Of the rastrums, there is nothing to say except that they are of steel and very even at the ends so that they touch the stone in all places. They serve to draw the five lines for music. For making the broad strokes for notes, one can use coarse drawing-pens, or coarsely cut steel pens; but the best are those adjustable drawing-pens that are made from three blades. The brush for spatter-work, the wiping-machine, and the dauber will be described in the description of the styles of work for which they are used. Ink-rollers and balls are for laying on the printing-color. The latter are made from soft leather, stuffed with horsehair, like the ordinary book-printer's balls. The former are wooden cylinders with thin handles, of any requisite length and about four to five inches thick. They are wound with two or three thicknesses of woolen cloth and then covered very firmly and evenly with leather. Usually there is used sheep's leather from which the grease has not been entirely removed. Calfskin, worked white, is good and more durable. Dogskin is considered best. Some printers use soft red calfskin, turning the inner side out. The leather must not be stitched with linen but with silk thread, because linen does not take the ink as well as leather and silk do. The leather must be dampened when being drawn over the cylinder. A fair stock of these rollers is required, because they are liable to become water-soaked during use, when they lose much elasticity and fail to give good service, so that dry ones must be on hand. It is not well to have movable handles on the rollers, because then they are likely to roll over the stone too lightly and it is not within one's power to lay on the ink thoroughly. To prevent blistering the hands, thick leather covers may be used. Then it is possible to use any desired pressure. Paper presses are needed both to obtain a uniform dampening of the paper as also to restore the proper flatness to the printed paper. Models are to be seen at the shops of all book-printers and binders. CHAPTER V CONCERNING PAPER Three kinds of paper are used mainly in lithography. They are:-- (_a_) the transparent, oiled or varnished paper; (_b_) underlay or waste paper; and (_c_) the printing-paper. I TRANSPARENT PAPER, AND THE TRANSFER OF OUTLINES TO THE STONE Oiled paper is used for tracing a drawing accurately and then transferring it to the stone either by transferring or by re-tracing it on the stone. It must have the following properties:-- (1) It must not smut the original drawing on which it is laid. Consequently it must be absolutely dry. (2) It must be very transparent, like glass, so that the underlying drawing or painting can be seen perfectly. (3) The ink or lead crayon used for copying must lie on it easily and plainly.