80 



effected in the upper part of the reservoir. A separate and shallow 

 basin should be formed, with an accurately levelled weir over which 

 all the water should pass in an almost imperceptible stream, and 

 the filtering of the water might be further secured by a bank of 

 gravel and broken stone along its whole length. It is hardly 

 necessary to add that this scheme contemplates the passage of the 

 whole water service through the reservoir, under ordinary curcum- 

 atances. By no other means can the water be properly purified 

 before it enters the town. 



