Just as in the example with the straight piece of wire between the electron Source and Destination, any break in this circuit will prevent electrons from flowing through it: An important principle to realize here is that it doesn’t matter where the break occurs. Any discontinuity in the circuit will prevent electron flow throughout the entire circuit. All we need to maintain this flow is a continuous means of motivation for those electrons, which we’ll address in the next section of this chapter. It must be realized that continuity is just as important in a circuit as it is in a straight piece of wire. Any break, anywhere in a circuit prevents electron flow throughout the circuit. The location of a break in a circuit is irrelevant to its inability to sustain continuous electron flow. Now, we have the capability of supporting a continuous flow of electrons indefinitely without the need for infinite electron supplies and dumps.
Using the marble-and-tube analogy, the marble source and marble destination buckets would have to be infinitely large to contain enough marble capacity for a “flow” of marbles to be sustained.