In the late 18th and early 19th century, the city became a center of the lucrative China Trade. Between 1789 and 1841 Providence was one of America's leading ports in the nation's direct trade with China. During this era, three of the seven US consuls to China came from Providence. Exchange with Canton and the East Indies benefited Providence merchants immensely. With their newly accrued wealth, many members of this merchant class constructed large mansions in College Hill; among these homes are the 1792 Nightingale–Brown House and Corliss–Carrington House (1812). After 1830, Providence's trade shifted to Canada, which supplied the rapidly industrializing city with coal and lumber.In the early 19th century, the economy began to shift from maritime endeavors to manufacturing—particularly machinery, tools, silverware, jewelry, and textiles. At one time, Providence boasted some of the largest manufacturing plants in the country, including Brown & Sharpe, Nicholson File, and Gorham Manufacturing Company. The city's industries attracted many immigrants from Ireland, Germany, Sweden, England, Italy, Portugal, Cape Verde, and French Canada.