The story of Pittsburgh: Glass

Bibliographic data

Multivolume work

Identifikator:: 1831622599

Document type:: Multivolume work

Title:: The story of Pittsburgh

Place of publication:: Pittsburgh

Publisher:: First National Bank

Year of publication:: 1919-1930

Collection:: Economics Books

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Volume

Identifikator:: 1831623056

URN:: urn:nbn:de:zbw-retromon-239768

Document type:: Volume

Title:: Glass

Volume count:: Vol. 1, nr. 5

Place of publication:: Pittsburgh

Publisher:: First National Bank

Year of publication:: 1920

Scope:: [ca. 16] Seiten

Digitisation:: 2022

Collection:: Economics Books

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Chapter

Document type:: Multivolume work

Structure type:: Chapter

Title:: Manufacture of Glass

Collection:: Economics Books

of the finer qualities of glass. We find more or less iron in nearly all materials in use, and this substance is the glass-maker’s constant enemy. So we use various decol- orizing agents, principally oxide of manganese and nickel. In the case of the finer qualities of glass, where we wish to produce beautiful colors, we use various coloring agents— such metallic substances as cobalt for making blue, with the oxide of manganese for producing pink and gold, and selenium for making rich ruby colors, as well as uranium and cadmium for producing topaz and orange colors. In its nature glass is peculiar, differing from almost every other manufactured article. It is amorphous, hav- ing no line of cleavage, and, while crystalline in appearance, the laws of crystallization do not in any manner apply to it. To manufacture glass successfully and with uniform re- sults, to make it commercially and meet the requirements of the trade, require constant vigilance on the part of the manufacturer, and sound judgment, founded on long experience. No manufacturer, no matter how much he knows himself as to how things should be done, and no matter how trustworthy he considers his men, is ever certain of results. When he fills his pots he can tell at what hour any particular pot of glass should be ready to work, but he can never be sure, because of the variable conditions to which the process is subjected. Moreover, when new pots are placed in the furnace, with walls from three to four inches thick, his “melt” will be much longer in preparation for working, than in the older pots whose walls may be worn down say to an inch in thickness. Then again, good glass may be spoiled by careless workmen “gathering” the glass when too hot or too cold. This produces streaky glass, or glass with blisters on it. Success in glassmaking can be obtained only approximately, and that by the exercise of constant vigilance and good judg- ment, and no manufacturer can say beforehand how much glass of a good quality he is going to be able to turn out in a given time. The following are the principal manufacturers of glass in the Pittsburgh district:

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