to the Town of Geelong. 55 



The working out of the last table (No. VII.) shows a 

 balance of water still on hand from the once filling of the 

 reservoir, and after supplying a 50,000 population for 

 eighteen months, and without receiving during that period 

 any additions to its quantity. 



It will be observed that the quantity would snffice for the 

 present population of 25,000 for two and a half years ; or, 

 by reducing the allowance per head to the Melbourne 

 standard of twenty-five gallons, for five years. 



This, let it be understood, is without infringing on but half 

 the rain-fall, the whole of which being (2,941,881,880) two 

 thousand nine hundred and forty-two millions of gallons — 

 see Table No. VI. Were it impounded, it will readily be 

 understood that there would be a sufficiency (after deducting 

 for yearly evaporation) for nearly double the above periods ; 

 say three, five, and eight years respectively, quite sufficient 

 to lull all anxieties respecting the probability of a water 

 famine, even if three or four consecutive years of drought 

 should ever unhappily again occur, as it has in the memory 

 of many of the early settlers. It leaves a very ample mar- 

 gin to meet contingencies of any nature or kind, and more 

 particularly all cavil. 



It may be, that superficial observers, or persons who have 

 not made hydraulic questions their study, may at first sight 

 imagine that I have either set down the available rain-fall at 

 a high figure, or from imaginary data. 



In contravention of such idea, I append Table No. VIII. 

 of actual rain-fall at Yan Yean reservoir, and quantities 

 ascertained both by careful gaugings at mouth of inlet 

 tunnel, and checked by water-gauge staff, permanently fixed 

 at the outlet tower of the reservoir. I wish to show the 

 several facts deducible therefrom. 



