In the British Museum is a brass signet stamp, more than two thousand years old, on which two lines of letters are very neatly engraved in relief, in the reversed order necessary for printing; and as the interstices are cut away very deeply and roughly, there is little doubt but that this stamp was used with ink on papyrus, parchment, or linen, for paper was not then known. Indeed, the experiment of taking impressions from it in printing-ink has been tried, and found to answer perfectly. A large surface so engraved would at once have given to the world an equivalent to what is now regarded as the most advanced state of the art of printing; that is, a stereotype plate. Vergil mentions brands for marking cattle with their owner's name; probably this kind of brass stamp, but larger. I could cite many more examples of ancient engraving which would yield impressions on paper, either by pressure or friction. But our business is with printing rather than engraving; I will, therefore, go back to the subject, and cite a very early and interesting example of stamping engraved letters on clay. I mean the Babylonian bricks, supposed to be four thousand years old, mostly sun-baked, but some apparently kiln-burnt almost to vitrification. Of these there are now many examples in England, added to our stores by the indefatigable researches of Layard, Rawlinson, and others. These bricks, which are about a foot square and three inches thick, are on one side covered with hieroglyphics, evidently impressed with a stamp, just as letters are now stamped on official papers. Another evidence of the same kind, and of about the same age, is the famous Babylonian cylinder found in the ruins of Persepolis, and now preserved in the library of Trinity College, Cambridge. It is about seven inches high, barrel-shaped, and covered with inscriptions in the cuneiform character, disposed in vertical lines, and affording a positive example of an indented surface produced by mechanical impression. Such cylinders are supposed to have been memorials of matters of national or family importance, and were in early ages, as we know by tradition, very numerous. Stamped or printed blocks of lead, bearing the names of Roman authorities, are to be found in the British Museum.