BOXINGS OF A WINDOW, are the two cases, one on each side of the window, into which each of the adjacent shutters is folded, when light is require in the room. The leaves which appear in the front of each boxing, are denominated front shutters ; and those in the back, are called back yaps. In order to estimate the breadth of flaps, and the depth of boxing-room ; suppose each boxing to be filled with the shutters which are to cover half the breadth of the opening : add the thicknesses of all the folds together, with as many one-sixteenths of an inch as there are breadths, and the sum is the depth of the boxing. Thus, suppose a window to he four feet wide, placed in a brick wall eighteen inches thick, let the sash-frame be six inches thick, and placed four inches and a half from the face of the wall, or the breadth of a brick ; this will reduce the wall to seven inches and a hal.
thick ; to this arid the necessary thickness for lath and plaster, about two inches, gives nine inches and a half for the breadth of the shutter : nine inches and a half will be contained in twenty-four inches, or the half of tbur feet, twice, with a remainder; therefore there must be three leaves or folds in a shutter, viz.. a front leaf, and two back flaps. The front leaf should be necessarily the whole breadth of the boxing, or nine inches and a half; and the two back flaps between them, the remainder between nine inches and a half and twenty-fimr inches, that is, fourteen inches and a half: The back flap slit wld always be the least, in order that the shutters may go freely into the boxing; the middle one, therefore, may be eight inches, and the back one six inches and a half, for 91 ±S +61=2 ; but if the flaps are rebated into one another, which i.s most commonly the ease, whatever be the breadth
of the rebate and the number of them, then so much more ought to be added to the whole breadth. In the present example, the three folds will require two rebates ; let each rebate be a quarter of an inch, then, instead of reckoning twenty-four, it must be twenty-fiiur inches and a half, and as no alteration can be made on the front flap, it must be added to one of the back flaps; the three flaps may therefore stand thus, Besides this allowance in breadth, there is another for the rebate at the meethng in the middle of the window of the two back flaps; if this rebate be a quarter of an inch also, it may be added to the shutters on either side of the window, or it may be divided in any pro portion between ; let it be equally divided, then the breadth of the flaps may stand thus, Tn find the thickness. suppose the front flap to be one inch and a half, the two back flaps each one inch and a quarter, then 1 1+ l++ 1 1--1--A=.4-A-, for the depth of the boxing-room. If there is a back lining, that must he taken also into the account. When shutters are in many ft dds, they are troublesome to shut, and this must always be the ease in thin walls, or with wide windows. To remedy this. the architraves are either made to project. considerably before the plaster, or the lath and plaster are brought to a considerable distance from the rough wall.