Substance of the speeches of the Right Honourable William Pitt, on the 23rd and 31st of January, 1799 : including a correct copy of the plan, with the debate which took place in the House of Commons on the proposal for an union between Great Britain and Ireland : to which are annexed, the celebrated speeches of the Right Honourable John Foster, late chancellor of the Exchequer, now Speaker of the House of Commons of Ireland, on the 12th and 15th days of August 1785, upon the commercial propositions