AQU 



served the longitude and latitude of the 

 Mars in Apus, which Hevelius in his pro- 

 Iromus 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 has 

 represented the figure of Apus, and its 

 stars, in his Firmamentum Sobiescianum, 

 According to Halley's account; Noel has 

 'lone the like, according to his own ac- 

 count. Wolfius, with what justice we will 

 not pretend to say, gives the preference 

 to this last. 



AQUA fortit. Another name for NI- 

 TRIC ACID, which see. This name is 

 applied to denote the common nitric acid 

 used by workmen, which often contains a 

 slight portion of muriatic acid. See CHE- 



MISTBT. 



Aai'A regia, another name for the nitro 

 muriatic acid. See MCBIATIC ACID. 



AQUJEDUCT, a tonthdt of water, in 

 architecture and hydraulics, is a construc- 

 tion 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 aquxducts are 

 visible, and others subterraneous. Those 

 of the former sort are constructed at a 

 great height, across vallies and marshes, 

 and supported by piers and ranges of 

 arches. The latter are formed by pierc- 

 ing the mountains, and constructing them 

 below the surface 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 

 :md rain. Of these aquxducts, some are 

 double, and others triple ; that is, sup- 

 ported on two or three ranges of arches. 

 Of the latter kind are the Pout-du-gard, 

 i n Languedoc, supposed to have been built 

 by the Romans to carry water to the city 

 of Nismes ; that of Constantinople, and 

 that which, according to Procopius, was 

 constructed by Cosroes, King of Persia, 

 near Petra, in Mingrclia, and which had 

 three conduits in the same direction, each 

 elevated above the other. Some of these 

 aquxducts were paved, and others con- 

 veyed the water through a natural chan- 

 nel of clay : and it was frequently con- 

 ducted by pipes of lead into reservoirs of 

 the same metal, or into troughs of hewn 

 stone. Aquxducts 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 

 continued arches, or by means of other 



AQU 



works, when it was necessary topenetratc 

 mountains and rocks, may well ; 

 us. If we consider the incredible quan- 

 tity of water brought to Rome for the uses 

 of the public, for fountains, baths, fish- 

 ponds, private houses, gardens and coun- 

 try-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 acknow- 

 ledged 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 

 andfountains in the city audits neighbour- 

 hood. But when the number of houses 

 and inhabitants was considerably augment- 

 ed, they were obliged to bring water from 

 remote places by means of aquxducts. 

 Even Tiberius, Claudius, Caligula, and 

 Caraccalla, though in other respects not 

 of the best character, took care of the 

 city in this useful article. There are still 

 to be seen in the country about Rome 

 wonderful remains of the ancient aqux- 

 ducts, some elevated above the ground by 

 arches continued and raised one above 

 the other, and others subterraneous, pass- 

 ing through rocks ; such is that seen at 

 Vicovaro, beyond Tivoli, in which a ca- 

 nal pierces a rock to the extent of more 

 than a mile, and about five feet deep and 

 four broad. At certain distances vents 

 were provided, so that the water which 

 was accidentally obstructed in its passage, 

 might be discharged till its ordinary pas- 

 sage was cleared ; and in the canal of the 

 aquxduct itself there were cavities, into 

 which the water was precipitated, and 

 where it remained till its mud was depo- 

 sited; and ponds, in which it might purify 

 itself. In the construction of these aqux- 

 ducts, there was a considerable variety 

 that called the Aqua Martia had an arch of 

 sixteen feet in diameter; it was construct - 

 edof three kinds of stone, and was formed 

 with two canals, one above the other. The 

 most elevated was supplied by the wa- 

 ters of the Tivcrone, and Anionovus; the 

 lowest by the Claudian water. The entire 

 edifice was 70 Roman feet high. The arch 

 of the aquxduct, which brought to Rome 

 the Claudian water, was constructed of 

 beautiful hewn stone. This is represent- 

 ed t>y Pliny as the most beautiful of all 

 that had been built for the use of Hume. 

 It conveyed the water through a vaulted 

 canal, through the distance of 40 miles, 

 and was so nigh, that it supplied all tin- 

 hills oft lie city. According to him, and 

 the computation of Bud xus, the charge of 

 this work amounted to 1,385,500 crowns. 



