2 The Examination of Waters. 



these determinations do not prove in the slightest degree 

 whether the water is fit to drink, or whether it carries the 

 germs of disease, ready and able to reproduce the disease 

 whenever any one of the germs may meet a suitable 

 subject. 



When the results obtained are what may be considered 

 abnormal, they simply show that a source of contamination 

 should be sought for ; and for this reason these tests should 

 be continually applied to all our large sources of public 

 supply. The determination of combined carbon and chlorides 

 seems to me to be of less value' here than in England, for all 

 our surface waters are more or less saline, with the excep- 

 tion of those derived from the mountain ranges and the 

 more elevated portions of the colony. Many of the streams in 

 the more level parts of the colony become brackish during 

 droughts, or in our ordinary summer weather; and an idea 

 of the amount of salt these streams carry may be formed 

 when we look at the lakes in the Western District, and see 

 that all those which have not some natural outlet become 

 strong brines during the summer months, though they are 

 filled by streams of almost tasteless water in the winter; 

 they yield annually many tons of salt to. the factories. In 

 most of our river valleys we have numerous mineral springs, 

 many of them yielding waters charged with alkaline carbon- 

 ates ; and these alkaline salts, acting upon the dead organic 

 matters, dissolve some of the carbonaceous substances, and 

 carry it into the stream and reservoirs. These facts show 

 that we must be very careful in drawing conclusions from 

 our analytical results. If we have some previous know- 

 ledge of the impurities in a water, our analysis will, however, 

 indicate any changes that may be taking place, and the 

 necessity for a careful examination of the sources of supply. 

 For instance, in the year 1877 the waters from the Geelong 

 supply gave as an average in one million parts, 0*00085 

 of a part of free or saline ammonia, and 0'0076 of albuminoid 

 ammonia, and still less nitrogen as nitrites or nitrates. The 

 water which had been cleared by lime contained only a 

 little more than one-half of the quantity of albuminoid 

 ammonia given in these small fractions, and the people of 

 Geelong flattered themselves that they had one of the purest 

 water supplies in the colony. 



At the present time we find 150 times as much free 

 ammonia, and of albuminoid ammonia nearly 200 times as 

 much, besides a very notable amount of nitrites and nitrates 



