In order to throw some light upon his views, Mr. Wheatstone got “a number of Daguerreotypes of the same bust taken at a variety of different angles, so that he was enabled to place in the stereoscope two pictures taken at any angular distance from 2° to 18°, the former corresponding to a distance of about six feet, and the latter to a distance of about eight inches.” In those taken at 2°, (the proper angle,) there is “an undue elongation of lines joining two unequally distant points, so that all the features of a bust appear to be exaggerated in depth;” while in those taken at 18°, “there is an undue shortening of the same lines, so that the appearance of a bas-relief is obtained from the two projections of the bust, the apparent dimensions in breadth and height remaining in both cases the same.” Although Mr. Wheatstone speaks thus decidedly of the relative effect produced by combining pictures taken at 2½° and 18°, yet in the very next paragraph he makes statements entirely incompatible with his previous observations. “When the optic axes,” he says, “are parallel, _in strictness_ there should be no difference between the pictures presented to each eye, and in this case _there would be no binocular relief_, but I find _that an excellent effect_ is produced when the axes are nearly parallel, by pictures taken at an inclination of 7° or 8°, and even a difference of 16° or 17° _has no decidedly bad effect_!” That Mr. Wheatstone observed all these contradictory facts we do not doubt, but why he observed them, and what was their cause, is a question of scientific as well as of practical importance. Mr. Wheatstone was not aware[51] that the Daguerreotype pictures which he was combining, taken with _large lenses_, were not pictures as seen with two human eyes, but were actually binocular and multocular monstrosities, entirely unfit for the experiments he was carrying on, and therefore incapable of testing the only true method of taking binocular pictures which we have already explained. [51] Mr. Wheatstone’s paper was published before I had pointed out the deformities produced by large lenses. See p. 130.