TiiK srr.sTANCKS OF Till-: EAUTii. 1 ;^> 



(IJoSO^), muriatic ur hydrot-liloi-ic acid (IJCi^, ]»lios])lu)- 

 ric acid (II.jPO.,), silicic acid (tI^Si(J4), cai'ljonic acid 

 (CO,,), nitric acid (UNO..), etc. 



Bases arc a class of snUstaiices whose nature is very 

 different froui tliat of acids. A ])ortion of them arc 

 called alkahcs, or alkahne substances, and have a hot, 

 sharp taste. 



Some of the bases arc potash (KoO), sodium (Na), 

 lime (CaO), magnesia (MgO), oxide of iron or iron rust 

 (FeO), etc. 



Acids and bases have a strong attraction for one an- 

 other, and when united form a class of substances called 

 salts. They are so named because many of them have a 

 taste similar to that of common salt. 



They are called sulphates, chlorates, phosphates, 

 etc., as chlorate of potash (KCIO3), phosphate of lime 

 (CaOPp,), nitrate of soda (NaNO,), etc. ' 



Gypsum, or land |)laster, is sulphate of lime and water. 

 It is the result of a combination of sulphuric acid and 

 quicklime : 



ILSO, + CaO = (CaSO, + H,0). 



Phosphate of lime is produced by a union of phosphoric 

 acid and quicklime : 



2 PI,P04 + CaO = CaOP,05 + 3 H.O. 



If a feather is di[)ped in hydrochloric acid and held 

 over an open bottle of ammonia, the ammonia, escaping 

 bj evaporation, will unite with the acid and form a white 

 powder upon the feather, called amnionic chloride : 



NH3 + IICl = NII.Cl. 



When the two parts of a rochellc i»owder are dissolved 

 and poured together, the acid of the one nnites with the 

 base of the other, producing a salt, which remains dis- 



