PUPJFICATTON OF WATER FOR DRINKING PURPOSES 137 



unfiltered water in the several beds exhibited con- 

 siderable variations as regards the number of micro- 

 organisms, the maximum being 2,548, the minimum 

 244, and the average 792 per cubic centimetre. 



Lambeth Watenvorks, Thames Ditton, August 26, 1892 



Filtered Water 



No. of Colonies 

 from 1 c.c. 

 of Water 



92 

 36 

 35 

 41 



8 

 11 



9 

 12 

 10 

 13 



No. of Colonies 

 from 1 c.c. 

 of Water 



1,217 

 1,108 

 1,118 



Lost 



Lost 



968 



Lambeth Waterworks, Thames Ditton, September 30, 1892 



No. of 

 Filter Bed 



New "Works : 



No. 10 



No. 9 . 



No. 8 



No. 7 . 



No. 6 . 



No. 5 . 



General filter well of 

 New Works . 



Filtered. Water 



Age of Filter 

 Bed in days 



3 



24 

 36 

 10 

 28 

 22 



No. of Colonies 

 from 1 c.c. 

 of Water 



50 



23 



10 



8 



4 



6 



