MANUAL OF NATURAL HISTORY. 601 



inland seas, in brine springs, or in beds, prin- 

 cipally in New Eed-Sandstone ; 5, as Biborate, 

 or "Borax/' in oblique prisms, H. 2-2*5, sp. gr. 

 1*71, grayish-blue, rather brittle, in Thibet, 

 Peru, and Ceylon ; 6, as Carbonate, or " Na- 

 tron/' the Nitre of Scripture, in rhombic octo- 

 hedrons, H. 1-1*5, sp. gr. 1*423, effervesces 

 with acids, in Egypt ■ and 7, as Sesquicar- 

 bonate, or " Trona/' in rhomboid prisms, H. 

 2*5 — 3, sp. gr.2*ll, gray, translucent, in Mara- 

 caibo and at Fezzan. Salts of Soda tinge 

 flame of a deep yellow colour. Symb. Na. 



6. Family. — Kaliides. Minerals containing com- 



pounds of Potassium. Occur as Sulphate, or 

 " Aphthitalite/' trimetric, H. 2-3, sp. gr. 1*73, 

 whitish, translucent, on Vesuvian lava; 2, as 

 Nitrate, or " Nitre/' in rhombic prisms, H. 2, 

 sp. gr. 1*93, white, sub-transparent, brittle, 

 deflagrescent, in crusts on the earth in various 

 places; 3, as Chloride or " Sylvine/' cubical, 

 H. 2, sp. gr. 2, white, vitreous, on Vesuvius. 

 Salts of potassa colour flame violet. Symb. K 



7. Family. — Lithiides. Minerals containing com- 



pounds of Lithium. Occur sparingly as 

 Oxide in some Siliceous minerals, as " Lepi- 

 dolite," "Petalite," " Spodumene," and «Li- 

 thion-mica." Lithia and its salts give a red 

 tinge to flame. Symb. Li. 



IY. ORDER— Molibdexides. 

 Minerals containing metals of the lead series, in 

 various states of combination ; solid. 



