A R C H I T 
bafilicas, triumphal arches, maufoleums, bridges, and 
other public buildings, were profufedly enriched with co-- 
lumns; as were likewife the courts, vedibules, and halls, 
of their private villas and hotifes. 
In imitation of the ancients, the moderns have made 
the orders of architecture the principal ornaments of their 
fh uCdures. We find them employed in almod every build¬ 
ing of confequence; where they are fometimes merely or¬ 
namental, but at other times of real ufe, ferving to fup- 
port the incumbent weight of any drmShtre erected upon 
them. On fome occafions they are employed alone; the 
whole compolition confiding only of one or more ranges 
of columns, with their entablature. Upon other occafions 
the intervals between the columns are filled up and adorn¬ 
ed with arches, doors, windows, niches, ftatues, baffo-re- 
lievos, and other fimilar inventions. The columns are 
cither placed immediately on the pavement, or raided on 
plinths, pedefials, or bafements; either engaged in the 
walls of the building, or (landing detached, either near, or 
at fome didance from them; and frequently different or¬ 
ders are placed one above another, or intermixed with 
each other on the fame level. In thefe, and in all other 
cafes, in which the orders are introduced, particular mea- 
fures, rules, and precautions, are to be obferved, which 
we diall now endeavour to explain and illudrate. 
Of INTERCOLUMNIATIONS and ARCADES. 
Columns are either engaged or infulated; and, when 
infulated or detached from the wall, they are either very 
near, or at a confiderable didance from it. When they are 
placed at a confiderable didance from the wall, they are 
dedined to fupport the entablature; and their didance from 
each other diould be confident both with their real and 
apparent folidity. Engaged columns are attached to the 
wall, and are not limited in their intercolunmiations, as 
they depend on the breadth of the arches, doors, windows, 
niches, or other decorations, placed in them. 
Palladio fays, the intercolumniation of the Tufcan or¬ 
der was adapted to farm-hotifes and other rudic works, as 
it afforded a paffage for carts, and was attended with the 
lead expence. In drudhires built entirely of done, they 
ufed a lliorter interval, more fuitable to the length of their 
marble blocks, and more agreeable to the ponderous fa¬ 
bric which they occafionally fupported ; for which reafon 
the diadyle and eudyle modes were fometimes applied to 
this order. The moderns have indeed adopted thefe two 
as their general rule, and apply them to every order ex¬ 
cept the Doric. The areodyle, however, is fometimes, by 
a modern contrivance authorifed by a few examples of the 
ancients, introduced in porticos and peridyles. This mode 
of the areodyle is from Perrault, and is managed by pla¬ 
cing two columns together at the angles, fo clofe as to 
admit the two capitals nearly into contact. This manner, 
which is termed grouping, takes off from the excedive 
width of this kind of interval, whild it adds to it both 
real and apparent ftrength, as is exemplified in St. Paul’s 
church in London, and in the palace of the Louvre at Paris. 
Arches, or arcades, are not fo magnificent as colonnades; 
but they are more folid and lefs expenfive. They are pro¬ 
per for triumphal entrances, gates of cities, of palaces, of 
gardens, and of parks, and, in general for all openings that 
require an extraordinary breadth. There are various man¬ 
ners of adorning arches. Sometimes their piers are radi¬ 
cated ; fometimes they are adorned with piladers, termini, 
or caryatides; and fometimes they are made fufficiently 
broad to admit niches or windows. The circular part of 
the arch is either furrounded with rudic key-dones, or 
with an archivolt enriched with mouldings ; which, in the 
middle, is fometimes interrupted by a conlole, or mafk, 
ferving at the fame time as a key to the arch, and as a 
fupport to the architrave of the order. The archivolt is 
fometimes fupported by an impod at the head of the pier; 
and at others by columns placed on each fide of it, with a re¬ 
gular entablature, orarchitraveand cornice. There are alfo 
indances of arcades without piers, the arches being turned 
Vol. 11 . No. 60. 
E C T U R E. io s 
on fingle columns, as in the temple of Faunus at Rome, &c. 
