ABSTRACT OF PROCEEDINGS. IxXXlX. 



in the water. He concluded that although the protection 

 afforded by ordinary storage was inefficient, that could not 

 be said of Prospect Reservoir, which is practically a lake, 

 and would effect a more complete subsidence due to the 

 greater distance to be traversed and the greater time 

 available for that purpose. A lake such as this might be 

 expected to offer a greater barrier than an ordinary storage 

 reservoir. He described the characteristics of a sand filter, 

 the relative efficiency of intermittent and continuous 

 filtration, the effect of aeration and the action of the film. 

 He found that as typhoid fever has resulted from the use 

 of filtered water, a sand filter cannot be regarded as an 

 entirely efficient safeguard. Nevertheless it has proved 

 itself over and over again to have afforded protection when 

 unfiltered water was causing disease, so that, though not 

 flawless, the filtration of water through sand is extremely 

 valuable. 



Mr. McKinney, m. inst. c.b., discussed the subject generally 

 and drew attention to the difference between European and 

 American practice as regards filtering area. 



Dr. Quaife and Mr. Houghton having spoken, the latter 

 moved the adjournment of the meeting. 



Second Day of the Third Session, 81st October, 1904- 



Mr. E. A. Whitehead, Engineer and Manager, Broken 

 Hill Water Works, communicated a paper to the discussion. 

 He alluded to the wide variation in the depth of filter beds 

 and he thought that increasing the depth of sand to decrease 

 the rate of filtration was an unnecessary expense. He 

 agrees with the author that filtration through sand is 

 straining water through insoluble media, but that the 

 further action of oxidation has been overlooked. He 

 objects to the mode of constructing filter beds as carried out 

 at Lawrence, Mass., and considers that air and imprisoned 



