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WATER IN THE HOME 



What we mean by solution. You are all aware of the 

 fact that sugar placed in your lemonade soon dissolves in 

 it and disappears, but you can taste the sugar in all parts 

 of the glass of lemonade. If you were to allow crystals 

 of eosin (the material from which red ink is made) to dis- 

 solve in a bowl of water, in a short time the eosin would 

 have passed to all parts of the water, giving it a uniform 

 pink color. 



When a substance completely dissolves in a liquid so as 

 to become permanently a part of it, we say the substance 



is soluble in water, 

 and that we have 

 a solution. Water 

 takes up mineral 

 matter in solution. 

 Rain water, al- 

 though perfectly 



Formation of caves by water running through lime- pure as it drODS from 



the clouds, after 



soaking into the ground may soon take up into itself mineral 

 matter by solution. Certain minerals, particularly com- 

 pounds of calcium (lime) and magnesium, are slightly soluble 

 in ground water, and indeed in some parts of the country, 

 great gaps and caves have been formed by water gradually 

 running through limestone and dissolving it out. We 

 must not confuse solutions with muddy water, for if we 

 allow a glass of muddy water to stand, the mud eventually 

 settles to the bottom, or if the water is passed through filter 

 paper, it remains on the filter ; but when mineral substances 

 are in solution, they pass through the filter with the water. 

 Hard and soft water. Water that has taken up a con- 

 siderable amount of soluble mineral material is called hard 



