A suitable ink may be made by dissolving 1 part of aniline black (soluble in oils) in (5 or 8 parts of oil of cloves by a gentle heat; while still warm, apply it to the pad with a camel-hair brush. Another ink may be prepared by grinding together very carefully 1 part of gas black and 5 parts of oil of cloves; but to make the latter pro-perly, a grinding plant is necessary. If the pad is worn, it is useless trying to treat it.