Browning and Goodman — Estimation of Vanadium. 357 



Ammonium Tartaric 



V2O5 taken. 



Y2O5 found. 



Error. 



molybdate. acid 





grm. 



grm. 



grm. 



grm. grm 



(0 



0-1620 



0-1790 



0-0170 + 



1 2 



C^) 



0-1624 



0-1619 



0-0005 — 



1 2 



(3) 



01294 



0-1416 



0-0253 + 



1 2 



4) 



0-1296 



0-1361 



0-0065 + 



1 2 



h 



0-1291 



0-1312 



0-0021 + 



1 2 



(6) 



0-1293 



0-1324 



0-0031 + 



1 2 



(^ 



0-1636 



0-1760 



00124 + 



1 2 



(8) 



0-1640 



0-1724 



0-0084 + 



1 2 



(9) 



0-1622 



0-1624 



0-0002 + 



1 3 



(10) 

 (11) 



0-1622 



0-1632 



0-0010 + 



1 3 



0-1619 



0-1879 



0-0260 + 



1 3 



(12) 



0-1292 



0-1360 



0-0068 + 



i 3 



(13) 



0-l«60 



0-1917 



0-0057 + 



1 3 



(14) 



0-32V4 



0-3733 



0-0459 + 



1 4 



(15) 



0-2324 



0-2383 



0-0059 + 



1 4 



We next tried the action of tartaric acid upon the vanadium 

 solution in the cold and found that the reduction could be car- 

 ried on to completion under these conditions if the tartaric 

 acid was in large excess, the time sufficient and the volume of 



the solution small, 

 mine these points : 



The following series was made to deter- 



(') 



(2) 

 (3) 

 (4) 

 (5) 

 (6) 

 (7) 

 (8) 

 (9) 



VaOo taken, 

 grm. 



0-1646 

 01640 

 0-1293 

 0-1633 

 0-1293 

 0-1298 

 0-1295 

 0-1617 

 0-1623 



2O5 found, 

 grm. 



0-1649 

 0-1606 

 0-L264 

 0-1628 

 0-1288 

 0-1299 

 0-1279 

 0-1597 

 0-1622 



Error, 

 grm. 



00003 + 

 0-0034 — 

 0-0029 — 

 0-0005 — 

 0-0005- 

 0-0001 + 

 0-0016 — 

 0-0020 — 

 0-0001 — 



Time. 



days. 



1 

 1 

 2 

 2 

 3 

 3 

 3 

 4 

 4 



Tartaric 

 acid, 

 grm. 



4 



4 



3 



4 

 2-5 

 2-5 



3 



2 



3 



Total vol. 

 cm^. 



25 

 65 

 55 

 65 

 50 

 50 

 55 

 70 

 80 



ammonium 



Solutions containing sodium tungstate and 

 molybdate were allowed to stand from one to four days with 

 varying amounts of tartaric acid without giving any evidence 

 of reduction. 



In the series which follows may be seen the results of a 

 number of determinations of vanadium in the presence of 

 molybdenum and tungsten made in the cold and allowed to 

 stand from one* to four days. It will be noticed that the 

 results on standing one day with five grams of tartaric acid are 



* Some of the determinations designated in the table as having stood one day 

 in reality" stood only about fifteen hours, from 6 p. M. to 9 a. m. 



