The floor of each room is graded slightly toward the center, and a trench dug through the center from end to end. It should have a grade toward the front of the house of about two inches in a rod. At the rear of the house it may be nine inches square, gradually increasing to double this size at the front of the house. Lateral drains, alternating on either side, are desirable. If the surface drainage sets toward the house, it should be intercepted and conducted away. After the trenches are made they are filled with broken stone or cobbles about nine inches deep at the start, and double the depth at the front of the house. The side trenches may be six or eight inches wide, and filled about the same depth. On top of the stones, shavings, straw, reeds, or other porous filling, is placed, to the level of the floor. The entire floor is now covered with a layer of charcoal, or with coal ashes placed several inches deep. On top are laid boards, not too closely placed, with length toward the main drain. The spaces between the boards form channels to conduct the waste water to the drains. Where the drains emerge from the house they are trapped, to prevent any air currents from entering through them, and collected into one or more main channels. Plate _A_ illustrates the drainage plan, and a section view is presented in Plate _B_. In porous soils, which can be depended on to carry off the wastage, drains are not so necessary. For very large houses, however, they should not be entirely neglected. In warm climates and for city supply houses, cement floors are the best. For loading cars for winter shipments, the platforms illustrated in plates _A_, _C_ and _D_ are used for handling large quantities. The ice cakes are elevated on the incline to runways (see _R_, in Plates _A_, _C_ and _D_), and slide by gravity until landing on the platform. An endless chain with cross-bars passes over the top of this platform, carrying a cake before each bar. Where a railroad siding is placed on both sides of the platform the work is expedited, as no delay is occasioned by waiting for cars, a loaded train being pulled out and empty cars run in on one track, while loading continues on the other. [Illustration: FIG. 53. PLATE _E_. HOISTING GIGS AND REVERSING ENGINE.] THE INCLINED WAYS shown in Plate _C_ are rigged with endless chains, which carry cross-bars. In filling the house, the ice cakes are floated to the foot of the incline, and fed on to it, one or two cakes at a time in front of each bar, and thus is made to travel up the incline. The cakes are passed through gates on to the runways at the various levels desired, and pass over these, by gravity, into the ice house.