Capt. Joseph Smethurst's 1746 probate inventory includes "1 Negrow Woman 15'0'0" and "1 Negro Boy 35'0'0" listed among the kitchen property. A subsequent entry, largely illegible due to a tear in the paper, contains "...Beding [sic] Negros 3'3'0."

Bibliography:

Joseph Smethurst, Essex County, MA: Probate File Papers, 1638-1881.Online database. AmericanAncestors.org. New England Historic Genealogical Society, 2014. (From records supplied by the Massachusetts Supreme Judicial Court Archives.) https://app.americanancestors.org/DB515/i/13855/25814-co42/31487256, 25814.