Mr. J. H. Whitehurst of Richmond, Va., has introduced a revolving background, which is set in motion during the operation, and produces a distinctness and boldness in the image not otherwise to be obtained. The effect upon the background of the plate is equally pleasing; it having the appearance of a beautifully clouded sky. In practising Photographic drawing on paper, the student must bear in mind that it is positively essential, to secure success in the various processes, to use the utmost precaution in spreading the solutions, and washes from the combination of which the sensitive surfaces result. The same brush should always be used for the same solution, and never used for any other, and always washed in clean water after having been employed. Any metalic mounting on the brushes should be avoided, as the metal precipitates the silver from its solution. The brushes should be made of camels or badger's hair and sufficiently broad and large to cover the paper in two or three sweeps; for if small ones be employed, many strokes must be given, which leave corresponding streaks that will become visible when submitted to light, and spoil the picture. These few preliminary hints and suggestions, will, I trust, be of some service to all who adopt this pleasing art as a profession; and will, with a due attention to the directions given in the practical working of the Daguerreotype, Calotype, etc., ensure a corresponding measure of success. CHAP. V. DAGUERREOTYPE APPARATUS. The entire Daguerreotype process is comprised in seven distinct operations; viz: 1.--Cleaning and polishing the plate. 2.--Applying the sensitive coating. 3--Submitting the plate to the action of light in the camera. 4.--Bringing out the picture; in other words rendering it visible. 5.--Fixing the image, or making it permanent--so that the light may no longer act upon it. 6.--Gilding: or covering the picture with a thin film of gold--which not only protects it, but greatly improves its distinctness and tone of color. 7.--Coloring the picture. For these various operations the following articles--which make up the entire apparatus of a Daguerrean artist--must be procured 1.--THE CAMERA.--(Fig. 5.). The Camera Obscura of the Italian philosophers, although highly appreciated, on account of the magical character of the pictures it produced, remained little other than a scientific toy, until the discovery of M. Daguerre. The value of this instrument is now great, and the interest of the process which it so essentially aids, universally admitted. A full description of it will therefore be interesting. [Illustration: Fig. 5 (hipho_5.gif)]