130 



ELEMENTS OF GENERAL SCIENCE 



length. At the bottom it is connected with the pipe, some- 

 times called the suction pipe, which extends down into the 

 water in the well, and at the top with a pipe leading to 

 the spout, or the spout may be connected directly with the 



Fi. 66 The lift pump 



Three stages of the stroke of the pump are shown: A, down stroke; B, up 



stroke ; C, completion of the stroke. By noting the position in each case of v 



(valve), p (piston, or plunger), and cyl. (cylinder), the action of the pump may 



be understood 



cylinder. At the bottom of the cylinder, over the opening 

 leading to the pipe, there is a valve so constructed as to 

 allow the water to pass upward but not downward. In 

 the cylinder there is a tightly fitting piston which slides up 

 and down, and in this piston there is another valve which 

 allows the passage of the water upward. Other parts, for 

 example, the handle, may be added for convenience or ease 



