its length. yards. T'he question has been considered The models shown in the illus- ever since the time of the Romans, trations give an idea of the different who tried to pass around the rocky types of boats used in the exe- bank called the Prigrada by con- cution of this great work. It was… … forms. In some of these, rapids and are made strong enough not
Internet Archive · Public domain (published before 1931). Free to use for anything.
