M. Berzelius on Vanadium. 32y 



extracted from it by means of an alkaline hydrosulphuret, by 

 fusing the residue with sulphur and carbonate of potash. Sul- 

 phovanadate of potash is formed, from which sulphuret of 

 vanadium may be precipitated by sulphuric acid. 



Vanadium is very difficult of reduction by the usual methods, 

 that is to say, by heating the oxide in a charcoal crucible ; for 

 it is reduced only at the places in which it is in immediate 

 contact with the charcoal, and the interior is a suboxide, as in- 

 fusible as the metal itself at the temperature at which man- 

 ganese undergoes fusion. 



With potassium the reduction is easy ; pieces of vanadic 

 acid, which have been previously fused, are to be mixed with 

 pieces of potassium of equal bulk in a porcelain crucible; the 

 cover is to be well fastened on, and the crucible is to be heated 

 with a spirit-lamp. The reduction occurs almost instantane- 

 ously with a kind of detonation. The crucible, when cold, is 

 to be put into water to dissolve the potash, and the reduced 

 vanadium is to be collected on a filter; it is obtained in the 

 state of a black powder, which shines in the sun, and takes a 

 grayish metallic lustre underthe burnisher. But in this way a 

 true idea of the aspect of the metal is no more obtained, than 

 of that of gold precipitated from solution by the salts of iron. 



When the method discovered by M. Rose for the reduction 

 of titanium is employed to reduce vanadium, the experiment 

 succeeds more completely than with potassium. For this pur- 

 pose, chloride of vanadium is prepared, by passing a current 

 of dry chlorine over a mixture of vanadic acid and very dry 

 charcoal. This chloride is a volatile fuming fluid, and it is to 

 be introduced into a glass bulb blown on a barometer tube; a 

 current of dry ammoniacal gas is passed through the tube until 

 the chloride is entirely saturated. Sal ammoniac subhmes, 

 which may be expelled from the tube by another spirit-lamp. 

 The reduced vanadium remains in the bulb, and an inconsi- 

 derable portion is reduced at that part of the tube which is 

 kept iiot. On cutting the bulb afterwards in two, the vanadium 

 is found in the state of a silvery white stratum, whicii on the 

 side next the glass reflects like a mirror, and is white like po- 

 lished stet'l. If water and atmospheric air are not entirely 

 excluded, a small quantity of black powder is found in the 

 middle of the mass ; this is suboxide of vanadium, and is easily 

 detached. 



Vanadium is white, and when its surface is polished it re- 

 sembles silver considerably, or molybdenum, which of all 

 metals it is most like. It is not ductile, and is easily reduced 

 to a powtler oi'an iron gray colour. I iiave not enough of it, 

 nor arc my specimens in a convenient form, to determine its 

 2 T 2 specific 



