DIRECTION: molecules on the flow of signal cable, i.e. copper are burned in a direction through current constantly flowing in a particular direction as long as floating earth is either non exsinting or equal at both ends,is as if you have a tube a meter or so in lenth say 3" diameter and 1" of sand in the base then by flowing water in one direction the sand will go with the flow "molecules" i thinks through practice and theory,regards nando.