PHYSIOGRAPHY. 1S1 



Soda-Nitre Solfatarite. 



Cleavage, perfect parallel with the primary faces. Frac- 

 ture conchoidal, almost imperceptible. Surface smooth. 



Lustre vitreous. Color white. Streak white. Trans- 

 parent. 



Rather sectile. Hardness = 1-5 ... 2-0. Sp. gr. = 

 2-0964. Taste cooling. 



Compound Varieties. In efflorescences. 



1. It melts and deflagrates with a yellow light upon red-hot charcoal, 

 but not so violently as Nitre. It is soluble in three times its weight of 

 water, at 60 F. If rubbed in an isolated state, it acquires a very strong 

 negative electricity. 



2. Analysis. 



By BERZELIUS. 



Nitric acid .-.'.... 54-97 



Soda - 45-03 



It contains a little sulphate of potash. 



3. It is found in immense quantity in the District of Tarapaca in Peru, 

 near the frontiers of Chili, three days' journey from La Conception, a 

 port of Chili. It also comes from Iquiqui, a port in the south pf Peru. 

 In these countries, it forms a bed many feet thick, which in some places 

 appears on the surface, occupying aji extent of more than forty leagues. 

 It is frequently mixed with clay and sand. 



4. Very large quantities of this salt, purified by solution and crystal- 

 lization, are carried into Europe, and imported into the United States. 



SOLFATAR1TE. Prismatic Alum-Salt.' 



Massive ; composition columnar, individuals thin, straight 

 and parallel. Cleavage in one direction, perfect. 



Lustre vitreous, to pearly. Color white ; transparent 

 to translucent. 



Hardness=2-0...2-5. Sp. gr.==l-88. Taste sweet- 

 ish astringent. 



1. It is more soluble in water than alum. 



