WATER STORAGE AND CANALIZATION. 315 
age of hills nearly bordering on the Black Sea, from 
hich they supplied large covered cisterns in Constantinople 
a 
. thick. 2 feet from the base iron ties were inserted at intervals 
_ 030 inches, to hold the side walls together and prevent outward 
4 syphon, which rested on masonry piers, which afterwards con- 
ce dueted it to the palace. The Nismes conduit, constructed in the 
ver 
Seville, Evora, and Lisbon, 
i sed deep 
*$ an hour, and in its course it crosses SeV: 
aol Targe lakes 
of enormous dykes. It is available both for navigation 
