214 Scientific Proceedings, Royal Dublin Society. 
Some reference to the decidedly large quantity of nitrates, 
shown by the above analyses to be present in the filtered water, is 
necessary. I have not had occasion to analyse before the Vartry. 
water immediately it leaves the filter-beds, and therefore cannot of 
my own experience say whether the quantity given in the above 
table is to be regarded as normal or not; it is certainly much 
higher than we are accustomed to find in the same water as 
delivered in Dublin. Idonot remember for instance to have ever 
found a larger quantity than that represented by ‘01 parts of 
nitrogen per 100,000 in water drawn from the main which supplies 
the Royal University, and I have from time to time examined 
many samples of the water supplied to the Laboratory of that 
University. 
