Were a comparison to be made between the development of the various minor arts, it would be difficult to find a wider contrast than that between the history of porcelain and that of glass. The knowledge of porcelain was confined for nearly a thousand years to China, the country where it was first made, and where it was slowly brought to perfection. Let loose, as it were, in the West early in the eighteenth century, it had then a short period of glory, but before the end of the century the art had already fallen upon evil days. The manufacture of glass, on the other hand, had long been carried on in Egypt, and perhaps in other Eastern lands, by a primitive process, although it only became an article of general use after the discovery of the blowing-iron. When and where this discovery was made we do not know—perhaps somewhere in Syria or Mesopotamia, in the third or second century before Christ. The art of blowing glass was known, no doubt, if not fully developed, at the time when the kingdoms of the Ptolemies and of the Seleucidæ fell under the rule of the Romans. By them it was before long brought to perfection and carried into every corner of the West, so that by the second or third century of our era the production of glass in Europe was probably greater than at any subsequent time, at least until quite recent days. Nor was the art of glass-making completely extinguished by ‘the advance of the barbarians.’ Indeed, some of the Germanic tribes not impossibly brought with them a knowledge of the process not only of preparing but also of blowing glass, picked up on their journeyings through East Europe, or perhaps even learned in Western Asia. This was an instance of the passage to the North and West of the arts of civilisation, by what we may call the back-road of Europe, in opposition to the high-roads that led directly from Italy by way of the Rhone and the Rhine. But in the West the manufacture, though continuously carried on in many spots, was after the fall of the Western Empire relegated to the woods,—for nearly a thousand years little glass was produced of any artistic interest. Indeed, but few examples of this forest or green glass of the Middle Ages have survived to our time. During all this long interval, in one direction only, in the West, was any advance made. Within this period falls the great development of stained glass: we must turn to the glorious windows of the cathedrals of France and other Western lands, to see what the glass-workers of the time were capable of producing. In the East, on the other hand, in the lands ruled from Constantinople or influenced by Byzantine civilisation, what we know of the glass of the early Middle Ages is almost confined to the mosaic coverings of the walls of the contemporary churches. But just as distinctly as the glass in the windows of the Gothic churches, this mosaic work, for the reason we have already given, falls outside our limits.