John Menzies immigrated from Scotland and was a successful and well respected watch and clock maker who worked at various addresses on South Front Street in Philadelphia from 1804 to 1838. He's reported to have been a mechanical genius who attempted to construct a perpetual motion machine (Hollan, 373).
John Menzies Pocket Watch
CT Case Maker's Mark
Average quality fusee and verge movement with turned baluster pillars and enamel dial (replaced), serial number 27.
The silver pair cases have London assay date mark for 1814 and case maker mark "CT" likely Charles Tisdall of London.
John Menzies watch paper shown for reference. It simply reads: Watch Maker, Corner of Front & Spruce Streets, PHILADELPHIA
Additional References and recommended reading:
Catherine Hollan, Philadelphia Silversmiths and Related Artisans to 1861, Hollan Press, Missouri, 2013