Excerpt from Heat Transmission in Boilers, Condensers, and Evaporators It would hardly be necessary to enlarge upon the expensive nature Of boiler experiments. With regard to the measurement of gas temperatures, it might be said that, even in the case Of large boilers, it is the common practice to measure the ue gas temperature by a single thermometer, having the bulb well inserted into the current of gas. Except when the boiler works lightly, such a position is probably sufficient to get an average temperature reading, seeing that the ow of gases is usually more or less turbulent. Quite apart from thermometer errors, however, there is one source of error which is nearly always neglected, and that is, the in uence of radiation from or to the thermometer bulb or cover. Usually the thermometer, whatever its type, is placed where it is more or less subject to the radiations from the comparatively cold boiler tubes or drums, which causes it to read below the true temperature of the gas. Some examples of this are given on p. 18 of Heat Transmission by Radiation, Conduction, and Convection. 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."