Certain practical points concerning vaulting--Ribs of early and late vaulting--Filling in of intermediate surfaces or cells--Methods adopted in France and England--Sexpartite vaulting--Crypt of Glasgow Cathedral--Choir at Lincoln--Chapter-house, Lichfield--Caudebec, Normandy--Octagonal kitchen of the Monastery, Durham--Lady Chapel, Salisbury--Segmental vaulting--Temple Church--Lady Chapel, St. Saviour’s, Southwark--Westminster Abbey--Intermediate ribs--Presbytery at Ely--Chapter-houses of Chester and Wells--Exeter Cathedral--Cloisters, Westminster--“Liernes”--Ely Cathedral--Chancel, Nantwich Church--Crosby Hall and Eltham Palace--Choir at Gloucester--Winchester Cathedral--Fan-vaulting--Cloisters at Gloucester--King’s College Chapel, Cambridge--Divinity Schools, Oxford--Roof of Henry VII.’s Chapel, Westminster--Ideal of its _design_. My last lecture brought the subject of vaulting to its full _functional_ development,--that which contains all elements whose origin can be traced to the demands of utility, but none which have been introduced purely for decorative purposes. In my present lecture I must supplement what I then treated of with some cases of its application which I had not then time to detail, and then proceed to carry on my subject into its more distinctly decorative developments. Before, however, I proceed further, it may be advantageous--though construction does not, perhaps, come within the range of lectures in this Academy, excepting so far as it exercises an influence upon form--to say a few words on certain practical points which are necessary to the full understanding, even of the artistic portion of the subject we are considering. In the earlier forms of vaulting, the entire strength lay in the continuous arched surface, which was constructed of brick or of stone, or of rubble bonded at intervals with brick or stone; the rubble or stone being often of the cellular material called tufa, which was much used by the early builders on account of its lightness as well as the tenacity with which it united itself to the cement. Transverse ribs were next introduced at intervals to strengthen the wider spaces; and, at a later period, the angles were similarly fortified. [Illustration: Fig. 356.] [Illustration: Fig. 357.] These ribs, in early examples, sprang distinctly as separate arches from the impost, the vaulting passing over them (sections, Fig. 356). At a later period--even in round-arched vaulting--we find the practice coming into vogue of uniting the ribs, and even the springers of the vaulting itself, by cutting them at the base out of the same blocks of stone. We see an early specimen of this in St. Bartholomew’s Church (Fig. 357).