Climate.
The subject of the climate of Rome is naturally connected with that of the nature of the soil and configuration of the hills and valleys.
It is not difficult to see why the peculiar geological formation of the Campagna proves, without careful drainage, extremely deleterious to health. We have there a district containing numerous closed valleys and depressions in the soil without outlet for the waters which naturally accumulate. The tufa which composes the surface seems commonly to take the shape of isolated hills with irregular hollows between them, so as to impede the formation of natural watercourses. Under this tufa is a quantity of marl and stiff clay, which retains the water after it has filtered through the tufa, and sends it oozing out into the lower parts of the country, where it accumulates, and, mixed with putrescent vegetable matter, taints the surrounding atmosphere. A want of movement in the air caused by the mountainous barriers by which the Campagna is enclosed is another source of malaria.
The sites of Veii, Fidenæ and Gabii, once the rivals and equals of Rome are now entirely deserted except by a few shepherds and cattle stalls. Along the coast stood Ardea, Laurentum, Lavinium and Ostia, all of them towns apparently with a considerable number of inhabitants. Of these Ostia is now a miserable village, Ardea contains about sixty inhabitants, while Laurentum and Lavinium are represented by single towers. During a part of the year the ancient Roman nobility lived in great numbers on these very shores now found so deadly. Pliny the younger describes the appearance of their villas near Laurentum as that of a number of towns placed at intervals along the beach, and he writes an enthusiastic letter in praise of the salubrity and convenience of his own house there.[124] Lælius and Scipio used to make the seaside at Laurentum their resort, and to amuse themselves there with collecting shells.[125] Nor was it only on the seacoast that the country villas were placed. Six miles from Rome on the Flaminian Road, at the spot now called Prima Porta, there stood a well-known country house belonging to the Empress Livia, part of which has lately been excavated.[126] This was a highly decorated and commodious house, as the rooms which have been discovered, in which was found a splendid statue of Augustus, and the busts of several members of the imperial family, amply testify. The views from this spot over the Campagna and the Sabine Hills are most lovely, but the contrast between the beauty of nature and the haggard and fever-stricken appearance of the modern inhabitants is melancholy enough. A few squalid houses occupied by agricultural labourers stand by the roadside. Among their tenants not a single healthy face is to be seen, and even the children are gaunt, hollow-cheeked, and sallow in complexion. No wealthy Roman would now consent to live on the site of Hadrian’s stately villa in the Campagna near Tivoli. Tivoli itself, which Horace wished might be the retreat of his old age, and which was celebrated as a healthy place in Martial’s time, has now lost its reputation for salubrity, and is known as—
Tivoli di mal conforto,
O piove, o tira vento, o suona amorto.
Strabo speaks of the now desolate district between Tusculum and Rome as having been convenient to live in. But there is no need to multiply proofs which might be gathered from all sides of what is an acknowledged fact, that the malarian fevers of the present day were not nearly so deadly in the classic times of Rome, or even in the Middle Ages. The troops of labourers who, fearing to pass the night in the country, are met returning to Rome every evening, the forsaken towers and buildings which stand rotting everywhere about the Campagna, all tell the same tale of a pestilence-stricken district.
The peculiar physical features of the district have had no little influence in determining the mode in which the population was grouped in ancient times. Everywhere we find the hills of Rome reproduced on a reduced scale. Small isolated flat-topped hills, irregularly divided by deeply cut watercourses, and edged with steep low cliffs, afford numerous sites for the settlement of limited independent communities. Such are the hills on which Laurentum, Lavinium, Fidenæ Antemnæ, Ficulea, Crustumerium and Gabii stood, and similar places abound in many parts of the district. Such hills afforded suitable sites for the small fortified towns with which ancient Latini was thickly studded. Their sides can be easily scarped so as to afford a natural line of defence, and they are in general fairly supplied with water from numerous land springs.
Thus, although the general aspect of the Campagna is that of a plain country, yet the main level of its surface is broken by numerous deep gullies and groups of hillocks.
The tertiary marine strata, already described as forming the Janiculum and other hills upon the right bank of the Tiber, do not rise to the surface in the Campagna, except on the flanks of the Æquian and Sabine hills. These hills themselves consist of great masses of Apennine limestone jutting out here and there into the spurs upon which some of the more considerable cities of the Latin confederacy stood, as Tibur, Præneste, Bola and Cameria.
The Alban Hills form a totally distinct group, consisting of two principal extinct volcanic craters somewhat resembling, in their relations to each other, the great Neapolitan craters of Vesuvius and Somma. One of them lies within the embrace of the other, just as Vesuvius lies half enclosed by Monte Somma. The walls of the outer Alban crater are of peperino, while those of the inner are basaltic. Both are broken away on the northern side towards Grotta Ferrata and Marino, but on the southern side they are tolerably perfect.