"One evening, going into the laboratory after dark, I observed with astonishment what looked like a lambent flame upon the table. In my alarm I ran forward to put it out, but found that there was no heat in it; lighting my lamp I could no longer see it, but on the table I found a few grains of the stuff I had been experimenting on. Turning out the lamp the light was again visible, and after much thought I concluded that it was similar to the light given by the little creatures called glowworms, and which in its turn somewhat resembles the light that can be seen at times in a pile of decaying fish. I tried many experiments, but as nothing came of them I gave them up, not seeing that any use could come of a fire that gave out no heat. I produced a powder, however, that when rubbed on any substance, became luminous in the dark, presenting an appearance strange and sufficiently alarming to the ignorant.

"Thinking the matter over some time ago, I took a little of this powder from the phial in which I had stored it away, and, moistening it, rubbed it on the wall in the form of circles, triangles, and other signs. I did this just before it became dark. As the moisture dried, these figures gradually assumed a luminous appearance. I saw the use to which this could be put in awing a mob, and, setting to work, made a large supply of this powder."