The receiving battery has a core pole of katultron and an outer shell of metultron. The receiving battery, of course, picks up all frequencies, the undesired ones being tuned out in detection. Tuning, however, is only a convenience for privacy and elimination of interference in ultrophonic communication.

As radium is constantly giving off electronic emanations and changing its atomic structure thereby, so katultron is constantly giving off ultronic emanations, and so changing its sub-electronic form, while metultron, its complement, is constantly attracting and absorbing ultronic values, and so changing its sub-electronic nature in the opposite direction.

Thin plates of these two substances, when placed properly in juxtaposition, with insulating plates of inertron between, constitute a battery which generates an ultronic current. It will flow, for instance, through an ultron wire, from the katultron to the metultron plate, as electricity will flow through a copper wire.

The pioneer expeditions of our engineers into the ultronic order, I am told, necessitated the use of most elaborate, complicated and delicate apparatus, as well as the expenditure of most costly power, but once established there, all necessary power is developed very simply from tiny batteries composed of thin plates of metultron and katultron.

For phonic communication a spherical sending battery is a ball of metultron, surrounded by an insulating shell of inertron, and this in turn by a spherical shell of katultron, from which the current radiates in every direction, tuning being accomplished by frequency of intermissions, with audio-frequency modulation.