326 
PROFESSOR ROSCOE'S RESEARCHES ON VANADIUM. 
(3) 0*5227 grm. of substance was dissolved in water and reduced by means of zinc 
and sulphuric acid until the liquid acquired the permanent lavender tint of hypovana- 
dous salt. A standard permanganate solution (1 cub. centim. =0*00066 grm. oxygen) 
was then added until the oxidation was complete ; cub. centims. needed, 57*8 = 0*03815 
grm. oxygen, corresponding to 0*1451 V 2 0 5 , or 15*60 per cent, of vanadium. 
(4) 0*5858 grm. substance was precipitated with lead acetate, and yielded 0*6845 grm. 
of 2(Pb 2 V 2 0 7 )+Pb0 (see lead salts) dried at 100°. Hence the pyro-salt contained 
0*09487 grm. of vanadium, or 16*19 per cent. 
(5) 0*5285 grm. of a third preparation yielded on precipitation with sal-ammoniac 
0*1506 V 2 0 5 , corresponding to 16*06 per cent, of vanadium. 
Sodium determinations : — 
(1) 0*5858 grm. substance (Analysis No. 4) yielded in the filtrate from the lead 
precipitate 0*2655 grm. Na 2 S0 4 , corresponding to 14*67 per cent, of sodium. 
(2) 0*5415 substance of another preparation yielded in a similar way, on evaporation 
and ignition, 0*2470 grm. Na 2 S0 4 , corresponding to 14*79 per cent, of sodium in the 
crystallized salt. 
(3) 0*5285 grm. of the crystals (Analysis No. 5) gave 0*1925 grm. NaCl, corre- 
sponding to 14*57 per cent, of sodium. 
Water Determinations. — The crystals lose at 100° C. seventeen molecules of water; 
at 140° C. eighteen molecules are driven off: — 
(1) 0*572 grm. crystals dried at 140° lost 0*290 grm., or 50*69 per cent, of water. 
(2) 0*5415 grm. lost on ignition 0*2893, or 53*4 per cent, of water. 
(3) 0*5285 grm. lost on ignition 0*2719, or 51 *44 per cent, of water. 
In vacuo over sulphuric acid or at 100° C. : — 
(1) 0*6535 grm. in vacuo lost 0*3185=48*73 per cent. 
(2) 0*499 grm. of another preparation lost in vacuo 0*234=46*89 per cent. 
(3) 1*0755 grm. dried at 100° lost 0*5205 = 48*39 per cent. 
(4) 0*572 grm. dried at 100° lost 0*279 =48*77 per cent. 
The numbers obtained from the foregoing analyses agree with those calculated from 
the formula 
Na 4 Y 2 0 7 +18H,0. 
Calculated. Found. 
r 
A 
'N 
f 
Vv 
Mean. 
Na 4 . . 
. 92*0 
14*58 
14*67 
14*79 
14*57 
14*68 
V 2 ■ • 
. 102*6 
16*27 
16*29 
15*71 
[15*60] 16*19 16*06 
16*06 
o 7 • . 
. 112*0 
17*77 
— 
— 
— 
ISHo O . 
. 324*0 
630*6 
51*38 
100*00 
50*69 
53*40 
51*44 
51*84 
When a solution of tetrasodium vanadate is treated with carbonic acid the salt is 
