434 Vanadic Acid. 



Bavaria, but have not ascertained how much, this mineral 

 generally contains; neither did Sefstrom nor Schultz and 

 Bodeman determine the quantity of vanadium present in the 

 iron ores which they investigated. Deville likewise detected the 

 presence of vanadic acid in bauxite, an aluminiferous mineral, 

 from Baux, in the south of France, utilised in the manufacture 

 of aluminium. The quantity of vanadic acid present in the 

 flower-pots of the Jardin des Plantes was not determined. To 

 allude to some substances which usually accompany vanadic 

 acid in clays, I will mention that titanic acid and tantalic have 

 been both found by myself and other chemists ; also phosphoric 

 acid is very usually present in small quantities. 



One hundred parts of vanadium ochre gave me on analysis 

 water and a little organic matter, 12' 60 ; oxide of iron, 57'50 

 alumina, 5'00; vanadic acid, T90; phosphoric acid, 2*20 

 titanic acid, traces ; magnesia, 0*30 ; lime, 0'20 ; carbonic 

 acid, 0-24; silica or quartz, 20-00 =99'94. 



Let us take 0*05 per cent, as the probable quantity of 

 vanadic acid contained in the greater bulk of that vast geo- 

 logical deposit known as the London clay. At this rate one 

 ton of London clay would contain about 1 lb. 2 oz. of vanadic 

 acid, say 1 lb. to the ton in round numbers. If we suppose 

 that there exists only about a million tons of this clay at the 

 west end of London, for instance, in the Hyde Park and 

 Bayswater districts alone, we have evidently there upwards of 

 445 tons of vanadic acid ! 



And if we calculate the quantity of vanadic acid which 

 exists in the London clay of the metropolis, supposing London 

 to cover fifty square miles, and taking the stratum of clay at 

 the moderate thickness of four yards, we find that, under this 

 city alone there lies probably far more than 303,443 tons, or 

 about 679,712,320 lbs. weight of vanadic acid; the present 

 price of this substance in shops where chemical curiosities are 

 sold being about one shining and sixpence per grain, or £32 5s. 

 6d. an ounce ! 



I have not the slightest doubt that all clays contain similar 

 quantities of vanadic acid, and if it can be extracted with 

 tolerable ease, both this substance and the metal it contains 

 may sooner or later prove themselves new industrial agents in 

 the hands of man. It remains only to discuss the most advan- 

 kageoua method of extracting vanadic acicj, and it will be seen 

 fehat the operation may be reduced to a very simple process : — 

 M. Bcauvallet, M. Pisani, and myself began by boiling the 

 baked clay of the flower-pots with three per cent, of its weight of 

 c;nl)onato of soda and a sufficient quantity of water. Finding 

 that caustic soda, as recommended by H. Deville, appeared to 

 answer better, I repeated the experiments with it in place of 



