28 



CHEMICAL MAXUEES. 



phosphorite is found as nodules with a smooth and pohshed surface,, 

 rarely rugose or exfoliated, sometimes greasy to the touch and 

 resembling polished cast-iron, 2 to 2^ inches in diameter ; some are 

 8 inches in diameter. Their composition is as follows : — 



TABLE XX.— ANALYSIS OF RUSSIAN PHOSPHOEITE NODULES. 



The richest and most extensive phosphate deposits are those 

 of Central Eussia. They occur chiefly in the governments of 

 Podolsk, Kostromo, >molensk, Koursk, Woronesch, Simbirsk, Tam- 

 bow, and on the banks of the Volga, from which they trend towards 

 the West as far as Niemen ; they occupy a surface of 20,000,000 

 hectares (50,000,000 acres). The richest deposits consist in part of 

 phosphate of lime, mixed with organic matter. According to a 

 recent announcement it has been found that the building- stone 

 used in the whole district is nothing but phosphate of lime. That 

 is a highly interesting fact. The phosphorite contains :• — 



TABLE XXL— ANALYSIS OF CENTRAL EUSSIA PHOSPHORITE. 



These immense deposits are not utilized. They are to all 

 appearance destined to form the reserve from which Europe will 

 draw^ when the deposits now being used up will be exhausted. 



YIII. Spain. — There exist in the province of Estremadura ex- 

 tensive phosphate deposits, forming well-defined veins. At Log- 

 rosan the veins occupy a space of 12 to 20 sq. miles, they 

 traverse the granite and the Silurian schists and only contain 

 phosphate and quartz. The phosphate is apatite. It occurs as 

 regular, generally dull hexagonal prisms of a yellowish or greenish 

 colour, and unequal. It is found in its gangue first as more or less 

 voluminous, crystalline fragments of 0-2 to 1 inch in length, then 

 as crystals almost invisible to the naked eve, and distributed 



