186 Probable Influence of Evaporation on the 
Diamond Creek, called the Sugar Loaf Creek, would be the 
only stream that would be practically available as a feeder 
for the reservoir; and although the watershed area of the 
Sugar Loaf Creek is very limited, and its discharge in 
summer very insignificant, much tunnelling through hard 
schists would be requisite, in order to convey any portion of 
its water to Yan Yean. 
The contamination of river water caused by a dense popu- 
lation on its banks, has been very frequently assigned as a 
very cogent reason for preferring the Plenty water to the 
Yarra water. 
Yet, for that very reason, a decided preference should have 
been given to the Yarra. For the banks of the Upper Yarra 
consist, with few exceptions, of steep, rocky, stringy-bark 
ranges, frequently precluding all access to the water, and 
totally unsuited for the location of a dense population. But 
the Upper Plenty District, around the Yan Yean reservoir, 
is a fine, rich, well-watered, and well timbered tract of 
country, already possessing within its limits, a numerous 
agricultural population, and the rising village of Whittlesea, 
Now, supposing that one of the owners of land abutting 
on the Yan Yean reservoir, or draining into it, were to 
convert such land into a township, and by puffing it into 
notoriety on account of its proximity to a magnificent fresh- 
water lake, lovely scenery, rich land, and so forth, were to 
cause the township on paper to become a township in reality, 
a population of only two thousand persons thus located, 
would cause a greater amount of deterioration in the water 
of the reservoir, than would be inflicted on the Yarra by a 
densely-peopled town of fifty thousand inhabitants formed on 
the banks of that river at Heidelberg. Although the Plenty 
affords an unusually soft and excellent water, that of the 
Yarra, taken from any point above Dight’s Mills, has been 
proved by a quantitative and qualitative analysis to be yet 
more excellent; and I see no reason for departing from the 
opinion I formerly expressed, relative to the superior purity 
of a supply derivable from the Yarra, above the Yarra Bend 
Asylum. ‘Those persons whose impressions of the Yarra 
have been influenced by its sluggish aspect near Melbourne, 
would have formed a more favourable opinion of this beauti- 
ful stream had they seen it in the upper portions of its course, 
where it rapidly rushes down its stony bed with sparkling 
page oe or else forms foaming cataracts over ledges of 
rock. 
In concluding my remarks, I have avoided all allusions to 
