A Manual Of Photography

254 PRACTICE OF PHOTOGRAPHY. Section VI.—Simplification of the Daguerreotype. The following experiments for the simplification of the daguer- reotype processes, which were made by me many y ears since, do not appear to be entirely uninstructive; the original paper is therefore retained, with a few verbal alterations only. The extreme expense of the apparatus and plates, as supplied by the patentee, induced me, in the very first stage of my ex- periments, to endeavour to construct for myself a set which should be equally as effective, and less expensive. I was soon satisfied that all the arrangements might be much simplified. . . „ My apparatus consisted of a deal box the size, of my plates, and three inches deep, with a thin loose board in the bottom. This board is well saturated with the tincture of iodine; the spirit is allowed partially to evaporate, and then, being put in its place, the plate is adjusted at a proper height above it, varying the height according to the temperature : the box being closed, the operation is completed in about three minutes.. Another deal box, having a glass in one side, and a bottom of sheet iron, which is slightly concaved to contain mercury, with grooves upon whieli the plate may rest at the proper angles, serves to mercurialize the plates. My camera, which 1 use for every photographic process, is described in a formel chapter. It is sometimes convenient, particularly when travelling, to use a piece of amalgamated copper, which may be prepared, when wanted, by rubbing it with some nitrate of mercury. The ex- pense of the plates may be very much reduced: instead of using copper plated with silver, I would recommend the use of silvered copper, which every one can prepare for himself at a very small expense. The following is the best method of proceeding :— Procure a well-planished copper plate ot the required size, and well polish it, first with pumice stone and water, then with snake stone, and bring it up to a mirror surface with either rotten-stone or jewellers' rouge. Plates can be purchased in a high state of preparation from the engravers. Having prepared the copper plate, well rub it with salt and water, and then with the silvering powder. IS o kind answers better than that used bj clock-makers to silver dial-plates. It is composed of one part of well-washed chloride of silver, five parts of cream of tartar, and four parts of table salt. This powder must be kept in a dark vessel, and in a dry place. Ior a plate six inches by five, as much of this composition as can be taken up on a shilling is sufficient. It is to be laid in the centre of the copper, and the