TEL 



T E M 



Analysis of the ore from Nagyag 

 Tellurium 

 Lead 

 Gold 



Silver 

 Copper 



1 jihur . 



by Kmprolh : 

 :.: 

 r.i-it 



9-0 



(>:> 



!: 



8-0 



KM)' 



Brandos and Berthier have also analyzed this ore from 

 NacyAg : tlu j ir results differ considerably from the above, 

 and 'also from each other. 



linmutfiic Tellurium. Trlluret nf Bismuth. Occurs 



'ilizcd in small six-sided prisms. Cleavage ) 

 to'the liiiM- <>!' the prism. Fracture indistinct. Hardness : 

 he* calcareous ~pai. and is snatched hv fluor-spar. 

 Ciilo\ir stccl-irrey or zinc-white, Lustre metallic. 

 cifio eravitv 7'*i 



Fusible by the blowpipe, and disengages the odour of 

 selenium. Acted on by nitric acid, anal the solution is 

 precipitated by water. 

 It is found in Norway. 

 Analysis of Wehrle : 



Tellurium ..... 34-6 

 Bismuth ..... 60-0 

 Sulphur and traces of selenium . 4-K 



90-4 



We shall now describe the more important binary com- 

 pounds of tellurium, beginning with 



Oxygen anil Trlluriuin. It has been already mentioned 

 that when tellurium is heated in contact with air, it 

 burns, and a white %apour is formed : this is oxide of tel- 

 lurium. or tellurous acid. It may also be obtained by 

 the action of nitric acid on the metal; by adding water to 

 the solution, part of the oxide is precipitated, and <he, 

 remainder is obtained by evaporation to dryncss. The 

 properties of this substance, are, that it is a white granular 

 anhydrous powder, which slowly reddens moist litmus- 

 paper, and is insoluble in water and acids. It is dissolved 

 by a solution of potash or soda, and by fusing with their 

 carbonates ervstallizable salts are formed : when th' 

 decomposed by acids, hydrated telh'rous acid is precipi- 

 tated, which, it' washed with very cold water, and dried at 

 iiperature not above 5:1, may be preserved without 

 tutt'crinar change, and is soluble in water, acids, ammonia, 

 and the alkaline carbonates, which last it decomposes : the 

 aqueous solution reddens litmus-paper: when zinc, tin, 

 and some other metals are left in a solution of tin 

 they deoxidize it, and metallic tellurium is precipitated in 

 tho state of a black powder. Its salts are called tellurites. 

 It is composed of 



One equivalent of oxygen . . 8 

 One equivalent of tellurium . . :)'J 



Equivalent . . 40 



liiioxide of Tellurium, or Tell urir. Acid. This is ob- 

 tained: by fusing tellurous acid with nitrate of potash : by 

 this it is oxidized completely, and the result is tcllurate of 

 potash : when chloride of barium is added to it, telluratc 

 of barytes is precipitated, which, being decomposed by 

 sulphuric acid, yields a solution of telluric acid : thi's 

 yields hexagonal crystals of |h c acid: it acts but feebly 

 as an acid, the dilute solution reddening litmus-paper 

 with difficulty, and its taste is rather metallic than sour- 

 the i utain water, two-thirds of which th 



at about 212", and the remainder below a red heat be- 

 comes a mass of a fine orange colour, which is completely 

 insoluble in water, either cold or boilinir. or hot hydro- 

 chloric or nitric acids, or solution of potash. Ii is d.-'i om- 

 posed at a high temperature, and converted into a white 

 powder, which is tellurous acid. Its salts are called lel- 



12 



It consists of 



One and a half equivalent of oxygen 

 One equivalent ol tellurium ... 



