The composition obtained by the formula may be used either in a powdered condition by dusting it over articles previously coated, in whole or in part, with an adhesive substance, or it may be intimately mixed with paints, inks, or varnishes, serving as vehicles for its application, and in this way be applied to bodies to render them luminous. The formula for obtaining the composition is as follows: To one hundred parts of unslaked lime, that obtained from calcined oyster shells producing the best results, add five parts of carbonate of magnesia and five parts of ground silex. Introduce these elements into a graphite or fire-clay crucible containing forty parts of sulphur and twenty-five parts of charcoal, raise the whole mass nearly or quite to a white heat, remove from the fire, allow it to cool slowly, and, when it is cold or sufficiently lowered in temperature to be conveniently handled, remove it from the crucible and grind it. The method of reducing the composition will depend upon the mode of its use. If it is to be applied as a loose powder by the dusting process, it should be simply ground dry; but if it is to be mixed with paint or other similar substance, it should be ground with linseed or other suitable oil. In heating the elements aforesaid, certain chemical combinations will have taken place, and monosulphide of calcium, combined with carbonate of lime, magnesia, and silex, will be the result of such ignition. If, in the firing of the elements, as above set forth, all of the charcoal does not unite with the other elements, such uncombined portion should be removed from the fused mass before it is ground. If it is designed to mix the composition with paints, those composed of zinc-white and baryta should be chosen in preference to those composed of white lead and colored by vegetable matter, as chemical action will take place between the composition and paint last mentioned, and its color will be destroyed or changed by the gradual action of the sulphureted hydrogen produced. However, by the addition of a weak solution of gum in alcohol or other suitable sizing to the composition, it may be used with paints containing elements sensitive to sulphureted hydrogen without danger of decomposing them and destroying their color.