WATER, AND ITS USES 89 



Water itself is practically incompressible even under 

 enormous pressure. Because of this fact the density of the 

 water in the depths of the ocean is. approximately the same 

 as at the surface. Bodies heavy enough to sink beneath the 

 surface will go to the bottom. This incompressibility of 

 water is in striking contrast with the ready compressibility 

 of gaseous matter such as the atmosphere. 



"Soda water" is carbonated drinking water sweetened 

 and flavored by use of fruit syrups. Substances chemically 

 prepared, and having flavors similar to those of various 

 fruits, are sometimes used in place of the real fruit because 

 of cheapness. Their use may be attended with harmful 

 results, especially for those whose digestion is at all impaired. 



SUMMARY 



The important uses of water are too numerous to be named here. 

 Very many of these uses are named elsewhere in this text in different 

 connections. In agricultural, commercial, and industrial life, and in 

 all relations of life affecting health and well-being, water occupies a 

 most important place. 



A detailed study of water as a typical liquid is made in Physics. 

 Brief studies of other liquids can then be made by comparison. Its 

 composition, and its usefulness in chemical changes, are both empha- 

 sized in Chemistry, while in the other sciences the uses of water appear 

 in manifold relationships. 



The boiling and freezing temperatures vary for different liquids 

 These temperatures are changed for any liquid by variations in atmos- 

 pheric pressure, and by the presence or absence of substances in 

 solution. 



The high specific heat of water, and the excessive value of the heat 

 involved in its vaporization, are of utmost importance in any con- 

 sideration of climate. 



Abundant as are the waters of earth, it is a most difficult problem to 

 secure a supply of water sufficiently free of organic and mineral matter, 

 and of disease germs, to warrant its use for household purposes. 

 Oceanic waters, and those of certain inland lakes, seas, and springs, 

 hold in solution so much salt, "lime," and other minerals as to be 

 unfit for drink and for the preparation of foods. 



