Encyclopaedia Britannica > Volume 3, Anatomy-Astronomy

336 A Q U E
Aqueduct, ber of arches, and enough to give an idea of the ex-
tent of the whole. It extended across the Moselle, a
very considerable river, and very broad in this place ; and
served to convey the delicious waters of the Gorse to the
city of Metz. These waters, according to Meuripe, in his
history of the bishops of Metz, printed in 1634, were so
abundant that they furnished water for floating the ves¬
sels every time that a naval fight was to be exhibited.
They were collected into a reservoir, and from thence con¬
ducted by subterraneous canals constructed of hewn stone,
and so spacious that a man could easily walk in them up¬
right. They then passed the Moselle by means of the
aqueduct, which was situated about six miles from Metz,
and from thence were conducted under ground in stone
channels, similar to the others, to the city, to the baths, to
the place of the sea-fight, and all over the city. Judging
from the drawing, this aqueduct seems to have been
nearly 1000 feet in length, the arches 50 feet high at the
deepest part, and 50 in number. They formed only one
series, the height not requiring a double row. Theywrere
so well built and cemented together, that, excepting the
middle part, which the descent of ice down the river has
in the lapse of ages carried away, they have resisted, and
will continue to resist, the effects of time and of the most
violent seasons.
The Pont du Gard was executed by the Romans in the
reign of Augustus, and wras then merely an aqueduct for
bringing the waters of the fountain of Hure to Nismes.
It was composed of three rows of arches filling up the
valley between two mountains, between which ran the
river Garden. The first row comprehended six arches, each
60 feet span, excepting one, which was the largest, and
was 75 feet span; the second row contained 12 arches
of the same span as the first; and the third had 36 little
arches, on the top of which was the channel for con¬
ducting the water. This bridge exhibits a decided im¬
provement and superiority over all the other Roman
aqueducts, in the lightness and striking boldness of its
design. The arches are wider, and the piers in proportion
lighter, than any other structure of the kind previously
constructed; and had the same principle been extended
so as to have formed only a single row from top to bottom,
it would have equalled in the skill and disposition of its
materials (circumstances in which the Roman works were
almost universally wanting) any of the more judicious and
elegant structures of modern times. About the year
1740, this bridge, being of no more use as an aqueduct,
was converted into a road-way, by widening it, or rather
building in a manner another bridge to the side of it,
having all the arches of the same span and dimensions.
The execution of the work was attended with consider¬
able difficulties, but these were all successfully overcome
by the French engineer Pitot.
The aqueduct of Segovia, according to Culmenares,
who travelled in Spain, and has written the history of
Segovia, may be compared with the most wonderful works
which antiquity has transmitted to us. There still re¬
main of it 159 arches, all built with large stones, and with¬
out any cement. There are two rows of arches, one above
the other, and the whole height of the edifice is 102 feet.
It runs quite across the town, and passes over the greater
part of the houses which lie in the hollow.
French In modern times various aqueducts have been formed
Aqueducts. after the manner of the Romans, particularly in France.
The most remarkable are those which were constructed in
the reign of Louis XIV., at vast expense, for conducting
water from Marly to Versailles. Of these the famous aque¬
duct bridge of Maintenon, which was erected for conveying
the waters of the river Eure to Versailles, is without doubt,
in point of magnitude and height, the most magnificent
DUCT.
structure of the kind in the world. In Plate XLV. we Aqueduct,
have given a view of a portion of this work, on the same
scale as the other aqueducts here represented. Had the
whole been delineated on the same scale, it would have
extended to four times the breadth of the plate. It ex¬
tends about 4400 feet in length, being nearly seven
eighths of a mile, and upwards of 200 feet in height, and
contains 242 arcades, each divided into three rows, form¬
ing in all 726 arches about 50 feet span. Of the subter¬
ranean aqueducts in France the finest is that of Arcueil,
which serves to conduct water to that village. It is 44,300
feet in length, or upwards of eight miles, extending from
the valley of Arcueil to the castle at the gate of S't
Jaques, all built of hewn stone. It is about six feet in
height, and has on each side a foot-path 18 inches wide;
it has a declivity of one foot in 1300. Another aqueduct
of this kind is that of Rocquancourt, part of the system
which brings water to Versailles; it is 11,760 feet in length,
or upwards of two miles, and a declivity in its whole course
of only three feet. In some parts of its course it was
necessary to make excavations 80 or 90 feet deep, which
rendered the execution very difficult.
The great waterworks that supply the city of Marseilles
with the water of the Durance, by a canal about 60 miles
in length, are among the boldest undertakings of the kind
in modern times. This canal, begun in 1830, and not yet
completed (1852), has already cost above L.2,000,000 ster¬
ling. It is conveyed through three chains of limestone
mountains by forty-five tunnels, forming an aggregate length
of 877 miles, and across numerous valleys by aqueducts ; the
largest of which, the Aqueduct of Roquefavour, over the
ravine of the River Arc, about 5 miles from Aix, surpasses
in size and altitude the ancient Pont du Gard. The im¬
mense volume of water, which passes at the rate of 198,000
gallons per minute, is carried across as in the old Roman
aqueducts by a channel of masonwork. The height of this
aqueduct is 262 feet, and its length 1287. The number of
cubic yards of masonry contained in it is 57,000; the total
cost has been L.151,394.
One other aqueduct of recent construction is worthy of Aqueduct
notice. In those parts of British India where the fall of of the
rain is scanty and uncertain, recourse is had to artificial irri- Ganges,
gation, and the waters of many of the rivers of the country
have been rendered available for this purpose by means of
public works constructed by the government. Of these the
most important is the Ganges Canal, which traverses the
north-western provinces of Bengal, and distributes over their
vast area nearly the whole volume of the waters of the Gan¬
ges. See Ganges. The canal begins at the point where
the river issues from the mountains and enters the plains of
Bengal. About twenty miles from its source, the line of
the canal crosses the valley of the Solani River, and the
works for effecting the transit are designed on a scale worthy
of the undertaking. The valley is between two and three
miles in width. An earthen embankment is carried across,
raised on an average between 16 and 17 feet above the sur¬
rounding country, and having a width of 350 feet at its base,
and 290 feet in the upper part. This embankment forms
the bed of the canal, which is protected by banks 12 feet in
depth and 30 feet wide at the top. To preserve these banks
from the effects of the action of the water, lines of masonry
formed into steps extend on each side throughout their en¬
tire length. The Solani River is crossed by an aqueduct
920 feet long, having side walls 8 feet thick and 12 deep,
the depth of the water being 10 feet. The water of the
canal passes through two separate channels. That of the
River Solani flows under fifteen arches, having a span of
50 feet each, constructed in the most substantial manner and
springing from piers resting on blocks of masonry sunk into
the bed of the river. The cost of the aqueduct was upwards