280 
WISCONSIN STATE AGRICULTURAL SOCIETY, 
and strongly-rooted weeds. A cure for such an invasion of the 
pipe joints, which will infallibly lead to choking the drains, has 
lately been pointed out by Mr. Mechi, and that is the coating them 
over with coal tar, since roots will persistently turn away from this 
material. 
A matter of paramount importance is the declination which is 
given to the pipes. If this be inadequate, stagnation will ensue, 
and a costly and troublesome flushing be repeatedly necessary. 
Inside a drain in use, everything should be in gentle motion. If 
laid too flatly, the heavier effete matters are deposited and clog the 
way, and if the incline be extravagant, the water will hasten away 
and leave the solid wastes behind. In a late work, a writer states 
that too great a fall cannot be given to a drain; but when the fall 
of the tributary drain has been in excess, that part of the main 
drain which received the contents of such house drain will be found 
almost choked up. Some authorities formerly recommended a 
quarter of an inch fall to each foot, but the best practice is to allow 
a fall of 2f inches or 3 inches to every ten feet. 
Drain-pipes can be too large. Some people use nine-inch pipes 
throughout a house, and think it commendable, when a four-inch 
pipe would answer every purpose. A four-inch drain-pipe for sinks, 
back-yards, and basements, is ample. Even the closet-drains in a 
house need not be more than six inches in diameter. Six-inch 
pipes well laid will suffice for the largest house, and in the largest 
mansion nine inches will not be required until it is sought to carry 
the sum total of the smaller sized drains away in one channel to 
the sewer or manure-tank. Drain-pipes of too large diameter are 
incompatible with that steady onward movement of the sewage 
which every addition to the contents of the drain beneficially in¬ 
creases. 
The junctions of the drain-pipes should never be of the right- 
angled kind; an obtuse-angled or curved junction should be used; 
in other words, the sewage should be delivered in the line of the 
flow of sewage. A T or L shaped delivery is very apt to cause a 
deposit at that particular part of the drain. 
It is considered wise to give the drain a little extra dip where- 
ever a bend or junction occurs in its length, in order to counter¬ 
act the effects of friction. A very small amount of dip will usually 
suffice. In laying down a system of drains to a house, it will ofte 
