Personal letter from the Duke of Atholl to Lord Mansfield (Lord Chief Justice) seeking legal and strategic advice on the impending sale of the Isle of Man to the British Crown. The Duke outlines the island's economic value, recent revenue figures (£43,934 over six years), potential for customs duty increases, and manufactures development, while arguing for delay in the sale. References earlier correspondence from 1759 between the previous Duke and the Duke of Newcastle.