31J 



IX. WATERY LIQUIDS. 



NATURAL WATERS. 



The salts obtained by tbe evaporation of a mineral water are 

 not to be considered as its real contents, because new combinations 

 are formed during the process, and the most insoluble compounds 

 possible are separated iirst : whereas, in the original water there is 

 good reason to suppose tiie real mode of composition is that of the 

 most soluble compositions that are capable of being formed from 

 the remote principles contained in the water. Hence those com- 

 mon products, sulphate of lime and muriate of soda, probably exist 

 in mineral waters as sulphate of soda and muriate of lime, and it 

 is to the presence of the latter salt that much of the medical effects 

 of mineral waters is to be ascribed. 



River water, Aqua fluviatilis ; — Rain water, Aq. pluvialis. 

 Are the purest of the common waters. 



Snow water, Aq. nivalis. Is also very pure. 



Spring water, Aq. fontana. Generally contains sulphate of lime 

 and muriate of soda. The purest spring waters hitherto discovered 

 the Malvern spring water of England, and the Madras spring 

 ater of India, which is even superior to the Malvern. 



Acidulous waters, Acidulce, Taste acid, sparkle on being 

 floured out ; contain an excess of carbonic acid, and almost con- 

 tantly common salt, with some of the earthy carbonates. 



Chalybeate waters, AqtuB dialybeatce. Strike a black 

 colour with oak bark or other vegetable astringents, sometimes are 

 also acidulous ; these deposit their iron upon boiling, as those of 

 the Spa and Pyrmont ; others vitriolic, and retain their power 

 of striking a black colour after being boiled and filtered, as that 

 of Westwood in Derbyshire. 



Sulphureous waters, Aq. sulphnreo'.. Stink like rotten eggs, 

 blacken silver and lead, contain sulphuretted hydrogen, either 

 uncombined or united to lime or an alkali. Harrowgate is well 

 known. 



Hard waters, Aq. fontana. Curdle soap even after boiling; 

 contain sulphate of lime. 



Salt waters, Aq. salimc. Easily recognised by their saline 

 taste, and the salt crystallizing in cubes ; precipitate the solution 

 of silver, lead, or quicksilver in spirit of nitre, forming a white 

 cloud. 



Purging waters, Aq. catharticce. Bitter, purgative, preci- 



