Having described, in former articles, the composition and modes of manufacturing bottles and window glass.our readers will understand the methods employed for pressed glass ware by a very brief description. The pressed glassware is made by pressing glass into molds of iron, and. the articles thus formed aproximate in beauty and regularity of form to those of cut glass, described further on. The operation requires less skill in manipulation than glass-blowing, but is, nevertheless, interesting. It will be best understood by describing the manufacture of some special article—say a fruit dish, thextfowl of which is saucer-shaped, and its foot formed like trie bell of a trumpet. Such an article would be made in two parts, the bowl and the foot being pressed in separate molds, and afterward joined to-together. A boy takes upon the end of an- iron rod or " pun-ty," a quantity of glass from the melting pot.and holds it over the open mold. The weight of the molten glass causes it to depend in the form of a largo pear-shaped drop. The principal workman, who has charge of the mold, cuts off this drop with a pair of shears.as soon as,in his judgment.enough has depended to exactly fill the mold. As soon as the glass has fallen into the mold, it is closed with a lever which forces the glass into every part of the matrix. The molds are made in two parts corresponding to the convex and concave sides of the piece. So accurate is the judgment of the skilled operators in this process that they rarely fail to properly apportion the glass to the capacity of the closed mold. The glass is removed from the mold as soon as it cools enough to become rigid, and is carried by an assistant to the annealing oven, if complete; or, if, as in the particular case of the fruit dish, it requires to be joined to another portion, it is cemented to its fellow by a small portion of plastic glass, and then placed in the annealing oven. Varieties of form and pattern may be attained "by this method which are impossible in the blowing process, and the larger portion of goblets, salt-cellars, and other glass table ware, in common use, is made in this manner. The finer and most costly articles of glass ware are finished by a process called cutting, which is, however, really a grinding process, performed by means of iron, sandstone, or copper disks, of various sizes and forms, according to the nature of the work to be performed. The disks s,fe fixed, by proper chucks, to lathes, and are supplied with sand for rough grinding, and emery for finer work. A stone wheel is also used to efface the sand marks, and wood disks are used for polishing, supplied, at first, with a mixture of pumice and rotten stone, and finally with " putty powder," a preparation of tin and lead. Flint glass is the best for this purpose, as its superior hardness enables it to take a finer polish. Great skill and artistic taste is shown by the artisans, in this department, and cut-glass wares command a higher price than any others. Plate glass constitutes a large and important branch of the glass manufacture, and may form the subject of a future article. The numberless uses to which glass is now applied, render all information, respecting its manufacture, of value, and although the manufacture of plate glass has not yet been successfully introduced into the United States, the extent of the demand here would seem to justify further attempts at home production.
This article was originally published with the title "Manufacture of Pressed and Cut Glass Ware"