3^4 METALS. loi. Columbium. 102. Tantalium* 



lOK COLUMBIUM, Brownifh-black internally 

 iron-grey, with a chocolate-brown ftrcak and 

 powder, hardifh, very brittle, of an imperfedly 

 foliated texture, opake, not attraded by the 

 magnet: fpeci fie gravity 5,918. 



&mfa8um\ Columbium. 



Colum'^ite. Them/on chem. 4, p i 27, 



Sent CO Sir Hans Sloanc from Majjachufets, and is at prefent in 

 the Brit fh Mufeum; colour darK grey-brown with a glaffy 

 III lire : rather hard, and very brittle; longitudinal frafture 

 imperfeftly lamellar, crofs-frafture fine grained : when ex- 

 pofed to a violent heat for a long time was found in a Hate of 

 black powder: contains, oxyde of columbium 78, oxydc 

 of iron 2i« 



i02^ T4NTALIUM. BlackiHi-grey, foftilh, of a 

 granular fracture, not magnetic, fi>ecific gravity 

 6,500: not foluble in any acid, nor altering its 

 colour when heated to rednefs; melting with 

 phofphate of foda and borax into a colourlefs 



glais. 



m&ng^mesi-' Confifting of oxyde of tantalium combined with the ox- 

 ^ufr.% ydes of iron and raanganefe. 



Tantalitc*. Thumfon chem 4 /,i27« 



Found 9X Kimits in Finland^ in irregular cryftals; colour be- 

 tween bluifli grey and blackifti-grey ^ furface fmooth with 

 metallic lullre : very hard, not magnetic, fraftur-e compad : 

 fpecific gravity 73953. 



jttrtaism, ConOftlng of oxyde of tantalium combined with the ox- 



ydes of iron and yttria. 

 Yt'Totantalite. Thomfon chem. 4. p. t 28. 

 Found at KimiU in Finland^ in fmall kidncy-forni mailes of 



inconfiderablc hardnefs: fradlure granular, iron-grey, of 



metallic kftre: may be fcratched with a knife, and gives a 



grey powder,* fpeciiic gravity 5,130. 



