Electrical resistivity and conductivity results in the important concept of "quasineutrality", which says the density of negative charges is approximately equal to the density of positive charges over large volumes of the plasma ("n" = <Z>"n"), but on the scale of the Debye length there can be charge imbalance. In the special case that "double layers" are formed, the charge separation can extend some tens of Debye lengths. The magnitude of the potentials and electric fields must be determined by means other than simply finding the net charge density. A common example is to assume that the electrons satisfy the Boltzmann relation: Differentiating this
Experiments and Observations on Electricity the Leyden jar had an accumulation of electrical fire, which he labeled as "positive" ("plus"), and the other side had a deficiency of electrical fire, labeled "negative" ("minus"). These losses and gains of electrification were exactly equal and are essentially the modern law of charge conservation except that it is now recognized that negative charges exist in their own right, not just as a deficiency of positive charges. It is an important principle in modern science that explains the microphysics of the electrification of gross bodies. In these letters, Franklin introduced technical words that we use today for things related