1902 Encyclopedia > Rome > Roman Topography and Archaelogy - Introduction

(Part 20)




Rome is situated (41° 53' 52" N. lat, 12° 28' 40" E. long.) on the banks of the Tiber, Italy, 14 miles from its present mouth, in a great plain of alluvial and marine deposit, broken into elevations by numerous masses of volcanic matter. The nine or ten hills and ridges on which the city stands are formed of masses of tufa or conglomerated sand and ashes thrown out by neighbouring volcanoes now.i?xtinct, but active down to a very recent period. One group wMtiese volcanoes is that around Lago Bracciano, while another, still nearer to Rome, composes the Alban Hills. That some at least of these craters have been in a state of activity at no very distant period has been shown by the discovery at many places of broken pottery and bronze implements below the strata of tufa or other volcanic deposits. Traces of human life have even been found below that great flood of lava which, issuing from the Alban Hills, flowed towards the site of Rome, only stopping about 3 miles short, by the tomb of Cecilia Metella.


The superficial strata on which Rome is built are of three main kinds : (1) the plains and valleys on the left bank of the Tiber are covered, as it were, by a sea of alluvial deposit, in the midst of which (2) the hills of volcanic origin rise like so many islands ; and (3) on the right bank of the Tiber, around the Janiculan and Vatican Hills, are extensive remains of an ancient sea-beach, conspicuous in parts by its fine golden sand and its deposits of greyish white potter's clay. From its yellow sand the Janiculan has been sometimes known as the Golden Hill, a name which survives in the church on its summit called S. Pietro in Montorio (Monte d'Oro). In addition to these three chief deposits, at a few places, especially in the Aventine and Pincian Hills, understrata of travertine crop out—a hard limestone rock, once in solution in running water, and deposited gradually as the water lost its carbonic-acid solvent, a process still rapidly going on at Terni, Tivoli, and other places in the neighbourhood. The conditions under which the tufa hills were formed have been very various, as is clearly seen by an examination of the rock at different places. The volcanic ashes and sand of which the tufa is composed appear in parts to lie just as they were showered down from the crater ; in that case it shows but little sign of stratification, and consists wholly of igneous products. In parts time and pressure have bound, together these scoria? into a soft and friable rock ; in other places they still lie in loose sandy beds and can be dug out with the spade. Other masses of tufa again show signs either of having been deposited in water, or else washed away from their first resting-place and redeposited with visible stratifications; this is shown by the water-worn pebbles and chips of limestone rock, which form a conglomerate bound together by the volcanic ashes into a sort of natural cement. A third variety is that which exists on the Palatine Hill. Here the shower of red-hot ashes has evidently fallen on a thickly-growing forest, and the burning wood, partly smothered by the ashes, has been converted into charcoal, large masses of which are embedded in the tufa rock. In some places charred branches of trees, their form well preserved, can be easily distinguished. The so-called " wall of Romulus " is built of this conglomerate of tufa and charred wood ; a very perfect section of the branch of a tree is visible on one of the blocks by the Scalfe Caci.

Physical Changes in Site

So great have been the physical changes in the site of Rome since the first dawn of the historic period that it is difficult now to realize what its aspect once was. The Forum Romanum, the Velabrum, the great Campus Martins (now the most crowded part of modern Rome), and other valleys were once almost impassable marshes or pools of water (Ov., Fast., vi. 401 ; Dionys., ii. 50). The draining of these valleys was effected by means of the great cloacae, which were among the earliest important architectural works of Rome (Varro, Ling. Lat., iv. 149). Again, the various hills and ridges were once more numerous and very much more abrupt than they are now. At an early period, when each hill was crowned by a separate village fort, the great object of the inhabitants was to increase the steepness of its cliffs and render access difficult. At a later time, when Rome was united under one government, the very physical peculiarities which had originally made its hills so populous, through their natural adaptability for defence, became extremely inconvenient in a united city, where architectural symmetry and splendour were above all things aimed at. Hence the most gigantic engineering works were undertaken : tops of hills were levelled, whole ridges cut away, and gentle slopes formed in the place of abrupt cliffs. The levelling of the Velia and the excavation of the site for Trajan's forum are instances of this. The same works were continued in the Middle Ages, as when in the 14th century an access was made to the Capitoline Arx from the side of the Campus Martius ; up to that time a steep cliff had prevented all approach except from the side of the Forum. And under the present Government an even more extensive plan, called the "piano regolatore," is being (1886) gradually carried out, with the object of reducing hills and valleys to one uniform level, on which wide boulevards are being constructed on the chess-board plan of an American city. The constant fires which have devastated Rome have been a great agent in obliterating the natural contour of the ground. The accumulated rubbish from these and other causes has in some places covered the ground to the depth of 40 feet, especially in the valleys.

Climate and Health

The climate of Rome in ancient times appears to have been colder than it is at present. Malarious fever in and around the city existed to some extent, but to a much less degree than it does now. The magnificent villa of Hadrian and other country houses near Rome are built on sites which are now very unhealthy. The sanitary superiority of the Campagna in ancient times was mainly due to its more complete drainage and thicker population. That fever did exist is, however, proved in many ways. Altars to the goddess Febris were erected on the Palatine and other hills, and on the Esquiline was a grove dedicated to Mephitis. The population of Rome increased with great rapidity, till, during its most populous period in the 4th century, it was probably not less than 2 1/2
millions. 2


The limited space available for the following article is devoted mainly to those buildings of which some remains still exist, to the unavoidable neglect of a large number which are known only from documentary evidence. The plan of the Forum (Plate VII.) and nearly all the cuts have been measured and drawn by the author specially to illustrate this article.

By the great flight of marble steps up to S. Maria in Ara Coeli

See a good article on this subject in the Monografia di Roma, vol. ii., 1878.

Works to be consulted.— GEOLOGY.—Brocchi, Suolo di Roma, 1820, and its supplement by Ponzi, Storia fisica di Roma, 1867 ; Mantovani, Descrizione geologica delta Campagna di Roma, 1875 ; Giordano and Mantovani, Monografia di Roma, 1878, vol. i. pp. i.-exxiii., and pp. 51-79 ; Mauro, Analisi cliimica delle ague potabili di Roma, 1884; Pinto, Ague potabili mil' Agro Romano, 1883. BOTANY AND ZOOLOGY.—Bonaparte, Fauna Italica, 1835 ; Sanguinetti, Prodromus Floras Romanes ; Deakin, Flora of the Colosseum, 1855 ; Terrigi, "Flora, &c, del Quirinale," in Acad. Pont. d. Lincei, May 1882

Read the rest of this article:
Rome - Table of Contents

About this EncyclopediaTop ContributorsAll ContributorsToday in History
Terms of UsePrivacyContact Us

© 2005-23 1902 Encyclopedia. All Rights Reserved.

This website is the free online Encyclopedia Britannica (9th Edition and 10th Edition) with added expert translations and commentaries