Sole Agents in the United Kingdom for VOIGHTLANDER & SON'S celebrated Lenses for Portraits and Views. General Depôt for Turner's, Whatman's, Canson Frères', La Croix, and other Talbotype Papers. Pure Photographic Chemicals. Instructions and Specimens in every Branch of the Art. GEORGE KNIGHT & SONS., Foster Lane, London. * * * * * PHOTOGRAPHY.--Collodion (Iodized with the Ammonio-Iodide of Silver)--J. B. HOCKIN & CO., Chemists, 289. Strand, were the first in England who published the application of this agent (see _Athenæum_, Aug. 14th). Their Collodion (price 9d. per oz.) retains its extraordinary sensitiveness, tenacity, and colour unimpaired for months: it may be exported to any climate, and the Iodizing Compound mixed as required. J. B. HOCKIN & CO. manufacture PURE CHEMICALS and all APPARATUS with the latest Improvements adapted for all the Photographic and Daguerreotype processes. Cameras for Developing in the open Country. GLASS BATHS adapted to any Camera. Lenses from the best Makers. Waxed and Iodized Papers, &c. * * * * * PHOTOGRAPHY--The AMMONIO-IODIDE OF SILVER in Collodion, prepared by MESSRS. DELATOUCHE & CO., Operative Chemists, 147. Oxford Street, is now generally used by Photographers, and cannot be surpassed in the beautiful results it produces. Specimens may be seen on application. MESSRS. DELATOUCHE & CO. supply Apparatus with the most recent Improvements, Pure Chemicals, English and Foreign Papers, and every Article connected with Photography on Paper or Glass. Instruction given in the Art. See HENNAH'S new work on the Collodion Process, giving the most practical directions yet published, price 1s., or free by post 1s. 6d. * * * * * TO ALL WHO HAVE FARMS OR GARDENS. THE GARDENERS' CHRONICLE AND AGRICULTURAL GAZETTE. (The Horticultural Part edited by PROF. LINDLEY) Of Saturday, March 26, contains Articles on