Uranium
3 of the 6 encyclopedias on this shelf carry an entry for Uranium. All 3 are reproduced below, so you can see where they agree and where they differ.
The Encyclopedia of Founding (1892)
A metal found in a few minerals, as pitchblende, which is an oxide, and uranite, which is a phosphate. The former is its principal ore. The metal, according to the process by which it is obtained, is either in fused white malleable globules or in a black powder. It is used for imparting a yellow tint to glass. See METALS. Vacuum denotes a space empty or devoid of all matter. When air is removed from a vessel with an air-pump a vacuum is said to be produced. Sometimes a vacuum occurs from natural causes, but it is only for an instant, as the surrounding air rushes in to fill them. The most perfect vacuum until recently was the space above the mercury in a barometric tube. See TEMPERATURE.
Aiton's Encyclopedia (1910)
a metallic element having a specific gravity of 18.6. It was identified in 1789. The name was given in honor of the newly discovered planet Uranus. Uranium is found chiefly in the greenish material known as pitchblende. This ore is found chiefly in Bohemia, but also in Cornwall, Saxony, Hungary, Turkey, Connecticut, and North Carolina . This is the mineral, it may be remembered, from which radium is obtained. Uranium occurs in connection with copper in Saxony and Cornwall. Pure uranium was obtained in 1841. It was not obtained in compact form until 1856. It is a malleable white metal resembling nickel. A compound with sodium, known as uranium yellow, is used in the manufacture of Bohemian glassware. It is used also in painting glass and china.
Collier's New Encyclopedia (1921)
a metallic element, symbol U, atomic weight 238.5. Discovered in 1789 by Klaproth, in pitchblende, but first prepared in the pure state by Peligot, in 1840. Its principal ore is pitchblende, but it is also found in clevite, carnitite, samarskite, and fergusonite. It is a white metal, capable of taking a very high polish, with a density of 18.7. It melts at a white heat, and can be distilled in the electric furnace. Chemically it is allied to chromium, molybdenum, and tungsten, and forms two series of salts, uranous and uranyl.
What Has Changed in the Last Century
To the 1892 Encyclopedia of Founding, uranium was chiefly a colouring agent "used for imparting a yellow tint to glass," and even Collier's in 1921 described it only as a chromium-like metal forming uranous and uranyl salts. In 1938 Otto Hahn and Fritz Strassmann split the uranium nucleus, and within seven years the element had powered the first nuclear reactor (Chicago, 1942) and the bomb dropped on Hiroshima in 1945. Uranium-235, less than one per cent of natural uranium, now fuels the world's power reactors and its weapons; the Bohemian pitchblende of Joachimsthal that all three accounts point to became one of the earliest sources of uranium for both. The atomic weight of 238.5 given by Collier's has been refined to about 238.03, and the element is now known to be radioactive — the parent, not merely the host, of the radium Aiton's mentions.
Written for this edition, 2026.