File:Bell telephone magazine (1922) (14570228547).jpg

Identifier: belltelephonemag19amerrich (find matches)
Title: Bell telephone magazine
Year: 1922 (1920s)
Authors: American Telephone and Telegraph Company American Telephone and Telegraph Company. Information Dept
Subjects: Telephone
Publisher: (New York, American Telephone and Telegraph Co., etc.)
Contributing Library: Prelinger Library
Digitizing Sponsor: Internet Archive

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the last disclosed has notbeen passed on to us. Experience wasthe principal guide, and one not in- 142 Bell Telephone Quarterly APRIL frequently upset when a manufacturerelected to change the quality of a par-ticular brand during the course oftime or even to discontinue it. The A. T. and T. engineers decidedto establish a range of standard papersadequate for telephone needs, accord-ing to basic types. They found thatan adequate range was availableamong the regular commercial gradesand concluded that, despite volumesufficient to justify manufacture ofspecial grades, this procedure shouldbe avoided. To ensure that they werefully informed regarding all availablegrades, they visited paper mills manu-facturing qualities varying from thepoorest to the best. Paper and Paper Making -Taper manufacturing processes aregenerally similar and, in so far asbroad principles are concerned, rela-tively simple. Paper is basically cel-lulose fibre, obtained principally fromwood and from cotton rags. The
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wood or rags are reduced to pulp towhich a small amount of sizing mate-rial is added, consisting of rosin, glueor starch to serve as a binder. Pro-portions of clay and others fillers areadded also to improve opacity andfinish. Spruce and pine are the low-est-cost sources of cellulose and are,accordingly, the principal raw mate-rial. For ground wood pulp, which is themajor component of newsprint and ofmany stationers papers, the wood isdebarked, knots are removed, and itis then ground against a stone in thepresence of water, to shred the fibresapart. This method of pulp manu-facture is the least expensive, but itis also rather drastic and the pulp isweaker and less permanent than thatproduced by chemical processing,which is employed for the bettergrades. The chemical processes consist ofreducing the wood to chips and boilingthese for a number of hours witheither an acid or alkaline solution, de-pending upon the characteristics de-sired in the pulp—to free the fibres bycooking out the

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