[Vectorcardiographic significance of three-dimensional devices ended and nevertheless without boundaries]

The circular boundary of a disk may be suppressed by connecting it to that of an other disk presenting the same characteristics (isomorph). In such a condition, energizing the first element indirectly feeds the second one by the same amount than it would be delivered to infinite surroundings. In mathematical terms, this means that summing up the potentials arising at the same points of the two connected disks leads to the potential identically located in the disk activated as before but disconnected from its isomorph: the statement being true except for a constant. In three dimensions, the problem is somewhat more difficult because a single isomorph cannot drain all the current that would be transmitted by a sphere to the infinite medium in which it is immersed. So, connecting two spheres results in a partial confinement which, however, does not rule out the aforementioned statement. On the other hand, the potential differences around the isomorph centre are well-suited to a vectorcardiographic use like Rijlant's one; this method is consequently justified as to its principle. Finally, we have studied the radial alinearity which is introduced by Rijlant to improve his instrument. We have shown the changes related to Rijlant's way of building his network and we conclude that the use of many equivalent layers bears on grounds similar to that which are developed for the linear isomorphs.