10 GLASS was commenced in London in 1557; and soon afterward flint glass also was made there. The production of plate glass was undertaken in 1670 at Lambeth by the duke of Buckingham, who imported Venetian workmen. The gov- ernment encouraged the enterprise by a bounty upon the glass intended for exportation ; and un- der this protection, also extended to the differ- ent branches of the manufacture, by which the cost was reduced from 25 to 50 per cent., many other glass factories sprung up in different parts of the kingdom ; but their prosperity and the progress of the art were afterward greatly checked by the excise duties imposed, and the surveillance of crown officers over all the ope- rations of the works. The bounties and the duties, with their annoying restrictions, were abolished in 1845, when the suddenly increased demand for home consumption brought into existence many more establishments. Their capacity for production became immense, 'as is shown by the fact that the firm of Chance and co. executed the large order in sheet glass for the crystal palace in 1851 without mate- rially affecting their ability to fill their general orders. The quality of the English crown glass is unrivalled. Glass appears to have been one, of the earliest branches of manufacture in- troduced into the United States; but to what extent it was carried on in early times is un- known. In Salmon's " Modern History " (Lon- don, 1746), vol. iii., p. 440, mention is made of glass works which were commenced at James- town, Va., and the completion of which was interrupted by the Indian massacre of March 22, 1622; and in Howe's "Historical Collec- tions of Virginia," p. 39, is a quotation from "Smith, book iv., p. 18," in which, under date of 1615, it is said that "for a long time the la- bor of the colony had been misdirected in the manufacture of ashes, soap, glass, and tar, in which they could by no means compete with Sweden and Russia," In Felt's "Annals of Salem," Mass., reference is made to the " Glass- house Field," so named from the fact that in 1639 and 1640 several acres of land were ap- propriated to Ananias Conklin and others for the purpose of aiding them in the manufacture of glass, which was carried on for a consid- erable period. About 1750 works were es- tablished by Germans at Germantown, Mass. (now a part of Quincy), for the manufacture of bottles, but they were burnt before the revolu- tion. But the first glass factory in the United States of which we have a precise account was built by Mr. Robert Hewes of Boston, in the town of Temple, N. H., in 1780. It appears that the works were established there on ac- count of the cheapness of fuel and labor. In the winter of 1780-'81 they were destroyed by fire. From a reference to this subject by Washington in his diary (1789) it would ap- pear that glass was made at that time in New Haven. It is believed that in Salem and in Uewes's works only bottles and ordinary ware were made, and that the first window glass was manufactured in Boston. In 1787 a company was incorporated for the manufacture of crown glass, and after numerous embarrassments the first glass was made in 1793, under the super- intendence of a German named Lindt. The shares of the company attained a high value, and the Boston crown glass became celebrated for its excellence. The subsequent failure of the company was owing to the mismanagement of a board of directors who attempted to substi- tute American for German clay, and made other expensive and unsuccessful experiments ; among these was the expansion of their busi- ness by the erection of other works for ma- king thin crown glass at South Boston and sheet glass at Chelmsford. Works were es- tablished by the New England crown glass company for the manufacture of that article in East Cambridge about 1825, and others for bottles and for flint glass about the same pe- riod. Other crown glass works were erected in New York and other states at subsequent periods, but all were discontinued many years ago. The New England glass company, estab- lished in 1817 at East Cambridge for the man- ufacture of flint glass, is still in existence, and has gained a wide reputation for the excellence of its wares. Besides these works, the chief es- tablishments for the manufacture of flint glass in the United States are in Sandwich, Mass., Brooklyn, N. Y., and Pittsburgh, Pa., and its vicinity. Sheet glass is made in Lanesbor- ough, Mass., New Jersey, New York, Pennsyl- vania, and in a few places in the western states. The first plate glass manufactory was established at Cheshire, Berkshire co., Mass., about 1853. The company afterward removed their works to Lenox in the same county, and became known as the " Lenox Rough Plate Glass Company." They have the machinery for making polished plate glass, but have not yet produced it in large quantities. Henry R. Schoolcraft was employed in his youth in the works at Cheshire, and in 1817 he published a treatise entitled " Vitreology," designed to ex- hibit the application of chemistry to this art. Glass is a chemical compound of variable ingre- dients, different substances of similar character replacing each other to produce its varieties. Silicic acid or silica is its principal element, which combines with the potash, soda, oxide of lead, lime, alumina, and other substances that may be added, to produce silicates of these bases. By the manufacturer the bases are classed as fluxes. Boracic acid may take the place of silicic acid to produce vitreous borates or glass. The proportions of the bases named admitting in their use of indefinite va- riations, a wide scope is given for the exer- cise of the skill of the manufacturer in pro- ducing any particular quality of glass. The metallic oxides also afford hirn abundant re- sources for imparting any desired hue to his product, according as these are judiciously se- lected and introduced. The important requi- site in all the varieties of glass is a fusible
