Page:Popular Science Monthly Volume 69.djvu/161

Rh had the new meaning. Consider, for example, what astrology meant to Roger Bacon and what it means to us. He had no difficulty in reconciling the fateful influence of the stars with a scheme of salvation for men possessed of free-will. Words had different meanings to him and to us. His mind was conscious of no conflict between his religion and his science. His religion—that of the thirteenth century—is in absolute conflict with our science—that of the twentieth. This one example may stand as a type of many that might be brought forward.

The Greek architects long ago discovered that a cylindrical column looked at from a distance would not appear to have its two sides parallel, but that on the contrary these two sides would be hollowed in, convex towards each other. A long colonnade of cylindrical columns would exaggerate the unbeautiful effect. The Greeks felt the lack of beauty and afterwards proceeded to discover a rule for making the outer surface of a column convex, so that a colonnade of convex columns would appear to the spectator to be comprised of cylindrical, or conical, surfaces, beautiful to the eye. This increase of the middle diameter of columns was called entasis.

In the early part of the nineteenth century, an English architect, Mr. Penrose, visited the Parthenon, for the purpose of making accurate measurements of its principal dimensions. What was his astonishment to find that something of the nature of entasis had been given by the Greeks to the architraves, cornices and other members of the building. The long horizontal lines of the friezes were convexed outwards in order that they should not appear hollow to the eye. Other horizontal members were also convexed in order that they should not appear to tilt upwards. Similar measurements made on the Maison Carrée, at Nîmes, demonstrated that like rules were employed by the subtle architect for similar purposes. Measurements made on the temples of Egypt have shown that their floors are convexed in order that they may appear flat.

The Egyptians, the Greeks and even the Romans were possessed of eyes and senses so subtle that certain architectural devices were demanded by them in all edifices designed to give high pleasure. The entire western world was ignorant of these devices until a couple of generations ago. With the destruction of Rome, even the traditions of these changes were lost, so that all the Gothic cathedrals of Europe and every great building erected between the end of the fifth century and the middle of the nineteenth were constructed on geometrical lines, so to say, and not to satisfy the eye.

Mr. Penrose's discoveries were made with a foot-rule, not by a sensitive eye. They have borne fruit in our own time and in our own great city. The beautiful library of Columbia University is built on Greek principles. Let any one glance along the edge of one of the steps of