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43 
them. The two rows of pipes (before named) have each a sep- 
arate stop cock. The upper of these passes through the upper 
part of the street reservoir, and serves to exhaust the air, the 
lower passing into the interior of the street reservoir and nearly 
to the bottom and is used to extract the sewage. The operation 
is as follows:—The air pump maintains a vacuum in the large 
reservoirs and mains during the whole of the day. Two men 
patrol the district; coming to a small street reservoir or tank 
(air tight), they open the lids whereby access is given to the stop 
cocks which shut off each pipe from the tank. (For distinction 
call the men Aand B). A fixes his key on the stop connecting 
the central or vacuum pipe with the tank. B has his key on the 
stop belonging to one of the street mains leading to the houses. 
The moment A turns his key, he opens a connection between the 
central pumping station and the tank, the air in the tank is at 
once exhausted and a vacuum established, the extent of which 
is indicated by a small meter. He (A) then shuts the stop, 
while B opens the stop on the main leading to the buildings, 
and lets loose the force on this main. The consequence is that 
the vacuum in the tank is at once reduced by the inrush of the 
air contained in the house main. This action repeated two or 
three times brings all fecal matters into the tank, thus clearing 
the whole district which this tank serves. The fecal matter is 
at once sucked by the air pump to the central or large reservoir 
and there dealt with. 
The Berlier system is still in its experimental stage only, so I 
do not purpose venturing any remark upon its efficacy. 
Although placed among the pneumatic systems, the ‘‘ Shone ’ 
is in reality more of a mixed system, being part water carriage 
(by gravity) and part pumping by compressed air. It was invented 
by Mr. Isaac Shone, a mining and civil engineer of Wrexham, 
Wales. Ié differs from the two other pneumatic systems before 
named in that a plenum is used instead of a vacuum. In this 
system the town is divided into districts as before named, but the 
drainage (which by the way includes all domestic wastes, but not 
rain water or any surface drainage) falls to the lowest part of such 
district by gravity. At these points is fixed a pneumatic ejector 
into which the sewage flows, and from which it is raised by the 
pressure of compressed air into a system of iron sealed pipes, and 
by them conveyed to the point of discharge, the compressed air 
acting in these pipes to the very end of the service. Another 
method is to raise the sewage into an upper tier of pipes, and 
through them convey it by gravity to the point of discharge. 
This, of course, depends on the nature of the topography of the 
district. The air required to work the ejectors is compressed at 
a convenient central station by a compressor worked by steam or 
water power, and supplied to the ejectors through small iron pipes 
’ 
