Excerpt from A Preliminary Study of Chemical Denudation The African material is very scanty. In addition to the figures already cited for the Nile, with a drainage area estimated at square miles, I have found only analyses of three small Algerian rivers which exhibit all the peculiarities of waters from other semi-arid districts. Ignoring the latter I shall estimate that square miles in Africa are represented by the Nile with the denudation factor of 16 tons. I shall also assume that square miles are fairly equivalent in character to South America, with the same composition of the waters and the same denudation factor of 50 tons. The desert regions, like the Sahara, of course count for nothing. Analyses of water from the Niger, Congo, Orange, and Zambesi are much needed. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.