supposing the tympanum to rise a ninth of its base; the height of the columns is 21 feet 74 inches, and their united mean diameter 12 feet 9 inches, which being multiplied together produce 275 feet 8 inches, or nearly equivalent to the area of the mass they support. To obtain the exact quantity of mass and void, the mean diameters of the columns as well as of the intercolumniations should be taken; the greater the probable delicacy of execution, the greater is the necessity for the architect to balance his quantities exactly. In the subject now under consideration the whole is comprised within a square and a half; the supports and the entablature are equal, and the intercolumniations as much as the two together or one-half the whole. The height of the architrave is 2 feet 11 inches; that of the frieze 1 foot 11 inches, and the level part of the cornice 10 inches.

Roman Tetrastyle. Ionic Temple of Fortuna Virilis.-The width is 33 feet 6 inches, and height, including half the pediment, 37 feet 1 inch, comprising an area of 1242 feet 4 inches, one quarter of which, 313 feet 1 inch, nearly agrees with the quantity contained in the entablature as well as in the columns which support it; their height is 27 feet, and their united diameters 12 feet 4 inches, which multiplied together produce 333 feet for the area of the supports. The height of the entablature with half the pediment is 10 feet 1 inch: this multiplied by its width, 33 feet 6 inches, gives 337 feet 10 inches for the area of that supported: the intercolumniations are together 21 feet 2 inches, which multiplied by their height, 27 feet, gives 571 feet 6 inches for their area, about 100 feet less than the quantity comprised in the columns and entablature.

Without the pediment this façade is nearly square; its proportions rank very high in the estimation of all admirers of Roman architecture; it has, however, undergone many reparations before the stucco was put upon the columns; they were lighter, as was the entablature, the upper members of the cornice being somewhat heavier than is usual in the early examples of this order; if divested of these additions, and giving a trifle more to the intercolumniations, we shall obtain half the area for the columns, and a quarter for each of the other divisions; at present the columns equal in quantity the mass they carry.

If it be required to draw a tetrastyle portico in exact accordance with the rules laid down, after forming the square each side should be divided into 12 parts, or 144 squares, arranged like those of an abacus: one of these divisions on the base would become the diameter of the column, and nine their height, the other eight on the base would be devoted to the intercolumniations, and the upper three of the height to the entablature. The columns, 9 diameters in height, would thus comprise 36 squares, the intercolumniations 72, and the entablature and half pediment 36; consequently the columns and entablature would be equal in quantity, and the intercolumniations half the whole, or equal to the contents of the supports and supported.

Roman Hexastyle. Corinthian, Maison Carrée at Nismes. This beautiful temple has undergone several restorations; its entire width and height to the apex of the pediment is 43 feet 8 inches, from whence it has derived its name. The height of the columns, includ

ing base and capital, is 29 feet 6 inches, that of the entablature 6 feet 9 inches, and of the pediment 7 feet 5 inches; taking away half the height of the pediment, we have 39 feet 11 inches and 6 parts, which may be considered as 40 feet; this multiplied by the width produces for the entire area 1746 feet 8 inches. The superficial content of pediment and entablature, 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 feet 2 inches more than a quarter of the whole. The united diameter of the six columns is 17 feet 6 inches, and that of the intercolumniations 26 feet 2 inches, so that they are in the proportions to each other of 2 and 3, the whole being 5, one having an area of 515 feet 9 inches, the other 772 feet; when added together they are nearly three times the area of the part supported.

The proportion between the columns and intercolumniations of the temple at Assissi is also similar, the height of the columns is 32 feet 10 inches, and the total width of the six 52 feet, which dimensions multiplied together produce 1707 feet 4 inches, one-fifth being 341 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 pedestals upon 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 the diameter, to obtain the same proportions as those laid down for a tetrastyle portico, the height up to the centre of the pediment must include 12 only of those parts, which would give a portico of a square and a half, comprising 216 squares; the 6 columns, each 9 diameters in height, would require 54; the 5 intercolumniations, double that number, or 108, and the entablature and half pediment 54.

Roman Octastyle. - -The Pantheon at Rome, which has a portico of 8 columns, is one of the best examples that can be selected for examination. The total width is 109 feet 10 inches; the diameters of the eight columns 39 feet 5 inchos, and the seven intercolumniations 70 feet 5 inches, or nearly in the proportion of 1 to 2. The height of the columns is 46 feet 5 inches, and that of the entablature and half pediment 23 feet 2 inches, together 69 feet 7 inches, nearly a square and a half, the area of which is 7647 feet 2 inches.

The united diameter of the columns, 39 feet 5 inches, multiplied by their height, gives 1829 feet 7 inches, and the collected intercolumniations multiplied by the same height will be 3268 feet 6 inches: multiplying 109 feet 10 inches by 23 feet 2 inches, we obtain for the 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.

