SECTION II 



Inorganic Materia Medica 



WATER 

 AQUA. Hydrogen Oxide or Monoxide. H 2 0. 



WATER exists in the solid, liquid, and gaseous forms. It is 

 transparent, neutral, colourless, odourless, and tasteless. A 

 minim weighs *91 grain ; a fluid ounce, 437*5 grains. It is 

 the standard of comparison for specific gravities of liquids, 

 its specific gravity being represented as 1 or 1000. It solidi- 

 fies, freezes, or crystallises at 32 Fahr., expanding and giving 

 out latent heat ; it reaches its greatest density at 39 0< 2 Fahr.; 

 it slowly volatises at all temperatures ; at 212 Fahr. it 

 boils, rising in steam, and increasing in bulk 1700 times. A 

 cubic inch of water becomes a cubic foot of steam. When 

 the solid ice melts, heat is absorbed or becomes latent ; when 

 the liquid water boils, or gives off gas, still more heat is 

 absorbed. A cubic foot of water on conversion into steam 

 renders latent 900 units of heat. The melting ice and 

 evaporating water, thus abstracting heat from bodies in 

 contact with them, are valuable refrigerants. 



Water is almost a universal solvent ; it readily dissolves 

 many mineral matters, gases, and organic substances. 

 From soils and rocks through which it passes it takes up 

 salts, especially of calcium, magnesium, and sodium, and 

 occasionally of lead. It absorbs atmospheric air, carbonic 

 acid, and other gases, some adding to its sparkling, refresh- 

 ing, and palatable qualities, others rendering it disagreeable 

 and unwholesome. Gases are more soluble in cold than in 

 hot water ; solids, conversely, are generally more quickly 

 and freely dissolved by hot than by cold water. Organic 

 matters are present, especially in river and marsh waters, 

 causing them to spoil rapidly when kept, and sometimes to 



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