PROFESSOR ROSCOE’S RESEARCHES OH' VANADIUM. 
Ho. of expe- 
Weight of trichlo- 
Weight of silver 
Percentage of 
riment. 
ride taken. 
required for complete 
chlorine*. 
precipitation. 
1 . 
2*4322 
4*5525 
61*49 
Analyst A. 
2. 
4*6840 
8*7505 
61*37 
55 
3. 
4*2188 
7*8807 
61*37 
55 
4. 
3*9490 
7*3792 
61*39 
5. 
0*9243 
1*7267 
61*37 
55 
6. 
1*4330 
2*6769 
61*37 
7. 
2*8530 
5*2853 
60*86 
Analyst B. 
8. 
2*1252 
3*9535 
61*11 
55 
9. 
1*4248 
2*6642 
61*43 
55 
Mean result . 
. . 61*306 
Gravimetric Determination of the Chlorine. — As a check on the volumetric analysis, 
weight estimations were made 
in the usual way, 
it having been proved that no trace of 
vanadium is 
carried down with the silver in nitric acid-solution. 
The trichloride used in these experiments was 
taken from four different preparations ; 
analyses Nos. 4, 5, and 7 were made from the 
same sample by two 
different experi- 
menters. 
Ho. of expe- 
Weight of trichlo- 
Weight of silver 
Percentage of 
riment. 
ride taken. 
chloride obtained. 
• chlorine. 
1 . 
1*8521 
4*5932 
61*33 
Analyst B. 
2. 
0*7013 
1*7303 
61*01 
55 
3. 
0*7486 
1*8467 
61*00 
55 
4. 
1*4408 
3*5719 
61*30 
55 
5. 
0*9453 
2*3399 
61*21 
55 
6. 
1*6183 
4*0282 
61*55 
7. 
2*1936 
5*4309 
61*22 
Analyst A. 
8. 
2*5054 
6*2118 
61*31 
55 
Mean result . 
. . 61*241 
The atomic weight of vanadium calculated from the mean (61*276) of the above seven- 
teen determinations is 
(106*371x100) -•(122*371 x 61*276) „ . 0 n 
61*276 — ol*^J. 
Taking the mean of the numbers found (1) by the reduction of vanadium pentoxide in 
hydrogen, viz. 51*37, and (2) by the determination of chlorine in vanadyl trichloride, 
viz. 51*29, we have the number 51*33 as the mean atomic iveight of vanadium. 
Determinations of Vanadium. — The vanadium in vanadyl trichloride was directly 
estimated in some instances (Nos. 1 and 4) in separate portions of the trichloride, whilst 
in other cases (Nos. 2 and 3) it was estimated in the filtrate from the chlorine deter- 
minations. 
* Stas’s numbers are here used, viz. 0 = 16, Ag = 107-93, Cl = 35-457. 
