Gravitation 7 



water, in trying to flatten out, forces the lower water up 

 through the ground on the hillsides or in the valleys.) 

 So people have to get their water from underground or 

 go to lakes for it. And these lakes are strange sights. 

 Storms toss up huge waves, which remain as ridges 

 and furrows until another storm tears them down and 

 throws up new ones. 



But with no rivers flowing into them, the lakes also 

 are used up in time. The only fresh water to be had 

 is what is caught from the rain. Even wells soon be- 

 come useless; because as soon as you pump up the 

 water surrounding the pump, no more water flows in 

 around it ; and if you use a bucket to raise the water, 

 the well goes dry as soon as the supply of water standing 

 in it has been drawn. 



You will understand more about water seeking its 

 own level if you do this experiment : 



Experiment i. Put one end of a rubber tube over the 

 narrow neck of a funnel (a glass funnel is best), and put the 

 other end of the tube over a piece of glass tubing not less than 

 5 or 6 inches long. Hold up the glass tube and the funnel, 

 letting the rubber tube sag down between them as in Figure 

 i. Now fill the funnel three fourths full of water. Raise 

 the glass tube higher if the water starts to flow out of it. 

 If no water shows in the glass tube, lower it until it does. 

 Gradually raise and lower the tube, and notice how high 

 the water goes in it whenever it is held still. 



This same thing would happen with any shape of 

 tube or funnel. You have another example of it when 

 you fill a teakettle : the water rises in the spout just as 

 high as it does in the kettle. 



