I).—lα

Receipts : 1898, 170,350 francs—£6,Bl4 ; 1899, 566,377 francs—£22,6ss ; 1900, 1,490,450 francs— £59,618. Expected to rise to 2,500,000 francs—£loo,ooo. Tariff varies from 720 francs to 250 francs per horse-power per annum. Mean taken to be about 500 francs —about £20 a year. There is a compensation-reservoir of 395 acres area to store surplus water from slack workinghours. The figures do not appear to show that the " Jonage " is yet a commercial success, but it is an indication of the amount of capital that may be spent on the development of hydraulic power in a locality possessing industries enough to utilise it. Under equal conditions it will be shown further on that some immense schemes may be possible in New Zealand in the future, but while much larger, they will be relatively less costly, in many cases much less costly than the " Jonage." Aratiatia Rapids. When levels were taken the top of these rapids was at a level of 74-7 ft. below Lake Taupo level (this height will no doubt vary with the state of the lake and river), and just less than 10 ft. below the bottom of the Huka Falls. The river below the rapids at the first good site for a power-station to utilise all the fall was almost 100 ft. below the top of the rapids, the direct distance between the two points being a little over three-quarters of a mile. To use all the water it would be necessary to build a weir in the river-channel. Only approximate data are available, but the weir would not apparently be a very large work, though it might prove to be somewhat more difficult than it looks, if the river-bottom consists of fissured and decaying rocks. This weir would only be a little above the water-level at the top of the rapids, and its cost might be £60,000 or more, according to the difficulties met with. The power available, supposing the lake-outlet not controlled, may be taken to be 47,000 b.h.p., and if the lake is controlled, 59,500 b.h.p. The terraces on either side of the river did not appear to me to be very favourable for the construction of canals or tunnel conduits, and for the present it may be taken that the water would have to be conveyed most if not all the distance required in pipes. The cost of these, with all necessary works, would be over £500,000, but a complete survey of the terraces is required before more than a very rough approximation can be made of the cost of the works required for the utilisation of the Aratiatia Rapids. It would be possible to cut a short intake from the river, and draw off part of the water for a partial scheme, to give, say, 10,000 or 15,000 b.h.p. I think this may perhaps be possible without a weir at the top of the rapids, but until Huka was overtaxed, no scheme at the Aratiatia would be justifiable on account of the distance the water has to be carried in pipes. It would be possible to build a dam at the top of the Aratiatia to dam the water up to lake-level. This would give the maximum amount of power obtainable from the Waikato down to the foot of the Aratiatia Rapids. The cost would be over £300,000, or somewhat over £800,000 for dam and pipes alone. The power obtainable would be over 92,000 b.h.p. —somewhat more than the Aratiatia and Huka, as above outlined, combined ; but the increase is not great enough to justify the extra cost, and it is likely the water would be dammed back over the Wairakei geysers, the Huka Falls lost, and the valley flooded. Orakeikorako. There is a rapid in the Waikato River at Orakeikorako. The fall, in a relatively short distance, is about 35 ft. This might be utilised at a considerable cost by a dam and conduit of sufficient length. Some distance further down there is a narrow gorge where the river could be dammed a considerable height and power got, but the water would be dammed back over the Orakeikorako rapids, so only one of the two schemes is possible. The lower one would likely be the better one. This site is about half-way between Orakeikorako and Aniwhaniwha. Aniwhaniwha Falls. These falls are about 20 ft. high. The terraces on both sides of the river are about 60 ft. to 70 ft. high, and by a dam this height above water-level above the falls about 80 ft. of fall could be obtained, giving, say, 35,000 to 45,000 b.h.p., according as the flow from Taupo is regulated or not. A dam at these falls would interfere with the dam at the gorge mentioned in the preceding paragraph. Atiamuri. There is a rapid at Atiamuri having a fall of about 25 ft. in a relatively short distance. No great height of dam could be built except at some cost. If high, the length would be considerable. The collection of the necessary data would require some survey-work, but this site does not seem a very favourable one for developing power. A dam here, even if not very high, would interfere with a scheme at the Aniwhaniwha Falls. There are only three or four miles between the places, and the rate of fall in the river is not very great in this reach. The Huka and Aratiatia schemes should be almost free from flood-rise, except the rise and fall due to variations in the level of Lake Taupo. At the lower sites flood-rise would begin to be felt, and some loss in efficiency might result, and some extra cost in works be necessary. The lower Aniwhaniwha Rapids near Cambridge should give some power, but I have no data regarding them. Rotoaira. This lake is part of the Lake Taupo drainage-area. It is situated between Tongariro and Pihanga Mountains. Its drainage-area is forty-eight square miles, and the area of the lake is six square miles. The lake-level could very easily be increased 45 ft. by a dam, the Poutu flowing through a narrow gully

5