It need hardly be said, however, that in practice this enormous flow of artesian water could not be utilised solely either for human consumption or for irrigation. Under existing conditions the first claim upon it may be said to be for the sustenance of live stock, as the domestic consumption in the region of the flow is comparatively trifling. And here arises a problem of vast importance. Will this flow be perpetual, or will it gradually decline until exhaustion of the sources of supply ultimately takes place? The latter contingency there seems to be little reason to fear, for the area of the intake beds, estimated by Dr. R. L. Jack at 5,000 square miles, affords the assurance that our artesian springs will be constantly replenished by the rainfall over that large extent of country. Yet, when the existing number of artesian wells has been doubled or trebled, it seems not improbable that many of them will become sub-artesian, and only yield their fertilising streams in response to pumping-power. On this question, however, expert opinions widely differ. But, taking the experience of America and other countries in which artesian springs have been tapped, it may be said that the flow steadily decreases as the number of bores multiplies. The Hydraulic Engineer estimates that about two-thirds of the artesian water at present tapped flows to waste. As to the definition of "waste," however, there is sharp conflict of opinion. A pastoralist who distributes a supply of a million gallons of bore water a day by replenishing dry creeks or constructing artificial channels may contend that in his case the loss by evaporation or soakage is not waste, but an expenditure of water necessary to make his artesian well serve its desired purposes. To control and distribute by means of reticulating pipes the product of all Queensland's flowing bores would involve a heavy investment of capital, and one not warranted by the existing population in the artesian area--a population mainly dependent upon sheep-raising and wool-growing for subsistence. But the time may come when it will be deemed indispensable that flowing wells should be brought under Government control, or their product be subject, as in the case of surface water, to riparian rights. The pastoralist who has spent several thousand pounds in sinking a successful bore not unnaturally claims the water issuing from it as his own property; but public policy may require that after diverting so much as may be requisite for his reasonable individual uses the remainder shall be made available for the occupiers of neighbouring lands.