crystalloengraving

A mode of ornamenting gla ware by taking impre ions from intaglio, and impre ing them on the ware while casting. The die is first sprinkled over with Tripoli powder, then with fine dry plaster and brick-dust, and then with coarse powder of the same two materials; it is placed under a pre , and at the same time exposed to the action of water, by which the sandy layers become solidified into a cast. This cast thus obtained is placed in the iron mold in which the gla ve el is to be made, and becomes an integral part of the ve el so produced; but by the application of a little water the cast is separated, and leaves an intaglio impre ion upon the gla as sharp as the original die. The cake thus used seldom suffices for a second impre ion.