ALUM BORAX NITRE SALT SODA 87 



B.F. fuses with difficulty on the edges. Dissolves slowly 

 in nitric acid without effervescence. In Canada occurs 

 extensively in limestone of the Laurentian age. 



ALUM (hydrated sulphate of potash and alumina). 

 Is best known by its astringent, sweetish taste. 



H. 2 to 2-5; S.G. 1-8. 



Soluble in its own weight of boiling water. 



Found in clay slates. 



BORAX (lor ate of soda). 



A white, opaque mineral of vitreous lustre, of conchoidal 

 fracture, and of a sweetish alkaline taste. Before B.F. it 

 swells up and becomes opaque, but melts afterwards to a 

 transparent globule. Found as a lake deposit in Tuscany, 

 Nepaul (India), and in various parts of America. 



NITRE (saltpetre). 



Is usually found native as an efflorescence on the soil. 

 Is soluble in water. When thrown on live coal, causes vivid 

 combustion. Composed of potash and nitric acid. 



COMMON SALT (chloride of sodium). 



Colour white or greyish, sometimes rose red. Crackles 

 when heated. Taste saline. 



Salt deposits are found in strata of various ages, and often 

 associated with gypsum, magnesia, soda, &c. 



NITRATE OP SODA. 



Of various colours. Found as an efflorescence, also in a 

 crust-like form. Soluble in water. When heated it de- 

 liquesces and burns with a yellow light. It may be dis- 

 tinguished from nitre by its deliquescing on exposure. 

 Found in surface deposits, and under a conglomerate con- 

 taining felspar, phosphates, &c. Associated with it are 

 common salt, gypsum. Immense quantities are obtained 

 from Chili. 



