The seventh edition of the “Encyclopædia Britannica” was finished, as we have previously stated, in 1842, and met with, not only an immediate, but also a continuous sale, but human knowledge refuses to be stereotyped, and at the close of 1852 the eighth edition was commenced, occupying nine years in the publication. The proprietors justly claim for it the proud title of “the largest literary enterprise ever undertaken by any single house in Great Britain.” The editorial charge was entrusted to Dr. Thomas Stewart Trail, professor of medical jurisprudence in the University of Edinburgh; and, among the more important new contributors, we may mention Archbishop Whately, Professor Blackie, and Dr. Forbes, the latter of whom contributed a new “Dissertation” to the introductory volume. Lord Macaulay contributed five of the leading biographies “as a token of friendship to the senior proprietor.” “Any article of any value in any preceding edition,” says the editor, “has been reprinted in this--in all cases with corrections, and frequently with considerable additions. Besides these, it has received so great an accession of original contributions, that nine-tenths of its contents may be said to be absolutely new,” and this will probably apply with the same force to the ninth edition, which is to be commenced next year. Long before this date Mr. Adam Black was assisted in his business by his sons. He retired from the house in 1865, and now laden with honours in public, and successes in business, life, he may fairly claim to be the Nestor of publishers. He must have seen many changes in the literary world, and marked many vicissitudes in the “realms of print;” but the changes as far as they operated for him were for the better, and vicissitudes seem invariably to have kept outside his charmed circle. In the year 1861, a very valuable work--the “Collected Writings of the late Thomas De Quincey”--came into the hands of Messrs. Black; but, as the public are almost entirely indebted to the laborious care and patient perseverance of another publisher, Mr. James Hogg, then of Edinburgh, for the production of this collection, which then consisted of fourteen volumes, we have thought it better that this account should form a kind of supplement to our present chapter.