. Appleton's dictionary of machines, mechanics, engine-work, and engineering. er with the most, authentic information obtainable concerning them. The general understanding of the principal differences of the woods will be greatly assisted by abrief examination into their structure which is now so commonly and beautifully developed by the sec-tions for the microscope. The Figs. ;i>)JS, 8929, 8980 are drawn from thin cuttings of beech by the optician for that instrument: the principal lines alone are represented, and those aremagnified to about twice their linear distances, for
. Appleton's dictionary of machines, mechanics, engine-work, and engineering. er with the most, authentic information obtainable concerning them. The general understanding of the principal differences of the woods will be greatly assisted by abrief examination into their structure which is now so commonly and beautifully developed by the sec-tions for the microscope. The Figs. ;i>)JS, 8929, 8980 are drawn from thin cuttings of beech by the optician for that instrument: the principal lines alone are represented, and those aremagnified to about twice their linear distances, for greater perspicuity. Fig. 3928, which represents the horizontal or transverse section of a young (ice or a branch, showsthe arrangement of the annual rings around the centre or pith ; these rings are surrounded bv an ex-terior covering, consisting also of several thinner layers, which it will suffice to consider collectively, intheir common acceptation, or as the bark. The fibres which are seen as rays proceeding from tlte pithto the bark, are the medullary rays or 916 WOODS, VARIETIES OF. Figs. 3929 and 3930 are vertical sections of an older piece of beech-wood. Fig. 3929 is cut througha plane, such as from a to a, in which the edges of the annual rings appear as tolerably parallel fibresrunning in one direction, or lengthways through the stem; the few thicker stripes are the edges oisome of the medullary rays.
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Keywords: ., bookcentury1800, booksubjectmechanicalengineering, bookyear1861
