The China trade formally began on 22 February 1784 with the voyage of the Empress of China, owned by a consortium led by Robert Morris. The ships carried a cargo mainly consisting of ginseng. In August, the Empress of China became the first American ship to reach Canton. The ship returned to New York on 11 May 1785 carrying tea, nankeens (Nanking cotton cloth), chinaware, and silk. Those items subsequently made up the bulk of Chinese exports to the United States. Samuel Shaw, the supercargo, was appointed consul at Canton in 1786. All trade was conducted at Canton through the cohong, native Chinese merchants with a monopoly on foreign trade. The largest export item from Canton was tea. American merchants shipped between three and five million pounds per year during the late 1790s and reached over ten million pounds per year after the War of 1812. Most of the tea was reexported. New York became the center of the tea business. Silk was also a major export, surpassing tea in the trading seasons of 1822-1823 and 1830-1831. Beginning in the early nineteenth century, the search for a product to sell to China ended with the introduction of opium. James and Thomas H. Perkins of Boston began trading in opium in 1806, and by 1825 their company was the largest opium dealer in China, dominating the American China trade along with Archer and Jonas Oakford of Philadelphia and T. H. Smith of New York.