U R A 



IJ R A 



fulphuric acids, alfo with the acetic, the tartaric, the 

 phofphoric, and fluoric acids, and with thofe of tungften 

 and molybdena. Richter formed likewife the borate, oxa- 

 late, citrate, malate, benzoate, fuccinate, and febate of 

 uranium ; but the properties of the latter falts have not been 

 defcribed. See Salts and Acids. 



Ores of Uranium. — Pitch-blende or Pitch-ore, Pecher-z, 

 Werner ; Uran Osidule, Hauy. This mineral was firft ob- 

 I'erved in a mine at Johan-Gsorganttadt, in Saxony. From 

 its black colour, and other properties, it was for fome time 

 fuppofed to be a blende, or ore of zinc. M. Werner 

 placed it among iron-ores, and afterwards fuppofed that it 

 contained wolfram. KJaproth analyfcd this ore in 1789, 

 and found that it confifted principally of fulphur, combined 

 with a metal to which he firll gave the name of uranium. 

 Tliis ore occurs in veins in primitive rocks, in feveral places 

 in Cornwall, in Saxony, and in Norway ; it is commonly 

 accompanied with galena, coppier pyrites, and iron ochre, 

 and with quartz, calcareous fpar, and fulphate of barytes. 

 It is alfo fometimes affociated with ores of filver and co- 

 balt. 



The colour of pitch-blende is velvet-black, or greyifh- 

 black, fometimes inclining to green and brown. It occurs 

 mafiive, and diffeminated alfo reniform, botryoidal, and 

 pulverulent. The luftre internally is refinous, more or lefs 

 ihining. The ftrufture is fometimes imperceptible ; in 

 other fpecimens it is lamellar. Pitch-blende is brittle ; the 

 IraSure is imperfeftly conchoidal ; the fragments are an- 

 gular and fharp-edged. It yields readily to the knife, but 

 the colour of the llreak is not changed. The fpecific gra- 

 vity of this ore is 7.5. 



Pitch-blende is infufible without addition by the blow- 

 pipe : with borax it yields a grey flag ; with phpfphate of 

 foda, a clear green globule. It difTolves imperfeftly in the 

 iulphuric and muriatic acids, but is almoft entirely diffolved 

 in the nitric and nitro-muriatic acids. The folution has a 

 pale orange-green colour ; and from this folution the metal 

 is precipitated by the phofphate of potafh ind the alkalies : 

 with the former, the colour of the precipitate is a brownifh- 

 red ; with the latter, yellow. 



The conftituent parts of this ore, as given by Klaprotl), 

 are, 



Oxyd of uranium - - 86.5 



Black oxyd of iron - - 2.5 



Galena . - . . 6 



Silex .... 5 



100 



Pitch-blende may be diftinguifhed from brown blende by 

 its colour, fpecific gravity, frafture, and ftreaks ; from wol- 

 fram by its ftreak and frafture. 



Uranite, or Uran mica, Urane oxide, Hauy. The colour 

 of this ore is lemon-yellow, palling into orange, and into 

 apple-green and emerald-green ; it becomes brownifh by de- 

 compofition. It occurs cryftallized in reftangular prifms 

 and tables, and fometimes in imperfect oftohedrons. The 

 edges of the cryftals are frequently bevelled and truncated. 

 The ftrufture is lamellar, with diliinft joints in one direc- 

 tion, parallel to the bafes of the cryftals ; the other jonits 

 are indillmft. The lamellx are inflexible, and tranfparent 

 or tranflucent, with a Ihining pearly luftre. Uranite yields 

 eafily to the knife ; the fpecific gravity is 2.19. The cryf- 

 tals are generally fmaH. Sometimes this mineral occurs 

 maflive, in granular diftinft concretions ; and fometimes it 

 is found pulvtruleii'-., and in fmall tubercle?, which have a 

 glimmering or dull luftre, and an orange or green or reddifh- 



brovm colour. Uranite decrepitates violently before tliA 

 blow-pipe; it lofes about ^^3 per cent, by ignition, and ac- 

 quires the colour of brafs. With borax it yields a yellowifh- 

 green glafs. This ore diflblves without effervefcence in 

 nitric acid, and communicates to it a lemon-yellow olour. 

