Art of photography : instructions in the art of producing photographic pictures in any color and on any material, for the use of beginners and also of persons who have already attained some proficiency in the art, and of engravers on copper, stone, wood, etc. (1854)
Halleur, G. C. Hermann, Schubert, F. (Franz) · London : J. Weale · leaf 33
ject-glass ; by which means the operator is enabled to employ, if need be, object-glasses of different focal lengths. The whole apparatus is so arranged, that it may be readily folded and packed. It weighs only half as much as a common camera, and when packed up, occupies only about half the space… … As this camera may be lengthened, without the intervention of a sliding box, it is particularly suited for copying pictures in enlarged or reduced sizes. To do the former, and more especially to copy enlarged
Photography
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
