Nitrogen
3 of the 7 encyclopedias on this shelf carry an entry for Nitrogen. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
N., at. wt. 14.01, colorless, odorless, tasteless gas, forming, approximately, four-fifths of the atmosphere. Slightly lighter than the air. Discovered in 1772 by Rutherford, in the University of Edinburgh. It can be prepared by passing air over some reagent which will readily react with and absorb oxygen, such as reduced iron, alkaline, pyrogallol, or phosphorus; or by liquefying air and distilling, when the more volatile nitrogen is vaporized. Nitrogen is found in all vegetable and animal life, usually in organic combination, and in varying quantities in the earth's crust in both organic and inorganic combination. It is a necessary constituent of plant and animal food. Certain legumes have the power of fixing the nitrogen of the air by means of root nodules, and obtain their supply in this way, while electric discharges in the atmosphere cause the union of nitrogen and oxygen, the resulting oxides of nitrogen being washed into the soil by rain. These sources are not sufficient, however, to enrich the soil to the extent needed for intensive cultivation, and by acid. The name is generally restricted far the greater part of nitrogen is added, either in the form of decomposof cotton, which consists of a mixture ing organic matter (barnyard manure, guano, etc.) or inorganic salts (nitrates, ammonium sulphate, etc.). The most commonly used inorganic nitrogenous is petre, NaNO3, but it is believed that the supply of this material will become exhausted in less than forty years. Moreover, nitrogen in the form of nitric acid, nitrates, or ammonia is an important raw material in the manufacture of explosives, dyes, sodium bicarbonate, and other products, while ammonia is widely used for refrigeration. The supply of nitrogen in the atmosphere is practically inexhaustible, the air over every acre of ground being estimated to contain 31,000 tons of nitrogen, and many attempts have been made to manufacture nitro- Three methods have given successful regenous compounds from this source, sults on a manufacturing scale: (1) the formation of ammonia by combining the nitrogen with hydrogen; (2) the formation of oxides of nitrogen by passing an electric arc through air, and (3) , and (3) the formation of cyanan cyanamide by absorbing nitrogen in calcium lcium carbide, heated to white heat in an electric furnace.
Aiton's Encyclopedia (1910)
ni'tro-jen, an important element. In nature it is a gas without color, taste, or odor. It has been converted into a liquid and also frozen. It is a trifle lighter than air, but does not burn; that is to say, it does not combine readily with oxygen. If it did our atmosphere would burn up, for air is a mixture of seven parts of nitrogen to two of oxygen, or, to be more exact, seventy-nine to twenty-one by volume, and seventy-seven to twenty-three by weight. Nevertheless, nitrogen forms five distinct compounds with oxygen. Of these the most noted is nitrous oxide or laughing gas. It is made up in the ratio of two atoms of nitrogen to one of oxygen. Since 1844 laughing gas has been administered by surgeons and dentists. By inhaling this gas a patient becomes unconscious and insensible to pain. Nitric acid is a compound of hydrogen, nitrogen, and oxygen. It is a strong, yellowish, disagreeable, acrid acid. It is often called aqua fortis or strong water, because it eats or dissolves metals with avidity. Nitric acid is used in etching steel and copper, in dissolving, tin, in dyeing, in assaying, in small quantities as a medicine, and as a caustic. It is present in delicate perfumes and vile odors, aniline dyes, medicines and poisons, dynamite, and gunpowder. Nitrogen is an essential element of animal and plant life. Plants derive nitrogen from the air or from the soil. The human body secures the needful amount from nitrogenous foods, especially milk, eggs, cheese, beans, peas, lean meat, and oatmeal. See Ammonia ; Clover ; Nitroglycerin ; Saltpeter ; Gunpowder ; Photography ; Etching
The Encyclopedia of Founding (1892)
A gas discovered by Rutherford in 1772. It is extensively diffused in nature, forming about four fifths of the atmosphere, in which it plays the important part of diluting the oxygen and adapting it to the conditions of life. It is an important element of the vegetable kingdom, entering in considerable quantity into many of its compounds. It is supplied to plants by ammonia and nitric acid. Our food is largely composed of nitrogen, and it forms 16 per cent of the tissues of the animal body. Nitrogen is not found in any of the mineral formations of the earth's crust, except in some varieties of coal. See ATMOSPHERE; OXYGEN; AMMONIA.