correspondence which shows how fully and accurately Spencer himself must have had the whole vast plan marked out in his mind down to the veriest details, before he sat down to commit himself to the pinning of a single line.
And here, having followed Mr. Spencer to the verge of the great undertaking to the prosecution of which he has devoted the energies of his after-life, we draw our paper to a close; our present purpose not embracing any direct consideration of that undertaking in itself. The hope which we have ventured to entertain is, that even such a rapid review as we have thus taken of the earlier period of Mr. Spencer's intellectual activity may prove to be not altogether without its uses to the earnest student of that wonderful series of works which, by the common consent of all those most entitled to judge, have won for their author a foremost place long the greatest thinkers of all time.
By EMIL DE BOIS-REYMOND.
ON still another side the development of photography has secured instructive data for art. In the year 1836 the brothers William and Edward Weber, in their famous work on the Mechanism of the Human Organs of Locomotion, represented a man walking in the positions which it was theoretically supposed he must go through during the time of making a step. The strange feature was remarked that while the pictures corresponded at the beginning and the end of the step, when the man for a short time had both feet on the ground, with the representations which the painters had always given of a walking man, in the middle of the step, when the moving leg was swinging by the stationary leg, the most eccentric and ludicrous spectacle was presented. The man appeared, like a drunken street musician, to be stumbling over his own feet. Never had anybody seen a walking man in such a situation. The brothers Weber proposed on the last page of their work to test the correctness of their schematic drawings by the aid of the stroboscopic slides of Stampfer and Plateau, as in the figures of Horner's dædaleum. which has curiously come back to us from America as a novelty under the name of the zoetrope or
- Address on Leibnitz Commemoration-day in the Academy of Sciences at Berlin, July 3, 1890.
- Philosophical Magazine, etc., January, 1834, Ser. III, vol. iv, p. 36. Peggendorff's Annalen, etc., 1834, vol. xxxii, p. 650.