366 PROCEEDINGS OF THE SECTIONS. 
the lower end, clear in proportion to the treatment it has received 
and to the capacity of the tanks. The tanks are designed of sufti- 
cient capacity to allow of plenty of time for the sewage to precipi- 
tate the solids ; and at the inlet a liquid charged with some pre- 
cipitating drug,as sulphate of iron, dribbles a proper proportion of 
the drug in such a way as to thoroughly charge the sewage ; this is 
allowed quietly to settle, and the supernatant liquid when properly 
treated runs off as clear water. 
In a situation where the waste water flows into a branch of the 
Harbour waters the cost of drugs is much less than that entailed 
to render the efiluent fit for entering a fresh-water river, as the 
purity need not be so high. 
The tanks are required in duplicate or triplicate, in order that 
settlement may take place and the water be drawn off; the sludge 
is then spread in the open,so as to solidify and become portable for 
transmission to farms or other destination, it having been deodorized 
by the first process. 
Sydney ? 
_The acquisition of suitable land for the above purpose will be 
difficult, but in view of the paramount importance of the question 
it should not be impossible, and when secured it should be the 
depot for as large an area as can practically drain into it, so as 
not to multiply such establishments. 
| Sydney, we know from experience how the residents of a 
uty within a radius of miles will rise up to object to the 
establishment of such a depot. 
_ tishere assumed that the procuring of land, while it is difficult, 
1s not impossible. 
A few days since, I visited the model farm at Rookwood Station, 
nd that since my last visit a stupendous amount of work 
had been done in breaking up ground, trenching, draining, 
