PEOFESSOE EOSCOE’S EESEAECHES ON VANADIUM. 
27 
Analysis (2). Weight of nitride taken =0-2000 grm. 
Observed vol. of nitrogen 
(measured moist). Pressure. Temp. Vol. at 0° and 760 millims. 
112 vols. 682-1 millims. 13° 31-8 cub. centims. 
(1 vol. =0-331 cub. centim.). 
This corresponds to a percentage of 20-0 nitrogen. 
Calculated. Found. 
Vanadium . . 61-3 78-6 77-8 
Nitrogen . . . 14-0 21-4 20-3 20-0 
65-3 
2. Vanadium Dinitride, VN 2 =79-3. — This substance is obtained as a black powder 
by passing dry ammonia over vanadyl trichloride heated in a glass tube to expel sal- 
ammoniac, washing with ammonia-water, and drying in vacuo over sulphuric acid. 
This nitride was obtained in 1858 by Uhrlaub*, but this chemist made no direct 
determination of the nitrogen, by which alone the true nature of these compounds can 
be discovered; and he, adopting, as a matter of course, the atomic weight 68-5, showed 
that the body obtained as above described cannot be represented by any simple formula. 
If, however, Uhrlaub’s experimental results be calculated with the true atomic weight 
51*3, it is seen that, according to the mean of three determinations, the substance con- 
tains 64-1 per cent, of vanadium, the formula VN 2 requiring 64-6 per cent. 
The existence of vanadium mononitride, V N, not only demonstrates with absolute 
certainty the true atomic weight of the metal, but it also serves as the starting-point 
from which to commence the study of the metal, as well as of an entirely new class of 
bodies, viz. the compounds of the metal vanadium with chlorine and the other halogens, 
which I have in vain endeavoured to obtain from vanadyl compounds. In the next 
communication I hope to describe these interesting substances. 
* Pogg. Ann. Bd. ciii. p. 134. 
