Drawings of specimens or other objects were once made with brush and pencil or with pen and ink, by means of measurements taken with dividers or by viewing the specimen through a camera lucida. Each of these methods is still used, but by using the camera lucida in sketching: the outlines and details more accurate proportions and relations can be produced, whether the object is to be enlarged or reduced, than by any other means except photography. BRUSH AND PENCIL DRAWINGS. In all drawings or photographs of specimens, except photomicrographs of thin sections, the light should appear to come from the upper left quarter. A disregard of the well-established rule that the direction of illumination should be uniform throughout a series of drawings would cause confusion or uncertainty in the interpretation of the relief shown in them. Reynolds's three-ply and four-ply bristol board affords a satisfactory surface for brush and pencil drawings. Its surface is smooth and hard and, being free from coating of any kind, permits satisfactory erasures without great injury; its color is pure whits; and it is durable. Boss's relief hand-stipple paper is also well adapted to many kinds of brush drawings as well as to its primary use for producing stippled effects. Very delicate gradations of color or light and shade can be produced on its surface with brush and lampblack or with india ink, and high lights can be made by scraping off the chalky surface. The draftsman who is preparing brush and pencil drawings should have first of all a knowledge of the principles of light and shade, of reflected light, and (for drawing specimens) of shadow perspective. He should also have delicacy of touch and ability to see and interpret form and to reproduce the soft blending of light and shade shown in a good photograph. He should be provided with pencils equal in quality to the Koh-i-noor B, F, 4H, and 6H; the best quality of red sable brushes of the sizes of Winsor & Newton's Nos. 3, 4, and 6; the best quality of stick india ink; a cake or pan of lampblack; and a porcelain saucer or slab. In drawings of fossils and of some other specimens a combination of pencil and brush work produces satisfactory results and tends to increase speed. The gloss produced by penciling, however, is objectionable and should be obviated by a preponderance of brush work. Stick India ink is the best pigment to use in delicate wash drawings, and lampblack is preferable for large work on which the softer tones of the shading are not so important and for drawings that are to be considerably reduced when engraved. Gouache (an opaque mixture of Chinese white and lampblack) may also be used, but it is best suited for large work.