26 ARCHITECTURE. 
commencing, and being continued from thence upwards (pl. 20, jig. 10); 
or of giving it the largest diameter at the height of the human eye, and 
reducing it from this point both upwards and downwards (fig.11). The 
greatest diameter of columns of the latter description is called the swell 
(entasis). , 
The columns are placed either on single stone cubes, or on a continuous 
plinth (stylobates). The space between the columns is styled the columnar 
distance, and varies very much. Different terms are applied to the various 
distances. If the space between the columns be equal to 4 diameters they 
are said to be placed distantly (aryostylos); if the space be equal to 3 
diameters, widely (dzastylos); if 24 diameters, beautifully (ewstylos); if 2 
diameters, closely (szstylos); and if only 14 diameters they are said to be 
thickly placed (picnostylos). As a general rule the two corner columns are 
for optical reasons placed somewhat nearer together than the others of the 
same row. Another contrivance, intended to correct an optical delusion 
with regard to colonnades, is mentioned by Vitruvius by the name of scamzlla 
empares. According to this author on ancient Roman architecture, a row of 
columns standing on a substructure would, when viewed from a distance, 
appear convex, and elevated at both ends, and this effect would be averted 
by the scamillz. Unfortunately, all the drawings which might have illus- 
trated the works of Vitruvius have been lost, and as, moreover, the ancient 
Roman buildings exhibit no architectonic moulding which seems to serve 
the purpose ascribed to the scamllc by Vitruvius, his commentators are 
greatly at variance in their explanations of the idea he means to convey. 
Most of these learned men agree in this, that the scamdllus was a distinct 
moulding, which being placed above and below the column, would make it 
appear to recede. Some columns found among the ruins of the theatre at 
Laodicea seem to corroborate the correctness of this view. Pl. 7, fig. 19, 
shows one in connexion with the substructure and architrave, and jigs. 20, 
a, 6, one of a different order on a larger scale. We see here at a and B 
small mouldings inserted above the top of the capital and under the foot of 
the base. The latter is slightly higher on one side, producing the impression 
of a slight inclination in the column; the upper one has a similar excess of 
body on the opposite side, apparently levelling the slanting surface of the 
capital, and supporting the entablature with its full surface. But other 
authors say, that these small mouldings had no other object than to relieve 
the mouldings proper of the base and capital. Still others maintain that 
Vitruvius originally wrote camillum and not scamillus, and that he applied 
it to the columnar distances, which were to decrease as they receded from 
centre, and in proportion with them the pannels in the substructure (camlla) 
were to be reduced in size (jig. 15). One commentator, Bertanus, is of 
opinion that a moulding introduced in the base (jig. 16, c) would produce 
the effect ascribed to the scamilli impares ; and another, Placentius, follows 
this view, but places the moulding as in fig. 17, p. Both make the mouldings 
a little higher at one of the sides. Blanconius, finally, explains seamili 
impares as applied to the inequality of the side walls of the flights of steps 
leading to the colonnade, and supposes that the first ought to be the highest 
26 
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