The art of the lapidary, or science of glyptics, is a most interesting study, and it would be a mistake not to consider it for a few moments on its technical side. It is very ancient as an art. In Ecclesiasticus the wise Son of Sirach alludes to craftsmen "that cut and grave seals, and are diligent to make great variety, and give themselves to counterfeit imagery, and watch to finish a work." Theophilus on glyptics is too delightfully naive for us to resist quoting his remarks. "Crystal," he announces, "which is water hardened into ice, and the ice of great age hardened into stone, is trimmed and polished in this manner." He then directs the use of sandstone and emery, chiefly used by rubbing, as one might infer, to polish the stones, probably _en cabochon_ as was the method in his time; this style of finish on a gem was called "tallow cutting." But when one wishes to sculp crystal, Theophilus informs one: "Take a goat of two or three years... make an opening between his breast and stomach, in the position of the heart, and lay in the crystal, so that it may lie in its blood until it grow warm... cut what you please in it as long as the heat lasts." Just how many goats were required to the finishing of a sculptured crystal would be determined by the elaboration of the design! Unfortunately Animal Rescue Leagues had not invaded the monasteries of the eleventh century. In sculpturing glass, the ingenuous Theophilus is quite at his best. "Artists!" he exclaims, "who wish to engrave glass in a beautiful manner, I now can teach you, as I have myself made trial. I have sought the gross worms which the plough turns up in the ground, and the art necessary in these things also bid me procure vinegar, and the warm blood of a lusty goat, which I was careful to place under the roof for a short time, bound with a strong ivy plant. After this I infused the worms and vinegar with the warm blood and I anointed the whole clearly shining vessel; which being done, I essayed to sculp the glass with the hard stone called the Pyrites." What a pity good Theophilus had not begun with the pyrites, when he would probably have made the further discovery that his worms and goats could have been spared. In the polishing of precious stones, he is quite sane in his directions. "Procure a marble slab, very smooth," he enjoins, "and act as useful art points out to you." In other words, rub it until it is smooth! Bartholomew Anglicus is as entertaining as Theophilus regarding crystal. "Men trowe that it is of snow or ice made hard in many years," he observes complacently. "This stone set in the sun taketh fire, insomuch if dry tow be put thereto, it setteth the tow on fire," and again, quoting Gregory on Ezekiel I., he adds, "water is of itself fleeting, but by strength of cold it is turned and made stedfast crystal."