A Manual Of Photography

2765. 1852. ] GRIFFIN’S SCIENTIFIC CIRCULAR. ___________________________105 Pressure Frames, for producing Positive Pictures, copying Botanical Specimens, Flowers, &c. (fig. 2765). 2765. For pictures 6 inches by 5 inches, 7s. 6cZ. 2766. For pictures 81 inches by 61 inches, 9s. 2767. For pictures 12 inches by 10 inches, 12s. PRESSURE Frame, so constructed that the deve- lopment of the picture may be ascertained without shifting the paper. 2768. For pictures 81 inches by 61 inches, 12s. 2769. For pictures 12 inches by 10 inches, 16s. 2770 Pressure Frame, Improved, for copying Negative Collodion Pictures on glass, and adapted also for producing Positives of the Calotype process; size for glass plates up to 6Z inches by 4|inches, 8s. 2771. Ditto for plates up to the full size, 12s. 2772. Steam Apparatus for developing the Photographic Picture by a jet of steam, 6s. The employment of this apparatus prevents the browning of the picture which sometimes takes place when a dry heat is employed. 2773. Oil Lamp, with yellow glass shade, for viewing the development of the Daguerreotype Picture, preparing paper for the Calotype, &c., 3s. 6^. 2774. Balance, and set of weights, with brass pans, in oak box, 3s. 2775. Balance, and set of weights, with steel beam of superior make, and glass pans, in mahogany box, 10s. 6^. 2776. DISTILLING Apparatus for preparing pure water ; a tin-plate still of one gallon capacity, with a worm-tub, complete, 16s. 2777. Stoneware Water Bottle, with stopcock, 1-gallon size, for holding dis- tilled water, 4s. SILVER PLATES FOR DAGUERREOTYPES, of a superior manu- facture :— 2778. Size, 2^ inches by 2$ inches, 6s. 6J. per dozen. 2779 Size, 2f inches by 3^ inches, 10s. per dozen. [For Boxes to hold 2780 Size’ inches by 41 inches, 14s. per dozen. *e A'»3- 2781- Size, 4^ inches by 6| inches, 11. 10s. per dozen. 2782. Size, 6| inches by 8å inches, 2/. 12s. 6tZ. per dozen. Daguerreotype plates sometimes contain so thin a layer of silver, that even with the greatest care the copper will show itself after the plate has been used to obtain two or three pictures. The plates above enumerated are of a superior description, containing one-thirtieth of silver. GLASS PLATES for the Collodion Process. Best plate-glass, free from scratches, &c., with ground and polished edges :— 2783. 4A inches by 31 inches, 4s. per dozen. 2784* 61 inches by 4^ inches, 6s. 6^. per dozen. 2785. 81 inches by 6| inches, 14s. per dozen.