In 1745 Hume quitted the residence of his mother and brother, in compliance with an invitation from the Marquis of Annandale; the friends of that young nobleman having thought that his health and mind required the aid which such a tutorship, or companionship, for we hardly know which to call it, would afford. Hume states, that his employment during the twelve months thus passed in England made a considerable accession to his small fortune. “I thus received,” he says, “an invitation from General St. Clair to attend him as a secretary to his expedition, which was at first meant against Canada, but ended in an incursion on the coast of France. Next year, to wit 1747, I received an invitation from the General to attend him in the same station in his military embassy to the courts of Vienna and Turin. I then wore the uniform of an officer, and was introduced at those courts as aid-de-camp to the General, along with Sir Harry Erskine, and Captain Grant, now General Grant. These two years were almost the only interruptions my studies received during the course of my life.” In 1747 Hume re-cast the first part of his Treatise of Human Nature, and published it under the title of an Inquiry concerning Human Understanding. But this amended performance also failed to produce any immediate effects; and a new edition of his Essays Moral and Political, published about the same time in London, found scarcely a better reception. Still looking to the hopeful side of things, our author composed during 1749 and 1750 the second part of his Essays, which were called Political Discourses; and also his Inquiry concerning the Principles of Morals, which was another part of his ill-fated Treatise of Human Nature, in a new form. By this time some of the more obnoxious parts of that treatise began to call forth opponents, and it became evident that its author, though much more frequently censured than applauded, was a man of rising reputation. This result was favoured by his determination never to reply to any of his critics, a resolve which the peculiarities of his temper enabled him to act upon to the end of life.