ping or folding almost in the face of the camera, and it was therefore found necessary to devise some means by which the exposure could be deferred until the bird was in repose. The result is shown in the accom- panying figures. When the bird alights upon the perch «, the check resting on the wheel b is removed and as the wheel revolves the heav- ier of two weights c, sliding on rods, descends and enters d and e, the negative and positive poles of a dry battery. The circuit is thus closed and by means of a small electro -magnet on the camera the shutter is released and exposure made. How the bird is to be induced to alight on the perch is a problem which each user of this modern development of a bird trap must solve for himself. The accompanying pictures of Bluebirds were obtained by placing the perch near their nest ; the camera was then focused on it and the whole BLUEBIRD ON ELECTRIC PERCH afifair left until, on returning, the shutter was found to have been sprung, when the exposed plate — representing, potentially, the trapped bird — was removed, a new one introduced and the 'trap' set for another capture. No other trial has as yet been made, but in addition to its use near nests, the apparatus couKl doubtless be employed with success in large fields or meadows frequented by Hawks, or, carrying the comparison with a trap still further, it might be baited with meat, seeds, or fruit which would induce birds to alight on the perch .and unronsciousK- K-ave their image.
