2146. I have long held an opinion, almost amounting to conviction, in common I believe with many other lovers of natural knowledge, that the various forms under which the forces of matter are made manifest have one common origin; or, in other words, are so directly related and mutually dependent, that they are convertible, as it were, one into another, and possess equivalents of power in their action. ... [p. 2] 2148. ... I recently resumed the inquiry by experiment in a most strict and searching manner, and have at last succeeded in magnetizing and electrifying a ray of light, and in illuminating a magnetic line of force.
Published before 1923