Excerpt from The Ventilation of TunnelsSources OF foul air The sources of foul air are various. During construction noxious gases arise from.the lamps and torches used to light the interior of the tunnels where electric plants are not used for lighting. The respirations of men and beasts also cause objectionable odors. However, the principle source of noxious gases is blasting, and the fumes that arise from.the exp plosives are so dense that they must be cleared from.the working face before the men are able to resume their work.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.