358 Browning and Goodman — Estimation of Yanadium. 



for the most part satisfactory, and an increase in the length of 

 time does not cause any apparent redaction of the molyb- 

 denum. 



Sodium 

 Ammonium tung 

 Error. molybdate 



V2O5 taken, 

 gfm. 



1552 

 1289 

 2583 

 1293 

 2582 

 2582 

 1297 

 1291 

 2582 

 1293 

 2582 

 1550 

 1556 

 1289 

 1549 

 1553 

 1556 

 1293 

 1295 

 1293 

 1293 

 1289 

 1293 

 1556 

 1291 

 1550 

 1554 

 1556 



(1) 



0- 



(2) 



0-. 



('^) 



0- 



(4) 



0- 



(5) 



0-^ 



(6) 



0-^ 



(^) 



0- 



(8) 



0. 



,(9) 



0- 



(10) 



0- 



(10 



0- 



(12) 



0- 



(13) 



0- 



(14) 



0- 



(15) 



0- 



(16] 



0- 



(17) 



0- 



(18; 



0- 



(19> 



0- 



(20; 



0- 



(21) 



0- 



(22) 



0- 



(23] 



0- 



(24) 



0- 



(25) 



0- 



(26) 



0- 



(27) 



0- 



(28) 



0- 



V205 



found, 

 grm. 



0-1558 

 0.1301 

 0-2587 

 0-1299 

 0-2591 

 0-2588 

 0-1308 

 0-1289 

 0-2568 

 0-1299 

 0-2579 

 0-15S8 

 0-1545 

 0-1296 

 0-1527 

 0-1548 

 0-1554 

 0-1310 

 0-1299 

 0-1289 

 0-1301 

 0-1299 

 0-1292 

 0-1567 

 0-1289 

 0-1557 

 0-1557 

 0-1557 



grm. 

 0006 + 



00 1 2 + 



0004 + 

 0006-=- 



0009 + 

 0006 + 

 0011 + 



0002 — 

 0014 — 



0006 + 



0003 — 

 0012— 

 0011 — 



0007 + 

 0022 — 



0005 — 

 0002 — 

 0017 + 



0004 + 

 0004 — 



0008 + 



0010 + 

 0001- 



0011 + 



0002 — 

 0007 + 



0003 + 

 0001 + 



grm. 



state, 

 grm. 



Total Tartaric 

 Time in volume, acid. 



days. 



0-5 

 1- 

 1- 

 1- 



1- 



0-5 

 1- 

 1- 

 1- 



1- 

 0-5 



cm^ 

 25 

 25 

 50 

 25 

 50 

 50 

 25 

 25 

 50 

 25 

 50 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 25 

 30 

 25 

 25 

 25 

 25 



grm. 

 6 

 5 

 5 

 6 

 6 

 5 

 5 

 6 

 5 

 8 

 5 

 5 

 5 

 5 

 5 

 5 

 5 

 6 

 6 

 7 

 5 

 5 

 7 

 5 

 7 

 5 

 5 

 5 



Friedham* has shown that vanadium is reduced from the 

 condition of the pentoxide to that of the tetroxide by boiling 

 with oxalic acid. The reduction is so complete that he has 

 developed a method for the estimation of vanadium upon this 

 reaction and shows that it may be applied in the presence of 

 molybdenum and tungsten, the acids of these elements not 

 being reduced by the oxalic acid. When the vanadic acid is 

 reduced the oxalic acid is oxidized and a definite amount of 

 carbon dioxide evolved according to the reaction. 



V,0. + H,C,0.= V,0. + H,0 + 2C0,. 



This carbon dioxide Friedheim conducts by an appropriate 



* Zeitschr. fiir anorgan. Chem. i, 312, 



