148 Chemical Examination of Waters. 



rivers named were the purest examined. Their great softness 

 points to the deficiency of limestone in these coal measures. 



The Botany water may be viewed as a fair representative of the 

 drainage of sandstone districts, and this, taken in conjunction 

 with the interest attaching to it as supplying Sydney, made it 

 desirable to have a full and careful analysis of it. The sample 

 chosen for this purpose was drawn from a pipe at the gate lodge 

 of the University, on the 1st November, 1867. There had been 

 no rain, or only a mere sprinkling, for three weeks, and the 

 water was in fair average condition. Temperature of specimen 

 when drawn, 71'. When viewed through a considerable bulk it 

 showed a brownish colour, and it had a faint taste of peaty 

 matter. The following table shows the nature and proportions 

 of the earthy and saline part of the solid residue obtained on 

 evaporation ; — 



Grains per gallon. 



Chloride of sodium (common saH 



o 



2863 



Chloride of potassium 





0112 



Chloride of magnesium 





0118 



Carbonate of magnesia 





0049 



Sulphate of magnesia 



... 



0128 



Sulphate of lime 





0233 



Silica 





0-222 



Peroxide of iron, with trace of 



phosphate 





of lime 







0082 



Total inorganic matter ... ... 3*817 



By direct estimation the total solid residue was found to be 5'2 

 grains per gallon. On ignition, this lost 1*5, leaving 3'7 

 for fixed salts, and showing that about one-tenth of a grain had 

 been driven off in excess of the organic matter. The hardness of 

 this specimen was not directly determined, but, probably, it was 

 seven-tenths of a degree. A specimen drawn in December, 1867, 

 was examined for ammonia. None was found ready formed, but 

 the nitrogen of the organic matter being converted into ammonia 

 yielded at the rate of one part in 6-^ million parts of water, or 

 one grain in 93 gallons. Another specimen drawn in the present 

 month gave the same results. The Loch Katrine water in Scot- 

 land contains exactly the same proportion of ammonia. In the 

 sample of rain water collected 7th December, 1867, there was 

 ammonia ready formed to the extent of two parts in a million, or 

 about one grain in seven gallons. 



The water derived from districts covered with the shales and 

 clays grouped by the Rev. W. B. Clarke under the name of 

 Wianamatta deposits is very different in character from sand- 



