Sections Of Classical Mouldings 0700218

Fig. 5.

27. Bases, capitals, lintels, cornices, imposts, and archivolts are composed of separate members of straight or curved profiles, and these members are called mouldings.

28. Classical mouldings may be divided into five classes: crowning, supporting, binding, separating and prone. The mouldings most frequently used are the quarter round, Fig. 5 (E); the cove or cavetto, (A); the torus or half round, (J); the cyma, (C);

Sections Of Classical Mouldings 0700219

Fig. 6.

the ogee or cyma reversa, (H); and the scotia, (O). The quarter round, cove and torus are simple mouldings whose outline is an arc of a circle; the cyma, ogee and scotia are composite mouldings outlined by the arcs of two or more circles. The fillet (M), while never occupying an important position, is continually used to finish off or to separate the more important mouldings.

29. Classical architecture includes five Orders that differ in the proportions of their columns and in richness of their ornamentation. These Orders have long been called the Tuscan Order, (Fig. 6); Doric Order, Ionic Order, and Corinthian Order, (Plate I) and Composite Order, (Fig. 17). The Doric, Ionic and Corinthian orders are the most important, as they are now in more general use.

30. The five orders have one proportion in common, viz.: the relation of the height of the column to the height of the entablature. The entablature in all five orders is one quarter the column height. The height of the column in any order is therefore the height of four entablatures, and the height of the entablature, although a variable quantity, will always bear a certain relation to the general height of the order.

31. The height of the entablature divided into one hundred parts establishes a scale which may be used in determining the proper proportions of all parts of the order. This scale unit is called the Entablature or "En" and its one hundred parts are, where necessary to show more minute divisions, sub-divided into tenths which are expressed decimally.

Sections Of Classical Mouldings 0700220

PLATE I.

(A reproduction at small size of Portfolio Plate I.)

32. Another system of measurements which is often used is based upon a unit called the "Module" which is always equal to the radius of the column shaft at the base. This unit, like the "En," may vary in different examples but will always have a definite relation to the order as a whole in any particular case. The "Module" is sometimes subdivided into twelve parts, sometimes into eighteen and sometimes into thirty, depending upon the order considered and the system of measurement to be adopted. It is, therefore, not so reliable a unit as the "En," and the latter will be used in this work. Some of the plates from Vignola and Palladio, however, are drawn according to the "Module" system. It is only necessary to remember that the "Module" is always equal to the semi-diameter at the base of the column.

33. The figured dimensions of a drawing are written along vertical lines in measuring heights, and along horizontal lines in measuring widths. A figured drawing is one whose dimensions are expressed in figures, and the extent covered by each measurement is denoted by dotted measuring lines and by spurs or arrow heads, two of which when meeting form a cross.

34. The most striking difference between the Orders is in the proportions of the columns, whose heights, as already noted, are equal to four entablatures, but whose diameters just above the bases are as follows:

Tuscan order,

55

parts

of the

Entablature

or "En."

Doric order,

50

"

"

"

"

Ionic order,

45

"

"

"

"

Corinthian order

40

"

"

"

"

Composite order

40

"

"

"

"

From the Tuscan to the Corinthian Order the thickness of the column decreases evenly by five parts at each step.

35. The shafts of columns, as we have already seen, are less thick at the capital than at the base. The upper diameter of the columns of the different orders is: for the-

Tuscan

Order,

48

parts.

Doric

,,

44

,,

Ionic

,,

39

,,

Corinthian

,,

36

,,

Composite

,,

36

,,

36. The Tuscan and Doric columns have one relation in common,the height of their capitals, which is twenty-six. The cornice in both these orders has a height of thirty-seven.

37. The entablatures of the Ionic. Corinthian and Composite orders have certain general proportions in common, and all the general proportions of Corinthian and Composite columns are identical.

38. When orders are set upon pedestals, the latter must harmonize in their proportions and decoration with the orders carried by them. The height, however, is variable, being generally prescribed by the practical requirements of each building. A good average height is 1 En 40 parts or 140 parts. Although pedestals are not component parts of the orders it is convenient to call them according to their characteristics, Tuscan pedestals, Doric pedestals, Ionic pedestals, etc., as the case may be. The several orders differ in the complexity of their mouldings and the richness of their ornamentation.