Pantoscope Paper, Alubmenised
water lens (fig. 87, p. 432), with which curved plates were used. The principle of the most usual type of panoramic camera is perhaps sufficiently explained in the article Cylindrograph (p. 171); but it should be understood that rigidly attached to the lens setting and inside the camera is a tube which terminates in a vertical slot near the surface of the curved film, thus limiting the exposure at each instant to that portion of the plate well covered by the lens. The panoramic camera best known in this country is that of Johnson & Harrison, in which the lens moves on a vertical axis, as in Mcessard's cylindrograph, and the lens setting carries with it a casing with vertical slot. Instead, how-ever, of the sensitive surface being curved, a long plate is used and this plate is so moved by gearing that the portion actually under the action of the lens always has a position corresponding to a tangent on the circle described by the vertical slot. With the long plate, mechanical limitations make it difficult to con-struct the camera so that it shall describe a complete circle. Damoiseau's cyclograph and Colonel Stewart's panoram are constructed on a similar principle, but instead of a long plate a band of film is used, and a complete circle - or, indeed, several circles in succession - may be photographed on a band of film. Other forms of panoramic camera, by which 3600 may be included, are Chevalier's plane table, in which an image is reflected downwards from a revolving lens to a circular plate and M. Noe's oroheliograph, in which the lens looks upwards at a convex paraboloid reflector. These, however, give distorted images, but are serviceable in connection with photogrammetric observations. Mr. A. H. Smith has constructed a form of camera, which he calls by the same name as M. Damoiseau's instrument above mentioned, and it photographs the whole cir-cumference of a cylindrical object which revolves in front of it. (See Cyclograph.)
Pantoscope. (1) An apparatus for viewing photographs, and generally similar to the Alethoscope and Lanternoscope (q.v.). (2) A wide-angle lens manufactured by Busch, and shown in section (fig. 84, p. 431).
Pantoscopic Camera. See Panoramic Camera.
Paper, Albumenised. See Albumenised Paper.