I'm reading On Faraday's Lines of Force by Maxwell, and I imagine this may be one of the origins of the hydrodynamic analogies that we often hear to help picture voltage, current and so forth. What I'm struggling with is that while I don't have a great deal of trouble picturing current (since I know there are real charges actually moving through a wire) I do have trouble picturing fields. Of course, there are lines of force, but unlike the analogy of flowing water, those lines of force aren't in motion and so make it difficult to picture how they exert energy on charges in their path. Electric fields, being vector fields, would seem to be analogous to particles passing through a unit area per second, so one could I suppose make a hydrodynamic analogy and say that an electric field is like the water that flows and its strength is water units per unit area per unit time, but I'm not sure that's right either, is it? I notice that Wikipedia's http://en.wikipedia.org/wiki/Hydraulic_analogy#Equation_examples" don't include one for the electric or magnetic field. Does anyone know what would go there, if anything? Thanks for any guidance on this.