326 SALTSSULPHATES. 



b.) Taste sharp and bitter. 



c.) Solubility at 60 ; water 1, salt 2 ; at 212, equal parts. 



d.) During its solution it produces cold. 



e.) Little affected by the air, or slightly efflorescent. 



/.) Heated, suffers watery fusion, sublimes in part, and is then 

 sour, and reddens vegetable blues. By a still higher heat, com- 

 pletely decomposed, and resolved into nitrogen, water, and sulphu- 

 rous acid. 



5. COMPOSITION. 



Acid, 53.1 or 1 propor. =40 

 Ammonia, 22.6 1 " =17 



Water, 24.3 2 " =18 



100.0 75 its equivalent number. 



If water be subtracted, it leaves 57 for anhydrous sulphate, which 



is known only in theory. Dr. Thomson admits but one proportion 



of water, in the crystallized salt, which would reduce its equivalent 



to 66. 



6. DECOMPOSITION. 



The nitric and the muriatic acids decompose about J of the salt. 

 Potassa and soda, baryta, strontia and lime, liberate the gas 

 ammonia, forming a sulphate of the base. Sulphate of soda, and 

 sulphate of ammonia, when mingled, form a triple crystallizable salt.* 

 (c.) Deflagrates with melted nitre, being resolved into water and 

 nitrogen. 



SULPHATE OF LIME. 



1. PREPARATION, NATURAL HISTORY, &c. Formed by the mu- 

 tual action of diluted sulphuric acid and marble, or chalk, or by the 

 same acid and any soluble calcareous salt, or lime water; the sul- 

 phate precipitates. 



2. PROPERTIES. 



Melts before the blowpipe, and in furnace heats. 

 Solubility in cold water, 500 parts to 1, in 450 at 212, and 

 crystallizes on cooling. Soluble entirely in dilute nitric acid. 



(c.) Causes waters to be hard, decomposing the soap that is 

 mingled with them ; the acid unites with the alkali, and the oil with 

 the earth, to form an earthy soap ; by adding solution of soap to so- 

 lution of sulphate of lime, this effect is manifested. 



(d.) Thrown down by alcohol from its aqueous solution. 



(e.) Decomposed by boiling with baryta, strontia, potassa and soda, 

 and by their carbonates, or at least by those of the fixed alkalies ; 

 see those articles. 



Th. Ill, 362. 



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