When the negotiations for the Union between Scotland and England began, Gregory was appointed along with Paterson, the founder of the Bank of England, to decide what equivalent was to be paid to Scotland for bearing her share of the debt of England, which was of course afterwards to be considered as the debt of Great Britain. Amongst the many thorny questions which emerged in the course of the deliberations about the Union, there was none about which so many difficulties arose. Sir John Clerk of Penicuik, who had so much to do with the affairs of Scotland at that time, wrote his views upon the criticisms of the general public on this matter. ‘Amongst all the articles of the Treaty of Union,’ he says, ‘there has been none more talked of and less understood than the 15th, concerning the Rise, Nature and Management of the Equivalents. ‘Upon this subject those who desired to be thought very wise, of deep understanding, and Great reach of Thought, did vent themselves with a certain Air, as if they pitied the Credulity and Ignorance of the Contrivors, and so had Recourse to the ordinary Refuge of dull People, who think they show their wit by laughing at what they do not understand.’ Of such commentators Gregory no doubt had his share, and the question was one which was of necessity unintelligible to the ordinary mind, but those who were in authority were absolutely satisfied with the manner in which the work was done. It was a long task, and involved many journeys, including one to Scotland, to set things on a proper working basis. Of this prospect he writes to Dr Charlett, the Master of University College. * * * * * ‘LONDON, _20 June, 1707_. REVEREND SIR,—The occasion of giving you this present trouble is to recommend to your civility My Lord Deskford and his Governour. He is son to the Earle of Seafield, Lord Chancellor of Scotland. He is to stay two or three months at Oxford. He has been regularly educated at the University, and has past some time beyond sea. You will find him a sober and grave young Nobleman. You may depend upon it, that he is what you and I wish all such as him in Church affairs and all thereunto belonging. I know I need say no more. ‘Though Dr Arbuthnot gott a promise of the N.T. from the Queen, He has not yet gott the book it self. It was forgotten to be laid out before the Queen went to Windsore.