Carbon
3 of the 7 encyclopedias on this shelf carry an entry for Carbon. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
one of the important chemical elements. Pure carbon occurs in two widely different forms, the diamond and graphite or plumbago. Charcoal, soft coal, and hard coal are largely carbon. The purer the carbon, the better the quality of the coal. Under ordinary circumstances carbon is an inactive element. A piece of charcoal, or graphite, or a diamond will lie for ages in ordinary water unchanged. They are without taste or odor and cannot be melted; yet under favorable conditions carbon is distinguished for the number of chemical combinations into which it enters. Carbon is the great fuel. Under the influence of heat it burns; that is, it unites with oxygen and disappears in a gas. In coal, kerosene, gas, oil, fat, lard, tallow, suet, blubber, wood, or any form of fuel whatever, carbon is the element which burns and, uniting with oxygen, gives heat and light. Carbon is an important and indispensable part of animal and plant life. Any substance that chars with heat contains carbon. Charcoal is merely the carbon of wood left behind when the volatile parts of the wood are evaporated by heat. A black char of carbon may be obtained from any flesh or vegetable substance by driving off the other substances by heating. Black as carbon is, it is an important part of all the grains. Green grass, hay, sugar, starch, alcohol, limestone, marble, and chalk contain carbon. It is present in tea, coffee, bread, wine, vinegar, milk, and in almost every article, especially fatty articles of food. A trace is present in all spring water, and mineral waters of note contain considerable quantities of carbon. See Diamond ; Coal ; Charcoal ; Sugar ; Oil ; Food ; Carbon Dioxide ; Bone Black; Filter
Collier's New Encyclopedia (1921)
a tetrad, non-metallic element, symbol C. At. At. wt., 12. Carbon occurs in three allo allotropic forms-two crystalline (diamond and graphite), and Diamond one amorphous (charcoal). crystallizes in forms belonging to the regular system. It is transparent, either colorless, or yellow, pink, blue, or green. The hardest substance known, refracts light strongly, is infusible, but is burned into CO2 in oxygen gas at white heat. Sp. gr., 3.5. It is a non-conductor of electricity. It is found in gravel in India, Brazil, etc. Graphite crystallizes in six-sided prisms. Sp. gr., 2.3. It is gray-black, with a metallic luster. It is a good conductor of electricity. Graphite often separates in scales from molten iron; it is used for lead pencils; it is often called black-lead. Amorphous carbon occurs more or less pure in lampblack, wood charcoal, coal, coke, and animal charcoal. Sp. gr., from 1.6 to 2. It is porous, absorbs gases, removes color from organic liquids, is used as a disinfectant, and burns in the air at red heat, forming CO2. When boiled with H2SO4, it is oxidized to CO, and SO₂ is also formed, which escape in gas used as a reducing agent. Carbon forms two oxides with oxygen, CO and CO2, carbonic oxide and carbonic anhydride. The compounds of this element are more numerous than those of all the other elements taken together. With hydrogen 345. especially it forms a very large number of compounds, called hydrocarbons, which are possessed of the most diverse properties, chemical and physical. With oxygen, carbon forms only two compounds, but union between the two elements is easily effected. It is one of the regular and most characteristic constituents of both animals and plants.
The Encyclopedia of Founding (1892)
A simple combustible, which constitutes a large proportion of all animal and vegetable substances. We are familiar with it in the diamond, and the various kinds of charcoal, mineral coal, lampblack, etc. Carbon unites with all the simple combustibles. With iron it forms steel and plumbago, and with copper it forms a carburet. The diamond is the purest form of carbon. See DIAMOND; GRAPHITE; CHARCOAL; CAST IRON; STEEL.