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A glow-in-the-dark world

A short notice in the Phrenological Journal from April, 1879, reports on the self-luminous properties of calcium sulfide. A Prof. Morton from the Stevens Institute of Technology had analyzed the material painted onto the faces of self-luminous clocks and discovered that it was just a “sulfide of calcium.” The compound absorbs light when exposed to sun or artificial light. It then glows in the dark. Seemingly miraculous, one dial covered with this compound continued to glow for five days after it had been removed from light.

Notice in Phrenological Journal about a self-luminous compound.

Professor Morton was enthusiastic about the possibilities:

…if further advances should be made in this direction, it is easy to imagine some wonderful results, before which even Mr. Edison’s new electric-burner would fade into insignificance. Thus, if our walls were painted with such a substance, they would absorb light enough during the day to continue luminous all night, and thus render all sources of artificial light useless. The coloring of houses on the outside with a like material would also obviate need of all street lamps.

Professor Morton (and the person reporting on Morton’s work) seems to be, perhaps, a bit optimistic. I doubt that calcium sulfide would ever give off enough light to “obviate need” of any artificial lighting. Moreover, given the eerie red glow typically emitted by calcium sulfide, it would be like living in a horror movie.

The glow given off by Calcium Sulfide.

If, however, you want to try to reduce your electric bill by painting the inside and outside of your house with calcium sulfide, here’s how you can make your own from oyster shells.