The people of Babylonia never succeeded in mastering the bas-relief work, so effectively used in Assyrian palaces. Enamelled tiles took the place of these, and they were either painted in some design and glazed, or simply tinted. "Quite as old as the trade of the carver in ivory was that of the porcelain-maker. The walls of the palaces and temples of Babylonia and Assyria were adorned with glazed and enamelled tiles on which figures and other designs were drawn in brilliant colors; they were then covered with a metallic glaze and fired. Babylonia, in fact, seems to have been the original home of the enamelled tile and therefore with the manufacture of porcelain. It was a land of clay and not of stone, and while it thus became necessary to ornament the plain mud wall of the house, the clay brick itself, when painted and protected by a glaze, was made into the very best and most enduring of ornaments. The enamelled bricks of Chaldea and Assyria are among the most beautiful relics of Babylonian civilization that have survived to us, and those which are now in the Museum of the Louvre are unsurpassed by the most elaborate productions of modern skill." The trade of the vintner was lucrative. Wines were made from dates and grapes; beer was doubtless made from grain. It seems to have been the custom to supply laborers with beer with their daily rations. Organizations among workmen corresponded to the guilds of later years. Those who would learn a trade, whether freemen or slaves, had to serve as apprentices a certain time and learn the work thoroughly. Wages were always so low that they amounted to little. It has been estimated that the average wages of a workman was about 12s., or $3.00 a year; unskilled laborers were contented if merely supplied with food. In the reign of Cambyses a butcher is recorded to have been paid 75 cents for a month's work--freemen had always to compete with slave labor, and if only the employer furnished food and clothing, he could command any amount of labor. Babylonia early exchanged her grain and dates for the products of other lands. For example, teak-wood and cotton were brought from Arabia, cedar from Lebanon, marble from the east, gold from the peninsula of Sinai. Sometimes the raw materials were made up in Babylonia and returned to the lands from whence they came together with grain, rugs and cloth of wool. Because of her geographical position, Babylonia was able to command an important commercial position, importing and exporting constantly.