Exhibition of Lantern Slides.

The lecture room of the Fogg Museum was crowded last evening by the audience that assembled to hear Professor Moore's third lecture on the Fine Arts of the Middle Ages. Professor Moore began with the organic Lombard Romanesque architecture in northern France, and traced the development of the Gothic style, which culminated in such buildings as the cathedral of Paris.

One of the distinguishing features of the Gothic style is the pointed arch. It was first used as a structural device in vaulting, the pointed arch being better adapted for spanning openings where the height of the arch can not be limited by its span. The only means of using a circular arch where the height is to be greater than the span, is by elevating or tilting it. This is a cumbrous construction and belongs to the Romanesque architecture. The circular arch was long retained in covering window openings, and in the arch construction of the triforium.

The sexpartite vaulting was accidentally developed by the introduction of intermediate shafts. Intermediate transverse ribs were sprung from these shafts passing through the intersection of the diagonal ribs. This construction became an element of great beauty.

Flying buttresses were found necessary to receive the thrust of this system of vaulting. They were at first rather awkwardly constructed but in the thirteenth century became more graceful and ornate. The foliate ornamentation of the Gothic capitol rivals in beauty of line and surface any of the Greek forms, and the sculpture, though inclined to the grotesque, resembles the Greek in some of its methods.

The views shown were for the most part chosen from cathedrals and churches in the neighborhood of Paris, for it is there that most of the examples of the early Gothic architecture are found.