Subordinate to the principal outline there follows the prolific subject of suitable ornamentation; which in plain turning, takes the form of fillets, mouldings and small curves, separated by cylindrical and other plain portions. The success of these ornaments depends upon the correct form and relative proportions of their members, a suitable variety or contrast, or when similar mouldings are employed in different positions, variety in their dimensions, with the same view, and the employment of a sufficient quantity without profusion. While it should also be observed that these enrichments, the main curves and other portions of the outline, all require to be finished to smooth regular lines without any break, flat, or indentation in their length; but these faults, technically called "elbows," may always be avoided in turning, in which the uninterrupted continuity of the lines is easily obtained.
These qualities being less abstract than excellence in outline, lie more nearly under rule. Perhaps no such common fault is met with in turned works as that of a redundance of ornament, which is as objectionable as ill shaped and meaningless form in the ornament itself. The juxtaposition of several complete mouldings with the view of adding to the enrichment, is to be deprecated and offends by transgressing simplicity; for, whether individually good or bad in form, too closely approached, each moulding will to a great extent interfere with the effect of its neighbour, the result of the entire group being confused and disagreeable. The best effect is produced when the mouldings are sufficiently separated by cylindrical or other plain portions of the work, and the balance to be observed between these latter and those enriched by ornament, while again somewhat a question for individual taste, should be specially insisted on as of no slight importance to effect; the plain portions of the work giving greater force and value to the enrichments, while nothing can be aesthetically worse or more wasteful, than to conceal a beautiful form by excess of ornament. In the illustrations which follow, the plain portions largely preponderate, and although additional ornament might be employed in some instances, it would be at a corresponding sacrifice of simple to more florid style.
A pedestal turned to accord with some of the architectural orders, or a column approaching the same rules, may serve to illustrate these and some other points. In both, the proportion left plain is large, the mouldings at either end terminate the straight plain shafts, to which their figured projections give the requisite variety, and in the column, relieve what would otherwise be an abrupt junction of the shaft with neighbouring portions of the work. The upper mouldings forming the cornice or capital, as in the pedestals figs. 663. 707 and in the columns, figs. 708. 733, usually entirely differ from those at the base or plinth; while should similarly formed mouldings be employed in these two positions, they generally differ in magnitude to avoid monotony, figs. 730. 747; although, as none of these statements are without exceptions, in some analogous works, as in figs. 727. 731, the mouldings receive exact repetition at either end of the column. Mouldings in these relative positions, are usually correct in their individual proportions when the greatest diameter of that forming the base, stands either as the lowest member or nearly so, while in the capital or cornice this order is reversed; the two then gradually taper towards the shaft, figs. 707. 731 spreading as a foot below and a support above, their original purposes. Occasionally these proportions are reversed, the mouldings standing the other way uppermost with good effect, as in some Moorish and Egyptian columns, the forms of which are very well suited for reproduction in the lathe ; but the effect of the transposition is usually less pleasing and rather abrupt, sometimes giving the appearance of want of strength.
The only recognised positions for the enrichments founded on the classic models being towards the two extremities, the shaft may receive no further ornament, except in the case of the Doric column, which is sometimes rusticated. The shaft may then he said to be surrounded by quasi-cylindrical portions at regular intervals, all along its slightly tapering length, these additions having plain edges and being in width some four or five times that of their intervals; which latter, should be about as deep as wide. This nevertheless still preserves the same general outline, as the rusticated column may be otherwise described as having its shaft larger in diameter and cut into a series of rather shallow square grooves; a groove being next to both capital and base, which remain as before. In another variety cubical blocks replace the added cylindrical ornaments, the column then appears as if finished cylindrical only at regular intervals along an original square shaft, or as threaded through a series of cubes. These styles of ornamentation are easily produced in the lathe and may sometimes be carried still further, as in the mirror, fig. 733, by the alternation of cubes with beads or other forms.
A different taste has introduced or revived the employment of one considerable increase of diameter at the center of straight slender shafts, or of one principal and central increase with one or more subordinate, placed at equal distances above and below it; forms of ornament effectively employed in Church and other furniture, probably derived from the Lom-bardo-Romano school of architecture. The central piece is frequently turned from a different material and enriched with mouldings or inserted ornament by the method described, fig. 755; when it is of the same material but of largely increased diameter to the shaft, it is very often added in the form of a ring, the addition being concealed in the manner shown by fig. 763; thus producing a column of considerable effect with a minimum of material. Many other shafts and rods, especially those employed for balusters and portions of domestic furniture, have their lengths broken and ornamented by a greater or less number of beads and mouldings connecting their various curved or straight lines; while most of the plain or ornamented shafts referred to, may be readily grouped together in plain turning to form clustered columns, as described in figs. 721 to 726.