264 



GENERAL SCIENCE 



on the top stories of high buildings will have less pressure than the 

 water coming from faucets on the bottom stories. Water pressure 

 is reduced by friction of pipes, joints and valves. 



Wherever towns or cities are located near mountains the water 

 is piped from lakes or streams that have an elevation greater than 

 the place supplied. Such a system is called a Gravity System. 



FIG. 166. These fish live at a great depth in the ocean. The depth is so great 

 that light does not penetrate the waters. In this semi- or total darkness fish 

 must develop their own light to see. Some of the fish have light organs just 

 below their eyes, others have a long slender antenna on the end of which is a 

 strong flash light for searching out their prey. All these fish are carnivorous, 

 since plant life cannot grow at the depth where fish of this type dwell. The 

 tissues of the fish are filled with fluid and loosely knitted together, and the bones 

 are cartilaginous in order to stand the pressure of thousands of pounds to the 

 square inch. When they are brought up from the deep to the surface the 

 tremendous pressure is relieved, causing the exploding gases within the body 

 to bulge out the eyes and to force out through the mouth the heart, liver and 

 intestines. 



If cities or towns are located in level places where there are no 

 elevations from which to get water, the water must be pumped 

 into standpipes or reservoirs higher than any building in the town. 



Problem.. Investigate the use of the water turbine. 



