THE MAGIC WRITING. Dissolve a small portion of green-copperas in water, and soak in it sheets of writing paper, so as to allow them to be taken out whole, and then dried; then, cover the paper with very finely powdered galls, and write on it with a pen dipped in water; when dry, brush off the galls, and the writing will appear. TWO LIQUIDS MAKE A SOLID. Dissolve muriate of lime in water until it will dissolve no more; make also a similar solution of carbonate of potash; both will be transparent fluids; but if equal quantities of each be mixed and stirred together, they will become a solid mass. TWO SOLIDS MAKE A LIQUID. Rub together in a mortar, equal quantities of the crystals of Glauber’s salts and nitrate of ammonia, and the two salts will slowly become a liquid. A SOLID OPAQUE MASS MADE 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. TWO COLD LIQUIDS MAKE A HOT ONE. Mix four drams of sulphuric acid, (oil of vitrol,) with one dram of cold water, suddenly, in a cup, and the mixture will be nearly half as hot again as boiling water. QUADRUPLE TRANSMUTATION. Dissolve a small piece of nickel in nitric acid, and it will appear of a fine grass-green colour; add to it a little ammonia, and a blue precipitate will be formed; this will change to a purple-red in a few hours, and the addition of any acid will convert it to an apple-green. QUINTUPLE TRANSMUTATION. Heat potassium over the flame of a spirit-lamp, and the colour will change from white to a bright azure, thence to a bright blue, green, and olive. COMBINATION OF COLOURS. Cut out a disc or circle of pasteboard, and cover it with paper half green and half black: cause the disc to be rapidly turned round, (like the shafts of a toy wind-mill,) and the colours will combine and produce white. UNION OF TWO METALS WITHOUT HEAT. Cut a circular piece of gold-leaf, called “dentist’s gold,” about half an inch in diameter; drop upon it a globule of mercury, about the size of a small pea, and if they be left for a short time, the gold will lose its solidity and yellow colour, and the mercury its liquid form, making a soft mass, of the colour of mercury. MAGIC BREATH. Half fill a glass tumbler with lime-water; breathe into it frequently, at the same time stirring it with a piece of glass. The fluid, which before was perfectly transparent, will presently become quite white, and, if allowed to remain at rest, real chalk will be deposited. TWO BITTERS MAKE A SWEET. It has been discovered, that a mixture of nitrate of silver with hypo-sulphate of soda, both of which are remarkably bitter, will produce the sweetest known substance. VISIBLE AND INVISIBLE.