imposts into the arch itself, instead of the force being directed downward, as in the Roman arch.
The pointed arch made its appearance in the several countries of Europe almost simultaneously, but it took nearly a hundred years to entirely supplant the round arch. During that time pointed and round arches were used indifferently in the same building, as occasion might require or taste dictate; but in the thirteenth century the pointed form was finally established. Another change is now apparent, showing the application of a principle which, perhaps more than any other, distinguishes the best examples of Gothic architecture—a desire to rely for the beauty of the work on the form and arrangement of the constituent parts, and to make it as independent as possible of added decoration. This is evidenced by the deeply cut moldings, in continuous lines, strongly marking out the construction, which are so noticeable in what are called "Early English" buildings. More lightness is also obtained by means of clustered pilars, molded arches, tracery in the windows, and especially by the use of buttresses. The buttresses, first used to give additional strength to an already substantial wall, were completely altered in form. Instead of being, as in the Norman period, broad and flat, projecting but slightly from the surface of the wall, they were now placed with their breadth at right angles to the wall. They were also lightened by being divided into stages, and divided in their lower parts by arches. By this arrangement the weight of the roof and upper portions of the building was transferred to points outside the walls, and this enabled immense progress to be made in the light-seeking principle by leaving a much larger portion of the sides of the building available for windows.
The art having now assumed a definite and decided character, the succeeding varieties of style show a steady progression on the lines established. The simple pointed arch was formed by describing it from two centers instead of one; by using more centers, trefoils and quatrefoils were obtained, and the intersection of the circles produced the cusp, another form of point. Points now appear everywhere; buttresses are prolonged into pinnacles, and towers are surmounted by spires. Ribs under arches and vaults are multiplied, to distract the eye from the weight of the material which they appear to support. Horizontal lines and divisions gradually disappear, or are broken up, until in some cases there is no line to mark where wall ends and roof begins. Even the beautiful geometrical forms of the fourteenth century had to give way to the perpendicular, which in the fifteenth century reigned supreme.
As an example of mediæval architecture at the highest point of development it was permitted to reach, we may take the chapel of King's College, Cambridge, one of the finest specimens of advanced Gothic art in Christendom. On entering the chapel the prevalence of the upward principle is at once apparent. On either side innumerable ver-
