o 



38 WATEE-BEARIXG STEATA. 



50 feet above mean sea level, with an absence of any streams 

 having their origin from head springs. 



I estimate the area contributing to the yield of water from 

 these wells as equal to 8| square miles, which gives a quantity 

 of nearly 6^ million gallons per day, which is borne out by 

 the amount of pumping which has to be resorted to as far as 

 the area acted upon by the cone of exhaustion has been 

 developed. 



The form of well which lends itself to the least labour and 

 expense is undoubtedly the circular form, but it is not 

 always adaptable to the pumping plant required to be placed 

 in it. 



The well the sinkins; of which I am about to describe is 

 one of a series sunk at Chelvey, and is of a circular form. 



This well is 7 feet diameter, and 160 feet in depth ; for 

 the first eighteen feet of its depth it was sunk through the 

 red marls, a small quantity of water being met with. 



The sinking then went on at the rate of 10 feet per week 

 down to a depth of 67 feet, when the water proving too much 

 for the small pump in use, a 10-in. pump (fixed from timbers 

 near the top of the well) was brought into use, driven by a 12 

 horse-power horizontal engine. The sinking was then stopped 

 for a few months, and when again renewed, a cast-iron curb 

 was put in, and 9-in. walling to break joint brought up to 

 the surface from the curb. 



These curbs were nogged into or set back in the marl, 

 upon a benching, in segments, with internal flanges, having 

 lips forming a trough standing out beyond the face of the 

 steining about 3 inches, for the purpose of catching the water, 

 so that it could be conducted to the bottom of the sinking by 

 wooden and canvas shoots to the suction of the pump. 



The sinking was then proceeded with to a depth of 72 feet, 

 when it was suddenly interrupted b}^ the tapping of a 



