TO SMALL WATER SUPPLIES. 



to a harmless state, by oxidizing the organic matter 

 and allowing deposition of part of the inorganic, and 

 as stated allowing the escape of excessive volumes 

 of CO. 2 . Again, although a clear water supply is 

 very desirable, it does not necessarily say that turbid 

 waters are not fit for use after the turbidity has had 

 time to settle, the settlement meanwhile having the 

 effect of carrying down other forms of impurity 

 whose specific gravity would not otherwise allow of 

 their precipitation. It must, however, be made 

 certain that the turbidity is pure clay, load, or sand, 

 as the case may be, and not the result of foul slime 

 found in back waters, stagnant pools, etc., which are 

 usually the breeding grounds of organisms of a very 

 low state. Opposed to turbidity, which may not be 

 an indication of impurity, is opacity in water, and it 

 has been shown to indicate serious pollutions. No 

 satisfactory explanation is offered by textbooks re- 

 garding this opacity ; it suffices to say such water is 

 to be regarded with much suspicion. The writer 

 recalls a case of noticing this in the public supply of 

 a town in the north of England, 1 but he said nothing 

 and avoided the water. A few months later when 

 cleaning the reservoir a human body was found in 

 a very decomposed state lying over the bottom draw- 

 off pipe. Water which is palatable is generally 

 found on examination to be pure, although unpalatable 

 water may be of very excellent quality. The writer 

 does not consider the Vartry supply to Dublin at all 

 good for drinking, yet it is considered one of the best 

 in the world. Again, although not often noticeable, 

 water may have an objectionable odour to those 



1 In deference to the authorities the name of the town is withheld. 



