It is interesting to have so much of this valuable matter, as may have found its way into epistolary correspondence, preserved. The conversation of Hume's friends we have unfortunately lost, for there was no Boswell at his elbow. But their letters show how much of scholarship, and elegant literature, and philosophy slumbered in the minds of the Scottish gentry of that age; and assure us that in his intercourse with an Elliot, a Mure, an Edmonstone, an Elibank, a Macdonald, an Oswald, Hume was exchanging ideas with men not unworthy of literary fellowship with a mind even so highly cultivated as his own. William Mure of Caldwell, who was in 1761 made a Baron of the Exchequer in Scotland, was among those who seem to have earliest secured and longest retained Hume's esteem. The letters which passed between them are not often dated, but the circumstances under which many of them are written are attested by internal evidence. The following is one of the few which do not admit of being thus tested, but its merit is in a vein of quiet, easy, epistolary humour, rather than in its connexion with the events of the writer's life. HUME _to_ WILLIAM MURE _of Caldwell_. "_September 10._ "I made a pen, dipt it in ink, and set myself down in a posture of writing, before I had thought of any subject, or made provision of one single thought, by which I might entertain you. I trusted to my better genius that he would supply me in a case of such urgent necessity; but having thrice scratched my head, and thrice bit my nails, nothing presented itself, and I threw away my pen in great indignation. 'O! thou instrument of dulness,' says I, 'doest thou desert me in my greatest necessity? and, being thyself so false a friend, hast thou a secret repugnance at expressing my friendship to the faithful Mure, who knows thee too well ever to trust to thy caprices, and who never takes thee in his hand without reluctance. While I, miserable wretch that I am, have put my chief confidence in thee; and, relinquishing the sword, the gown, the cassock, and the toilette, have trusted to thee alone for my fortune and my fame. Begone! avaunt! Return to the goose from whence thou camest. With her thou wast of some use, while thou conveyedst her through the etherial regions. And why, alas! when plucked from her wing, and put into my hand, doest thou not recognise some similitude betwixt it and thy native soil, and render me the same service, in aiding the flights of my heavy imagination?'