Machines for blowing bottles, at first adapted to wide-mouthed bottles only were not commercially successful until about 1896. Such machines were operated at first by three skilled men, later by two and now by one. In 1908 there appeared a three-man machine for making narrow-necked bottles; in 1912, a one man machine for wide-mouth bottles, and, in 1914, a one-man machine for narrow-neck bot tles. The one-man machine automatically cuts off the quantity of molten glass sufficient for each mold. In establishments using machines bottles are blown by hand to 'fill small orders. From the earliest period of glass blowing until 1903 all glass that was blown was gathered on the end of a blow-pipe. In that year two revolutionary inventions were commercially in troduced, the bottle-making machine by Michael J. Owens and the flowing device invented by Homer Brooke, both Americans. With only an attendant, who is not a skilled operator, the Owens machine gathers the glass and blows the bottle or jar. When a mechanical con veyor is used, the ware is both made and de livered to the tear without handling. More nearly automatic than any other glass-making machine, its output is much greater. The operating speed of the largest type of Owens machines is indicated by the fact that it pro duces more than 75,000 quart fruit jars in 24 hours. The machine and the revolving tank that supplies it are costly and are used only in factories which produce large quantities of bottles or jars of uniform shape and size. The machines were introduced in Europe and more recently in Japan. By the Brooke device the molten glass flows from the furnace to the mold, the quantity sufficient for each mold being automatically severed. The chief advan tages of the Brooke device are that it dis penses with skilled labor; it can be operated during the hot months when hand gatherers are not readily obtainable, and by it the output is increased while the cost of production is decreased.
The making of coal-oil from coal led, about 1855, to a demand for lamps and lamp chim neys, the use of which greatly increased, about 1859, when refined petroleum was first mar keted. One of the first plants to make a specialty of lighting goods was started in Brooklyn by Christopher Dorflinger, in 1852, but, in 1865, he moved the business to White Mills, Pa., where he established a large cut glass factory. Lamps and lamp chimneys are still manufactured in considerable quantities and exported to many countries. Chimneys were at first blown off-hand on blow-pipes. Chimneys, light tumblers and other seamless blown ware are now made in paste-mold ma chines, the seams being removed by turning the ware while hot in molds lined with carbon or similar material. The incandescent lamp was perfected by Edison in 1879 and its manu facture became an important branch of the industry. The bulbs are blown in paste-mold machines. All kinds of lighting goods are now extensively made in the United States.
The popularity of American made cut glass was established by a splendid display by the Libby Company in a complete glass-melting and cutting establishment at the World's Fair, Chicago, in 1893. Both pressed ware and deep cut ware were exported to Europe before the war there began. Laboratory ware was little made in the United States before the war began in Europe, but since 1914 it has been produced here in quantities sufficient for domestic con sumption and for export. Beakers and flasks equal to Jena ware have been made by one factory in New Jersey since 1900 and by plants in several States since 1914. Photographic glass
was first made commercially in the United States in 1911 and the domestic production is now large. Optical glass was made experi mentally in the United States in 1912. As a result of the war, the quantity manufactured here became large, the quality being equal to the best European product.
Even with the extensive use of machinery, labor constitutes the chief single item of ex pense in the manufacture of glass. Of 334 industries reported by the census of manu factures for 1914, glass ranked thirteenth in percentage of labor cost based on the value of the product. A government report, issued in 1917, shows that of the total sales value of the product, the cost of labor in the manu facture of various kinds of glass was 40.6 per cent. The same report shows that of em ployees in glass factories, 2.5 per cent were under 16 years of age and 8.2 per cent women, the latter being more numerous in tableware and lighting goods factories than in plants of other kinds. Hand window-glass blowers receive higher wages than skilled work ers in other branches of the industry, and their working hours are relatively short, union hours being 44 a week. Unskilled workers average about 60 a week. Skilled labor is paid at piece rates, unskilled on a time-rate basis. In manu facturing window glass by hand and also blown and pressed ware, which includes tableware, bar goods, lighting goods and laboratory ware, the labor unions limit the output of workers, which restricts production and increases cost. Some branches of the industry operate only a part of theyear, hand window glass only about seven months and machine window-glass plants about eight months, while other branches lose one or more months a year. The reasons are fear of overproduction, inability of men to work around furnaces during the hot months and necessity for repairs.
Accompanying tables show statistically the development of the industry in the United States from 1869 to 1914. While the estimated population increased 19.6 per cent from 1904 to 1914, the value of glass manufactures in creased 54.6 per cent. Of the total value, $123,085,019 in 1914, window glass amounted to $17,495,956; polished plate glass, $4,554,326; pressed and blown ware, $30,279,290; bottles and jars, $51,958,728; other products, $4,022,932. In window glass, plate glass, pressed table ware, deep cut ware, lighting goods, laboratory ware and optical goods, the quality of the do mestic product is equal or superior to the best that is imported.
The imports and exports of glass and glass ware during the fiscal year 1879 were respec tively $3,281,543 aid $768,644; during the fiscal year 1914, respectively, $8,219,112 and $3,729,623.
The imports were 15.5 per cent of the domestic production, $21,154,571, during the calendar year 1879, and 6.7 per cent of the production, $123,08.5,019, in 1914. The average rate of duty was 57.6 per cent in 1879 and 33.8 per cent in 1914. Before the war in Europe began the principal glass importations were window glass, plate glass, fine blown tableware, toilet ware, colored ware, optical glass and bottles used as containers. Since the war began im ports have suspended and exports increased many fold. Of the imports in 1914, window glass amounted to $1,316,902, of which over 80 per cent was of the three smaller brackets (384 square inches and under), and plate glass amounted to $489,359, also mostly of the smaller sizes. Practically all of the imports of