PEOEESSOE EOSCOE’S EESEAECHES OX VANADIUM. 
9 
Boat, tube, and vanadic acid after first heating in air 1 hour . . . 2 7 • o 6 8 grms. 
„ „ „ „ second „ 2 hours . . . 27*3684 „ 
,, „ „ „ third ,, 2 hours ... 27*3684 „ 
Hence weight of vanadium pentoxide taken. =7*7397 grms. 
After the reduction the weighings were not begun until every trace of water had dis- 
appeared ; two weighings serve, therefore, to show that a constant weight has been 
reached. 
Boat, tube, and reduced oxide after first heating in hydrogen 5 hours. . 26*0120 grms. 
„ „ „ ,, second „ 3-| hours . . 26*0114 grms- 
The atomic weight calculated from these numbers, according to the above formula, is 
V= 51*257. 
Determination No. 2. — Platinum boat after first heating 
„ „ second 
in air + tube 19*6258 grms. 
„ „ 19*6259 grms. 
Boat, tube, and vanadic acid after first heating in air 2^ hours 
,, „ „ „ second „ 2^ hours 
26*2074 grms. 
26*2079 grms. 
Hence weight of vanadium pentoxide taken =6*5819 grms. 
Boat, tube, and reduced oxide after first heating in hydrogen for 3^ hours . 25*058 grms. 
,, „ „ „ second „ „ 3 „ 25*0569 ,, 
„ „ „ third „ „ 3 „ 25*0560 „ 
„ „ „ „ fourth „ „ 3 „ 25*0555 „ 
The atomic weight calculated from these numbers is V= 51*391 
In order to confirm this result, the reduced oxide was roasted in a current of dry air 
until it again attained a constant weight. The powdery acid obtained was of a very 
brilliant orange-colour ; the following numbers show that the original weight was 
regained to within 0*0004: — 
Platinum boat, tube, and vanadic acid after gently heating in a current 
of air for 14 hours 26*2075 grms. 
Ditto, after heating for 3 hours longer 26*2073 grms. 
Determination No. 3. — The pentoxide employed for this determination was prepared 
by the decomposition of another portion of rectified oxychloride by water. It was free 
from phosphorus, but was not treated with hydrofluoric acid. A hard glass tube heated 
in a magnesia bath was used in this experiment. 
Tube after first heating and cooling 38*4666 grms. 
„ second „ 38*4667 „ 
Tube and vanadic acid after heating 1 hour in dry air . 43*6562 
Plence the weight of vanadium pentoxide taken =5 1895 grms. 
lost 00004 grm., a weight perfectly appreciable with the balance employed, but without influence on the 
results. Stas likewise noticed a regular decrease of weight in a stoppered tube owing to the same cause. 
MDCCCLXVIII. 
C 
