It is essential for good work in the press that the stones be cut very true. The stones that are used for flooring in churches, etc., usually are cut so that the upper face is larger than the lower. This is done to make them set better in the mortar and to enable the stone-cutters to fit them closely together on the top. But this must not be done with stones for printing, because such stones could not be tightened properly in the press and would lift during the printing. Printing-stones must be cut absolutely true vertically. Indeed, in work where several plates are to be used to make one complete impression, and where steel guide-points in the frame are used instead of laying the paper on the plate, it is beneficial to cut the stones conically, so that the base is one fourth inch greater than the top. The plate can be tightened better and is less likely to be moved from its place during the impressions. Despite their hardness the stones are brittle, and a single light but sudden blow with any hard body, such as a steel tool, may cause a crack in the thickest stone. It is necessary to exercise great care to avoid all shocks. This property of the stone is used in Solenhofen to cut the stones according to desire. A small hammer of hard steel, weighing scarcely two ounces, is used. Its end is somewhat like a stone-chisel, but not nearly so sharp. With this hammer, which is set on a thin handle two or three feet long, the workman strikes light but very swift blows along the line of desired cleavage, each tap being about an inch from the preceding one. The stone is so laid that its greater part is free, resting on nothing. This light operation is sufficient to cleave the largest stones. The cleavage is not always uniform and true. Therefore the stone usually is finished with a sharp stone-chisel. It is possible also to divide a stone as desired by supporting it at both ends so that there is nothing under the part to be split, and then cutting along the line with a chisel of hardened steel, not too sharp, which is tapped lightly with a light hammer. The varying sound tells at once when the stone cracks, and then a few light taps with the hammer on the other side suffice to separate it. Before one attains the necessary skill, however, he will smash many a stone. Therefore it is not advisable to try this on a stone that has a design on it, for a single incorrect or over-heavy blow often will split the stone in the wrong direction. Blows that are too light, on the other hand, often make it almost impossible in the end to cause a cleavage along the desired lines. II POLISHING The stone plates that come from Solenhofen, even if polished according to stipulations, rarely are available for printing, but must be specially polished by one who understands the work thoroughly.