ON THE SEWERAGE OF TOWNS. 
♦ 
A PAPER BY W. COOTE, ESQ., C.E., BEAD BEFORE THE MEMBERS OF THE PHILOSOPHICAL 
SOCIETY OF QUEENSLAND, AT BRISBANE. 
There is scarcely any provision more neces- 
sary for the permanent health of the inhabitants 
of a town, and scarcely any one more generally 
neglected, than that of efficient sewerage. I 
do not mean drainage, which is a distinct 
matter. From not keeping this in view much 
confusion has arisen ; and from attempting to 
combine both in one system, great evils have 
often followed. In climates like ours, such 
evils w r ould be greatly multiplied, and hence the 
necessity for a clear apprehension of our re- 
quirements, and the provision to be made for 
them. 
In founding a city in ancient times, the 
water supply and the sewerage were thought 
matters of almost equal mement. Every school- 
boy has read of the Cloaca Maxima of Rome, 
which was but one amongst almost innumerable 
instances of the care which the Romans took in 
the preservation of cleanliness and health wher- 
ever they settled. In modern times we gene- 
rally wait till the soil is permeated with noxious 
gases, and then establish a sanitary commission, 
often composed of very unscientific members, 
by whom much twaddle is talked, and more 
money wasted. Moderate precaution at the 
outset would leave no excuse for the commis- 
sion, and save the waste of both time and 
expense. 
The first attempt at sewerage in Brisbane, as 
elsewhere, has been the digging cesspools to 
every house, sometimes steyned with dry 
bricks, and sometimes left without any lining. 
In all cases where wells or tanks are sunk 
within a moderate distance of such cesspools, the 
fluid content of the latter percolates through the 
soil and drains into them. Where no wells 
exist, the soil around the cesspool becomes 
impregnated with foetid matter, which evapo- 
rates after every rainfall, and contributes largely 
to the promotion of malaria, fever, and the 
incomes of doctors and undertakers. It is sup- 
posed that economy i3 obtained by the adoption 
of these cesspools, but leaving the doctor’s bill 
out of the calculation, it is very questionable 
whether the original cost of one, supplemented 
by that of the emptying and keeping in repair, 
is not more than would be required for the pro- 
vision of efficient drainage for the house to 
which it is appended. 
Supposing the inhabitants of any city to have 
arrived at this conclusion, and to have deter- 
mined on the construction of adequate sewerage, 
the first step is to ascertain the outfall and the 
general levels of the district. . This is best done 
by what are called contour lines — levels along 
streets only being not sufficient for the purpose. 
A contour line is one traversing every portion of 
a district which is on the same level. They may 
be taken at vertical distances of 2 feet — i.e. each 
line 2 feet below the level of the preceding one. 
The horizontal distance will be in proportion to 
the unevenness of the ground, becoming small 
when it is precipitous, and large as the slope is 
more gradual. These lines being accurately 
taken, it is easy to ascertain the difference 
of level between any points within their range. 
In all cases where a general system of drainage 
or sewerage is to be laid down, these contour 
lines are indispensable, and are now almost 
universally adopted on the continent of Europe 
as "well as in Great Britain. 
The levels and the point of outfall being ascer- 
tained, the separation of drainage from sewerage 
is next to be considered. By drainage is meant 
the carrying off surplus surface water ; by sewer- 
age the conveyance of sewage to some fixed reser- 
voir or outlet, where it wiU cease to be a nuisance. 
The two cannot well be combined, the conditions 
required for their discharge being essentially 
