URA 



URI 



universal affirmative and universal nega- 

 tive propositions, in which the universal 

 signs "all," "no," "every," are em- 

 ployed to indicate that the subject is 

 distributed. 



UNIVERSE; WORLD. The former 

 of these terms usually relates to all 

 created things, and hence the theory of 

 the Universe comprises all that is known 

 or conceived of the general arrangement 

 of the stars, planets, &c. The term 

 world was formerly synonymous with the 

 present term universe, but is now com- 

 monly restricted to our own planet. 



UNI'VOCAL NOUN. In Logic, a 

 common term is called univocal in re- 

 spect of those things or persons to which 

 it is applicable in the same signification, 

 as the term " man." Whately observes 

 that " the usual divisions of nouns into 

 univocal, equivocal, and analogous, and 

 into nouns of the ^rs^ and second inten- 

 tion, are not, strictly speaking, divisions 

 of words, but divisions of the manner of 

 employing them ; the same word may be 

 employed either univocally, equivocally, 

 or analogously ; either in the first inten- 

 tion or in the second. The ordinary 

 logical treatises often occasion great per- 

 plexity to the learner, by not noticing 

 this circumstance, but rather leading him 

 to suppose the contrary." 



UNLIMITED. A term sometimes 

 employed by mathematicians in the sense 

 of indefinite, in order to avoid the use of 

 the word infinite. It is also used to de- 

 scribe a problem which may admit of an 

 infinite number of answers. 



UNSTRA'TIFIED ROCKS. Rocks 

 which are not disposed in beds or strata. 

 These are also called massive and over- 

 lying rocks, and comprise those usually 

 termed Plutonic, Igneous, Trap, &c. 

 Many of these are so intimately related 

 to granite, as scarcely to be distinguished 

 from it, while others as obviously pass 

 into lava and other products of active 

 volcanoes. 



UPU'PID^. The Hoopoe tribe; a 

 family of the Insessores, or Perching 

 birds, named from the upupa, or hoopoe, 

 the last genus of Cuvier's Tenuirostres. 



U'RAMIL. A crystalline substance 

 obtained by treating a hot saturated solu- 

 tion of thionurate of ammonia with hy- 

 drochloric acid in excess. By decom- 

 posing this substance an acid is obtained, 

 called the uramilic. 



URANGLI'MMER. An ore of ura- 

 mium, formerly called green mica, and 

 by "Werner chalcolite. See Uranite. 

 854 



U'RANITE. The yellow uranite or 

 uran mica, and the green uranite or 

 chalcolite, are phosphates of oxide of ura- 

 nium ; they are distinguished by the 

 former containing a small portion of 

 phosphate of lime, and the latter an 

 equivalent portion of phosphate of 

 copper. 



URANIUM. A metal discovered in 

 1781, in the mineral called, from its black 

 colour, pitch-hlende. It was named by 

 Klaproth after the new planet Uranus, 

 the discovery of which took place in the 

 same year. 



U'RANOCHRE. An ore of uranium, 

 containing this metal in the oxidised 

 state. 



URANO'GRAPHY (owpavo?, the hea- 

 vens, 7pa0a), to describe). A subordinate 

 department of the science of astronomy, 

 presenting an account of the arrange- 

 ments which have been made by astro- 

 nomers for delineating the starry heavens, 

 and working the many mathematical pro- 

 blems of which they are the subject. 



U'RANUS or HERSCHEL. A planet 

 discovered by Sir W. Herschel in 1781, 

 March 13. Its apparent diameter is 

 about 4", from which it never varies 

 much, owing to the smallness of our 

 orbit in comparison of its own. Its real 

 diameter is about 35,000 miles, and its 

 bulk 80 times that of the earth. It is 

 attended by satellites — two at least, pro- 

 bably five or six — whose orbits ofier re- 

 markable peculiarities. 



URAO. A variety of sesqui-carbonate 

 of soda, found in Columbia. 



URATES. Compounds of uric or 

 lithic acid with the salifiable bases. 



U'RCEOLUS (dim. of urceus, a water 

 pitcher). A small pitcher-like body, 

 formed by the two bracts which, in the 

 genus Carex, become confluent at their 

 edges, and enclose the pistil. 



U'REA. Anormal cyanite of am- 

 monia. A substance existing in the 

 form of lactate of urea in human urine, 

 and combined with hippuric acid in that 

 of the cow and elephant. 



U'RETHANE. The name given by 

 Dumas to a substance which he con- 

 sidered to be a combination of urea with 

 carbonic ether. It is also considered as 

 a chloroxicarbonic ether, in which the 

 chlorine is replaced by amidogen. 



URIC ACID {olpov, urine). Lithic 

 acid. An acid existing in the urine of all 

 carnivorous animals, and forming the ba- 

 sis of most urinary concretions. It forms, 

 in combination with ammonia, the white 



