[Illustration: FIG. 85.--English seventeenth century horn book.] They were for children’s use, and the alphabet and the Lord’s Prayer are the commonest letterings upon them, always beginning with a cross, giving the first line the name of the “Christ cross” or “criss cross” row. The paper for true horn books is printed only on one side, and then laid down upon a flat piece of wood. Some unused eighteenth century horn book sheets are preserved in the Bagford fragments at the British Museum. Over the printed slip a piece of horn is put, kept in place by strips of brass fastened with nails having facetted tops, but it must be noted that after about 1820 the facetted tops were often replaced by flat heads. Like all books or objects which were originally cheap and common, horn books are now very rare, but they are so valuable that it is unluckily worth while to imitate them, and many fraudulent modern specimens are about. A horn book is, unfortunately, easy to copy, and it is sometimes a very difficult thing to say positively whether a given specimen is genuinely old or not. Modern frauds are often wrong in either the printing, the paper, the horn, or the nails, but they are often right as to the wood, which is easily made to have every proper appearance of age by means of soaking in water, rubbing with sand, staining by ammonia, and so on. Collectors should, if possible, get a properly authenticated history with every specimen offered to them. Small plaques for teaching the alphabet seem to have existed before the invention of printing, but in printed form they were most used towards the end of the sixteenth century until the nineteenth, when their character altered, the wooden frame and its horn covering disappeared, and a degenerate production in varnished cardboard, preserving the old form in some respects, took their place. These cards are often called battledores, but this name was an old one, and originally used for true horn books. The name battledore is probably derived from the batlet, which was used for beating clothes, the horn books somewhat resembling this in shape. Although the general run of horn books are simple, there are many instances in which they have been decorated; a certain analogy thus exists between the diptychs and the horn books. Lord Egerton of Tatton has a beautiful sixteenth century example, the back of which is ornamented with silver filigree work, and horn books backed with Dutch silver, engraved, are sometimes found. These generally have a bird or a tulip engraved upon them. Other ornamental examples are to be found in the Birmingham Museum and in private ownership. They are very decorative, and some of them have talc instead of horn in front.