Letter to William Clark: 25 June 1875, page 3

Is not the “Cooum” foul because the
surface washings (rainfall) get into it?
Might I ask how you mean to provide
for this? By some form of catch-
watering the sides was talked of?
In your kind note to me you allude
to this, & trust to keeping out the sewage:
which your scheme, there cannot be a
doubt, will succeed in doing. You have
in view also to keep out the foul
surface water?