Equivalent ... 44 

 trogen and Tellurium. When tellurium is alloyec 

 by fusion with tin or zinc, and the compound is acted upon 

 by hydrochloric acid, the hydrogen of the decomposed acic 

 dissolves tellurium, and telluretted hydrogen gas is ob- 

 tained. Thi ga has a smell somewhat resembling tha 



if Indrosulphuric acid : it is soluble in water, forming a 



laid ' ohitiMii ; and. as it j,,,^,..^,.., ncj,| p, 



U.it has been culled hvdrotelhine acid. 



my metal! 



ellurium with the other metal. 01 

 LTcn uf the air, all take the 

 iimim. 

 It coiisi-ts of 



One equivalent of hydrogen 

 One equivalent of tellurium 



ie, nitric acid, and 

 'in the U'l- 



1 



Equivalent . . 33 

 nnil Trlluriuin form two compounds. When 

 a feeble current of chlorite -rd o\er tellurium at 



a hi lib temperature, the dicliloiide i 

 a violet-coloured vapour, which -at first into a 



black liquid, and eventually into nc colour. 



It is decomposed \i\ the action of water into metalli 

 lurium, which is precipitated, and chloride of tellurium 

 remains in solution. 

 It is comprised of 



One equivalent of chlorine . . :!(i 

 Two equivalents of tellurium . . M 



Equivalent . . 100 



The C/t/nriilc nf Tellurium is obtained, as abo\e si 

 by the action of water on the dichloride, but is bettc: 

 cured by passing a larger quantiU of chloric 

 lurium at a lower temperature than in forming the dichlo- 

 ride. It is volatile, and any excess of chloi 

 rated by agitation with mercury and rectification, a white 

 crystalline solid is obtained, which is composed of 



One 'equivalent of chlorine 



One equivalent of tellurium . . .TJ 



Equivalent . . 68 



Sii/jifii/r mid Tellurium combine in two proportions : the 

 sulphurct is obtained when hydrosulphuric acid i. 

 passed through a solution of chloride of tellurium, tefluroua 

 acid, or of a soluble telhuite. It is of a dark brown colour, 

 and is soluble in a solution of potash. It is form 

 One equivalent of sulphur . . n> 

 One equivalent of tellurium . . '.\- 



Ei|nivalent 



IS 



PerntlphuTet nf Tellurium is obtained by mixing a 

 solution of persulphuret of potassium with one of . 

 of telluric acid. It is of a deep yellow colour ; but 

 a very unstable compound, for it speedily becomes black, 

 and is converted into protosulphuret. 



TELOPHO'NUS, Mr. Swainson's name for a genus of 

 iMiiiunrr [SHRIKES, vol. xxi., p. 410], which he thus cha- 

 racterises : 



Bill more lengthened (than in I*iniux', sliglrtlv ho. 

 the tooth smaller. Wing-, very short and rounded. Tail 



icned, graduated. Liitcia! . the innei 



slightly shorter than the outer. 



Example, Telo]'/>ni>n* taicogrammfcut. 



Hilt of Trloplionm Iciiciwr.iiniiiirui. (S., l'!,:nijicatiim i/Birdl, \u\. ii.) 



TELUGUorTKIJXCA LANGUAGE, film.-, 

 



TdMMASO, an architect who is belter 

 known by his writing n'lati\e to Ins art than by the build- 

 . hich he executed, was the son of an architect, and 

 phew of another an-lnlecl and 



was born at Venice in 17n.~>. Having iim- 

 matical .studies in tho school of 1'. mini 



and the eminent Man !,,-, 1'oleni, he wa-* ajipointed 

 although then only twenty-two one of the a-sistants. in 

 the Commission Of Engineer*, and in 1742 became the 

 chief of that body on Bernardino /?!- 



drini, a few years before' the latter's death (1747). His 

 share in the hydraulic commission caused him for awhile 

 to be involved in literary disputes, he having otl'endcd Hie 

 people of Padua by a publication entitled -Dell aiilico 

 Corso clc' Fiumi in I'udova e suoi Contorni ;' wherein he 

 asserts that their mice-tors had attempted to turn the 



