ELECTRICITY IN THE HOME 



153 



by the foot, so that both hands are left free to guide the 

 work. More work can be done, because more stitches per 

 minute may be taken when the motor is used than can be 

 taken when the machine is driven by the foot. 



A motor may be used to operate a pump. If one has the 

 pneumatic-tank system of supplying water to the house, 

 the motor may be attached to the pump and arranged to 

 start and stop automatically according to the pressure in 

 the tank. 



Electric bell. One very common application found in 

 many homes is the electric bell. This illustrates the ap- 



Door 



Drawing Room .Dining Room 



FIG. 53. Bell circuits. 



plication of two electric appliances, the bell itself and the 

 cell that operates it. By pushing a button, the circuit is 

 closed and the current from the battery operates the bell. 

 When the finger is taken off the button, the circuit is 

 broken and the bell stops ringing. 



The most important part of a bell is a special kind of 

 magnet called an electromagnet. Magnets may be formed 

 in several ways. There are found in nature natural magnets 

 called lodestones, which attract iron. Magnets may also 

 be made by rubbing a piece of steel with another magnet, 

 or by bringing iron or steel under the influence of a current 

 of electricity. If a number of coils of wire are wound around 