But this practice ought to be feldom imitated, as it is nei¬ 
ther folid nor handfome. When, however, arcades are 
employed to ornament domedic apartments, the breadth 
of the pier need not exceed one-quarter of the opening of 
the arch. When arches are clofed up to receive doors, 
windows, or niches, the recefs diould be fudicient to con¬ 
tain all the projections of what is placed therein, otherwife 
their appearance is olumfy, and will become too principal, 
which produces a bad eff'eCl in the compofition. 
When arches are large, the key-done diould never be 
omitted, but cut in the form of a confide, and carried 
clofe under the foffit of the architrave, which, on account 
of its extraordinary length, requires a fupport in the mid¬ 
dle. The impods of arches diould never be omitted; at 
lead, if they be, a platform ought to fupply their place. 
If columns are employed without pededals in arcades, they 
diould always be railed on a plinth. In arches of great 
magnitude, the circular part ought not to fpritig imme¬ 
diately from the impod, but take its rife at fuch a didance 
above it as is necedary in order to have the whole curve 
feen at the proper point of view. 
The void or aperture of arches diould never be higher, 
nor much low er, than double their breadth ; the breadth 
of the pier diould feldom exceed two-thirds, nor be lefs 
than one-third, of the breadth of the arch ; and the angu¬ 
lar pier ought to be broader than the others, by one-half, 
one-third, or one-fourth: the impod diould not be more 
than one-feventh, nor lefs than one-ninth, of the aperture ; 
and the archivolt mud not be more than one-eighth, nor 
lefs than one-tenth, of it. The breadth of the conlole mud, 
at the bottom, be equal to that of the archivolt; and its 
fides mud be drawn from the centre of the arch : the 
length of it mud not be lefs than one and a half of its 
finalled breadth, nor more than double. The thicknefs of 
the pier depends on the breadth of the portico ; for it mud 
be drong enough to relid the prelfure of its vault. But, 
to give beauty to the building, it diould not be lefs than one- 
quarter of the breadth of the arch, nor more than one-third. 
The proportions peculiar to the Tufcan arch, without 
ededals, are as follow : In height, their aperture isfeven 
iameters and a quarter, in width four, and from centre to 
centre of the columns fix diameters. According to the 
preceding remarks, the archivolt and impods are half a dia¬ 
meter, and from the top of the archivolt to the under fide 
of the architrave diould not be lefs than fifteen minutes. 
The breadth of the key-done at the bottom is equal to its 
archivolt; and its fpreading fides are determined by lines 
drawn from the centre of the arch. The Tufcan arch with 
pededals is in width four and a half, and in height eight 
diameters and a quarter; and from centre to centre of each 
pier is fix and three-quarters. In every other particular 
they are fubjedt to the preceding rules. 
The intercolumniation of the Doric order is often at¬ 
tended with peculiar difficulty, arifing from the driCt re¬ 
gard that is neceffarily paid to the width of the triglyph, 
and the perfectly-fquare form of the metopes, or their in¬ 
tervals. Befides that, it is abfolutely requifite, that a tri¬ 
glyph diould be placed exactly over the centre of every 
column. For thefe reafons, the mutules and triglyphs 
have been omitted in capital works, both ancient and mo¬ 
dern, as in the Colifeum at Rome, and the Royal Hofpital 
at Greenwich. Palladio has, however, given one indance 
of an ancient temple with angular triglyphs. This druc, 
ture, which he terms the Temple of Piety, is mentioned 
by Vitruvius, with an eye to the difficulty occafioned by 
the triglyphs being’-thus placed ; which reduces the inter¬ 
columniation of the two angular columns to one diameter 
and a quarter, which is lefs than the pycnoftyle. The 
next intercolumniation is dill greater, approaching nearly 
to the pireodyle, as is evidently neceffary to bring the tri¬ 
glyph over the centre of the third column from the angle. 
The next, which is the centre intercolumniation, and faces 
the entrance of the temple, is rather more than eudyle, or 
two diameters and a quartet ; and has, in the metopes, 
,Ee ditriglypl). 
