1904.] SMITH AND EXNER — ATOMIC WEIGHT OF TUNGSTEN. 123 

 THE ATOMIC WEIGHT OF TUNGSTEN. 



BY EDGAR F. SMITH AND FRANZ F. EXNER. 



{Read April 7, 190 4.) 



Literature. 



Berzelius, Pogg. An7t., 8, 1 (1826); Schneider, Jr. prakt. Chemie, 

 JO, 152 (1850); Marchand, Ann. Chein. Pharin., 77, 261 

 (1851); Borch, y>. prakt. Chem., ^4, 254 (1851); Riche, Jr. 

 prakt. Che7n., 6g, 10 (1857); Dumas, Ann. Cheni. Fharm.^ iij, 

 23 (i860); Bernoulli, Pogg. A?in., iii. 573 (i860); Scheibler, 

 Jr. prakt. Cheni., 8j, 324(1861); Roscoe, Ann. Chem. Phar7n., 

 162, 368 (1872); Waddell, Am. Chem. Jr., 8, 280 (1886); 

 Pennington and Smith, Z. f. anorg. Che?n., 8, 198 (1895); 

 Smith and Desi, Z. f. anorg. Chein. , 8, 205 (1895); Shinn, 

 Thesis, University of Penn'a (1896); Schneider, Jr. prakt. 

 Chem., ^j, 283 (18^6); Hardin, Jr. Am. Chem. Soc, ig, 657 

 (1897); it?id, 2r, 1017 (1899); Thomas, Jr. Am. Chein. Soc, 

 21, 373 (1899); Taylor, Thesis, University of Penn'a (1901). 



The literature pertaining to this subject covers a period of nearly 

 three-quarters of a century. Eight different methods have been 

 used in striving to solve the problem. They are : 



I. Reduction of Tungsten Trioxide. 



Berzelius (2). 



Schneider (5). 



Marchand (2). 



Borch (7). 



Dumas (8). 



Bernoulli (6). 



Persoz (2). 



Roscoe (3). 



Waddell (5). 



Schneider (3). 



Shinn (4). 



Hardin (29). 



A total of 78 reductions. 



