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.”

Of small specimens of sculptured crystal some little dark purple beads carved into the semblance of human faces may be seen on the Tara brooch; while also on the same brooch occur little purple daisies.

The Cup of the Ptolemies, a celebrated onyx cup in Paris, is over fifteen inches in circumference, and is a fine specimen of early lapidary’s work.  It was presented in the ninth century by Charles the Bald to St. Denis, and was always used to contain the consecrated wine when Queens of France were crowned.  Henry II. once pawned it to a Jew when he was hard up, and in 1804 it was stolen and the old gold and jewelled setting removed.  It was found again in Holland, and was remounted within a century.

In the Treasury of St. Mark’s in Venice are many valuable examples of carved stones, made into cups, flagons, and the like.  These were brought from Constantinople in 1204, when the city was captured by the Venetians.  Constantinople was the only place where glyptics were understood and practised upon large hard stones in the early Middle Ages.  The Greek artists who took refuge in Italy at that time brought the art with them.  There are thirty-two of these Byzantine chalices in St. Mark’s.  Usually the mountings are of gold, and precious stones.  There are also two beautiful cruets of agate, elaborately ornamented, but carved in curious curving forms requiring skill of a superior order.  Two other rock crystal cruets are superbly carved, probably by Oriental workmen, however, as they are not Byzantine in their decorations.  One of them was originally a vase, and, indeed, is still, for the long gold neck has no connection with the inside; the handle is also of gold, both these adjuncts seem to have been regarded as simply ornament.  The other cruet is carved elaborately with leopards, the first and taller one showing monsters and foliate forms.  Around the neck of the lower of these