If the excess and storage of electrons at the two ends of the wire were fixed at the definite quality, it would only be a very short time until all the excess electrons had traveled through the wire toward the positive end. the dry cell, however, continues the furnish excess electrons at one terminal and continue the remove electrons from the other terminal, so that the two terminals are positive and negative for the life of the cell.

Under these conditions, a constant stream of electrons begins to flow through the wire instant the wire is connected to the cell. electron constantly arriving at the negative end keeps applying a using force to the free electrons in the wire, and the constant removal of the electrons from the positive end keeps applying a pulling force on the free electrons.

If you have any difficulty in picturing what is happening inside the wire, suppose you examine a similar situation which makes us for more familiar components.imagine a large drain of draine pipe in which a large number of golf ball are suspendedby means of wire. now fill all of the space between the golf ball with a small metal balls the size of air refling shot.each small ball represents a free electrons.  

 Now imagine a army little men removing the BB's from one and of the pipe and remaining the backinto the other end.this army represents the dryt cells.since the pipe can not the packed any more tightly, and since it is too strong burst,all that can happen is that their will be a constant flow of small matel ball through the pipe.the faster the little men work and the harder they push , the greater will be flow of BB shot. 

The begin at the at the instant the army begin to work , and continuous at the same rate until the little men are too executed to move any more --the dry cell is than ”dead".  a very  a similar situation exists betweenthe draine pipe and a wire carrying an electric current. the main difference is that in the pipe, the metal ball press directly upon each other,while in the wire the electron them selves do not touch but their electric field press each other.

When current flow start in a wire,electrons start to move throughout the wire at the same time, just as the cars of a long trains start and stops together.