Since in every magnet the magnetic fluid is supposed to be regularly graduated from minimum quantity in the negative end to maximum quantity in the positive end, this is true in respect to the one magnet, consisting of the whole magnetic circuit, as well as in respect to each one of the sectional series. Consequently there must be the same quantity of magnetism in each negative pole of the sections as there is in the positive pole of the section immediately behind it. And the magnetism of the whole circuit between the positive and the negative posts is in its _least_ volume next to the _positive post_, and in _fullest_ volume next to the _negative post_. If we consider the circuit as divided into two equal halves, the _negative half_ is plainly that which joins the _positive post_, and the _positive half_ that which joins the _negative post_. From this it will be seen that what in practice are designated as the positive and negative _posts_, and also positive and negative _poles_ or _electrodes_ are _not_ such _in relation to each other_, but the _reverse_ of it; that is to say, the positive _post_ is not _positive_ in relation to the _negative post_, but is _negative_ to it; and the positive _electrode or pole_ is not positive in relation to the _negative_ electrode, but _negative_ to it. The positive _post_, like the positive _electrode_, is called _positive_, because it is the positive end of the sectional magnet next _behind_ it. And the _negative_ post, as also the negative electrode, is _called negative_ because it is the negative end of the sectional magnet next _in advance_ of it. THE CENTRAL POINT OF THE CIRCUIT. _The central point_ of the circuit--that point which divides between its positive and negative halves--is reckoned, in practice, to be the midway point in the line over which the current passes, in its whole course from the positive post around to the negative post. When the cords are of equal length, this point will always be in the person of the patient, about midway between the parts where the two electrodes are applied. This central point, or "point of centrality," is practically neuter--neither positive nor negative; and upon the two opposite halves of the circuit, the positive and negative _qualities_ of the current are in greatest force nearest to the posts, and in least force nearest to the central point. At this point they cease altogether, and the central point is _neuter_.