TAN 



cryftals, and by refifting the aaion of the h!ow-pip«, by 

 which yltryotai.talite is melted into a greenilh-yellow flag ; 

 lallly, tantulite is dillinguilhed from gadohmte, by its 

 greater ■fpocific gravity, uneven fraaure, and infufibihty. 

 Yttryotantahte, another ore of tantalium, contains the newly 

 difcovered earth called yttria, from Ytterby, near Rof- 

 lagen, in Sweden, where it was firft difcovered. See Tan- 

 TAi.iiM and Yttkyotantalite. 



TANTALIUM, or Tantalum, the metal obtamed 

 from tantalite and yttryotantahte. The method of reduc- 

 tion confifts in boihng the ores with alkalies, and adding 

 nitro-muriatic acid to the folution. The oxyd of tantalium 

 is thrown! down in white powder: this muft be wafhed, 

 dried, and ftrongly ignited in a crucible lined with charcoal. 



Berzehus preifed tlie oxyd into a cavity of the Cze of a 

 |;oofe-quill, made in a lump of well-burned charcoal, and 

 expofed it to a violent heat, in a HelTian crucible. The 

 reduced metal was not melted, but the particles of it 

 firmly adhered together, and formed a mafs, through which 

 water would not penetrate. The grains were hard enough 

 to fcratch glafs. The fpccific gravity, as afcertained by 

 Dr. Wollailon, was 5.61 ; but as the mafs had not been 

 melted, the weight of tantalium muft be fomething heavier. 

 Its colour is dark grey ; and when fcratched with a knife, it 

 affumes the metallic luftre, and has the appearance of iron. 

 It may be reduced to powder by trituration ; the powder is 

 of a dark brown colour, without the fmalleft metallic luftre. 

 This powder is not in the leaft altered by muriatic or nitric 

 icids, nor by aqua regia, though it be digefted with them 

 for feveral days. In this refpeA it agrees with chromium, 

 lita»ium, ofmium, iridium, and rhodium. 



When heated to rednefs, it takes fire, burns feebly with- 

 ojt flame-, and goes out direftly if it be removed from the 

 fire. By this means it is converted into a greyilh-white 

 matter, which may again be reduced to the metallic ftate by 

 heating it with charcoal : 100 parts of tantahum, treated in 

 this manner, combine with 8.5 or 4.5 of oxygen. But by this 

 procefs it is fcarcely poffible to oxydize tant£ium completely. 



If tantalium, when pulverized, is mixed with nitre, and 

 thrown into a red-hot crucible, a feeble detonation takes 

 place. The mafs is fnow-white, and is a compound of pot- 

 afh and oxyd of tantalium. 



The mean of four experiments on the reduftion of the 

 oxyd of tantalium to the metallic ftate, makes it a compound 

 of 100 metal with 5.485 oxygen. The fuppofition that the 

 exygen in the water, which converts the oxyd into a hy- 

 drate, is twice as great as that in the oxyd, would make it 

 a compound of 100 metal with 5.5 oxygen. Muriatic acid 

 throws down oxyd of tantalium, from its combinations with 

 potafh : it is then a hydrate of a white colour ; and when 

 walhed and dried, it is compofed of 100 of oxyd of tan- 

 talium and 12.5 water. From experiments of Berzelius, it 

 appears that the oxyd of tantalium poffefles acid properties. 

 He fucceeded in alloying feveral metals with tantalium, as tung- 

 ften andiron. Thomfon's Annals, September, 1816, p. 233. 



TANTALUS, in Ancient Geography, a town in the ifle 

 of Lefoos — Alfo, a town in Afia Minor, upon the bank of 

 the Meander. 



Tantalus, one of the many names given by chemifts to 

 mercury. 



Tantalus, in Mythology, a king of Lydia, Phrygia, or 

 Paphlagonia, according to fome, but, according to others, 

 the fon of Jupiter by the nymph Plota, who is faid to have 

 prefented the mangled members of his fon Pelops, whom he 

 murdered, to the gods, at a feaft, in order to prove their 

 divinity ; or, according to the modern explication of this 

 fable, he offered i^ his fon as a facrifice to the gods. 



