The geologic history of China and its influence upon the Chinese people / by Eliot Blackwelder.

  • Blackwelder, Eliot, 1880-1969.
Date:
1914
Catalogue details

Licence: In copyright

Credit: The geologic history of China and its influence upon the Chinese people / by Eliot Blackwelder. Source: Wellcome Collection.

    67/76 (page 3653)
    The three-centred arch given in 628 is con- structed by first deterinining the height and the span ; then make AC, BC, and DE all equal. Join EC and bisect in F. The intersection C of the bisecting line /’C'with DE produced is the third centre. Describe arcs from C, C, C, as centres. The depressed Tudor arch [629] is described from four centres. The ogee arch, or .sc-cailcd ass’s back, has either three [630] or four centres [631]. The pointed trefoil opening has the centres placed as shown in 632. The ]iarabola and ellipse may also be used for arch foi’ins. MOULDINGS In architecture mouldings form a constituent part of an order, and were used in eight forms by the Romans and the (Ireeks. Thc.se forms an named: the fillet, a narrow Hat band used to separate and combine curvcci mouldings ; the aslrngot or head, a narrow or small conve.v cylindrical mould- ing [634]; the/orv/s [635]. whicli is really a hu’ge form of the astragal, anel is often ust'd at the base of columns ; the ovoln, or echinus (meaning “egg- formed), a convex moulding [638 and 644], which appears to have originated in the capital of the Doric column ; the cavetto [639 and 645], which is the reverse of the ovolo ; the scotia [640 and 646], a concave moulding which gives a deep shadow on itself and is very effective when used on bases of columns ; the cyma recta [641, 642, 647, and 648], a mould- ing with the concave above the convex por- tion ; and the cyma reversa [643 and 649], which has the convex part uppermost. Besides the above, the chamfer [633], the reeds [637], and the flute, a concave channel used to ornament the shaft of a column, are often used. The characteristic differ- ence between Greek and Roman mouldings is that the former are described with parabolic, hyper- bolic, and elliptical curves, and the latter with arcs of a circle, but the Greek, are more graceful in con- tour. Figs. 638-643 are Roman, and 644-649 Greek mouldings. The mouldings were often decorated with carving or colour, a j)articular design being used for each moulding, as in 638 and 649. A thorough knowledge of the principles of design given in this chapter is essential if the student contemplates taking up Commercial Design, which is dealt with later in this course. He should always carry his sketchbook in rcadine.ss to note a characteristic piece of design or a beautiful detail of ornament. The jiatterns and schemes of decoration in use at different periods for buildings, furniture, domestic utensils, personal ornaments, and so forth, should form subjects for observation. WILLIAM R. COPE