84 Transactions.— Miscellaneous. 
There are two methods of dealing with water-carried sewage: either the 
whole, together with the rainfall on the streets, can be conveyed by sewers 
to the outfall, which is the ** combined system,” or it can be kept separate 
from the rainfall by a double set of pipes—one for the sewage and one for 
the rainfall, which is called the « separate system.” 
The General Board of Health, in England, recommended the latter 
system, and that the sewer be laid at the backs of houses in order to avoid 
_ laying the house-connections under the dwellings from back to front, any 
leakage from which would render the house unhealthy. 
The great advantages are, that pipes can be used to a far greater extent 
than by the former method, both for the sewers that take the house and 
yard drainage, and for the drains taking the road drainage. The sewers 
have then to carry off a regular daily flow, and so can be of much smaller 
size than they would be if they were to take the rainfall also. The road 
drains can also be smaller, because they can have as many outfalls as 
convenient into the nearest watercourse without polluting it and causing a 
nuisance. In fact, most towns would require only nine-inch pipes laid in 
the greater portion of the drained area. There is also a regular quantity 
thereby effecting a great saving in the cost of treatment. 
In all the best-drained towns of England, the sewers are laid in straight 
lines, with shafts at their junctions, and at regular distances apart. These 
shafts are man-holesand lamp-holes, or man-holes and ventilators alternately, 
both the man-holes and lamp-holes acting also as ventilators. When it is 
required to inspeet a sewer, a lamp is lowered down a lamp-hole, and a 
whether it is clear or not. If it is not, he places a flushing-board in the 
man-hole above the blockage, and in a few hours there is sufficient accumu- 
lation, and the board is drawn up, and the rush clears away the deposit 
or obstruction in the pipe. 
When a householder finds there is something wrong with his drains, 
it is proved to be clear, a trench is-cut down to the house-connection, and 
the pipes cleared with rods. A great savin 
The Town Surveyor should be able to refer at once, when necessary, to 
the block plans sent in when the house-connection Pipes are laid, and on 
which the position of the drains are shown. In some towns, sections, 
showing their falls, are required by the authorities. 
