Excerpt from The Smokiness of Oil-Burning Orchard Heaters Visual methods ordinarily used for smoke estimation in industrial regions are not applicable to a study of the smokiness of orchard heaters because of Operation at night and the prevalence of smoke throughout the citrus districts. Four other methods were developed permitting an accurate classification of orchard heaters as to smokiness. Two of these methods classify according to smoke blackness, and two according to smoke weight. 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.