30 



REPORT OF CHEMICAL LABORATORY 



The analyses as a whole, it was found, seemed to prove that " the best water from 

 a chemical point of view is that of Well No. 7, which is fed mainly from the deeper 

 layers." The recommendations made by Dr. Todd and Mr. Abel, the engineer called 

 in consultation, were, among others, to deepen certain of the wells and to cut off the 

 upper strata by the method detailed by Dr. Balfour in his note on these wells (loc. cit.). 

 The wells in use at the present time are Nos. 1, 6 and 7. Many examinations of these 

 have been made in the last year, the most recent results being as follows. They are 

 from Wells Nos. 1, G and 7, the others having been abandoned as unnecessary. 



Further 

 improvement 



The above analyses represent the water not as supplied to the town, but directly 

 it emerges from tlie air-lift. A further very marked improvement is effected by storage 

 in a large cement-lined reservoir. As a result of the very efficient aeration, due to the 

 use of the air-lift, not only is the iron oxidised and precipitated, but, what was 

 entirely unexpected, the manganese is carried down as well. The precipitation of the 

 iron and manganese probably also aids the direct oxidation of the small amount of 

 organic matter present, the effluent water attaining a remarkable degree of organic 

 purity. The following is a comparison of the water as it emerges from the air-lift 



