I sent about a fortnight ago the books which you ordered for the Duke of Buccleugh to Mr. Campbell at Edinburgh.[117] I paid for them, according to your orders, as soon as they were ready. I send you enclosed a list of them, with the prices discharged on the back. You will compare with the books when they arrive. Mr. Campbell will further them to London. I should have wrote to you of this a fortnight ago, but my natural dilatoriness prevented me.--I ever am, with the greatest esteem and regard, your most obliged and most obedient humble servant, ADAM SMITH. COLLEGE OF GLASGOW, _17th September 1759._ The second edition of the _Theory_, which Hume was anticipating immediately in 1759, did not appear till 1761, and it contained none of the alterations or additions he expected; but the _Dissertation on the Origin of Languages_ was for the first time published along with it. The reason for the omission of the other additions is difficult to discover, for the author had not only prepared them, but gone the length of placing them in the printer's hands in 1760, as appears from the following letter. They did not appear either in the third edition in 1767, or the fourth in 1774, or the fifth in 1781; nor till the sixth, which was published, with considerable additions and corrections, immediately before the author's death in 1790. The earlier editions were published at 6s., and the 1790 edition at 12s. This was the last edition published in the author's lifetime, and it has been many times republished in the century that has elapsed since. This is the letter just referred to:--