(_c_) In the etched or engraved methods, the needle will sink in much deeper when it passes over such softer spots, making a deeper and broader line which injures the clearness of the drawing. In etching, also, the softer places are more affected by the acid; and it is better, therefore, to use a soft stone whose entire surface is uniform, than to have a stone that is hard but uneven. A very soft stone cracks easily in the press, unless it consists of several layers, the lower of which are hard. But it is easier to engrave, and as a rule gives blacker impressions, because it sucks more color in, and holds it because of its greater porosity. Printing, however, is somewhat more difficult, because these stones take dirt readily; nor is it possible to get so many impressions. They are not useful for crayon work because the finest shadings are too easily etched away; and pen work is difficult on them, because the steel pen easily cuts into the stone, fills its point with fine dust, and thus gives no ink flow. This softest stone in Solenhofen generally looks yellow, or is marbled with red and white or has many yellow veins. Even those stones whose uniformity, thickness, and hardness make them best for all methods, often have defects, such as so-called glass spots or tiny, sometimes invisible holes, broad veins and cracks. All these must be avoided when selecting stone. Very small deep veins, which often are fine as hairs, yellowish and grayish spots, impressions of fossil plants and fishes, etc., are not harmful. It is rare to find a stone as large as a sheet of note-paper that is entirely free from these little defects. (3) The form of the stones also is to be considered, and must be selected according to need. To be sure, a small design can be drawn on a large stone; but apart from the inconvenience, the construction of the press demands that the stone be not much larger than the drawing. However, at the end where the impression begins and stops, there must be at least an inch margin to give sufficient room for the roller to take hold, as will be explained more particularly later. When one has to print small things like visiting-cards, etc., it will not be profitable to use large stones, especially if they are to be saved for future use. Small stones of the size of an octavo sheet are better. Therefore it will be wise to have stones cut to various sizes in the beginning. It would be well also that one of the printers, or the polisher, strive to attain skill in cutting stones to size. Sometimes polishing discloses defects in a stone, making it useless for a design of any size. But it is possible to cut it up into many small ones that are perfect. Sometimes a stone cracks under the press or breaks through accident. Skill in cutting will enable one to make small and good stones out of the pieces.