 Its conftituent parte, as given by M'Gregor, 3re, 

 Oxyd of uranium, vinth a trace of oxyd of lead 74.4 

 Oxyd of copper - . . . . 8.2 



Water ---...- 15,4 

 Lofs .-..-.. 2 



100 



Uranite occurs in veins in the mines of Cornwall, and in 

 Saxony and France ; it is generally accompanied vnth the: 

 ores of iron. 



The pulverulent uranite is called by the Germans uran- 

 ochre. Indurated uran-ochre alfo occurs with the other 

 ores of uranite, cither madlve or difleminated ; the colour is 

 the fame as the pulverulent. It is foft and brittle ; the 

 fpecific gravity is 3.15. According to Klaproth, the yel- 

 low varieties are pure oxyd of uranium ; but the brownifh 

 and reddifh contam a little iron. 



URANOPOLIS, in Ancient Geography, a town of Afia, 

 in Pamphylia, and in the country called Carbalia. Ptolemy. 

 — Alfo, a town of Macedonia, in the Chalcide ; fituated on 

 mount Athos, near the fouthern fide, and the promontories 

 Nymphaum and Auvathon. Pliny. Athenaeus fays, that 

 this town was founded by Alexp.rchus, the brother of Caf- 



fander, king of Macedonia Alfo, an epithet given by 



Athenaeus to the city of Rome. 



URANOSCOPUS, in Ichthyology, the name of a fifti, 

 called in Englifh ihtjiar-gazer ; and by fome authors, calli- 

 onymut. 



The uranofcopus, in the Linnaan fyftem, is a genus of 

 the order of Jugulares : its characters are, that the head is 

 deprefled, rough, and large ; the mouth has the upper jaw 

 Ihorter than the lower ; the branchioftege membrane has five 

 rays, and is covered with fmall eminences like teeth ; the 

 opercula are membranous and ciliated ; the anus is in the 

 middle of the body. Gmelin mentions two fpecies : viz. 

 Jcaber, or ftar-gazer, with bearded lips and fmooth back. 

 It is ufually caught about feven or eight inches in length, 

 but fometimes it grows to a foot ; its head is very large, of 

 a fort of fquare figure, covered by a ftrong bony cafe, 

 roughened by an infinite number of fmall crefts or protube- 

 rances ; each fide of this cafe is terminated above by two 

 fpines, the under part has five fpines fmaller than thofe 

 above. Its mouth is large, and opens perpendicularly 

 downward, being placed in the fame direftion with the eyes 

 i:i the upper part of the head ; the tongue is thick, (hort, 

 and roughened with a number of fmall teeth ; under its chin 

 is a beard or long cirrus extending to fome diftance beyond 

 the lips ; its eyes are fmall and prominent, and are fo placed 

 near each other in the upper part of its head, as naturally to 

 look up to the heavens, whence it has its name ; and though 

 many of the flat fi(h have their eyes placed like- thofe of this 

 fifti, yet the pupils in thefe are direfted fidevvays, whereas 

 in this only they are turned ftraighl upward ; the body is of 

 a fquarifti form as far as the vent, and then it becomes cy- 

 lindric : it is covered with fmall fcales, and marked near the 

 back by a lateral line, compofed of fmall pores or points 

 bending from the neck to the peftoral fins on each fide, and 

 from thence in a ftraight line to the tail : on the back are 

 two fins, the firft being much fhorter than the latter, and 

 furniftied with ftronger fpines ; the pefloral fins are large, 

 with foft rays ; the ventral fins are fmall ; the tail is of mo- 

 derate 



