of the Daguerreotype successfully to portrait taking--for when first introduced among us it took from five to ten minutes to produce a tolerable good view, while now but the fraction of a minute is required to obtain an accurate likeness. To iodize the plate perfectly it must be placed over the iodine vapor immediately after buffing. Scatter from a sixteenth to the eighth of an ounce of dry iodine over the bottom of your coating box, and slightly cover it with cotton wool. The plate is then dropped into the frame b, fig. 12, with its silvered surface downward, and thrust under the lid h. The bright surface of the plate is soon coated with a film of iodine of a fine yellow color; it is then removed and placed over the accelerating solution. It is not absolutely necessary to perform this operation in the dark, although a bright light should be avoided. Not so the next part of the process, viz; giving the plate its extreme sensitiveness, or coating with the accelerating liquids. In this great caution should be used to prevent the slightest ray of light impringing directly on the plate, and in examining the color reflected light should always be used. A convient method of examining the plate, is to make a small hole in the partition of the closet in which you coat, and cover it with a piece of tissue paper; by quickly turning the plate so that the paper is reflected upon it the color is very distinctly shown. Most of our operators are not so particular in this respect as they should be. ACCELERATING LIQUID.--Of these there are several kinds, which differ both in composition and action--some acting very quickly,