Natural Historj/. 197* 



all the kinds of mica, contain fluoric acid. Two species from 

 Sweden contained a considerable quantity. 



4. Tremolitc, — M. C. G. Retzius analyzed the tremolite, 

 and found it to contain — 



Silex 54.26 



Lime 23.16 



Magnesia • • 7.56 



Carbonate of Lime .. 13.86 

 Loss 1.16 



100. 



5. Volcanoes of Tariary. — M. Abel Remusat, in a letter to 

 M. Louis Cordier, relating to the origin of the sal ammoniac, 

 obtained by the Calmucs, and by them distributed through 

 Asia, quotes the following passage from the Japanese edition 

 of the Chinese Encyclopsedia, in the king*s library, which not 

 only describes the source of this salt, but also two active vol- 

 canoes in the interior of Tartary. 



"The salt, named (in Chinese) nao-cha^ and also salt of 

 Tartary and volatile salt, is obtained from two volcanic moun- 

 tains in Central Tartary. One is the volcano of Tourfan*, 

 which has given to this town (or rather to a town three leagues 

 to the east of Tourfan,) the name of Ho-Tcheou, or town of fire. 

 The other is the white mountain in the country of Bisch-Balikhf. 

 These two mountains continually emit flame and smoke. There 

 are cavities in them in which a greenish liquid collects, which, 

 when exposed to the air, changes into a salt, which is the 

 nao-cha ; the people of the country collect it for the prepa- 

 ration of leather, 



A column of smoke may be continually seen coming from the 

 Tourfan, which, in the night, is replaced by a flame similar to 

 that of a flambeau. Birds, and other animals, illuminated by 

 it, appear of a red colour. This mountain is called the Hill of 



* Lat. 43°. 30'., long. 87°. 11'. according to P. Gaubil. 



t A town situated on the river 111, to the S. W. of the lake of Balgasch 

 >vhich the Chinese name the hot sea. The latitude of the lake of Balgascb, 

 is 46°. ; long. 70°. 11 . according to P. Gaubil. 



