70 iieport — 1877. 



instance, where the rainfall is much greater from the district being hilly* — 

 meander through the low-lying Triassic country and supply their quota. 

 Many of these rivers have loose sandy beds, favourable for percolation ; and, 

 with fissures, however contracted, to convey the water to a distance, a con- 

 stant circulation must necessarily be kept up. If we assume the absorption 

 to be as much as 10 inches, a circle having a radius of just over 1| mile 

 from the well would be sufficient to keep up the supply to 3 million gallons 

 per diem. I am not by any means suggesting that nature acts in this uni- 

 form sort of way ; on the contrary the water may travel by faults and fissures 

 a long distance in one direction and a short one in another t; but of this I am 

 assured, that a good well depends upon these underground ramifications, and 

 that their existence or absence constitutes the main distinction between a 

 well being a good yielder or a bad one, more than on the actual constitution 

 of the rock itself, as, according to my experience, all the New Red Sandstone 

 is sufficiently porous, looked at as a filter. As regards a greater yield being 

 obtained by boring or not will be dependent upon the source of the deeper 

 yield and the depths to which the well is pumped down. At Alsagcr no 

 additional water was obtained by boring deeply into the rock. 



If the tube was well supplied by the rock first penetrated, and the fissures 

 (if any) intersected by the bore lower down had the same " head " or source, 

 the supply would not be greater; but if the water were to be pumped down 

 below its natural level instead of flowing out of an artesian tube, it is quite 

 possible the deep bore might begin to yield. 



As exhibiting the nature of the underground circulation I have made a 

 calculation from materials supplied me by the borough engineer of Liverpool, 

 Mr. Deacon. 



The Dudlow-Lane well is about 2 miles in a direct line from the Green- 

 Lane well, and while the engine stopped in November 1875, the water rose 

 to 95 feet above the bottom of the well. This would give a difference of 

 level at the time between the water in the Dudlow-Lane well and the Green- 

 Lane well of about 80 feet. The velocity of discharge in the 6-inch bore-hole 

 of Green-Lane well when delivering 817,000 gallons (see Report of Committee, 

 1875, p. 123) per diem would be 459 feet per minute ; a 9-inch pipe, with 

 the difference of level of 80 feet, would carry waiter from one well to the 

 other at a rate sufficient to supply the bore with the quantity of water it is 

 stated to have yielded. Or, to state it in another way, a 6-inch pipe 4000 

 feet long and 170 feet head would supply, roughly speaking, the same quan- 

 tity of water at the same velocity as that which passes through the bore. 



It is therefore evident that there must be fissures, having a large aggregate 

 area, to enable nature's rocky filter to supply water at the rate of 459 feet 

 per minute to the 6-inch bore-hole when we consider the smallness of the 

 available head, for the friction through rocky fissures would be excessive as 

 compared with smooth pipes. 



Quality of the Water : Hardness. — ; So few analyses having been given in 

 the papers returned to me, and wishing to further investigate some of the 

 questions flowing out of the inquiry, I was under the necessity of applying 

 to Dr. Campbell Brown, the public analyst of Liverpool, who has kindly 



* For the distribution of rainfall in England on the various groups of strata, see my 

 presidential address on ''Geological Time," Proe. Liverpool Geol. Soc, session 1876-7. 



t I am informed the Green-Lane Well has been proved to "draw" at a distance of 2^ 

 miles in a direct line. A reference to Mr. Robert Stephenson's report of 18. r )0 shows", 

 according to the evidence of Mr. Bold, that a well at Moseley Hill, distant 5000 yards, 

 was affected by the pumping-operations at Green-Lane well. 



