[mod.L. (Klaproth, c. 1790), f. the name of the planet URAN-US + -IUM.]
1. A rare, heavy, grayish metallic element, found esp. in pitchblende and uranite.
In first quot. erron. identified with pitchblende.
1797. Encycl. Brit. (ed. 3), XVIII. 691. Uranium, a fossil found … in Saxony, and … in Bohemia, and is, by the miners, called Pechblend.
1805. Phil. Trans., XCV. 348. The solution … contained oxide of uranium.
1842. E. A. Parnell, Chem. Anal., 169. Both the peroxide and protoxide of uranium are precipitated from their solutions by ammonia.
1843. Penny Cycl., XXVI. 39/2. Uranium is very combustible;… it burns with a remarkably white and shining light.
1857. Miller, Elem. Chem., Org., x. § 1. 592. Salts of uranium.
1868. Watts, Dict. Chem., V. 940. Péligot, in 1840, showed that the body previously regarded as metallic uranium was really the protoxide (UO); he likewise obtained the true metal.
1875. Vogel, Chem. Light, xvi. 267. Uranium itself is a rare metal whose combinations play a great part in colouring materials.
b. attrib., esp. in the names of salts, ores, etc., as uranium acetate, nitrate, -ore, oxide, phosphate, vitriol; also Comb., as uranium-bearing, -prepared.
Various other examples appear in special or recent Dicts., as uranium-bloom, -green, -ochre, -orange, -yellow (1868 Watts’ Dict. Chem. s.v.).
1837. Dana, Min., 372. Pitchblende. Uranius amorphus, Uncleavable Uranium-Ore.
1850. Watts, trans. Gmelin’s Handbk. Chem., IV. 175. Monosulphate. Found native as Uranium-vitriol.
1862. Catal. Internat. Exhib., Brit., II. No. 3054. Developments of uranium-prepared papers.
1873. Ralfe, Phys. Chem., 237. The solution of Uranium Nitrate.
1890. Cagney, trans. Jaksch’s Clin. Diagn., 269. Uranium acetate or nitrate is added in solution. Ibid. A solution of uranium oxide.
2. ellipt. A solution of a salt or nitrate of uranium. Chiefly attrib. and Comb.
1878. Abney, Photogr., 155. Printing with iron and uranium compounds.
1890. Anthony’s Photogr. Bull., III. 361. The uranium intensifier … in my own practice has proved the simplest and best of all intensifiers.
1892. Photogr. Ann., II. 422. Carbutt’s Positive Films … are amenable to uranium toning.
1900. J. A. Hodges, Pract. Enlarging, xiii. (ed. 4), 98. The appearance of a uranium-toned print.
