a—4

6

engine of a class such as would be commonly used. Assuming that an engine of thirty or forty indicated horse-power could be made to work at 41b. of coal per indicated horse-power per hour each, allowing, say 15 per cent, extra for friction, the amount of coal per annum per break horsepower would be nearly 16J tons. This result is hardly likely to be obtained with the average engines and boilers met with in the mining districts; as, even with the best makers' engines it is only by using first-class coal, experienced engine-drivers, and working under most favourable conditions for a short time, that the economical results claimed by them is arrived at. Those who are most interested in the scheme can form the best opinion, by comparing figures here given with their monthly coal-bills, remembering that the power given out by the electric motors is effective, not nominal or indicated horse-power, and that it includes cost of motors. The result of such comparisons would be, no doubt, that they will find that steam-power costs them nearly three times the amount. The number of motors allowed for in the two estimates is five and seven respectively. Fewer motors, but of larger power, would be employed if the plant was contained in one large batteryhouse.

Estimated Cost of Plant, and Annual Working-expenses, to deliver 165 Brake Horse-power at Kuaotumt: Power electrically transmitted from Gumtown on the Waiwawa River. £ s. d. Water- and tail-race ... ... ... ... ... 5,000 0 0 Water-pipes ... ... ... ... ... ... 445 0 0 Turbines and fittings ... ... ... ... . . 500 0 0 House for turbines and generators ... ... ... ... 250 0 0 House for transformers at Kuaotunu... ... ... ... 100 0 0 Electrical apparatus, poles, insulators and wires ... ... 6,553 0 0 Packing, freight, insurance, and general shipping-charges ... 573 15 0 Freight and cartage from Auckland, 90 tons, at 20s. ... ... 90 0 0 Erecting-pipes, turbines, generators, transformers, and power-line 375 0 0 Supervision ... ... ... ' ... ... ... 300 0 0 Sundries ... ... ... ... ... ... 100 0 0 £14,286 15 0 Yearly Cost. =i^=ii===is £ s. d. Interest, 6 per cent, on £14,286 15s. ... ... ... 857 3 8 Depreciation, 5 per cent, on £9,286 15s. ... ... ... 464 6 9 Depreciation, 2-J- per cent, on £5,000 ... ... ... 125 0 0 One engineer ... ... ... ... ... ... 250 0 0 One assistant ... ... ... ... ... ... 200 0 0 Two men at £15 per cent. ... ... ... ... ... 300 0 0 Oil and sundries ... ... ... ... ... ... 100 0 0 £2,296 10 5 Annual cost per brake horse-power at Kuaotunu, £13 18s. 4^d. Estimated Cost of Plant, and Annual Working-expenses, to deliver 219 Break Horse-power electrically transmitted from Gumtown, on the Waiwawa River. £ s. d. Water-and tail-race ... ... ... ... ... 5,000 0 0 Water-pipes ... ... ... ... . . ... 650 5 0 Turbines and fittings ... ... ... ... ... 700 0 0 House for turbines and generators ... ... ... ... 300 0 0 House for transformers at Kuaotunu ... ... ... ... 100 0 0 Electrical apparatus, poles, insulators, and wires ... ... 7,311 17 0 Packing, freight, insurance, and general shipping-charges ... 686 13 0 Freight and cartage from Auckland ... ... ... ... 100 0 0 Erecting pipes, turbines, generators, transformers, and power-line 450 0 9 Supervision ... .. ... ... ... ... 300 0 0 Sundries ... ... ... ... ... ... ... 100 0 0 £15,698 10 0 Yearly Cost. £ s. d. Interest, 6 per cent, on £15,698 10s. ... ... ... 951 0 0 Depreciation, 5 per cent, on £10,698 ... ... ... ... 534 18 0 Depreciation, 2-| per cent, on £5,000 ... ... ... 125 0 0 One engineer ... ... ... ... ... ... 250 0 0 One assistant ... ... .. ... ... ... 200 0 0 Two men at £150 ... ... ... ... ... ... 300 0 0 Oil and sundries ... ... ... ... ... ... 150 0 0 £2,510 18 0 Annual cost per brake horse-power at Kuaotunu, £11 9s. 3-6 d. E. E. Fletcher.