It is usually used for Gothic buildings and private mansions, but should not be adopted, as it is apt to be lifted off its spindle by the wind. When a down-current of wind takes place there is generally an up-current at the same time, and there is a possibility of the cock being blown off during a gale. If it is used it should have a long point fixed above it.
Fig. 7.
A better arrangement than either of the two preceding ones is to let the point go quite through the weathercock in an encasement. The cock is then supported on a small round embasement, upon which are placed three small rollers (see [fig. 7]); on these the vane revolves easily, the continuity of the lightning conductor is perfect, and the weathercock freely turns round on the point so long as the small rollers are in order. In this arrangement, as in most others, the best material for the point is copper. Steel has occasionally been used, but it was found that in a very short time the rust had so eaten into the joints that the cock would not turn with the wind.
The most complete and enduring method is that indicated in [figs. 8 and 9]; this is the plan adopted in England for all the best work. By this arrangement, the friction being very much diminished, the weathercock revolves with great ease and freedom; the possibility of its getting out of order is reduced to a minimum; and the continuity of the lightning conductor remains unimpaired.
Fig. 8. Fig. 9.
It is accomplished in this way:—A circular plate, through the centre of which the point passes, is permanently fixed some distance down the point. On this circular basement rest three glass balls, rolling on three axes radiating from the centre, i.e. the point, and fixed in their outward extremities to a ring which surrounds the balls (see [fig. 9]). On these balls is placed another circular plate, on which is fixed the weathercock. The weathercock and circular plate, with a hole through the centre, is simply put on to the point of the conductor, and allowed to rest loosely of its own weight on the balls of glass.