GLASS ash obtained by burning the trees of their im- mense forests. This glass was for a long time held in the highest estimation, but was des- tined to lose its fame when flint glass with lead was produced in England. The engraved glass of Bohemia became especially celebrated. The French, perceiving the importance of the busi- ness, early imitated the example of the Vene- tians, and gave extraordinary encouragement to any of the nobility who would prosecute the manufacture. In 1634 attempts were made to produce mirrors from blown glass, as was prac- tised so successfully by the Venetians; but about the year 1666 it was found necessary to procure workmen from Venice. Works were then erected at Tourlaville near Cherbourg, which was selected from the resemblance of the locality to that of the works at Murano. In 1688 Abraham Thevart introduced in Paris the method of making large plates by casting the glass instead of blowing ; he thus produced heavy plates measuring 84 inches by 50, while those previously made had barely reached in length the smaller figure named, and were ne- cessarily thin. In 1665 the manufacture of glass was established at St. Gobain. In the FIG. 6. Venetian Glass Bottle. 18th century the business became very success- ful, and has continued so to the present time, the products of the establishment ranking among the first in quality in the world. The first positive allusions to the use of glass for windows were made by Lactantius about the close of the 3d century, and by St. Jerome about the close of the 4th. It is asserted by the FIG. 7. Engraved Bohemian Drinking Glass. Venerable Bede that glass windows were first introduced in England in 674 by the abbot Benedict ; but at this time and for many cen- turies afterward the use of window glass was limited to ecclesiastical structures. Colored window glass is known to have been used in churches in the 8th century; but for private houses glass long continued to be a rarity, and in England in the 12th century houses provided with glass windows were regarded as magnifi- cent. Even in the 16th century in England and the 17th in Scotland only the dwellings of the wealthy were provided with glass. The manufacture of window glass, according to an old builder's contract brought to light by Hor- ace Walpole, and copied into his " Anecdotes of Painting," was conducted in England as early as 1439 ; but a decided preference was given to that "from beyond the seas." It
