Quodsi caput habeat libramenta ad moenia montesque medii non fuerint altiores, ut possint interpellare, sed intervalla, necesse est substruere ad libramenta, quemadmodum in rivis et canalibus.
If from the fountain head there is a fall to the city, and the intervening hills are not so high as to interrupt the supply, and if there are valleys, we must build up the pipes to a level as in the case of open channels.
final_alignments\Vitruvius_Architecture_Book_8.json