AQU 
the grass, and that offer so beautiful an object 
to the eye early in the summer’s morning, 
through the brilliancy of the dew-drops 
formed and suspended on their silken 
threads, and the reflexion of the sun’s rays 
from each, are the work of another species 
pf spiders. 
The different kinds of lice are exceed- 
ingly numerous, almost every kind of ani- 
mal having its particular sort ef vermin. 
They are all carnivorous, or perhaps rather 
sanguivorous insects, living on the blood of 
other animals. Their eggs are all nits. 
The Scorpio genus abound in hot climates, 
and are troublesome in neglected places, 
and where cleanliness is not attended to. 
The crab tribes cast their shells every year, 
and are then in a soft, helpless state, unable 
to make resistance, and therefore at that 
time become the prey of many kinds of 
fish. Their shells afford a principal consti- 
tuent in the formation of chalk-beds, and 
beds of marl, which are formed at the bot- 
tom of .tire sea. Specimens of entire shells are 
frequently met with in chalk-pits which are 
now many miles inland ; and there is little 
doubt, that in a comminated state, they 
form a principal ingredient in most calca- 
reous fearth. Under each genus will be 
found an account of a few of the more re- 
markable species. See Acarus, Aranea, 
Cancer, Scorpio, &c. 
APUS, in astronomy, a constellation of 
the southern hemisphere, placed near the 
pole, between the Triangulum Australe, and 
the Chameleon, supposed to represent the 
bird of paradise. There are four stars of 
the sixth, three of the fifth, and four of the 
fourth magnitude, in the constellation Apiis. 
Dr. Halley, in 1677, observed the longitude 
and latitude of the stars in Apus, which He- 
velius in liis prodromus reduced with some 
alteration to the year 1700. P. Noel has 
also given the places of these stars, with 
their right ascensions and declinations for 
the year 1687, but his observations differ 
widely from those of Dr. Halley. Hevelius 
lias represented the figure of Apus, and its 
stars, in his Firmamentum Sobiescianum, ac- 
cording to Hailey’s account ; Noel has done 
the like according to his own account. 
Wolfius, with what justice we will not pre- 
tend to say, gives the preference to this 
last. 
AQUA fori is. Another name for Nitric 
Acid, which see. This name is applied to 
denote the common nitric acid, used by 
workmen, which often contains a slight por- 
tion of muriatic acid. See Chemistr’v. 
AQU 
Aqua regia, another name for the nitro 
muriatic acid. See Muriatic Acid. 
AQUiEDUCT, a conduit of water, in 
architecture and hydraulics, is a construction 
of stone or timber, built on an uneven 
ground, to preserve the level of water, and 
convey it by a canal, from one place to 
another. Some of these aquseducts are vi- 
sible, and others subterraneous. Those of 
the former sort are constructed at a great 
height, across vallies and marshes, and sup- 
ported by piers and ranges of arches. The 
latter are formed by piercing the moun- 
tains. and constructing them below the sur- 
face of the earth. They are built of stone, 
brick, &c. and covered above with vaulted 
roofs or flat stones, serving to shelter the 
water from the sun and rain. Of these 
aquseducts, some are double, and others 
triple ; that is, supported on two or three 
ranges of arches. Of the latter kind are 
thte Pont-da-gard, in Languedoc, supposed to 
have been built by the Romans to carry 
water to the city of Nismes ; that of Con- 
stantinople, and that which, according to 
Procopius, was constructed by Cosroes, 
King of Persia, near Petra, in Mingrelia, 
and which had three conduits in the same 
direction, each elevated above the other. 
Some of these aquseducts were paved, and 
others conveyed the water through a natu- 
ral channel of clay ; and it was frequently 
conducted by pipes of lead into reservoirs 
of the same metal, or into troughs of hewn 
stone. Aquseducts of every kind were 
reckoned among the wonders of ancient 
Rome; their great number, and the im- 
mense expense of bringing water 30, 40, or 
60, and even 100 miles, either upon con- 
tinued arches, or by means of other works, 
when it was necessary to penetrate moun- 
tains and rocks, may well astonish us. If, 
we consider the incredible quantity of water 
brought to Rome for the uses of the public, 
for fountains, baths, fish-ponds, private- 
houses, gardens and country-seats ; if we 
represent to ourselves the arches constructed 
at a great expense, and carried on through 
a long distance, mountains levelled, rocks 
cut through, and vallies filled up, it must be 
acknowledged that there is nothing in the' 
whole world more wonderful. For 440 
years, the Romans contented themselves 
with the waters of the Tiber, and of the 
wells and fountains in the city and its neigh- 
bourhood. But when the number of houses 
and inhabitants was considerably augment- 
ed, they were obliged to bring water from 
remote places by means of aqueducts'. 
