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the cost of "the " Jonage " canal hereinbefore given, the cost for the hydraulic part of the scheme is less than half per brake horse-power. For a scheme to give 180,000 b.h.p. for twelve hours each day, the corresponding cost for hydraulic works only would be say £3,800,000. Until Southland industries are able to overtax the Hauroko scheme, there will be no need to develop the more expensive Te Anau-Manapouri scheme. There would be objections to the scheme on scenic grounds, for damming Te Anau would injure the appearance of the lake on the wooded shores. When the cost of electric and distributing plant is added, this scheme would cost a large sum of money. It would be a relatively costly one. The fall between the lakes is only about 80 ft., instead of 97 ft. as shown on some maps. This diminishes the value of the scheme materially. The higher fall was the one taken when the scheme was first suggested. To develop the powers of Te Anau and Manapouri to their full extent, the water from both lakes would have to be diverted into the sounds. For the Te Anau flow, it appears at present best to consider diversion to George Sound via Lake Hankinson. This lake lies at a level of a little over 20 ft. above Te Anau. The distance between the lakes is very short, and by cutting a channel of less than half a mile, the water from Te Anau would be taken about three miles nearer the sea. Lake Thompson lies between Lake Hankinson and the sea. If it could also be used, the cost of taking the water to the sea might be reduced. No information is available as to the height of Lake Thompson. The distance from the upper end of Lake Hankinson to George Sound is about six miles, but the correct distance has not yet been determined by accurate survey. The cost of all hydraulic works, exclusive of steel pipes at the George Sound end, may be taken at £3,500,000, and the power obtainable at 750,000 b.h.p. for continuous working ; the cost being under £5 per brake horse-power —a very low figure. Unless the conditions are very unfavourable, the total cost, including pipes for the hydraulic section of the works, should not be high per brake horse-power. It is probable that for scenic reasons the lake would not be dammed to the full height possible, if ever a scheme like this was developed. An alternative to taking the Te Anau water to George Sound would be to take it to Gear Arm, Bradshaw Sound, if the conditions at the other sound were found to be very unfavourable. It is likely a better transmission-line route could be got from this locality than from George Sound. At least there would not be the difficulty of getting across the Te Anau Lake fiords. The drainage-area of Te Anau Lake is about 1,354 square miles, and the lake-area 138 square miles, The fluctuation in level is about 15 ft. The winter level is about 3 ft. below the summer level. The flow from the lake in November last was 12,660 cubic feet per second, but by conserving all the water I think a considerably greater flow per second should be obtainable for power purposes. Manapouri. To take the water from Manapouri to the sea, a dam would be built across the Waiau River just below the junction of the Mararoa Eiver. A very small fall has been given from the lake to the Mararoa junction, and this seems to be correct in view of the very sluggish flow of the Waiau Eiver for the greater part of the distance down to the junction. The Mararoa Eiver carries a large volume of water. It has a drainage-area of about five hundred square miles. A dam to reverse the flow of the river to Lake Manapouri would not probably be more than say 15 ft. higher than at the Manapouri outlet, nor would it be longer. The cost of diverting the Mararoa would therefore be small. The banks of the Waiau at the junction are also high enough —about 60 ft. —to give ample storage-volume. The lake could be raised at least 55 ft. by a dam between the terraces a short distance below the outlet. Some of this height might be lost by a dam at the Mararoa junction. A complete survey only would supply data to determine the point. It is not likely, for scenic reasons, that a high dam would be built at Manapouri. The present beauty of the lake is worth preserving to the fullest extent. A large storage-volume can be got by damming the water a few feet above the high-flood level, and lowering the level of the draw-off tunnel. In this way 30 ft. or more in height can be got for storage. The lake summer level is 600 ft. above sea-level, as got from accurate levelling from a trig, to lakelevel. The winter-level is 5 ft. below, and high-flood level 12 ft above this level. The area of the lake is fifty square miles. The combined Manapouri and Mararoa drainage-areas are 1,010 square miles. The distance between the lake and the sea is six miles and three-quarter to seven miles. The power obtainable may be taken at 420,000 b.h.p. continuous working. The cost of dam, tunnels, sluices, &c, would be about £2,800,000. When the cost of pipes is added, unless this proves to be excessive, the cost of the hydraulic part of the scheme would be relatively low. It is likely a better route for a transmission-line would be got for this scheme than for the corresponding one for Te Anau. At least there would, I think, be less trouble in getting along the shores of the lake. No doubt in both schemes there would be serious difficulties to overcome in the mountains and along parts of the lakes, and troubles from climatic conditions. These two schemes will likely remain as reserves until all the smaller schemes are exhausted. It may happen that a great part of the power would be used at the power-station in the Sounds, in. electrochemical and electro-metallurgical work. The possession of such enormous possible hydraulic-power schemes at the seashore, with deep-water access, is, so far as I know, unique. This may lead to their utilisation, at no very distant date, for industries now non-existent. The data for both schemes should be made complete enough to enable complete preliminary estimates to be made. Mararoa. The Mararoa River has a fall of 1,480 ft. from Lake Mavora to its junction with the Waiau. The distance is about twenty-two miles, exclusive of windings of the river. There is a large volume of water flowing in the river, and there may be some possible power schemes. No examination of the river has been made.

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