Page:Popular Science Monthly Volume 37.djvu/173

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GLASS-MAKING.
161

for table or other domestic usage, taking form in the hands of the adroit workers. It is the scene of an intense and a highly ingenious activity. The bottles and dishes and globes intended for sub-sequent treatment in the atelier are all blown, the manipulations being varied in accordance with the special form it is desired to produce. As a rule, it may be said that it is cheaper to produce the pressed glass than the blown, since less time is required in Fig. 3.—The Operation of making Ground Glass Globes. fashioning the articles; but for the finer work the blown is always preferred, as glass worked exclusively in the air has a much more brilliant surface than that which has been formed in contact with the faces of the iron mold. The plain articles thus shaped are known in the trade as "blanks." The largest manufacturers of cut and engraved glass also make their own blanks, but there are a number of establishments which confine themselves exclusively to the processes of ornamentation. The articles intended for such decoration go from the blower to the annealing leer, where they are permitted to pass through a chamber of brick-work some sixty to eighty feet long, subjected to a gradually decreasing temperature for a period of twenty-four hours or less, according to the circumstances of the work. The articles to be annealed are placed in wrought-iron cars, and are slowly moved through the leer, coming out perfectly cold.

It is in this way that the blanks are prepared for the atelier proper. Here one finds a number of very interesting operations going on side by side. The untechnical visitor will perhaps be most attracted by the cutting process, since the results are so brilliant, and the articles possess so staple a value. He will get a good insight into the general principles by following the process of cutting a carafe.