On the Identity of Columhlum and Tantalum, 201 



every thing which may be presented in nature ; and the art 

 of advantageously applying the method, leads an " expert 

 eye to (ind the art of knowing how to dispense with it 

 altogether, 



[To be continued.] 



_,, , - .^ . . . <__ • tl t't , i I t r « i I I > « . 



XXXI V. On the Identity of Columlium and Tantalum. 

 By William Hvde VVollaston, M./). SecR.S,* 



W iTHiN a short time after the discovery of columbium 

 by Mr, Patchett in ISOlfj a metallic substance was also 

 discovered in Sweden by M. EkebergJ, differing from every 

 metal then known to him; and accordingly he described 

 the properties by which it might be distinguished from 

 those which it most nearly resembled. But although the 

 Swedish metal has retained the name of Tantalum giveu 

 to ii by M. Ekeberg, a reasonable degree of doubt has been 

 entertained by chemists, whether these two authors had 

 not in fact described the same substances ; and it has 

 been regretted that the discoverers themselves, who would 

 have been most able to remove the uncertainty, had not 

 bad opportunities of comparing their respective minerals, 

 or tlie products of their analyses. 



As I have lately obtained small specimens of the two 

 Swedish minerals tantalite and yttro tantalite. from which 

 I could obtain tantalum, and was very desirous of com- 

 paring its properties with those of columbium, Mr. Llat- 

 chett very obligingly furnished me with some oxide of the 

 latter, which remained in his possession. 



The resemblance was such in my first trials, as to in- 

 duce me to endeavour to procure a ftirther su})ply of co- 

 lumbium ; and by application to the trustees of the British 

 Museum, I was allowed to detach a few grains from the 

 original specimen analysed by Mr, Hatcheit. 



Notwithstanding the quantity enipioyed in my analyses 

 was thus limited, I have, nevertheless, by proportionate 

 oeconomy of the materials, been enabled to render my ex- 

 periments sutlicienlly numerous, and have found so manjr 

 points of agreement in ihe modes by which each of these 

 bodies can or cannot be dissolved or precipitated, as to 

 prove very satisfactorily that these American and Swedish 

 specimens in fact contain the same metal : and since the 



» From Phil. Trnnf. 1809, Part IL 

 + Phil, Trans, for 1 ao2. 



+ Ffienkups j^cadcmia^s Ha7ullingar. 1802, Tp. 6H.—Juiirnal '^des Mines, 

 vol. lii. p. 2*15. ** 



re-agents 



