Consider a barn planned to have the two rows of cows facing each other.
Remove all manure and other foreign matter together with such humps
of earth as may be necessary to give the floor a slight slope in the
direction in which the manure will be taken out. Begin the construction
of the floors at the two sides of the barn so that the middle and ends
may be used as working space.
On the earthen floor, at a distance of 4½feet from the side walls of
the barn, set on edge a line of 2 by 6-inch boards, extending the
entire length of the building. Support these boards by stakes driven
firmly in the ground on the side of the board away from the barn wall.
By means of a carpenter’s spirit level and a grade line, see that the
tops of these boards have an even slope (say ⅛-inch per foot) toward
the manure pit. Allowing a clear intervening space of 10 inches, set
up in a similar way a line of 2 by 8-inch boards with the supporting
stakes inside of the 10-inch space and with the top of this board 2
inches higher than the 6-inch board. In this space the drop gutter will
later be constructed.