While making some magnetic experiments lately with Mr Fox Talbot, I happened to notice that two equal rectangular pieces of tin plate, when standing nearly parallel to one another on the pole of a large electromagnet, acted on one another so that a vibration communicated to either was in a few seconds handed over to the other, and vice versâ.

The definiteness of the result led me to try the experiment with ordinary bar magnets. Taking two large magnetised bars of almost exactly equal mass, I suspended them with their axes in the same horizontal line, so that their (small) vibrations were executed in that line, their undisturbed periods being very nearly equal, and the distance between them (when at rest) so small compared with their lengths, that we need consider only the magnetic action of the two poles nearest together.