Mason was born in Mystic, Connecticut. At 15 he was sent to East Haddam to start the machines at a thread manufacturing mill. At 17 he set up the first power loom in the country for the manufacture of diaper linen. He later worked for a manufacturer of cotton machinery that he bought out in 1845, and became the largest manufacturer of machinery in the country. By 1853, he was also manufacturing locomotives and continued to improve them. Died of pneumonia.
Papers of William Mason of Taunton, Massachusetts--engine builder, machinist, and manufacturer of locomotives and cotton machinery--consist of bills, receipts, and correspondence concerning the operation of his household, the construction of his residence, and several incidental papers dealing with his business affairs.
William Mason Papers, 1839-1857, Archives Center, National Museum of American History