A line drawn through the centre of the pediment, another at half the height of the columns, and a third under the entablature, would divide the height into three equal portions, proving that, in this example, the Romans made the part supported onethird of the whole, and divided the other two between the columns and their intercolumnistions. The shaft of each column is cut out of a single block of granite; they are not sufficiently delicate to be exactly in the proportion of half the quantity contained in the intercolumniations; but if allowance be made for their diminution, the difference is not very great. The whole width being 109 feet 10 inches, the third, 36 feet 7 inches and 4 parts, is nearly a mean between the collected diameters of the top and bottom of the shaft, making the intercolumniations double the quantity contained in the supports, or equal to that of the supports added to the mass they carry. The whole would then be divided into four, as in the previous examples of the Ionic, and two portions given to the intercolumniations, The Pantheon Portico is a double square without the pediment, or nearly so, the length of the level cornice, which crowns the entablature, being double the height of the order: this, no doubt, was the outline of the proportions before the heavy pediment was placed upon it, which in all probability was heightened beyond the ordinary rise of a ninth, for the purpose of concealing the wall behind it. The Roman proportions are frequently made independently of the pediment; the tetrastyle porticoes are a square, the hexastyle a square and a half, and the octastyle, as in this instance, a double square without it.

To set out an octastyle portico, in which half the pediment should be comprised within the double square, after dividing the width into 24 and the height into 12, which multiplied produce 288 squares, 72 are given to the column, the same to the entablature and half pediment, and double that, or 144. to the intercolumnations, or proportions similar to those laid down for the tetrastyle and hexastyle porticoes. The columns in such a case would be nine diameters in height, the entablature and half pediment three: supposing the latter to rise a ninth of the span, the remainder would be distributed among architrave, frieze, and cornice.

We have endeavoured to show the proportions required in a tetrastyle, hexastyle, and octastyle portico among the Dorians, the Ionians, and their followers the Romans: the square and a half, or the double square, were the outlines or boundary figures from whence the other proportions were deduced.

The great difference of character in the Doric and Ionic designs arises from the distance at which the columns are placed, which affects the proportions of the entablature laid upon them, as well as that of the columns themselves; where these are six diameters in height or consist of six cubes, they are made to carry the same quantity, whatever may be their distance apart, and where drawn out to nine diameters, they have only their own weight to support; but the form given to this weight, or the proportions of architrave, frieze. and cornice, vary, as the intercolumniations are of one or more diameters.

It has been too generally considered that the orders derived their proportions from the lower diameter of the columns, without reference to their application: this has produced a variety of design, but at the same time occasioned a great departure from the true principles, and led to very important errors. The Tuscan, the Doric, the Ionic, the Corinthian, and Composite orders have been laid down in modules or measures of various kinds, which the young architect has adopted as mere isolations, regardless of the many other considerations which have stamped beauty on his model; hence we have imitations, but soul is wanting. The Doric order is treated of as so many diameters in height according to its age, and the entablature is said to be heavy or light, as it was of early or late execution; the other orders have been chronicled in a similar manner, and architecture has been fettered, and its great principles lost, or at least neglected: it is true that the outline which bounds the figure has undergone but few changes, but the subordinate parts or the filling-in are susceptible of interminable variety. An object inscribed within a circle is perhaps the most easily compassed by the eye, next that within the square, and when a building is vast, and distance is necessary to comprise a view of the whole, the double square; beyond this the ancients seem seldom to have gone for the proportions of their façades, or of a portico intended to be seen in front. After the masses were proportioned, their decorations were more various than the buildings themselves; no two are perfectly alike, but the great difference is in their ornaments and enrichments, or in the number of diameters contained in the height of the columns.

The Parthenon and Pantheon porticoes are both octastyle, each admitted to be as beautiful as they can be—one the perfection of sober grandeur, the other of cheerful lightness; one Greek Doric, the other Corinthian, both comprised within a double square, and having their columns equal in quantity to the mass of entablature they support: where, then, is the difference between the two examples? It results, as we have already seen, from the material in the one occupying two-thirds, and in the other only half the entire area. the façade of the Parthenon the eye has one-third void only to contrast with the solid matter, and in the Pantheon half, which proportions seem to have been established by the Ionians, and usually adopted by the Romans.

In

In proportioning the architrave, frieze, and cornice, care must be taken that no more is laid upon the columns than their own bulk: when the latter are one diameter apart, this quantity will be greater in height than when they are further distant; so that the greater the intercolumniation, the lighter in appearance will be the entablature, the columns still bearing the same weight, nor need they be increased after it is ascertained that they are competent to their duty: to do so would be to employ material in excess, which it should be the aim of an architect to avoid.

If we now examine the portico of the Pantheon, we cannot fail to perceive the agreement existing between the parts supported and their supports.

The mean width of the architrave and frieze is
Their height

The solid contents of the entire length, 110 feet, is

The mean width of the cornice is 7 feet, length 114 feet, height 3-6 feet, }

and its cubical contents

The solid content of entablature 5918 11

which leaves little more than 100 cubical feet of difference between one and the other; and if the crown moulding returned on the flank be comprised, the quantity contained in the entablature would equal that of the eight columns.

The pediment is omitted altogether in this calculation, it being in reality, though not in appearance, an additional load for the eight columns beyond their regular entablature, which is of marble, and weighs probably 452 tons; the granite columns with their marble bases and capitals are something more than that quantity, and these, including the entablature and pediment, probably contain upwards of 1000 tons of material.

The Capitals of the Columns of the Pantheon are admitted to rank among the best examples found in Rome: though not so highly and elaborately worked as those which decorate the columns of the temple of (Jupiter Stator) the Dioscuri, yet they are remarkable for the

elegant arrangement of the ornaments: further details will be found in Taylor & Cresy's Architectural Antiquities of Rome, whence the details here given have been selected.

Although the Romans did not improve the arts which the Greeks had spread among them, by the introduction of the arch they materially altered the character of the architecture practised before the time of the Republic: this feature alone produced entirely