The archæology of Rome, Part 8

by John Henry Parker

represent the four chambers. The channel of the aqueduct, coming at a tolerably high level, enters the chamber A. Thence the water passed (possibly over a large waste-pipe) into the chamber beneath, B. Between B. and C. there were small holes communicating through the wall (possibly provided with fine grating). Through the roof of C. there was a hole, and the water passed upwards, of course finding the same level in D. at its exit, as in A. at its entrance; on leaving the piscina the water was carried off into another specus. By the aid of sluice-gates the water could be transferred direct from chamber A. to chamber D. Access was obtained by an opening to the chambers beneath, and the mud was from time to time cleaned out. Curious details of the sluices, &c., have been found; but it is not easy to determine their age, as the aqueducts have undergone so many repeated alterations.

As a typical example of the size of the specus, or channel of the Aqueducts, the Marcian may be taken, which measures in the opening five Roman feet in height, two and a-half in breadth, and the thickness of the wall on each of the two sides one foot. The roof of the Marcian being surmounted by the Tepulan and Julian, no great solidity was needed; but so far as can be ascertained, the roofs were generally of considerable thickness, to prevent, as much as possible, the heat of the sun spoiling the coolness of the water. The channels and general structure of the Anio Novus and Claudian were larger in every respect, those of the Tepulan and Julian somewhat smaller, as shewn by the accompanying diagrams.

It will be seen that the period of the construction of the nine aqueducts which have been described, embraces some four centuries, as Frontinus was employed in surveying them towards the close of the first century after Christ, and the first aqueduct was commenced more than three centuries before the Christian era. If we omit the Alsietina, which was on the other side of the river, and which ought scarcely therefore to be taken into account, the order of level follows almost exactly the order of construction, the only exception being that of the Virgo. This increase of height of level as each new aqueduct was added, is pointed out by Frontinus in his eighteenth chapter.

It will be perhaps convenient to have the several aqueducts already described represented in a tabular form, shewing the dates when they were made, and the order as to level, together with the distances which they traversed.

The aqueducts, especially those which were mostly underground, it will be observed, made long detours, as compared with the direct line of road; as, for instance, in the first on the list, the distance by road was but eight Roman miles, but that by the channel of the aqueduct was eleven miles. The total length of all the channels of the aqueducts, constructed in less than four centuries, was upwards of 285.610 Roman miles, of which 242.697 miles were cut beneath the surface, and 42.918 miles carried on substructure, arched or not, as the case required, above the surface of the ground.

DATE.		No.	Order to Level.	NAME.	LENGTH OF CHANNEL.[152]
					Above ground.		Under ground.
					m.	p.	m.	p.
B.C.	312	I.	8th	AQUA APPIA	0	60	11	130
”	263	II.	6th	ANIO VETUS	0	221	42	779
”	145	III.	5th	AQUA MARCIA	7	463	54	247½
”	126	IV.	4th	” TEPULA	7	0	6	0
”	34	V.	3rd	” JULIA	7	0	8	426½
”	21	VI.	7th	” VIRGO	1	240	12	865
”	c. 10	VII.	9th	” ALSIETINA	0	358	21	714
							? in channel
A.D.	33	VIII.	2nd	” CLAUDIA	10	176	36	230
”	33	IX.	1st	ANIO NOVUS	9	400	49	300
Totals according to computation of Frontinus					42	918	242	692

Of the above, six are carried to Piscinæ on the Via Latina.

The three	{	V.	Julia	}	carried from the same reservoir on the same series of arches.
	{	IV.	Tepula	}
	{	III.	Marcia	}
The two	{	IX.	Anio Novus	}	carried on higher arches, which end after the Pallantian gardens.
		VIII.	Aqua Claudia
The one		II.	Anio Vetus, has a reservoir on the Via Latina.—(Fron., c. 19.)