127 



8156, 8157, "Washington Heiglits, New York : minute crystals. 



Silicate of vanadium ; a very rare mineral, said to always carry sosccelite, 

 gold. 1279, 3873, Granite Creek, El Dorado County, California. 



8552, country rock of the Lady Charlotte Mine, Kalgoorlie, Vanadium. 

 West Australia : stained with vanadium. 



A sulpho-vanadate of copper has recently been found in South 

 Australia. 



Sulph-arsenide of thallium. 6671, Alchar, Macedonia. Lorandite. 



3893, Selen-tellurium with durdenite, Honduras. Selenium. 



8291, metallic : artificially prepared. 



PHOSPHATES. Case 91. 



The large amount of phosphoric acid withdrawn from the soil 

 as plant-food has rendered the use of phosj^hatic manures indis- 

 pensable. Natural phosphates have now been found in most 

 parts of the world ; they vary much in appearance and character, 

 and, being generally of an earthy nature, their recognition is 

 not easy. 



Before natural phosphates can become available for plant-food 

 they generally have to be treated with sulphuric acid, which 

 converts the phosphate of lime into a soluble condition. The 

 linings from the converters used in treating phosphoric iron- 

 ores are of great manurial value. 



Crystalline phosphate of lime — apatite-^ — occurs in veins in Eock 

 Canada, Norway, and elsewhere, but the cost of mining is such 

 that the deposits are not now remunerative. Eock phosphate 

 occurs in ancient crystalline rocks. 



7488, 7159, green and red varieties respectively of Canadian 

 rock phosphate. 



6175, Norwegian rock phosphate. 



In France, Spain, Russia, and England, extensive deposits of other 

 nodular phosphate of lime occur ; these are of sedimentary °^^ ^ ^^' 

 origin. In Florida and Carolina immense beds are found, 

 variously known as "laud," "river," or "pebble" phosphates, 



* See case 102, page 160. 