9 



TAN 



Others, however, have charged him with revealing the fe- 

 crcts of the gods, ;'. c the rayfteries of their worftiip, of 

 which he was the high-prieft. But whatever was the nature 

 of his crime, the poets reprefent him as condemned to hell, 

 and tormented there with perpetual hunger and thirft in the 

 midft of plenty of both meat and drink. Some reprefent 

 him as ftanding up to the chin in water, which he was in- 

 capable of reaching ; or as ftanding under a tree, fome of 

 the branches of which, loaded with the fineft ripe fruits, 

 hung down juft before his mouth, which, the moment he 

 endeavoured to take, always waved out of his reach. Others 

 reprefent him as ftanding under a heavy ftone, which was 

 fufpended over his head, and which he fufpefted would 

 every moment fall and crufti him. 



Horace (lib. i. fat. i. v. 71.) feems to make Tantalus 

 only an emblem of the covetous r as Lucretius (lib. iii. 

 v. 1015.) makes Sifyphus, who is reprefented as bending 

 under the weight of a great ftone, or labouring to heave it 

 againft the fide of a fteep mountain, and which always rolls 

 precipitately down again- before he can fix it on the top, as 

 an emblem of the ambitious. 



Tantalus, in Ornithology, a genus of the order of 

 Grallae. Its charafters are, that the bill is long, thick at 

 the bafe, and fomewhat incurvated ; the face naked ; the 

 tongue fhort and broad ; the noftrils linear ; and the feet, 

 with four toes, palmated at the bafe. Linnjeus enumerates 

 twenty-one 



Species. 



Loculatok. With a blueifti face, reddiih bill, quills 

 and tail-feathers black, and white body : the curicaca of 

 Marcgrave, the wood pelecan of Cateftiy, and wood ibis of 

 Pennant. It is found in New Holland and South America. 



Falcinellus. With a black face, blueifli legs, wings 

 and tail violet, and chefnut body : the bay ibis of Pennant 

 and Latham, and green courhs of Buffbn. A variety is the 

 numenius caftaneus of Brifibn. It is found in flocks about 

 the lakes of Italy, fouth of Germany, Denmark, the Ural 

 defert, and the Cafpian and Euxine leas. 



MiNUTUS. With face, biU, and legs greenifli, ferru- 

 ginous body, beneath white : the lefter ibis of Edwards and 

 Latham. Found in Surinam. 



Ibis. With red face, luteous bill, grey legs, black 

 quill-feathers, and reddifti-white body : the Egyptian ibis of 

 Latham. Found plentifully in Egypt. See Ibis. 



Ruber. With face, bill, and legs red, fanguineous 

 body, and the apices of the wings black : the guara of 

 Marcgrave, Willughby, Ray, &c. and the fcarlet ibis of 

 Pennant and Latham. Found gregarious in the Bahama 

 iflands, in parts of America between the tropics, particularly 

 Eaft Florida. 



Albus. With red face, bill, and legs, white body, and 

 the tips of the wings green : the white curlew of Cateft)y, 

 and white ibis of Pennant and Latham. Found in the Bra- 

 fils and in Carolina. 



Fuscus. With red face, bill, and legs, brown body, 

 beneath white : the brown curlew of Ibis, and brown ibis 

 of Pennant and Latham. Found in the warmer parts of 

 America, and in fummer in Carolina. . 



ViRiDis. With black face and legs, green and cyaneous 

 wings, neck cinereous-black, beneath faiciated with white, 

 upper part of the body and tail green-golden, beneath and 

 rump brown-blackifti : the green ibis of Latham. 



Igneus. With black head and neck, green legs, body 

 cyaneous, refplcndent with green, beneath blackifti-red, with 

 the quills and tail-feathers green-golden ; the gloiTy ibis of 

 Latham. 



Leuco- 



