132 



MICRO-ORGANISMS IN WATER 



Large storage reservoir ; the greater part of its con- 

 tents had been stored for six months, and none 

 less than one month (leeward side) . 



Ditto (windward side) ... . . 



Old East Filter Bed 



Old Middle „ 



Old West „ . . . 



New East „ 



No. of Colonies 



from 1 c.c. 



of water 



464 

 368 

 1,178 

 1,627 

 1,413 

 1,776 



General Filter Well 



Filtered Water 



95 



80 



. . .... 80 



Average = 85 

 Grand Junction Waterworks, IIam]^tonj August 13, 1892 

 Filtered Water 



Filter Bed 



Old East 

 Old Middle . 

 Old West . 

 New West . 

 General Filter Well 



Old East Bed 

 Old Middle Bed . 

 Old West „ . 

 New West „ 



Age of Filter 

 Beds in days 



35 

 22 

 17 

 12 



TJnfiltered Water 



No. of Coloaiea 



from 1 c.c. 



of water 



25 



19 



17 



23 



23 



1,008 

 1,029 

 1,222 



288 



On June 25 the examination of the water on the 

 several filterbeds, four in number, showed that this con- 

 tained about the same number of bacteria as that in the 

 small storage reservoir from which the filters were being 

 supplied^ and rather less than that in the Thames water 

 at the intake itself. Unfortunately samples of the 

 filtered water as it issues from the individual beds 

 could not on this occasion be obtained, but only from 

 the well in which the filtered water from the several 

 beds collects. This filter well is, however, in imme- 

 diate communication with a small service reservoir, 

 so that the water in it is not necessarily wholly coming 

 from the filters directly, but may be more or less 



