Excerpt from Vertical Farming The Part Played by Water. - Much rock material is slowly dissolved out and carried away by rain water. This is usually carried long distances before being thrown back into a solid state by the evaporation of the water, or by coming into con tact with some other substance that causes it to be precipitated. Often this reforms into another rock that may be harder than the original one. 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.