Elements of plane and solid free-hand geometrical drawing, with lettering; and some elements of geometrical ornamental design, including the principals of harmonic angular ratios, etcIn three parts ..for draughtsmen and artisans; and teachers and students of industrial and mechanical drawing . In the first of these figures, the acute half angles are 20° and80*^, whose ratio is therefore f. In the second figure the cor-responding angles are 18° and 36°, having therefore a ratio ofI, and affording a more decidedly egg-shaped curve. Ex. 108. An egg-shaped oval may also be inscribed in aregular tr
Elements of plane and solid free-hand geometrical drawing, with lettering; and some elements of geometrical ornamental design, including the principals of harmonic angular ratios, etcIn three parts ..for draughtsmen and artisans; and teachers and students of industrial and mechanical drawing . In the first of these figures, the acute half angles are 20° and80*^, whose ratio is therefore f. In the second figure the cor-responding angles are 18° and 36°, having therefore a ratio ofI, and affording a more decidedly egg-shaped curve. Ex. 108. An egg-shaped oval may also be inscribed in aregular trapezoid, that is a figure having two unequal but paral-lel sides, both of which are bisected by the same line, perpen-dicular to both, thus:
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmechanicaldrawing
