TUN 



TUNES, in Ancient Geography, a town, of Africa, moftly 

 on a hill, to the W^, nnd on the border of the port named 

 Stagnum by Procopius, fituated S.E. of Carthage, and 

 furrounded by lakes and marfhes. See Tunis. 



TUNG, in Natural Hijlory, the nartie given by the 

 Indians to a little infeft, called by the Spaniards pique, 

 , which is very common and very troublefome in fome parts 

 [ of the Eaft and Weft Indies. 



It is of the fiy.e of a fmall flea ; its place of laying its 



eggs is within the {km of the human body, and it diligently 



fearches opportunities of doing this, and often fucceeds 



i in the attempt, to the great pain and trouble of the perfon 



who fuffers it. 



The creature, knowing that it (hall be foon crulhcd to 

 . death under the Ikin, generally makes its way either under 

 the nails, or where there is fome callus on the furface ; there 

 it eats its way along, and, in fine, lays its eggs, which hatch 

 into fo many young ones, and fpread themfelves between 

 the flelli and ikin all over the finger and hand, if not pre- 

 vented by taking out the old one in time. 



The perfon often does not perceive the creature's getting 

 in, it enters fo gradually and eafily ; but he is foon ad- 

 ' vertifed of the place where it is by a violent gnawing pain, 

 the creature really eating its way as it goes along. The 

 only remedy in this cafe, is to enlarge the orifice at 

 which it entered, and take it out whole ; the wound foon 

 heals up, and there is an end of the matter. This may often 

 be done with the point of a needle ; but if not, it is much 

 better to fubmit to the opening it with a lancet than to the 

 ill confequences which otherwife will attend it. Obferv. 

 fur les Coutumes de I'Afie, p. 184. 



TUNGA, in Geography, a town of Africa, in the king- 

 dom of Tunis. 



TUNGEBADRA, a river of Hindooftan, which runs 

 into the Kiftnah, 7 miles E. of Rachore, in the country of 

 Golconda. 



TUNGERSHEIM, a town of the duchy of Wurzburg, 

 ', on the Maine ; 9 miles N. of Wurzburg. 



TUNGINSKOI, a town of Ruflia, on the Irkut ; 80 

 lilies S.W. of Irkutfl^. N. lat. 51° 18'. E. long. 103° 14'. 

 TUNGONG, a town of Meckley ; 16 miles S.E. of 

 Munnypour. 



TUNGRI, or TONGRES, in Ancient Geography, the name 

 of a people who, according to Tacitus, fuccceded that of 

 German, by which vifere defignated the firft people who from 

 ;he other fide of the Rhine had abandoned their territory to 

 the Gauls. But according to other authors, the Tongres in- 

 I habited the country of Liege for a long time before the 

 1 entrance of the Romans into the Gauls. Conquerors of 

 [ the Eburons, they fncceeded them, fo that they were en- 

 tirely forgotten. Their conquefts were very extenfive ; and 

 though they were fubjugated by the Franks, and Attila, 

 ■ommanding the Huns, completed their extermination, yet 

 '. : heir bifhops long after retained their title. 

 1 TUNGSTEN, in Mineralogy; Scheelin cakaire, Haiiy. 

 i The name tungiten, denoting heavy ftone, was given to this 

 mineral on account of its great fpecific gravity. Its appear- 

 i ance is not metaUlc, it has a yellowifh or greyiih-white colour, 

 ; and is more or lefs tranflucent. The ftrufture is lamellar ; 

 '. It is infufible by the blowpipe, but becomes opaque. When 

 I powdered and digeftcd with nitric acid, it communicates to 

 i it a yellow colour. Thefe properties diftinguilh it from car- 

 bonate of lead, white tin-ftone, and barytes. Tungften 

 occurs both malTive and cryftallized ; the form of the cryftals 

 is moft frequently the odahedron. The primitive form of 

 the cryftal, according to Haiiy, is an acute oftahedron, 

 having fhe angle at the fummit 62° 24', and the angle 



TUN 



formed by the junftion of the planes at the bafe of each 

 pyramid 113° 36'. The prineipal planes of the cryftals are 

 fmooth, the luftre fplendent. Tungften yields to the knife, 

 and is brittle ; its fpecific gravity varies from 5.8cx> to 6.015. 

 This mineral occurs with wolfram, (fee Wolfram,) tin- 

 ftone, magnetic iron-ftone, and brown iron-ftone : it fomc- 

 times forms large or fmall granular diftinft concretions with 

 ftreaked and Ihining furfaces. It is found in the mines of 

 Cornwall, Sweden, Bohemia, and Saxony. Its conftituent 

 parts are, 



Acid of tungften - - 75-25 



Lime - . . . 18.70 



Silex .... i.yg 



Oxyd of iron - - - 1.25 



Oxyd of manganefe - - 0.75 



Tungsten, in Clxmijlry, is the metal obtained from 



the ore of the fame name above defcribed. By fome of the 



German chemifts it is denominated SchecUum, from Scheele, 



who firft pointed out the peculiar nature of one of its oxyds. 



Tungften was firft obtained in the metallic ftate by the 



Meftrs. D'Elhuyart from another of its ores called tuolfram. 



New experiments have been fince repeated by Vauquelin, 



Klaproth, MefTrs. Allen and Aikin, and others, with various 



fuccefs, and very lately they have been confirmed by 



Bucholz. 



This metal has been obtained by expofing the tungftate 

 of ammonia to a violent heat. It has never been procured 

 in the ftate of a folid button, or in large panes, but only in 

 fm.iU panes as fine as fand, having a ftrong metallic luftre, a 

 light iron-grey colour, and (lightly agglutinated. It is one 

 of the hardeft of the metals, and very brittle. Its fp. gr. 

 according to the D'Elhuyarts, is 17.6; according to 

 MelTrs. Allen and Aikin, 17.2 ; and according to the late 

 experiments of Bucholz, 17.4, which is about the mean of 

 the others, and probably very near the truth. Hence, next 

 to gold and platinum, it is one of the heavieft metals. 



This metal requires a heat of at leaft 170° of Wedgwood 

 (probably much higher) to melt it. It is not attracted by 

 the magnet. Expofed to heat in an open vefTel, it gradually 

 abforbs oxygen, and is converted into an oxyd. Two 

 oxyds of this metal were formerly known, oi/'k. the dark 

 blue or black, and the yellow or tungltic acid ; but befides 

 thefe, Bucholz has lately defcribed another of a dark 

 brownifh-red or reddifh-brown colour, and which he con- 

 fiders to be intermediate to the other two. Of thefe, tlie 

 bcft brown and moft important is the yellow oxyd, or 

 tungftic acid. This oxyd is without tafte. It is infoluble 

 in water, but remains long fufpended in it. It has no aftive 

 or vegetable colours. It is ftated to be compofed of 



Tungften 

 Oxvgen 



80 

 20 



Little is known of the nature and compofition of the 

 other oxyds of this metal, fo that we cannot with any de- 

 gree of certainty afcertain the weight of its atom. This 

 metal combines with fulpluir and phofphorus, and forms 

 alloys with many of the metals ; but tliefe compounds do 

 not appear to be interefting. The yellow oxyd, or tungftic 

 acid, feems capable of forming compounds with all the 

 alkaline, earthy, and metallic bafes, though very httle is 

 known at prefent oi the nature of thefe compounds. 



TUNGURAGUA, in Geography, a mountain of Peru ; 

 2 I miles S. of Riohaniba. 



TuKGUUAGUA. See Maranox. 



1 UN- 



