In the Roman buildings the walls were most commonly without projections, and of vast thickness, which was necessary in a vaulted building, erected upon a recti lineal plan, in order to counteract the ef forts of the resisting arches. Hence, if the building had been grained, the weight of the arches would have been thrown upon the springing points. From this it is evident that a vast quantity of materials must have been employed without effect; but this is not the case with the pointed style of architecture, for the walls were thickened by buttresses opposed only to the pressing points; and, • to aid the re sistance with still more powerful effect, the buttresses were surmounted with high pinnacles, and, from their sloping position, their general form Was almost one continued prop, in a straight line to the bottom : this straight line was a tan gent to the arch. Those that understand the nature of the centre of gravity will easily perceive, that a plain wall will be overturned with much more ease than one with buttresses, of the same length and height, the same quantity of materials being employed in both. The extremity of the aisles was sustained by strong pi lastered buttresses on the outside, and the other extremity rested on the imposts or capitals of the pillars. These pillars, with their superincumbent walls, not be ing assisted as on the outside with but tresses, were liable to be bent with the pressure of the arches, unless the sides of the nave had been of sufficient thick ness, which, in many of our churches, ex perience has proved to be the contrary, by the bending of the walls inwardly, which is a serious defect, and threatens ruin to many of those venerable piles of building. We cannot therefore expect these edifices to rival, in duration, the immortal constructions of Egypt, Greece, and Rome. As to the groining of the nave, the arches were equally resisted on both sides by the flying buttresses, which pressed forcibly at the imposts of the arches. It would appear, that the me thod practised in the erection of these edifices was, to insert the springing stones as the work went on, but to leave the vaulting to be turned after the walls had been carried up to their full height, and the whole roofed in. The roofs of Gothic buildings were very high pitched, a form more from choice than necessity, rather adopted in compliance with the pointed and pyramidal style of architecture, than rendered necessary by the climate, being generally covered with lead. These roofs are therefore faulty, in burdening the walls with an unnecessary load of timber and lead; and they are also deficient in the construction, by the omission of tye beams, to counteract their tendency to spread and thrust out the walls.
After having thus discussed the several styles of building, which have been gene rally and unmeaningly classed under the appellation of Gothic, we must now make a retrogression to Italy, where the Gre cian style had been revived for a consider able time, and was flourishing in great purity. Let us therefore retrace the steps by which it again rose to its ancient splen dour and magnificence.
Fillipo Brunelleschi, horn 1377, may be looked upon as the restorer of ancient ar chitecture, and the founder of the modern style.
After having prepared his mind by the study of the writings of the ancient au thors, and the ruins of Roman edifices, which he earefdly measured, he discover ed the orders, and recognized the simple forms and constructions of the ancients, and having thus formed a system upon un shaken principles, he was enabled to con struct works with beauty, solidity and du rability. He erected the dome of St.
Maria da Fiore at Florence, an undertak ing beyond the abilities of any other builder then living ; Arnolfo, the original architect of this vast cathedral, having been two years dead. This dome, rising from an octangular plan, is of great ele vation; and is only inferior in size to that of St. Peter's. It is constructed by two vaults, with a cavity between them, and was erected without centering. It is the only elevated dome supported by a wall without buttresses. From this, and many other buildings erected by Brunelleschi, the learned began to study the works of Vitruviits, and a general taste for the principles of the art begun to warm the breasts of the Italians.
Leo Battista Alberta, born ..k. D. 1.398, wa.s the first modern author who publish ed a learned treatise on architecture, from which he has acquired great reputation, and is justly styled the modern Vi trus. i us. Following the steps of Brimelleschi, reformed his precepts and designs ma ny of the abuses and barbarous practices which then prevailed among his country men.
Bramante had a considerable share in the restoration of ancient art, and built many magnificent eilifices. l'ope Julius II having projected the rebuilding of St. Peter's upon a scale of unequalled mag nificence, entrusted the execution of the design, 1513, to Bramante, who conceived the idea of' erecting the lofty oipola upon that immense structure. This vast undertaking was carried on successively. by Raphael, San Gallo, iind 'Michael An gelo, to whom the final design and com pletion of the work is principally due.
Architecture continued to flourish in the 16th century, under the great archi tects Vignola , Serlio, Palladio, and Sea. mozzi. To the unremitted assiduity of these distinguished artists in the study of the Boman edifices, and to their isvalua ble publications, the world hits been much indebted for the elucidation af the prin ciples of ancient art.
The list of the celebrated Italian artists closes with Bernini, who flourished in the 17th century.
The Grecian style building was re vived in France in the beginning of the 16th century-, and afterwards flourished under several architects of distinguished merit. Their vrincipal works are, the palace of Verssulles St Cyr, the church of Invalids, the Facs.de of the Louvre, a most bcautiful modern structure, the Porte St. Dennis, and the church of Gene vieve, the present Pantheon.
Grecian architecture was restored in :F.,ngland u nder the celebrated InigoJ ones, born 1752. His distinguished works at Greenwich, and Covent Gar den, will ever secure him a name among the architects of the highest reputation.
Sir Christopher Wren, an eminent ma thematician and philosopher, as well as an architect of the.first rank, has execu ted many of the finest buildings in Lon don, and other parts of England, in the modern style. St Paul's cathedral, infe rior to none but St. Peter's, in point of magnitude, but perhaps superior both in skilful construction and figuration, will perpetuatb his name to thelatest posteri ty. The exterior dome of St. Paul's is constructed of wood, and sustained by a cone of 18 inch brick-work, which also supports the lantern above.