In our estimate of causes at work during the middle ages, we must not forget that the alchemists exercised a very important influence. Their doctrine, that all the metals are compounds of the constituent parts of gold mingled with baser matters, which could be separated by the action of the philosopher’s stone, exercised eventually a powerful influence on the progress of arts. The long and patient research of the “adept” after this magic agent for turning all it touched to gold, though prompted by cupidity, resulted in many chemical discoveries and adaptations, and brought to light various useful products, for which, perhaps, we might long have waited, had not this strong motive been rooted in the minds of philosophers of the middle ages. The invention of printing will be noticed elsewhere; and the comparative state of the useful arts in Europe may be estimated from their history in our own country. It remains for us here to notice, in a supplemental manner, one or two branches of art which will not be elsewhere included. By this means we shall better illustrate a subject into which we cannot pretend to enter fully. In the preceding pages, the use of silk by the Greeks and Romans has been merely glanced at, because the tissues which they employed were strictly of foreign production. We will now shortly notice a manufacture, the history of which will illustrate many preceding remarks. Its origin must be assigned to China, where it doubtless reached a highly perfect state, before any other nations acquired an acquaintance with the mode of producing or working the raw material. It is probable that silk-worms were reared in China, and their cocoons extensively employed, 2700 years before the Christian era. The raw material subsequently was exported to Persia, Tyre, Berytus, and elsewhere, till, in our westward progress, we find the island of Cos receiving and manufacturing it. In the Augustan age silks were still rare, even in Rome, the centre of all luxuries; and so late as the third century it was deemed a display of wanton profusion for an emperor to dress entirely in silk.