I don’t know if this is any help to you. This watch was sold by Patton & Jones who were in business together from 1798 to 1814 in Baltimore & Philadelphia. They dealt with some of the best movement makers and were selling Massey Escapement watches as early as 1815. Don’t know when this watch was converted but likely mid 19[SUP]th[/SUP] century. Case is original. Chester hallmarks (1806 - 1822), but missing the date. Philip Priestley thought E.I. perhaps Edward Jones (1800-1827). Marked 18K but perhaps lower carat as seen before on Chester gold cases.
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