Rivers And Oceans. The basin of the Thames covers 5,500 square miles ; of the Rhine. 89,000; Euphrates and Tigris, 243,000 ; Brahma Pootra, 270,000; Nile, 707,000; Danube, 312,500; Indus, 410,000; Ganges, 443,000; Volga, 653,000; Yang-tse-kiang, 742,000 ; Mississippi, 1,101,000 ; Plata, 1,560-000; Amazonas, 1,920,000. These and hundreds of minor rivers are unceasingly replenishing the waters of the ocean, and thus pursue that uninterrupted round of interchange which characterizes all creation. In round numbers it may be considered that the ocean surface is equal to 160,000,000 square miles, and the earth's surface to 40,000,000.