Fig. 477.—Mechanical bird.
The movement made by the wing round a longitudinal axis, by means of which it always exposes its lower surface in front on rising, is obtained by the mechanism illustrated in fig. 478 a.
M. Tatin’s Bird.
This apparatus, looked at sideways or from behind, is composed of a light wooden frame, on which are two small supports crossed by an axletree so as to form two cranks. This axle receives a circular movement from an india-rubber spring. The crank on the foremost plane causes the rising and falling of the wings, which move round a common axis, and pass the dead points as the cranks of a locomotive do—so the action is maintained.
Fig. 478.—M. Tatin’s bird.
Fig. 478 a.—Detail of fig. 478.