SOLAR REFRACTION.
The theory of solar refraction may be beautifully illustrated as follows: Put a shilling into a basin, and pour some water on it, when the silver will be refracted through the medium; and, if the vessel be filled, you may withdraw to any distance from which the surface of the water will be visible, and, by the refraction from it, you can still observe the shilling.
INCANTATIONS.
Dissolve crystals of nitrate of copper in spirit of wine; light the solution, and it will burn with a beautiful emerald-green flame: pieces of sponge soaked in this spirit, lighted and suspended by fine wires, produce the lambent green flames now so common in incantation scenes: strips of flannel saturated with it, and applied round copper swords, tridents, &c., produce, when lighted, the flaming swords and fire-forks, brandished by the demons in such scenes: indeed, the chief consumption of nitrate of copper is for these purposes.
TO IMITATE THE LIGHT OF THE SEA.
It is well known, that on dark, stormy nights, the sea emits a brilliant light, the effect of which may be thus imitated. Scrape off four drams of the substance of putrefying fish, as whiting, herring, or mackerel, and put it into a white glass bottle, containing two ounces of sea-water, or of pure water with two drams of common salt dissolved in it; set the bottle in a dark place, and in three days a ring of light will be seen on the surface of the liquid, and the whole, if shaken, will become luminous, and continue so for some time. If it be set in a warm place, the light will be brighter; if the liquid be frozen, the light will disappear, but will re-appear on being thawed.
If more salt be added to the solution, the light will disappear, but instantly burst forth from absolute darkness by dilution with water. Lime-water, common water, beer, acids, even very dilute alkaline leys, as pearl-ash or soda and water, will permanently extinguish this spontaneous light.
INSTANTANEOUS LIGHTS.
The oxygenated, or chlorate matches, are first dipped in melted sulphur, and then tipped with a paste made of chlorate of potass, sulphur, and sugar, mixed with gum-water, and coloured with vermilion: frankincense and camphor are sometimes mixed with the composition, and the wood of the match is pencil-cedar, so that a fragrant odour is diffused from the matches in burning. To obtain light, a match is very lightly dipped in a bottle containing a little asbestos soaked in oil of vitriol.
Lucifers consist of chips of wood tipped with a paste of chlorate of potass mixed with sulphuret of antimony, starch, and gum-water: when a match is pinched between the folds of glass-paper, and suddenly drawn out, a light is instantly obtained.