CHAPTER IV 

 WATER 



IN this chapter we are going to consider Water, 

 and I hope we all of us know a great deal about 

 it already. We certainly ought to, for we can 

 see it, we can feel it, we drink it, we wash in it, 

 we row our boats on it and sail our ships over 

 it, we give it to our plants and animals to drink, 

 we skate and slide on it when it is frozen, and 

 it falls on us out of the clouds as rain and snow. 

 It is to be found on all sides of us, and we 

 cannot imagine what the world would be like 

 without it. 



What is the water made of? Is it just 

 water, something that we cannot divide or put 

 together again ? I do not think this is very 

 important for us to know about at present, for 

 we are not at all likely to want to make or 

 split it up. Still, we could do so, and if we did, 

 we should get a certain quantity of the gas we 

 have called oxygen and about twice as much 

 by volume of another gas that is known as 

 hydrogen. These two, then, are the con- 

 stituent elements of water, that is, they com- 

 pose, or make it up. Although it is not 

 probable that we shall require to know much 



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