however weighty and impetuous, were resisted by the solidity of the mass and the harmony of the parts; but the slightest touch would precipitate the fragments of arches and columns, that already nodded to their fall. [Footnote 6: Liber de Mirabilibus Romæ ex Registro Nicolai Cardinalis de Arragoniâ in Bibliothecâ St. Isidori Armario IV., No. 69. This treatise, with some short but pertinent notes, has been published by Montfaucon, (Diarium Italicum, p. 283--301,) who thus delivers his own critical opinion: Scriptor xiiimi. circiter sæculi, ut ibidem notatur; antiquariæ rei imperitus et, ut ab illo ævo, nugis et anilibus fabellis refertus: sed, quia monumenta, quæ iis temporibus Romæ supererant pro modulo recenset, non parum inde lucis mutuabitur qui Romanis antiquitatibus indagandis operam navabit, (p. 283.)] [Footnote 7: The Père Mabillon (Analecta, tom. iv. p. 502) has published an anonymous pilgrim of the ixth century, who, in his visit round the churches and holy places at Rome, touches on several buildings, especially porticos, which had disappeared before the xiiith century.] [Footnote 8: On the Septizonium, see the Mémoires sur Pétrarque, (tom. i. p. 325,) Donatus, (p. 338,) and Nardini, (p. 117, 414.)] After a diligent inquiry, I can discern four principal causes of the ruin of Rome, which continued to operate in a period of more than a thousand years. I. The injuries of time and nature. II. The hostile attacks of the Barbarians and Christians. III. The use and abuse of the materials. And, IV. The domestic quarrels of the Romans. I. The art of man is able to construct monuments far more permanent than the narrow span of his own existence; yet these monuments, like himself, are perishable and frail; and in the boundless annals of time, his life and his labors must equally be measured as a fleeting moment. Of a