132 DOMESTIC WATER SUPPLY OF BRISBANE, ETC. 



presence of carbonates of lime and magnesia, has rarely been 

 regarded as deleterious, in fact it is generally regarded as rather 

 heneficial than otherwise, particularly by writers of text books. 

 The lack of lime in a water supply has repeatedly been held 

 responsible for rickets or weak legs in children, though if a 

 child had to depend in any way on the lime it could extract 

 from Mt. Crosby water at say 12deg. hardness it would 

 fall far short of the necessary daily supply. The water at 12deg. 

 would contain about 4 grains of carbonate of lime. If a child 

 drank, say half-a-gallon a day, it would only imbibe 2 grains of 

 lime, about as much as it would get in a pint of milk or 

 4oz. of bread, while in the latter cases it would get it in the 

 form of bone-making phosphate and not as carbonate. Besides 

 the hardness of Mount Crosby, there is always a danger, 

 as in all river waters, of contamination with pathogenic 

 germs. In the present sparsely populated state of the country 

 this danger is small, though as the* water is not filtered, 

 if once contaminated it would be delivered in that state. 

 There is always some vegetable matter present in the Mt. Crosby 

 water, but it is only occasionally present in sufficient quan- 

 tity to be objectionable. If filtered through a Pasteur, or similar 

 filter, Mt. Crosby water could be considered a good and safe 

 drinking water. 



Enoggera and Gold Creek waters are totally different in 

 ■composition. There is not much mineral matter present, but 

 there is a most objectionably large amount of vegetable matter in 

 the water. The catchment area is granite, and is entirely reserved, 

 so that the water runs into the reservoir in a very pure state. 

 Unfortunately our semi-tropical climate soon causes the water to 

 teem with all sorts of minute animal and vegetable organisms. A 

 drop of Enoggera surface water from a settling jar is a perfect 

 aquarium under the microscope, and offers a splendid field of 

 investigation for any enthusiastic biologist. It is almost certain 

 that there are many species there which are not yet named or 

 classified ; and as it is certain that some one or two forms give 

 the Enoggera water its objectionable taste, useful scientific work 

 js waiting for some one to take it in hand. The algne and 

 many of the other organisms die on removal from light, 

 so when the water is passed into the mains the products 

 of decay make themselves manifest in that most objection- 

 able brown sediment with which most of us are only too 

 familiar. The porous earthenware filters are practically useless 



