Excerpt from Handbook of Mechanical Refrigeration Pressures - Pressures may be measured in inches of water, or of mercury, in atmospheres, or in kilograms per square centimeter. The custom in the United States is to use as a unit the pound per square inch. The ordinary gage records in pressures above the atmosphere, so that the absolute pressure is obtained by adding to the gage reading the equivalent Of the atmospheric pressure. Heat - It has been found by experiment that if two bodies of different temperature are placed near one another heat will flow from the hotter to the colder body until finally the same temperature is attained by each. The heat in a body may be sensible heat (indicated by its hotness or lack Of hotness) or it may be latent heat, a term used to denote the change of aggregation of the molecules such as is evident when the substance changes from a solid to a liquid, from a liquid to a gas, or vice versa. The unit of heat is taken as the British thermal unit which is defined as fi' of the amount Of heat required to raise one pound Of water from 32 to 212 deg. F. 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.