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ever since volta first produced a source of steady continuous current, men of science have been forming theories on this subject. for some time they could see no real difference between the newly-discovered phenomenon and the former understanding of static charge. then the famous french scientist, ampere (after whom the unit of current was named) determined the difference between the current and the static charges. in addition to it, ampere gave the current direction: he supposed it to flow from the positive pole of the source round the circuit and back again to the negative pole. we know him to be right in his first statement but he was certainly wrong in the second, as to the direction of current. the flow of current is now known to be in a direction opposite to what he thought. (we shall return to that problem later on.)
let us turn our attention, now, to the electric current itself. the current which flows along wires consists of moving electrons. in other words, the flow of moving electrons is one form of the electric current. what can we say about the electron? we consider the electron to be a minute particle having an electric charge.
