Pulp and paper magazine of Canada . Fig. 1 any particular fibre in a supposed pure rag , it m;ii lie safely asserted that the use of themicroscope is mainly confined to the examination ofpapers in order to determine their fibrous composi-tion, though maii\ interesting and valuable hints re-specting the composition of the paper and the changesin structure, which go on from stage to stage, shouldultimately prove more profitable. We have shown in the previous chapter that theprogress of beating and the reduction of the fibre to tb million required bj i tie paper to be produced. can be
Pulp and paper magazine of Canada . Fig. 1 any particular fibre in a supposed pure rag , it m;ii lie safely asserted that the use of themicroscope is mainly confined to the examination ofpapers in order to determine their fibrous composi-tion, though maii\ interesting and valuable hints re-specting the composition of the paper and the changesin structure, which go on from stage to stage, shouldultimately prove more profitable. We have shown in the previous chapter that theprogress of beating and the reduction of the fibre to tb million required bj i tie paper to be produced. can be watched very closely, and the gradual changesrendered visible by suitable microphotographs. Structure of Paper. The actual structure of a sheet of paper and theinterlacing of the fibres may easily be shown by tak-ing sections parallel with the surface and at rightangles to the surface uivinu longitudinal and transversesections Fig. 2 impossible to get the paper sufficiently smooth so thatall tlie fibres lies in the same plane. The crossing andrecrossing of the fibres on the surface prevents theformation of an absolutely smooth surface. Coated Paper.—A transverse section of an art paperaffords a similarly interesting study. In the firsl pi; the microphotograph reveals very clearly the mass of mineral matter adhering to the surface of tinpaper, and it is possible from the magnification ofthe photograph and the actual thickness of the paperin calculate the tMckness of the mineral coatingitself. In Pig. ?, this is clearly shown. The paperselected was a chromo, coated on one side only, andmachine finished on the bottom side. The paper hada thickness of thousandths of an inch. At a magni-fication of :;(i(i. the microphotograph measures depth, of which in. represents the amount ofspace occupied by the coating. The photograph thusdetermines the thickness of the coating and shows thatin this
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectpaperma, bookyear1903
