The phenomena of the storing-up of "N" rays, which are the object of the present note, ought naturally to be compared with those of phosphorescence; yet they present a quite distinct feature, as I intend to show shortly.
On the Strengthening Action of a Beam of Light on the Eyes, when the Beam is accompanied by "N" Rays (November 23, 1903).
While studying the storing-up of "N" rays by different bodies, I had occasion to observe an unexpected phenomenon. My eyes were fixed on a small slip of paper, dimly lighted, distant about i metre from me; a brick, one of whose faces had been sun-exposed, having been brought near laterally to the luminous pencil, with its sun-exposed face turned towards me, and a few decimetres distant from my eyes, I saw the slip assume a heightened glow; when the brick was removed, or when its non-exposed face was turned towards me, the paper grew
