Section I.--_The Daguerreotype._--The nature of the sensitive film.--Development of the Latent Image.--The strengthening of the Image by means of Hyposulphite of Gold 171 Section II.--_The Processes of Talbot, etc._--The Calotype.--The Waxed Paper Process of Le Grey.--The Albumen Negative Process.--Taupenot's Collodio-Albumen Process 176 PART II. PRACTICAL DETAILS OF THE COLLODION PROCESS. CHAPTER I. PREPARATION OF COLLODION. Mode of preparing soluble Pyroxyline by the mixed Acids--by the Nitre process.--Purification of the Ether and Alcohol.--Preparation of the iodizing compounds in a state of purity 185 CHAPTER II. FORMULÆ FOR SOLUTIONS REQUIRED FOR COLLODION PHOTOGRAPHS. Section I.--_Formulæ for direct Positive Solutions._--The Collodion.--The Nitrate Bath.--Developing fluids.--Fixing liquids.--Whitening solution 201 Section II.--_Formula for Negative Solutions._--The Collodion.--The Nitrate Bath.--Developing fluid.--Fixing liquid 208 CHAPTER III. MANIPULATIONS OF THE COLLODION PROCESS. Section I.--_Manipulations with moist Collodion._--Cleaning the Plates.--Coating with Collodion.--Exciting.--Exposing.--Developing. --Fixing 213 Section II.--_Simple directions for the use of Photographic Lenses._--Portrait Lenses.--View Lenses.--Mode of finding the chemical Focus 227 Section III.--_On copying Engravings, Etchings, Diagrams, etc._--Mode of intensifying the Collodion 231 Section IV.--_Rules for taking Stereoscopic Photographs._--Mr. Latimer Clark's arrangement for working with a single Camera 232 Section V.--_The Photographic delineation of Microscopic Objects.-_-Arrangement of the apparatus.--Mode of finding the chemical Focus.--Use of artificial light 235 CHAPTER IV. THE DETAILS OF PHOTOGRAPHIC PRINTING. Section I.--_Positive Printing by the ordinary process._--Selection of the paper.--Preparation of Albuminized paper--of plain paper--of Ammonio-Nitrate Paper.--Preparation of the fixing and toning Bath.--Manipulatory details of Photographic Printing.--Mode of washing and mounting the Proofs 240 Section II.--_Positive Printing by Development._--A process on Chloride and Citrate of Silver.--On Iodide of Silver.--On Bromide of Silver 259 Section III.--_The Sel d'Or Process for toning Positives._--Preparation of the toning Bath.--Manipulatory details 267 Section IV.--_On Printing enlarged Positives, Transparencies, etc., upon Collodion_ 272 CHAPTER V. CLASSIFICATION OF CAUSES OF FAILURE IN THE COLLODION PROCESS. Section I.--_Imperfections in Negative and Positive Collodion Photographs._--Fogging.--Transparent and opaque spots.--Markings of all kinds--under- and over-exposure, etc. 276 Section II.--_Imperfections in Paper Positives_ 285 CHAPTER VI. LANDSCAPE PHOTOGRAPHY BY THE COLLODION PRESERVATIVE AND COLLODIO-ALBUMEN PROCESSES.