a building to lay up or store corn in, especially that which is designed to be kept for a considerable time.
Sir Henry Wotton recommends that a granary should be made to look towards the north, because that quarter is the coolest and most temperate. Mr. Worlidge observes, that the best granaries are built of brick, with quarters of timber wrought in the inside, to which the boards, with which the inside of the granary must be lined, must be nailed so close to the bricks that there may not be any room left for vermin to shelter themselves. There may be many storeys one above another, but these should be near the one to the other, because the shallower the corn lies, it is the better, and the more easily turned.
The two great cautions to be observed in the erecting of granaries are, to make them sufficiently strong, and to expose them to the most drying winds. In many parts of England, particularly in Kent, corn is ordered in this manner. To separate it from dust and other impurities after it is threshed, it is tossed with shovels from one end to the other of a long and large room; the lighter substances fall down in the middle of the room, and the corn only is carried from side to side or from end to end of it. After this the corn is screened, and being then brought into the granaries, it is spread about half a foot thick, and turned from time to time about twice in a week; the screening of it is also repeated once a week. This sort of management is continued about two months, after which it is laid a foot thick for two months more; and during this time it is turned once a week, or twice if the season be damp, and now and then screened again. After about five or six months, it is raised to two feet thickness in the heaps, and then turned once or twice in a month, and screened now and then. After a year, it is laid two and a half or three feet deep, and turned once in three weeks or a month, and screened proportionally. When it has lain two years or more, it is turned once in two months, and screened once a quarter; and how longsoever it be kept, the oftener the turning and screening are repeated, the better the grain will be found to be preserved. It is proper to leave an area of a yard wide on every side of the heap of corn, and other empty spaces, into which the corn may be turned and tossed as often as required. In Kent two square holes are made at each end of the floor, and a round one in the middle, by means of which the corn is thrown out of the upper into the lower rooms, and so up again, that it may be the better turned and aired. Their screens are made with two partitions, to separate the dust from the corn, which falls into a bag; and when sufficiently full this is thrown away, whilst the pure and good corn remains behind. Corn has by these means been kept in our granaries thirty years; and it is observed, that the longer it is kept the more flour it yields in proportion to the corn, and the purer and whiter the bread is, the superfluous humidity only evaporating in the keeping. At Zurich in Switzerland, corn has been kept eighty years, or longer, by methods of a similar description.
The public granaries at Dantick are seven, eight, or nine storeys in height, having a funnel in the midst of each floor, to let down the corn from one to another. They are built so securely, that though every way surrounded with water, the corn contracts no damp, and the vessels have the convenience of coming up to the walls to be loaded. The Russians preserve their corn in subterranean granaries of the figure of a sugar-loaf, wide below and narrow at the top, the sides being well plastered, and the top covered with stones. They are careful to have the corn well dried before it be laid into these storehouses, and often dry it by means of ovens, the summer dry weather being too short to effect this sufficiently. Dantick is the grand storehouse or repository of the fruitful kingdom of Poland. The wheat, barley, and rye, of a great part of the country, are there laid up in parcels of twenty, thirty, or sixty lasts in a chamber, according to the size of the room; and this is turned every day or two, to keep it sweet and fit for shipping.
According to the rules of Vitruvius, a granary should always be at the top of a house, and have its openings only to the north or east, that the corn may not be exposed to the damp winds from the south and west, which are very destructive to it; but the contrary winds are very necessary and wholesome, serving to cool it and absorb all external humidity. There must also be openings in the roof, to be set open in dry weather, partly to let in fresh air, and partly to let out the warm effluvia which are often emitted by the corn. The covering of the roofs should always be of tiles, because in the worst seasons, when the other openings cannot be safe, there will always be a considerable inlet for fresh air, and an issue for the vapours by their joinings, which are never close. If there happen to be any windows to the south, great care must be taken to shut them in moist weather, and in the time of the hot southern winds. There must not be a cellar or any other damp place under a granary, nor should it ever be built over stables; for in either of these cases the corn will certainly suffer by the vapours, and be rendered damp in one, and ill tasted in the other.
M. Duhamel and Dr. Hailes recommend various contrivances for ventilating or blowing fresh air through corn laid up in granaries or ships, in order to preserve it sweet and dry, and to prevent its being devoured by weevils or other insects. This may be done by nailing wooden bars or laths on the floor of the granary, about an inch distant from each other, when they are covered with hair-cloth. only, or at the distance of two or three inches, when coarse wire-work, or basket-work of osiers, is laid under the hair-cloth, or when an iron plate full of holes is laid upon them. These laths may be laid across other laths, nailed at the distance of fifteen inches, and two or more inches deep, that there may be a free passage for the air under them. The under laths must come about six inches short of the wall of the granary at one end, on which a board is to be set edgewise, sloping against the wall; for, by this disposition, a large air-pipe is formed, which having an open communication with all the interstices between and under the bars, will admit the passage of air below forcibly through a hole at the extremity, and consequently carry off the moist exhalations of the corn. The ventilators for supplying fresh air may be fixed against the wall, on the inside or outside of the granary, or under the floor, or in the ceiling; but wherever they are fixed, the handle of the lever that works them must be out of the granary, otherwise the person who works them would be in danger of suffocation when the corn is fumigated with burning pristone, as is sometimes done for destroying weevils. Small moveable ventilators will answer the purpose for ventilating corn in large bins in granaries, and may easily be moved from one bin to another. If the granary or corn ship be very long, the main air-pipe may pass lengthwise along the middle of it, and convey air on both sides under the corn. In large granaries, double ventilators laid upon each other may be fixed at the middle and near the top of the granary, that they may be worked by a windmill fixed on the roof of the building, or by a water-mill.
The air is conveyed from the ventilators through a large trunk or trunks, reaching down through the several doors to the bottom of the granary, with branching trunks to each floor, by means of which it may be made to pass into a large trunk along the adjoining cross walls; and from these trunks several lesser trunks, about four inches wide, branch off, at the distance of three or four feet from one another, and reach through the whole length of the granary, their farther ends being closed. Seams of one tenth or one twelfth of an inch should also be left open at the four joinings of the boards, where they are nailed together, that the air may pass through them into the corn. In some of these lesser trunks there may be sliding shutters, to stop the passage of the air through those trunks which are not covered with iron, or to ventilate one part of the granary more briskly than others, as there may be occasion. There should also be wooden shutters, hung on hinges at their upper part, so as to shut close of themselves; and these should be fixed to openings in the walls of the granary on their outside; by which means they will readily open to give a free passage for the ventilating air, which ascends through the corn, but will instantly shut when the ventilation ceases, and thereby prevent any dampness of the external air from entering. The ventilation should be made only in the middle of dry days, unless the corn, when first put in, be cold and damp.
In lesser granaries, where the ventilators must be worked by the hand, if these granaries stand on straddles, so as to have their lowest floor at some distance from the ground, the ventilators may be fixed under the lowest floor, between the straddles, so as to be worked by men standing on the ground without or within the granary. A very commodious and cheap ventilator may be made for small granaries, by constructing a ventilator of the door of the granary, which may be easily effected by making a circular screen, of the size of a quarter of a circle, behind the door; but in order to this, the door should open, not inwards, but outwards, so that when it falls back, it may be worked to and fro in the screen, which must be exactly adapted to it in all parts of the circular side of the screen, as well as at the top and bottom. But there must be a stop at about eight or ten inches distance from the wall, to prevent the door falling farther back, and that there may be room for a valve in the screen to supply it with air, which will be driven in by the door, through a hole made in the wall near the floor, into the main air-trunk, in which also there should be another valve over the hole in the wall, to prevent the return of the air.