Excerpt from Hydrodynamics in Deep Aquifers of the Illinois BasinAlthough Hubbert' 5 original ideas have been extended into many areas of investigation, one important problem still needs some study and clarification: the problem of determining the direction and rate of flow of underground waters whose density varies from point to point because of changes in the concentra tions of dissolved solids.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis 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.