The gilding, however, has been more effectually preserved in the case of another cold process which came into vogue before the end of the seventeenth century, and rapidly spread from Bohemia, or perhaps rather from Silesia, to various parts of Germany. In the case of these _zwischen gläser_ we are taken back to an old process, already known to the Alexandrian Greeks. The plan adopted in no way differs in principle from that made use of in the decoration of the beautiful bowls from Canosa, now in the British Museum (see p. 46).[204] Very inferior to these in artistic merit are the little footless tumblers, with designs in gold, often hunting scenes, which seem to have been made on both sides of the Silesian-Bohemian frontier before the end of the seventeenth century. These are built up of two glasses, both somewhat tapering and both cut into an equal number of perpendicular sides, so that when the smaller of the two was inserted into the interior of the larger the glasses fitted exactly, and could not rotate one upon the other. The inner glass being somewhat the taller, we find the ring of junction, which is generally concealed by a band of gold, about half an inch or so below the top of the glass. The edges are so exactly bevelled that this line of junction is barely perceptible even to the touch. Before fitting the two glasses together, the inner one had been coated on the outside with gold-leaf, and the design carefully engraved on the gold with a steel point; while on the inside of the outer glass a coating of old linseed oil or of varnish had been smeared. I should add that a medallion of ruby glass, variously ornamented, is usually found at the bottom of these tumblers inserted between the two layers of glass, or sometimes replacing the base of the outer cylinder. These glasses will not stand warm liquids: an example in the British Museum is disfigured by some large flattened blisters, probably the result of heat.[205] Glasses built up in this manner may of course be decorated in other ways; the gold-leaf, for instance, may be replaced by silver foil. Kunckel, of ruby-glass fame, describes a method in which the inner glass is plainly gilt, while the outer one is painted on the inside in imitation of precious marbles (_Ars Vitraria Experimentalis_, 1679). I have seen examples of this manner of decoration in German museums. CHAPTER XVII THE GLASS OF GERMANY—_continued_ German Cut and Engraved Glass—The Ruby Glass of Kunckel—Milch Glass I have still to describe the origin and development of a method of decorating the surface which forms, I may almost say, the last main division in the artistic history of glass. For when I come in subsequent chapters to treat of Dutch and English glass—and with this my task practically closes—it will be found that this glass falls almost entirely under the head, and is in a general way an outcome, of the engraved or cut glass of Germany.