Part 3

VARIETIES OF CRYSTALS.

Make distinct solutions of common salt, nitre, and alum; set them in three saucers in any warm place, and let part of the water dry away or evaporate; then remove them to a warm room. The particles of the salts in each saucer will begin to attract each other, and form crystals, but not all of the same figure: the common salt will yield crystals with six square and equal faces, or sides; the nitre, six-sided crystals; and the alum, eight-sided crystals; and if these crystals be dissolved over and over again, they will always appear in the same forms.

HEAT FROM CRYSTALLIZATION.

Make a strong solution of Epsom salts in hot water, and while warm, bottle it, cork it closely, and it will remain liquid: draw out the cork, when the salts will immediately crystallize, and in the process, the remaining liquid and the bottle will become very warm.

SPLENDID SUBLIMATION.

Put into a flask a small portion of iodine; hold the flask over the flame of a spirit-lamp, and, from the state of rich ruby crystals, the iodine, on being heated, will become a ruby-coloured transparent gas; but, in cooling, will resume its crystalline form.

ARTIFICIAL ICE.

Mix four ounces of nitrate of ammonia, and four ounces of subcarbonate of soda, with four ounces of water, in a tin vessel, and in three hours the mixture will produce ten ounces of ice.

MAGIC INKS.

Dissolve oxide of cobalt in acetic acid, to which add a little nitre; write with this solution, hold the writing to the fire, and it will be of a pale rose colour, which will disappear on cooling.

Dissolve equal parts of sulphate of copper and muriate of ammonia in water; write with the solution, and it will give a yellow colour when heated, which will disappear when cold.

Dissolve nitrate of bismuth in water; write with the solution, and the characters will be invisible when dry, but will become legible on immersion in water.

Dissolve, in water, muriate of cobalt, which is of a bluish-green colour, and the solution will be pink; write with it, and the characters will be scarcely visible; but, if gently heated, they will appear in brilliant green, which will disappear as the paper cools.

CHAMELEON LIQUIDS.

Put a small portion of the compound called mineral chameleon into several glasses, pour upon each water at different temperatures, and the contents of each glass will exhibit a different shade of colour. A very hot solution will be of a beautiful green colour; a cold one, a deep purple.

Make a colourless solution of sulphate of copper; add to it a little ammonia, equally colourless, and the mixture will be of an intense blue colour; add to it a little sulphuric acid, and the blue colour will disappear; pour in a little solution of caustic ammonia, and the blue colour will be restored. Thus, may the liquor be thrice changed at pleasure.

THE MAGIC DYES.

Dissolve indigo in diluted sulphuric acid, and add to it an equal quantity of solution of carbonate of potass. If a piece of white cloth be dipped in the mixture, it will be changed to blue; yellow cloth, in the same mixture, may be changed to green; red to purple, and blue litmus paper to red.

Nearly fill a wine-glass with the juice of beet-root, which is of a deep red colour; add a little lime water, and the mixture will be colourless; dip into it a piece of white cloth, dry it rapidly, and in a few hours, the cloth will become red.

WINE CHANGED INTO WATER.

Mix a little solution of subacetate of lead with port wine; filter the mixture through blotting paper, and a colourless liquid will pass through; to this add a small quantity of dry salt of tartar, when a spirit will rise, which may be inflamed on the surface of the water.

TWO COLOURLESS TRANSPARENT LIQUIDS BECOME BLACK AND OPAQUE.

Have in one vessel some sulphuric acid, and in another an infusion of nut-galls; they are both colourless and transparent; mix them, and they will become black and opaque.

TWO COLOURLESS FLUIDS MAKE A COLOURED ONE.

Put into a wine-glass of water, a few drops of prussiate of potash; and into a second glass of water, a little weak solution of sulphate of iron in water: pour the colourless mixtures together into a tumbler, and they will be immediately changed to a bright deep blue colour.

Or, mix the solution of prussiate of potash with that of nitrate of bismuth, and a yellow will be the product.

Or, mix the solution of prussiate of potash with that of sulphate of copper, and the mixture will be of a reddish brown colour.

CHANGE OF COLOUR BY COLOURLESS FLUIDS.