Manipulations of Collodion process, 213; of Photographic printing, 251; of toning by Sel d'or, 267. Manuscripts, mode of copying, 231. Markings on Collodion Pictures, 281. Measures and Weights, 379. Microscopic Photography, 235. Moser, M. Ludwig, his researches on the development of invisible images, 37. Mounting Positive Prints, substances which should be avoided in, 155, 164; details of, 257. Negative processes for printing Positives, 259, 263. Negatives, definition of, 106; Collodion Negatives, theory of production of, 113; Calotype, 176; waxed paper, 178; Albumen, 180; Collodio-Albumen (Taupenot), 181; mode of developing Collodion Negatives, 37, 117, 223; of converting Positives into, 117; formula for solutions for Negatives, 208; the Collodion best adapted for Negatives, 114; spots and markings upon Negatives, 282; decomposition of Pyroxyline a cause of fading of, 166. Nitrate of Silver, preparation and properties of, 12; preparation of from standard coin of realm, 362; often contains free Nitric Acid, 13; when very strongly fused, contains Nitrite (_see_ Nitrite of Silver), 14; not acted on by light, 18; its reduction by Pyrogallic Acid explained, 31; the melted Nitrate more certain in its action, 13, 101; its presence essential in developing the image, 36, 98; increases sensitiveness of Collodion plate, 92; dissolves Iodide of Silver, 86; discoloured by Albumen, 245, 329; forms a compound with Honey, 289; with various other organic bodies, 21; very little acted on by Glycerine, 342; mode of recovering the Silver from, 372. Nitrate Bath, mode of preparing for glass Positives, 110, 203; for Collodion Negatives, 116, 211; its power of dissolving Iodide of Silver, its occasional acidity and alkalinity explained, 86; the mode in which Acetate of Silver may be formed in it, 89; a list of the substances by which it is decomposed, 90; changes by use, 91; effect of these changes on sensitiveness, 97; on intensity, 102; care required to prevent it from yielding foggy pictures, 104; a caution against the too frequent addition of alkali, 204; quantitative testing of the Bath, 371. Nitrite of Silver, adds to rapidity of development, 102; tends slightly to produce fogging, 104; solarizes the high lights, 111. Nitric Acid, its preparation and properties, 355; its oxidizing powers, 12; impairs sensitiveness of Collodion film, 93; lessens rapidity of development, 98; tends to prevent fogging, 104; sometimes usefully employed for glass Positives, 110; contra-indicated for Negatives, 116; its accumulation in the Nitrate Bath explained, 94; mode of removing it, 90; cannot exist in contact with Acetate of Silver, 116; produces stains on cloth, 215;