This is one of the trades longest preserved in Florence and other parts of Italy, and to this day silk is among the most important of our products. With this difference, however, that whereas in past times the weaving of the silk was our chief source of profit, at present we frequently export the raw material, repurchasing at an enormously increased price the fabrics returned to us from foreign looms. In old times we imported woollen and silk yarn, and exported Italian cloth and brocade; in these days, on the contrary, we send no small portion of our raw silk to Lyons, and receive it back in a manufactured state. In the same way other raw materials, which we might easily work up ourselves, are despatched to foreign factories. III. There was one branch of industry, however, almost solely the product of human talent and energy, in which the Florentines stood positively first. From the opening of the thirteenth to the end of the fifteenth century the money-changers' craft was an essentially Florentine business. For as soon as the merchants had established commercial relations with all the markets of the East and the West, they naturally put into circulation a large quantity of specie. Therefore it naturally ensued that if any trader of Antwerp or Bruges wished to forward money to Italy or Constantinople, the easiest and safest plan was to apply to some of the Florentine merchants in his own town. The latter bought up the wool and rough cloths, which, after being dressed in Florence, either returned to Northern Europe, or found their way to Constantinople, Caffa, or Tana (Azov), in exchange for silks, dyes, and spices. Accordingly the transmittal of any sum to any part of the then known world cost them little more trouble than the despatch of an ordinary letter, and was always a source of gain. For they received _agio_ on their money, and by sending it in the form of merchandise, reaped a second profit. When, on the contrary, any Florentine wished to send a hundred florins to London, he had only to walk a few steps to find some merchant of the Calimala or Por' Santa Maria, who, by a line to his correspondent in Lombard Street, caused the payment to be made. These so-called letters of exchange (_lettere di cambio_) proved one of the most useful of inventions for the advancement of modern trade. There has been much discussion as to whom this discovery was originally owed. Some attribute it to the fugitive, persecuted Jews in France and England; while others ascribe it, at a much later date, to the Guelphs banished from Florence in the thirteenth century. But it is very difficult to ascertain who was the first author of what cannot be justly styled a discovery, seeing that it is an arrangement so readily occurring to the mind, that examples of it are even to be found in very remote antiquity. Besides, the real importance of the letter of exchange consists not in its invention, but in its legally authorised