REPORT ON CHEMISTRY. 
>169 
1830, in the iron from the forges of Eckersholm in Sweden, 
and by myself in the beginning of 1831 in an ore of lead from 
Wanlock Head, and before Sefstrom had published anything 
upon the subject. It approaches nearest to chromium in its 
properties, and lies in a natural arrangement between that 
metal and molybdenum. It is characterized by giving, in the 
form of oxide, blue salts with acids, with oxygen forming a pe¬ 
culiar acid, which fuses at a red heat without decomposition, 
and on cooling is reddish brown and crystalline, and which gives 
with bases, colourless neutral and orange-coloured acid salts. 
Before the blowpipe it behaves itself like chromium, with this 
characteristic difference—that the green colour with borax can 
in the oxidizing flame be changed into a pale yellow. 
Vanadium has three degrees of oxidation, represented by V, 
«• 
V,v. . 
Protoxide. —Th e protoxide^, is dark brown or black, soluble 
in nitric acid and in aqua regia, but does not form salts. It is 
obtained by reducing vanadic acid in hydrogen gas. 
Blnoxide .—The binoxide , V, is black and infusible, heated in 
the air attracts oxygen, and is changed into vanadic acid. It 
forms salts with the acids, which when anhydrous are dark 
brown, and when they contain water of a deep blue, like the 
salts of copper. They crystallize with difficulty ; the sulphate 
forms a sirupy liquid in which crystals are gradually formed. 
Its salts have a sweetish astringent taste. It combines also 
with alkalies, giving brown soluble compounds ; with the other 
bases its compounds are insoluble, but are convertible, by 
heating in the air, into vanadiates. 
••• 
Vanadic acid .— Vanadic acid , V, in the state of powder is 
yellow; at a red heat it fuses readily, and on cooling crystal¬ 
lizes in beautiful prismatic crystals, transparent at the edges, 
of a reddish brown colour and a high degree of lustre. These 
crystals belong to the hemiprismatic system, have at least one 
axis of double refraction, and are remarkable for possessing a 
higher refractive power than any other known body. In some 
very huge crystals which I obtained by very slow cooling, Sir 
David Brewster found the polarizing angle = 69° 37', giving a 
refractive power = 2*691. That of chromate of lead is 2*5, 
and the highest determination for diamond that is to be de¬ 
pended on = 2*487. 
This acid is sparingly soluble in water and alcohol, to both 
of which liquids it imparts a yellow colour ; water does not take 
up T oijodth part. It forms with bases neutral salts, which in 
