Excerpt from The Farmer's Miscellany and Agriculturist's Guide: Treating Upon the Gases, Salts, Atmosphere, Manures, Seeds, Hot Beds, Grasses, Grains, Vegetables, Fruits, Gardening, Grafting, Pruning, and Animals; With Form of Agreement With Laborers, and a Great Variety of Useful Agricultural Matter Gas is an elastic fluid, or air, usually invisible, having a specific gravity or weight in some cases heavier, and in others lighter, than common or atmospheric air. Gases exist in nature, and are produced by artificial means; some are capable of being respired without injury to health, while others can not be taken into the lungs without producing fatal effects. Gases are supposed to be produced by the union of some substance with caloric or heat; some of them can be condensed into liquids by cold or pressure, and others can not by any means known. The principal gases necessary to be described here, are oxygen, hydrogen, nitrogen, carbonic acid, and ammonia. Oxygen is an invisible transparent fluid, without taste or odor, respirable, slightly heavier than common air, and having the most universal affinity of all known substances. It combines with the metals forming oxides and acids; it is combustible and a supporter of combustion; it is indispensable to animal life and the growth of plants, and supports the combustion of all fires. It exists in vast quantities in nature, and may be obtained by chemical process from several substances, most easily perhaps from black oxide of manganese. Hydrogen gas is the lightest of all known substances, being fourteen times lighter than common air; having no taste, color, or odor, combustible, but not a supporter of combustion; incapable of sustaining animal life, but destitute of poisonous properties. This gas was formerly used for filling air-balloons, but is now superseded by coal gas. It may be obtained by the action of sulphuric acid (oil of vitriol) on zinc. Nitrogen gas is widely diffused in nature; it constitutes about four fifths of the atmosphere, and unites with a great variety of other bodies; it is destitute of color, taste, or odor; a little lighter than common air; not a supporter of combustion or animal life, but, like hydrogen, not poisonous. It exists in all animal substances and many vegetables; it may be obtained from phosphorus. 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.