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LEFT GLASS 328 GLASS er. In 1899 he entered politics as a mem- ber of the Virginia Senate; served suc- cessively in that office until 1902 when he became a member of the 57th Con- gress for the unexpired term of P. J. Otey, Re-elected to the 58th Congress, he continued to serve in Congx-ess until, in 1920, he was elected U. S. Senator from Virginia, having previously been appointed to the unexpired term of Thomas S. Martin, deceased. His most conspicuous public services include his connection with the national banking legislation, as co-sponsor of the Owen- Glass Bill which became law in 1912. He was Secretary of the Treasury from Dec. 1918-Nov. 1919, and was elected U. S. Senator for the term 1919-1925. GLASS, a hard, brittle, transparent substance, formed by fusing together mixtures of the silicates of potash, soda, lime, magnesia, alumina, and lead in va- rious proportions, according to the qual- ity or kind of glass required. Flint glass is used in making table ware and many articles of domestic fur- niture and fittings. Crown and flint glass are combined in the manufacture of achromatic lenses. Plate glass is made by pouring it upon a table which has a marginal edge of a height equal to that designed for the thickness of the glass. A roller travels over the table, on the ledges, and flatten- ing out the glass, which is thus made of equal thickness throughout. Toughened glass is made by heating till it is about to soften, and then plung- ing it into a bath of oil at a greatly lower temperature. Usually, a mixture chiefly of oily substances, such_ as oils, tallow, wax, resin, and the like, is put in the bath; and some manufacturers who worked the process for a time dropped the newly made glass vessels, while still hot, into the oleaginous mixture, by which plan neither reheating nor anneal- ing by the ordinary process is required. After the articles acquire the tempera- ture of the bath, they are removed. Painted or stained glass is of two styles, enamel and mosaic glass. In en- amel glass proper, certain fusible pig- nents are painted on a sheet of white glass, which is then fired, and the result is a picture the tints of which even in the high lights are not wholly transpar- ent. A modification of this method pro- duces its picture partly by enameling on white glass partly by the use of pot- metal glass, the color of which is height- ened or modified by the use of enamels. Mosaic glass is made from a design wherein the drawing is given and the colors indicated, which is the working drawing of the glass painted. From this working drawing a kind of map is made which gives the various pieces of the mosaic. The glazier cuts these pieces out from sheets of glass of various col- ors, and hands them back to the painter, who proceeds first to paint the leading lines with a solid opaque enamel, the coloring matter of which is an oxide of iron. This being done the pieces of glass are stuck together temporarily (by means of wax) on a glass easel, and the painter slightly shades his bold traced lines with the same opaque color; using sometimes washes, and sometimes hatch- ing of lightly laid-on lines, as in a black and white drawing on paper. Sometimes both washes and hatching are used, and the washed shadows are stippled. In any case the object of the method of shading is to keep the shadows as clear, and to dull the glass as little as the explanation or expression of the subject will admit of. Two or three or more firings are necessary during the process of this painting. This being done, the glass goes back to the glazier's bench again, and he leads it up, and the win- dow, after having been solidified by a stiff cement or putty rubbed into the leaf of the leads, has then only to be put in its place and strengthened by the due iron stay bars. Of the origin of glass manufacture nothing is knovioi, but according to Egyptologists, the Egyptians made sham jewels of glass at least 5000 or 6000 B. C. In some of the most ancient tombs scar- abs of glass have been found imitating rubies, emeralds, sapphires, and other precious stones. It is probable that the great center of the glass industry _ of mediaeval and more recent times, Venice, received its early impulse and lessons from Constantinople. The art began there with the beginning of the city in the 7th century A. D., and there was a marked improvement after the conquest of Constantinople in 1204, and in 1291 the establishments were removed to the island of Murano, the manufacturers forming a guild with a register of nobil- ity and guarding their secret with the greatest jealousy. In 1436 their color glass came into note, and continued so till the close of the century; and in the 16th century lace patterns and mirrors were introduced. In the 15th and 16th centuries plain glass with tasteful orna- ments in gilt and enamel; in the 16th, crackled lace and reticulated glass; and in the 17th century, variegated or marbled glasses were produced. The Venetian glass enjoyed for a long time the monopoly of commerce, and within recent years there has been a marked revival of the skill and enter- prise of Venetian craftsmen. In Ger- many the oldest glass dates from the