MINERALOGY. 445 



SECOND ORDER. 

 ALKALINE SALTS ALKALIES. 



Mineral Salt is found both in the crystal form or in 

 compact masses. Luster vitreous ; slightly greasy ; 

 rather transparent ; mostly colorless, but sometimes 

 gray, yellow, or red ; rarely blue ; fracture conchoidal ; 

 taste purely salt ; crackles when put into the fire ; dis- 

 solves readily in water. H. = 2.5. G. = 2.2 to 2.3. 



Rock Salt occurs in large masses, forming remarkable 

 deposits, or hanging from the roofs of caves in the form of 

 stalactites. Salt beds are found in rocks of various ages^ 

 from the Red Sandstone primary, secondary in short, 

 in all the formations, mixed with clay, gypsum, and 

 lime ; in Europe the principal locations are Gallicia. 

 Spain, Saltzburg, and Poland. Those of Poland and 

 Hungary are the most remarkable. In the great salt 

 mine of the former, near Cracow, which has been worked 

 since 1251, its deep subterranean regions are excavated 

 into houses, chapels, and other ornamental forms. Illum- 

 ined by lamps, it presents a most imposing sight, the roof 

 being supported by pillars of salt, which, sparkling like 

 gems, fills the beholder not only with admiration but awe, 

 as serving to call up the wonders of creation. The salt 

 rocks of the Pyrenees rise up in lofty crags more than 

 one hundred feet high. Vast lakes of salt water exist in 

 many parts of the world. Lake Timpanoga, the Great 

 Salt Lake of North America, has an area of two thousand 

 square miles. The greater portion of common salt is 

 made from the water of salt springs which issue from 

 these saline rocks or deposits, or from wells made by 



