5

D.—s

time that the channel is being used. This can be utilized to drive a small turbine wheel to work a dynamo-electric motor; therefore the cost only amounts to the tear and wear on the plant, which is very small. I have consulted Dr. Lemon, Superintendent of the Telegraph Department, on the subject of lighting the sludge-channel with an electric light, and he kindly supplied all information relative to the first cost and placing it in position, which amounts to about £700, exclusive of the motive power; and he estimates the tear and wear on same will be about £30 per annum. A turbine water-wheel, with intermediate shafting and belts, and small house to cover the dynamoelectric motor, I estimate will be about £300, making the total cost to be about £1,000. In providing an electric light Dr. Lemon strongly advises the use of Siemen's dynamo-electric motor as being the safest, best adapted for the situation, and the least liable to go out of repair. He has one of these in use, which certainly gives a large number of lights for the power employed in working it. A 1-horse-power gas-engine, which is worked up to I^-horse power, produces twelve lights, each equal to from twelve to fifteen candles. The estimate is based on a dynamo-electric machine capable of lighting fifty lamps. This number may not be required, but it is better to provide for a machine sufficiently powerful, as the extra cost is but trifling, the greatest expense being in the main leading wire, which cannot be curtailed in any case on account of its length. To take the minimum cost of candles which I have estimated that it will take to light the channel, only using it eight hours per day, amounts to, in round numbers, £369. This would clear the cost of the electric light, plant, and maintenance in a little less than three years; and, if the channel is used for sixteen hours per day, the outlay in candles in about eighteen months would amount to the cost of the electric light. I would therefore recommend that steps be taken to procure an electric light, and have it placed in the channel tunnel as soon as possible. Dr. Lemon has kindly offered his services (if the Government decide to place it in the tunnel) to superintend its erection and instruct the Manager of the water-races with reference to the working of the machine, &e. In concluding my remarks on the whole subject, the cost of stone paving placed in the channel under favourable conditions has not yet been tried; and this ought to be done in order to get correct data to work on before increasing the size of the channel. The electric light, if placed in the tunnel, will likewise materially cheapen the cost of widening the channel at a future time, if found necessary, to accommodate a larger number of miners. I have, &c, Henry A. Gordon, The Under-Secretary, Mines Department. Inspecting Engineer.

By Authority: George Didsbury, Government Printer, Wellington.—lßß3.

2—D. 5.