In modern times paper-marks have become so numerous that it would be next to impossible to classify them; nor would it be of much advantage to the book collector even if it could be done. With old marks it is different, for _fac-simile_ reprints of scarce and ancient volumes are frequently detected by looking at the water-mark on the paper. Of course, this also may be imitated, but there is often considerable difficulty in attaining the requisite degree of perfection; and, under any circumstance, some little knowledge of the early history and appearance of water-marks will be found useful as well as interesting. The best books to consult on the subject are Herring's _Paper and Papermaking_ and Sotheby's _Principia Typographica_, 1858, the latter of which is a masterpiece of learning and constructive skill. FOOTNOTES: [4] It is very improbable that Caxton was born in 1412, as nearly all his biographers state, but about ten or twelve years later. Evidence of this is contained in the records preserved at Mercers' Hall, Cheapside, London, where his name is inscribed as having been apprenticed in the year 1438, the age at which apprenticeship was entered upon being most commonly between twelve and fourteen years. CHAPTER IV. THE COLOPHON--TITLE-PAGE--THE FIRST BOOK WITH A DATE--COLLATING--ROMAN NOTATION--LATINISED NAMES OF PLACES, WITH THEIR MODERN EQUIVALENTS. It must be borne in mind that the title-page of a book, though constituting a very old method of showing at a glance the nature of the contents, together with the place of publication and frequently also the date, is by no means the earliest means of attaining that object. The title-page, such as we see it, was first adopted in England in 1490, the year before Caxton's death, having been introduced on the Continent in 1470;[5] but previously--and, indeed, for some years after that date--the _Colophon_ was in general use.