Born in North Yarmouth, Maine. Mason was a stamp and coin dealer in Philadelphia, New York and Boston. He conducted 35 auction sales 1868 to 1890. He issued fixed price lists from New York in 1866, from Philadelphia 1868 to 1871 and from Boston up to 1890. Mason took credit for inventing the American scale for measurement of the diameter of coins and medals. A four inch circle was divided in increments of one-sixteenth of an inch.

He published a series of periodicals. Mason's Coin and Stamp Collector's Journal ran from 1867 to 1872. Financial problems kept him from publishing 1873 to 1879. He resumed with Mason's Coin Collector's Herald 1879 to 1882. Mason's Coin Collector's Magazine ran 1882 to 1890.

He died in Philadelphia.

bio: Adams I; CW/NM 6/2/76 obit: AJN 36 Jan 1902 p. 95