‹‹‹ Vitr. 3.3.10 | Table of Contents | Vitr. 3.3.12 ›››
11For, as the distances between the columns increase, so must the shafts of the columns increase in thickness. If, for instance, in the aræostylos, they were a ninth or a tenth part of the height, they would appear too delicate and slender; because the air interposed between the columns destroys and apparently diminishes, their thickness. On the other hand, if, in the pycnostylos, their thickness or diameter were an eighth part of the height, the effect would be heavy and unpleasant, on account of the frequent repetition of the columns, and the smallness of the intercolumniations. The arrangement is therefore indicated by the species adopted. Columns at the angles, on account of the unobstructed play of air round them, should be one-fiftieth part of a diameter thicker than the rest, that they may have a more graceful effect. The deception which the eye undergoes should be allowed for in execution.
11For the thickness of the shafts must be enlarged in proportion to the increase of the distance between the columns. In the araeostyle, for instance, if only a ninth or tenth part is given to the thickness, the column will look thin and mean, because the width of the intercolumniations is such that the air seems to eat away and diminish the thickness of such shafts. On the other hand, in pycnostyles, if an eighth part is given to the thickness, it will make the shaft look swollen and ungraceful, because the intercolumniations are so close to each other and so narrow. We must therefore follow the rules of symmetry required by each kind of building. Then, too, the columns at the corners should be made thicker than the others by a fiftieth of their own diameter, because they are sharply outlined by the unobstructed air round them, and seem to the beholder more slender than they are. Hence, we must counteract the ocular deception by an adjustment of proportions.