Now, let the same subject be treated by Professor Wheatstone's method, when the cameras would be eighteen feet apart. Situated thus, if placed on one line, and that parallel to the wall, the extreme end at the right could not be seen by the camera at the left, and _vice versa_; so that they {420} must radiate from the centre when the glass at back of camera would be oblique to the wall, and the plinth, coping, top and bottom of pedestal, would have _two_ vanishing points, at opposite sides of the centre, or observer's eye; both sides of the ass, both the legs of boy, and two heads to the drum would be visible; whilst the two sides of pedestals would have each a vanishing point, serving for all lines parallel to them. But these vanishing points would be so far apart that they could not, in the stereoscope, flow into one: the result would be, that the buttresses would be wider at back than in front, as would also the pedestal, while the stick held by the boy would appear like _two_ sticks united in front. This would be untrue to nature, false to art, preposterously absurd, and I pronounce it to be altogether erroneous. This being the case with a long distance, so must it be with shorter distances, modified in exact proportion to the diminution of space between the cameras, &c. For, let the object be a piece of wood three feet long, four inches wide, and six inches deep, with a small square piece one inch and six inches high, placed upright exactly on a line from end to end of the three feet (that is, one at each end) and midway between the sides. Let this arrangement be placed across another piece of wood three or four feet long, which will thus be at right angles to the piece at top. By my method all will be correct--true to nature and to art, and perfectly stereoscopic: whilst by the radial method (recommended by MR. SHADBOLT), with two feet space for cameras, there would be the top piece divided at the farther end, where there would be two small upright pieces instead of one; and this because the two vanishing points could not, in stereoscope, flow into one: whilst the lower piece of wood would have two vanishing points at opposite sides. This, then, being untrue to nature, untrue in art, in short, a most absurd misrepresentation, I pronounce to be utterly wrong. I have made the space two feet between cameras in order to show how ridiculous those pictures might become where there is an absence of taste, as, by such a person, two or ten feet are as likely to be taken as any less offensively incorrect. As regards range of vision, I apologise to MR. SHADBOLT for having misconceived his exact meaning, and say that I perfectly agree with him.