45 
gigantic power, sufficient to guard against all these casualities, 
the system could only be a failure.” 
I may just name some of the systems tried, such as ‘ The 
Archimedean Screw,” steam jets; fans; pipes conveying the 
sewer gas to the street lamps, it being there consumed ; pipes up 
the centre or cavity of the walls of buildings carried up to_ the 
roof; house drains left untrapped and extended above the root ; 
charcoal ventilation in the streets; and last and most commonly 
used, open grids on the top of manholes in the streets. All the 
systems named have been and are now in use with of course 
partial success. 
DisposaL AND UTILISATION OF SEWAGE. 
The commonest practice under this head is to turn all the sew- 
age into the nearest stream in its crude state, thus killing or 
stupifying all fish, and so fouling the water as to render it totally 
unfit for any domestic use. This practice is being rapidly stopped 
by law, and not before it is needed. Now it may be thought a 
strange thing, but all this vile and objectionable matter is most 
valuable. It may be used to izrigate land. For this purpose the 
sewage is gathered to one main outfall sewer, and so carried down 
to the sewage farm. Here it is turned on the land through small 
channels, the fluid, soaking through the ground and entering the 
subsoil drains, is conveyed by them in a pure state to any stream, 
where it does no harm. ‘The other great method of utilising 
sewage is Precrerration. There are upwards of 20 different pro- 
cesses of precipitating sewage. I will glance at three, viz :— 
Tue CovEeNTRY, 
Tue A.B.C, and 
Tue Lime Process. 
The Rivers’ Pollution Association, Limited, which was formed 
in 1877, ‘“‘ does not confine its operation to any particular system 
for treating sewage, but employs whatever is found to;be most 
suitable and best adapted to the local circumstances and require- 
ments of each place.” So says the prospectus; but the process 
employed at the works of the company at present, is;what 1s 
known as the ‘‘ Coventry ” process. Itis a chemical precipitation, 
the chemicals used being crude sulphate of alumina, salts of iron 
and lime, of course in such proportions as the managers may 
think fit, the quantity being the company’s secret. The eftluent, 
which is clear, is turned into any handy stream, the sludge made 
into cakes and sold for manure. These cakes contain about 50 
per cent. of moisture, the manure being sold at 2s.6d. per ton. 
The demand is not large. 
The A.B.C. process is the property of the Native Guano Com- 
pany, and takes its name from the initials of some of the chief 
