Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 3, 1802).djvu/70

52] first to be contracted by means of the cord, which ought to be properly stretched. The middle of the bow must be exactly fitted to the lath a, so that one inch only of the latter project; and the place which is intersected by the string c, c, should be accurately marked. The lath, from this mark to its extremity b, ought to extend somewhat farther than double the length of its upper part.

Having found the proportion between the length of the lath, and the semi-circle of the bow, every thing depends upon the proper joining of these two essential parts. Hence a superficial excavation should be made at about an inch from the extremity of the lath a, and a similar cut in the centre of the bow; both are then to be brought into contact, and fastened with strong thread or silk.

The extremities of the hoop should now be made exactly of equal length; when one end is to be tied with thin packthread to the bow at d, about half an inch from the point; and, after having made small excavations into the lath f, on all its sides, one arm of the hoop d ought to be drawn close to the transverse piece; the packthread twisted several times round f; and at length tied to the other arm at e. Now the two sides from d to f, and from f to e, ought to be measured: if they happen to be unequal, the difference may be adjusted by pulling the thread towards the shorter side. Next, the thread is to be extended from e towards a, where it should be turned round several times; and thence conducted to d, the place in which it is fastened, so that it will form the angle d, a, e, as represented in the figure.—A small incision must farther be made in the part of the lath marked b, to which the thread is extended in the direction from d to b, and thence again to e, where it is ultimately secured.

Thus, the skeleton of the kite will be arranged; and it now remains to ascertain its equilibrium, which may be effected in the following manner: The end of the lath projecting at a, should first be rounded by the knife, and placed on a table, when the opposite end b is to be poised on the tip of the finger. If both sides of the bow are in perfect equilibrium, the skeleton is then complete; but, if either of them incline to one side, the want of symmetry may be remedied by cutting or shaving off the preponderating side of the lath, so as to reduce it to an equipoise. The frame, thus finished, is next to be covered either with silk stuff, or thin paper previously oiled, that it may resist the effects of moisture: and to prevent folds either in the silken or paper cover, they should be wetted before they are applied, and afterwards dried in a cool place. In order to secure the whole covering to the frame, narrow slips of silk or paper should be pasted across the lath, and over the packthread in all the parts marked g; and, when the whole is perfectly dry, its equilibrium must again be adjusted, by putting such additional pieces on the light side, as may be requisite to restore the balance.

In constructing electrical kites, it is of the utmost consequence to apply the string h, h, below the body of the machine to its proper place: when the latter is five feet long, the cord ought to be eleven, one end of which should be passed through the two holes of the lath; namely,