PHYSIOGRAPHY. 77 



Natron. 



4. It has been found in the mine of Maria Loretto at Faceberg, near 

 Zalathna in Transylvania. It was melted to extract the gold, but has 

 now become very scarce. 



NATROLITE. (See Mesotype.} 

 NATRON. Hemi-prismalic Natron-Salt. 



. MOHS. 



In imitative shapes : composition columnar. Massive : 

 composition granular. Commonly occurring in the state of 

 powder, or efflorescent crusts. . 



Lustre vitreous on the fresh fracture. Color white, the 

 grey and yellow tints are owing to foreign admixtures. 

 Streak white. Semi-transparent. 



Sectile. Hardness =1-0 ... 1*5. Sp. gr. = 1-423. 



Taste pungent, alkaline. . . 



1. It is very soluble in water, effloresces with. acids, and melts before 

 the blow-pipe. Blue vegetable colors are changed by it to green. 



2. Analysis. 

 By BEUDANT. 



from Debreezen. from Egypt. 



Carbonic acid - - 30-40 - - - - 30 90 



Soda - - 4320 - - - - 4380 



Water - - 13-80 .... ]3-50 



Sulphate of soda - - 10-40 .... 7-30 



Chloride of sodium - - 2-20 .... 3-10 



Earthy matter 0-00 .... 1-40 



3. This salt loses its water on being exposed to a dry atmosphere, and 

 is therefore commonly met with in the state of an efflorescent powder on 

 the surface of the earth, on the shores of lakes, or in natural caverns. It 

 is held in solution by certain mineral waters. According to BERTHO- 

 I.ET, it is formed in part by a decomposition of common salt by carbonate 

 of lime. 



4. It occurs in considerable quantities in the plains of Debreezen, in 

 Hungary ; also in Bohemia, Italy and several other European countries, 

 but principally in the soda lakes of Egypt, and in same parts of Asia and 

 South America. 



7* 



