ON THE SUPPLY OP WATER TO TOWNS. 7l 



per day. After careful study of the facts with which he became acquainted, 

 he came to the following conclusions : — 



"That an abundance of water is stored up in the new red sandstone, and may 

 be obtained by sinking shafts and driving tunnels about the level of low water. 



" That the sandstone is generally very pervious, admitting of deep wells 

 drawing their supplies from distances exceeding one mile. 



" That the permeability of the sandstone is occasionally interfered with by 

 faults or fissures filled with argillaceous matter, sometimes rendering them 

 partially or wholly water-tight. 



" That neither by sinking, tunnelling, or boring, can the yield of any well 

 be very materially and permanently increased, except so far as the contri- 

 buting area may be thereby enlarged. 



" That the contributing area to any given well is limited by the amount of 

 friction experienced by the movement of the water through the fissures and 

 pores of the sandstone ; and 



" That there is little or no probability of obtaining permanently more than 

 about 1,000,000 or 1,200,000 gallons a day, and this only when not inter- 

 fered with by other deep wells." 



The hardness of the Liverpool public well-water varied from 5° to 28°, but 

 many of the private wells far exceeded this. They ranged from 23° to 352°, 

 the highest being evidently afiected by saline infiltration from the sea- water 

 of the Mersey. 



Assuming Mr. Stephenson's conclusions as to the probable yield of wells in 

 the new red sandstone as correct, although they are beyond what is realized 

 in practice, and that each well withdraws the water within a radius of one 

 mile, one million gallons per day will equal a depth of about 8 inches of water 

 per annum over the whole surface, which must be absorbed and conducted 

 to the well. The rain at Liverpool is 35 or 36 inches per annum on the 

 average. After allowing for the loss occasioned by evaporation, vegetation, 

 and such absorption as does not subsequently reappear in springs, and which 

 has been ascertained to be from 12 to 16 inches and upwards, there would 

 remain to supply springs and flow off in floods about 20 inches per annum, 

 of which 8 inches would appear to permeate the rock, and be available for 

 the supply of deep wells. 



Similar experience is derived from a deep well sunk into the new red 

 sandstone by the late Manchester Water-Works Company, at their works 

 at Gorton, about the year 1845. This well was expected to have yielded 

 2,000,000 gallons per day, and it is stated to have actually yielded at one 

 time 1,500,000. In 1850 it was represented to Mr. Stephenson as yielding 

 1,200,000, and in 1852, previous to its use being discontinued, the regular 

 yield from daily measurements was 750,000 gallons per day. Here the rain, 

 as at Liverpool, is about 36 inches per annum ; and assuming the same extent 

 of collecting area, the water raised, at 750,000 gallons per day, is equal to a 

 percolation of little more than 6 inches per annum. In the Midland Counties, 

 however, where the rain is much less in quantity, and where also there may 

 be some lithological difference in the permeability of the rock, the yield from 

 such wells as have been sunk with a view of obtaining water supplies is much 

 less. At Wolverhampton, where the rain is probably under 30 inches, the 

 yield of two wells sunk by the Water Company is only equal to about 

 200,000 gallons per day each. Some special causes may have affected the 

 supply at these wells, but no greater quantity could reasonably be expected 

 if the data afforded by Liverpool be made the groundwork for calculation. 

 The only rain observations in that district are those which have been made 

 at Lord VVrottesley's Observatory at Wrottesley, but as the rain-gauges are 



