237. Ice-houses should therefore be, in all their parts, _as dry_ as possible: and they should be so constructed, and the ice so deposited in them, as to ensure _the running away of the meltings_ as quickly as possible, whenever such meltings come. Any-thing in way of drains or gutters, is too slow in its effect; and therefore there must be something that will not suffer the water proceeding from any melting, to remain an instant.
238. In the first place, then, the ice-house should stand in a place quite open to the _sun and air_; for whoever has travelled even but a few miles (having eyes in his head) need not be told how long that part of a road from which the sun and wind are excluded by trees, or hedges, or by any-thing else, will remain wet, or at least damp, after the rest of the road is even in a state to send up dust.
239. The next thing is to protect the ice against wet, or damp, from _beneath_. It should, therefore, stand on some spot _from which water would run in every direction_; and if the natural ground presents no such spot, it is no very great job to _make it_.
240. Then come the _materials_ of which the house is to consist. These, for the reasons before-mentioned, must not be bricks, stones, mortar, nor earth; for these are all affected by the atmosphere; they will become _damp_ at certain times, and _dampness_ is the great destroyer of ice. The materials are _wood_ and _straw_. Wood will not do; for, though not liable to become damp, it imbibes _heat_ fast enough; and, besides, it cannot be so put together as to shut out air sufficiently. Straw is wholly free from the quality of becoming damp, except from water actually put upon it; and it can, at the same time, be placed on a roof, and on sides, to such a degree of thickness as to exclude the air in a manner the most perfect. The ice-house ought, therefore, to be made of _posts, plates, rafters, laths, and straw_. The best form is the _circular_; and the house, when made, appears as I have endeavoured to describe it in _Fig. 3_ of the plate.
241. FIG. 1, _a_, is the centre of a circle, the diameter of which is ten feet, and at this centre you put up a post to stand fifteen feet above the level of the ground, which post ought to be about nine inches through at the bottom, and not a great deal smaller at the top. Great care must be taken that this post be _perfectly perpendicular_; for, if it be not, the whole building will be awry.