proportions, and it is claimed that it has a flameless detonation. It, however, requires a much stronger detonator to explode it than dynamite. Where this auriferous cement came from is still a question not easily solved. The bed-rock on the one side is laid completely bare, and is quite hard and smooth, and shows that the depression through the range between Gabriel's and Monro's Gully is more due to a slide, that has at a very recent period taken place, than exclusive glacial action ; at all events, the rude stratifications of the cement itself shows that it has an inclination towards the north-east or face of the slide. The face of the slide itself is a highly indurated sub-schistoze rock, produced, no doubt, by the frictional heat when the movement took place ; and tho face of it presents a highly-polished slickenside, on which the blue cement abuts, having a thin film of glassy silica on the surface. If the depression