The architects after a time seemed to have felt this, and tried to remedy it by introducing ogee forms and sharp edges, with deep undercut shadows, thus applying to the pillars those forms which had been invented for the mouldings of the ribs of the vaults, and for the tracery of the windows. The expedient was perfectly successful at first, and, so long as it was practised in moderation, gave rise to some of the most beautiful forms of pillars to be found in any style. It proved, however, too tempting an opportunity for the indulgence of every sort of quirk and quibble; and after passing through the shapes shown in figs. 9 and 10, where the meaning of all the parts is still sufficiently manifest, it became as complicated as fig. 11, and sometimes even more cut up, so that all meaning and beauty was lost. It became moreover very expensive and difficult to execute, so that in later times the architects reverted, either to circular pillars, or to such a form as that shown in fig. 12, which was introduced in the 16th century. The change may have been partly introduced from motives of economy, and also to some extent from a desire to imitate the flutings of classical pillars; but from whatever motive it arose, it is singularly unmeaning and inartistic; and as the capital was at the same time omitted, the whole pillar took an appearance of cold poverty entirely at variance with the true spirit of Gothic art. This last change showed, perhaps more clearly than those introduced into any other feature, how entirely the art had died away before the classical styles superseded it. WINDOWS. Before painted glass came into use, very small apertures sufficed to admit the required quantity of light into the churches. These openings retained their circular-arched heads long after the pointed form pervaded the vaults and pier arches, because the architects still thought them the most beautiful; they moreover occupied so small a portion of the wall spaces that their lines neither came in contact nor interfered with the constructive lines of the building itself; but when it was required to enlarge them for the purpose of receiving large pictures, the retention of the circular form was no longer practicable. [Illustration: 649. Window, St. Martin, Paris. (From ‘Paris Archéologique.’)] [Illustration: 650. Window of Nave of Cathedral at Chartres.] [Illustration: 651. Window in Choir of Cathedral at Chartres.]