RESTORATION OF COLOR BY WATER.
Water being a colorless fluid, ought, one would imagine, when mixed with other substances of no decided color, to produce a colorless compound. Nevertheless, it is to water only that blue vitriol, or sulphate of copper, owes its vivid blueness, as will be plainly evinced by the following simple experiment. Heat a few crystals of the vitriol in a fire-shovel, pulverize them, and the powder will be of a dull and dirty white appearance. Pour a little water upon this, when a slight hissing noise will be heard, and at the same moment the blue color will instantly reappear.
Under the microscope the beauty of this experiment will be increased, for the instant that a drop of water is placed in contact with the vitriol, the powder may be seen to shoot into blue prisms. If a crystal of prussiate of potash be similarly heated, its yellow color will vanish, but reappear on being dropped into water.
[5]TWO LIQUIDS MAKE A SOLID.
Dissolve muriate of lime in water until it will dissolve no more; measure out an equal quantity of oil of vitriol; both will be transparent fluids; but if equal quantities of each be slowly mixed and stirred together, they will become a solid mass, with the evolution of smoke or fumes of muriatic acid.
TWO SOLIDS MAKE A LIQUID.
Rub together in a mortar, equal quantities of the crystals of Glauber salts and nitrate of ammonia, and the two salts will slowly become a liquid.
A SOLID OPAQUE MASS MAKES A TRANSPARENT LIQUID.
Take the solid mixture of the solutions of muriate of lime and carbonate of potash, pour upon it a very little nitric acid, and the solid opaque mass will be changed to a transparent liquid.