This comparative map of rivers (A Map of the Principal Rivers Showing Their Courses, Countries, and Comparative Lengths) was intended to relate the size and scale of the world�s major rivers at a glance. The map arranges the rivers not by size but by the orientation of the river mouths. For example, this puts the Colorado River right beside the Congo River. West flowing rivers are found on the right side; south flowing rivers are found at the top of the map; east flowing rivers are on the left; and north flowing rivers are at the bottom. A dozen rivers that couldn�t fit into the main circle are put up in the top corners.