8.3.1795 miss Williams at Foulkes / 7.4.1795 again / 25.2.1796 mrs Wood & Williams at Foulkes' / mss Williams 18.5.1796 at miss Mansel's.
Possibly Martha Roper Williams daughter of Robert Williams ("formerly of Charleston South Carolina Counsellor at Law now of London" will PCC 1808). She exhibited at Royal Academy 1793 and lived at 30 Lambs Conduit St, so near to Foulkes'. She married at St Andrew Holborn 16.12.1803 Richard Wrangham merchant (will PCC 1832). Unlikely to be Helen Maria Williams who was probably in France.
The 'mss' of 18.5.1796 might have included any of 5 sisters of Martha mentioned in her father's will