Water Power and Applications.

Frequent allusion has above been made to water power. The Puarenga, in its course from the gorge to the lower level of Whakarewarewa, furnishes means of obtaining probably 100 page break horse-power. This can be developed by several wheels or turbines placed in convenient situations and treated picturesquely in design. This power would be applied to various purposes, some of which have been already alluded to. These are:

1.	The circulation of hot water in the hot-houses. This need not be further dwelt on.
2.	Refrigerating Machinery.—This would be applied principally to the production of ice, the preservation of meats and fruits, the cooling of air and water for sanitary purposes. Skating and curling rinks of ice could be always at command, and, as before mentioned, an artificial winter obtained for horticulture.
3.	Electric Light.—This would be easily obtained by dynamos driven by water power, and storage in secondary batteries. A system of are lights for the grounds and incandescent lamps for the interiors of the whole establishment, would cost only the maintenance of dynamos and lamps.
4.	The working of cable tramways connecting the upper and lower establishments, and on other routes having much traffic.
5.	Pumping cold water to reservoirs situated above the level to which it would flow by gravitation, and also supplying the residences with hot water for house baths in special cases.

Water supply for domestic purposes cannot be obtained in sufficient purity from the Puarenga, and would depend on one or more of remarkably pure and clear streams of spring water. One of these, flowing perhaps one million of gallons per diem, is very conveniently situated for supplying Whakarewarewa. Another group of these streams, at the foot of Ngongotaha Mountain, on the north-west of the lake, will form the water supply of the large Rotorua population in the immediate future.