-- Frederick Scott Archer experimented with paper pulp, tanno-gelatine, and iodised collodion, and made collodion negatives in the autumn. 1849. Collodion _positive_ of Hever Castle, Kent, made by Frederick Scott Archer _early_ in the year. -- M. Gustave Le Gray _suggested_ the application of collodion to photography. 1850. "A Practical Treatise on Photography upon Paper and Glass," by Gustave Le Gray. Translated from the French by Thomas Cousins, and published by T. and R. Willats. This book is said to contain the first printed notice of collodion being used in photography. -- R. J. Bingham, London, suggested the use of collodion and gelatine in photography. -- M. Poitevin's gelatine process, published January 25th. 1851. Frederick Scott Archer published his collodion process in the March number of _The Chemist_, and introduced pyrogallic acid as a developer December 20th. -- Fox Talbot announced his instantaneous process, and obtained, at the Royal Institution, a copy of the _Times_ newspaper, while revolving rapidly, by the light of an electric spark. -- Niépce de St. Victor's heliochromic process, published June 22nd. Examples sent to the judges of the International Exhibition of 1862. See Jurors' Report thereon, pp. 88-9. -- Sir David Brewster's improved stereoscope applied to photography. 1851. "Photography, a Treatise on the Chemical Changes produced by Solar Radiation, and the Production of Pictures from Nature, by the Daguerreotype, Calotype, and other Photographic Processes," by Robert Hunt. Published by J. J. Griffin and Co., London and Glasgow. 1852. "Archer's Hand-Book of Collodion Process." Published May 14th. Second edition, enlarged; published 1854. -- "Archer's Collodion _Positive_ Process." Published July 20th. -- Fox Talbot's photo-engraving on steel process; patented October 29th. 1853. A Manual of Photography, by Robert Hunt, published. -- Photographic Society of London founded. Sir Charles Eastlake, P.R.A., President; Roger Fenton, Esq., Secretary. First number of the Society's Journal published March 3rd. -- Cutting's American patent for use of bromides in collodion obtained June 11th, and his Ambrotype process introduced in America. -- "The Waxed-Paper Process," by Gustave Le Gray. Translated from the French with a supplement, by James How. Published by G. Knight and Co., Foster Lane, Cheapside. -- Frederick Scott Archer introduced a triple lens to shorten the focus of a double combination lens. 1854. E. R., of Tavistock, published directions for the use of isinglass as a substitute for collodion. -- First series of photographic views of Kenilworth Castle, &c., from collodion negatives, published by Frederick Scott Archer. -- Liverpool Photographic Journal, first published by Henry Greenwood, bi-monthly. -- First roller-slide patented by Messrs. Spencer and Melhuish, May 22nd. -- Fox Talbot first applied albumen to paper to obtain a finer surface for photographic printing.