One of the generators or sources of current E, or F, may be dispensed with, but it is preferable to employ both, if they offer an appreciable resistance, as the two branches will be thereby better balanced. The translating or other devices to be acted upon by the current are designated by the letters G, and they are inserted in the branches C, D, in any desired manner, but in order to better preserve an even balance between the branches due regard should be had to the number and character of the devices as will be well understood.
Figures 2, 3, 4, and 5, illustrate what may be termed electro-magnetic devices for accomplishing a similar result. That is to say, instead of producing directly by a generator an electro-motive force in each branch of the circuit, a field or fields of force is established, and the branches led through the same in such manner that an active opposition of opposite effect or direction will be developed therein by the passage or tendency to pass off the alternations of current.
In figure 2, for example, A is the generator of alternating currents, B, B, the line circuit, and C D the branches over which the alternating currents are directed. In each branch is included the secondary of a transformer or induction coil, which, since they correspond in their functions to the batteries of the previous
