Excerpt from Progressive Furnace Heating: A Practical Manual of Designing, Estimating and Installing Modern Systems for Heating and Ventilating Buildings With Warm Air If you want to ventilate your room to warm it, and open the bottom aperture, you will succeed in both; because the fresh air will be the warmest, and will not stop until it comes in contact with the ceiling, where spreading out in a level strata over the whole ceiling, it will keep its relative position to the whole body until it reaches the bottom and passes out through the aperture. If we want to ventilate our room to cool it, we must let the air out at or near the top. 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.