r 208 j 
XXT. 
NOTE ON THE PRESENT CONDITION OF THE WATER IN 
THE RESERVOIR AT ROUNDWOOD. By W.E. ADENEY, 
F.1.C., F.C.S., Curator in the Royal University of Ireland. 
[Read NovemBer 22; Received for Publication Novemprr 24, 1893; Published 
Fepruary 12, 1894.] 
On Saturday, November the 11th, I paid a visit to the Vartry 
Waterworks at Roundwood, in company with my friend Mr. 
Moss, we both wishing to see the condition of the Reservoir after 
the prolonged season of drought through which we in Dublin and 
its neighbourhood have been passing. It is not, however, my 
object in this note to describe the condition of the Reservoir, but 
to record one or two interesting results which I have obtained 
from a careful chemical examination of samples of water therefrom, 
which I collected at points just before and after it had passed 
through the filter-beds. 
The condition of the unfiltered water in the Reservoir was, at 
the time of our visit, of particular interest, because the question 
naturally suggested itself, had the water suffered in quality in 
consequence of the prolonged drought? It was only to be 
expected that the water in the Reservoir would indicate, on 
analysis, more than ordinary contamination with organic matters ; 
for the water therein must have undergone considerable concentra- 
tion during the past seven months of dry weather; furthermore, 
the contents of the Reservoir had been appreciably augmented 
by somewhat heavy rains two or three days previously, which, in 
all probability, had washed more than ordinary quantities of dead 
vegetable matters into the Reservoir, considering the dryness of 
the collecting area and the advanced season of the year. 
The sample of unfiltered water which I brought away with me 
contained a good deal of yellow clay and some peaty matters in 
suspension ; it was very decidedly turbid, and of a greenish-brown 
colour. The sample of filtered water was, on the other hand, 
quite free from suspended matter; it was clear and bright, and 
tinged very faintly with a greenish-brown colour. 
