da ger'o type, the original photographic process, consisting in sensitizing a silver plate with the vapor of iodine and then placing it in a camera obscura, previously focused, and afterward developing the picture by vapor of mercury. It is then fixed by immersion in hyposulphate of sodium. After thorough washing and drying the picture is covered with glass to prevent its being rubbed off. The process is named from its inventor, Daguerre. It is now replaced by photography. See PHOTOGRAPHY.