Chap. XXXI.

PRINCIPLES OF PROPORTION.

1591

ing base and capital, is 29 feet 6 inches, that of the entablature 6 feet 9 inches, and of thepediment 7 feet 5 inches; taking away half the height of the pediment, we have 39 feet11 inches and 6 parts, which may be considered as 40 feet; this multiplied by the widthproduces for the entire area 1746 feet 8 inches. The superficial content of pediment andentablature, 456 feet 8 inches, is obtained by multiplying the entire width by 10 feet 5\inches, the height of the entablature and half the pediment, which superficies is only 20 feet2 inches more than a quarter of the whole. The united diameter of the six columns is17 feet 6 inches, and that of the intercolumniations 26 feet 2 inches, so that they are inthe proportions to each other of 2 and 3, the whole T>eing 5, one having an area of515 feet 9 inches, the other 772 feet j when added together they are nearly three times thearea of the part supported.

The proportion between the columns and intercolumniations of the temple at Assissi isalso similar, the height of the columns is 32 feet 10 inches, and the total width of the six52 feet, which dimensions multiplied together produce 1707 feet 4 inches, one-fifth being341 feet 6 inches nearly.

The area of the columns is 684 feet, and that of the intercolumniations 1023 feet 4 inches,giving a proportion of two-fifths and three-fifths. The entablature, pediment, and pedestalsupon which the columns are placed seem to have undergone a change since their erection.If the whole extent of an hexastyle portico be divided into 18 parts, and one be called thediameter, to obtain the same proportions as those laid down for a tetrastyle portico, the heightup to the centre of the pediment must include 12 only of those parts, which would give aportico of a square and a half, comprising 216 squares ; the 6 columns, each 9 diametersin height, would require 54 ; the 5 intercolumniations, double that number, or 108, and theentablature and half pediment 54.

Roman Octastyle. — The Pantheon at Rome , which has a portico of 8 columns, is one ofthe best examples that can be selected for examination. The total width is 109 feet 10inches; the diameters of the eight columns 39 feet 5 inches, and the seven intercolumnia-tions 70 feet 5 inches, or nearly in the proportion of 1 to 2. The height of the columns is46 feet 5 inches, and that of the entablature and half pediment 23 feet 2± inches, together69 feet inches, nearly a square and a half, the area of which is 7647 feet 2 inches.

OCTASTYLE PORTICO OP THE PANTHEON.

Fig. 2983.

The united diameter of the columns, 39 feet 5 inches, multiplied by their height, gives1829 feet 7 inches, and the collected intercolumniations multiplied by the same height willbe 3268 feet 6 inches : multiplying 109 feet 10 inches by 23 feet^l inches, we obtain forthe area of the entablature and pediment 2549 feet, which, rejecting parts of an inch, will,when added to the two other calculations, make up a sum agreeing with the entire area.

The supported is

The area of columns

of intercolumniations

1829-7 "I3268-6 /

Feet.

2549

5098

Together -

-

7647

5 i 4