A collection of three rare white enamel mourning rings, late 18th century

A collection of three rare white enamel mourning rings, late 18th century, each applied with white enamel between millegrain borders, with dedicatory inscriptions in reserve, inscribed 'LAURENTIUS BROCKETT B D OB24 JULY 1768 AET 43'; 'WM STANHOPE ESQ OB 12 OCT 1783 AE 73' and 'TC FOUNTAYNE ARM OB 1 JAN 1780 AE 22' respectively, each mounted in gold, sizes M1/2-P1/2, one with maker's mark PE