ABSTRACT OF PROCEEDINGS. lxxxv. 



by the cloth filters have never discovered the presence of 

 pathogenic germs and all tests were highly satisfactory. 



Mr. J. H. Maiden contributed a note on Aquatic Plants 

 in Reservoirs. He described the microscopic plants known 

 as fresh water algae and the effect they had upon the water 

 in reservoirs. He stated that American botanists gave a 

 good deal of attention to the pollution of water supplies 

 from this source, and while they found that each case requires 

 individual treatment, they recommend the addition of 

 copper sulphate to the reservoir, the salt being put in a sack 

 at the stern of a row-boat which is rowed regularly over the 

 surface of the reservoir. The amount used is small and 

 they point out that the amount of copper which thus goes 

 into the water supply is not injurious to the health of 

 human beings. The author offers to collect specimens of 

 these fresh-water algae from the storage reservoirs of the 

 State, in order to have them determined by specialists and 

 to ascertain the dose of copper sulphate necessary to 

 exterminate them. 



A discussion on " Filtration of Water " was then opened 

 by Mr. T. W. Kbele, m. inst. o.a, who stated that the lessons 

 to be learned may be briefly summed up as follows : — 



(1) To give the maximum period of storage for the 



unfiltered water. 



(2) To filter at a minimum rate. 



(3) To filter through a maximum depth of fine sand. 



(4) To frequently renew the filtering material. 



He quoted Dr. Frankland's opinion on the storage of un- 

 filtered water and the beneficial effect of sedimentation in 

 the reduction of bacteria, and pointed out that Prospect 

 Reservoir effected the sedimentation of Sydney Water 

 Supply exactly on the lines of Dr. Frankland's recommend- 

 ations. He dealt exhaustively with the rate of filtration 

 for filter beds, "the number of germs passing through the 



