Letters from John Gillon to HLP and Gabriel Piozzi, 1798-1808, in three volumes:
- Volume 1 (Eng MS 577), numbers 1-55, 1798-1800;
- Volume 2 (Eng MS 578), numbers 56-112, 1800-1803;
- Volume 3 (Eng MS 579), numbers 113-154, 1803-1808; numbers 1-19, 1799-1806.
Numbers 1-154 are to HLP, notes to Gabriel Piozzi being added to numbers 122-123. Number 21 consists only of notes on John Cator; number 154 is a fragment. Of the second series (Eng MS 579 ) numbers 1-18 are to Gabriel Piozzi, and number 19 is from A. Robarts to Piozzi and gives an account of Gillon's will.
John Gillon was a wealthy sugar planter in Dominica who was befriended in his youth by Henry Thrale. He later acted as confidential business adviser to HLP and was involved in her case against John Cator relating to Henry Thrale's legacy.