FIGURE 12.-Press and blow method of forming a bottle. This process is distinguished from the blow and blow method by the substitution of a pressing operation (at c) for the first blowing operation (at d in Figure 5). FIGURE 13. Hartford press machine, a type used for making articles such as tumblers and tableware which require a pressing operation only. FIGURE 14.-Conveyor, stacker, and lehr. The bottles at the lower right-hand cor ner have just emerged from the forming machine and are being stacked automatically on the conveyor belt which will carry them through the long lehr, or oven, to be cooled slowly. FIGURE 15.-Diagram of successive operations in automatic manufacture of bottles, illustrating the gob-fed process. In the Owens suction process the "feeder" and "former" are replaced by a single Owens suction machine, which combines the feeder and former operations. The raw materials are sand, lime, soda ash, and cullet, or broken glass. A schematic diagram of the manufacture of glass containers by the gob-fed process is shown in Figure 15. Development of the Glass Container Industry. The principal divisions of the glass industry are glass containers such as bottles and jars; pressed and blown ware other than containers, including electric light bulbs, tableware, etc.; and flat glass, comprising window glass, plate glass, and similar products. The container branch of the glass industry accounts for slightly less than half of the value of all glass produced in the United States (Fig. 16). The principal products of the division include ware for commercial packers of foods (28 percent); medicines and toilet preparations (24 percent); liquor ware (18 percent); milk bottles (9 percent); fruit jars and jelly glasses for household use (8 percent); and beer bottles (3 percent) (Fig. 17). Increase in volume and value of the production of glass containers in the past thirty-nine years has been marked. In 1899 there were produced one billion one hundred million containers valued at twenty-one and one-half million dollars. By 1935 this production had increased to slightly less than six billion containers valued at one hundred twenty million dollars (Fig. 18). Preliminary figures for 1937 indicate there were produced more than seven and three-fourths billion glass containers having a value of over one hundred sixty million dollars. Despite this increase in production the number employed in the industry was greater thirtynine years ago than in 1935. In 1899 there were 28,370 wage earners as compared with 24,044 in 1935. (See Fig. 18.) Consequently there has been a corresponding increase in the average production per man employed. At the turn of the century the average production per man was about 40,000 containers per year. By 1935 this figure had increased to 245,000 (Fig. 19). Concomitant with this increase in volume and value of glass containers produced the number of companies in the industry has declined precipitously. In 1904 there were 155 companies producing glass containers. At the present time there are forty (Fig. 20). Of these forty, five produce more than two-thirds of the total, leaving less than one-third to the thirty-five smaller companies (Fig. 21) SOURCES: United States Census of manufactures for divisions of the glass industry, volume and value of output in 1899 and 1935; Survey of Current Business for preliminary 1937 data on volume and value of output; United States Census of Manufactures and Bureau of Labor Statistics Bulletin No. 441 for early data on number of wage earners employed and production per man; Glass Factory Yearbook (Directory of the Glass Trade) for number of wage earners in 1935 and number of companies; Glass Container Association for production of five largest companies. |