176 



SODIUM CARBONATE. 



c. Soda ash, or British alkali. (Anhydrous Carbonate of 



Sodium.) 



d. Ditto, ground. 



e. Ditto, purified. 

 /. Yellow alkali. 



g. Carbonate of sodium in crystals, purified. 

 h. Ditto, exsiccated. 



Note. For fig. of crystal, see Per. Mat. Med., vol. i., p. 560 ; Phillips, 

 Transl. Pharm., 1851, p. 359. 



84. SESQUICARBONATE. 



f a. Native. (Natron, Trona.) 



Note. This mineral is the nitre of Scripture spoken of in Prov. 

 xxv. 20. The word translated nitre, should have been rendered natron. 



85. BICARBONATE. Na H C 3 ." (Hydric Sodic Carbonate, Acid 



Carbonate of Sodium.) 



a. Efflorescence from Carbonate of Sodium. 



b. Pure. 



c. Ditto. B. P., 1864. 



* d. Fine specimen of crystals of the carbonate, coated with 



an efflorescence of bicarbonate. 



Note. Specimen d will be found in the central window ledge of the 

 Chemical Mtuseum. 



86. CHLORATE. NaC10 3 . 



a. Pure, in crystals. 



87. CHLORIDE. Na Cl. (Common Salt, Muriate of Soda.) 



a. Native. (Rock Salt, Sal Gemmce, Sal Fossilis.) 



* b. Ditto, fine specimen. 



c. In hard cubical crystals. (British Bay Salt.) 



d. In minute crystals. (Table Salt, Culinary Salt.) 



e. In hollow pyramidal crystals. (Maldon Salt.) 



f. In crystalline masses. (Bay Salt, Sal Marinus, Sal 



Niger.) 



g. In crystalline powder, prepared from kelp. 



Note. Specimen e consists of crystals which form on the surface of the 

 brine during evaporation, the apex of the pyramid being first formed. 

 Some tolerably perfect specimens of these crystals may be seen in the 

 case containing the glass models of crystalline forms (Case 9). See Per. 

 Mat. Med., vol. i., p. 586. Specimen c was obtained by slow evaporation, 

 and specimen d by rapid evaporation of the brine of brine springs. 

 Specimen / was made from sea water. 



88. HYDRATE. NaHO. (Caustic Soda.) 



a. Crude, in tabular pieces. 



b. Purified. 



c. Pure, from Sodium. 



