Put into a small long-necked bottle, resting on a little sand, one part of fine gold filings, and three parts of aqua regia, (nitro-muriatic acid.) When the gold is dissolved, pour the solution into a glass, and add five or six times the quantity of water. Then take spirit of sal ammoniac or oil of tartar, and pour it drop by drop into the solution, until the gold is entirely precipitated to the bottom of the glass. Decant the liquor that swims at the top, by inclining the glass; and, having washed it several times in warm water, dry it at a moderate heat, placing it on paper capable of absorbing all the moisture.
If a grain of this powder, put into a spoon, (it should be an iron one,) be exposed to the flame of a candle, it will explode with a very loud report.
To melt a piece of Money in a Walnut-shell, without injuring the shell.
Bend any thin coin, and put it into half a walnut-shell; place the shell on a little sand, to keep it steady. Then fill the shell with a mixture made of three parts of very dry pounded nitre, one part of flowers of sulphur, and a little saw-dust well sifted. If you then set light to the mixture, you will find, when it is melted, that the metal will also be melted at the bottom of the shell, in form of a button, which will become hard when the burning matter round it is consumed: the shell will have sustained very little injury.
A Liquid that Shines in the Dark.
Take a bit of phosphorus, about the size of a pea; break it into small parts, which you are to put into a glass half full of very pure water, and boil it in a small earthen vessel, over a very moderate fire. Have in readiness a long narrow bottle, with a well-fitted glass stopper, and immerse it, with its mouth open, into boiling water. On taking it out, empty the water, and immediately pour in the mixture in a boiling state; then put in the stopper, and cover it with mastich, to prevent the entrance of the external air.
This water will shine in the dark for several months, even without being touched; and, if it be shaken in dry warm weather, brilliant flashes will be seen to rise through the middle of the water.
Luminous Liquor.
Put a little phosphorus, with essence of cloves, into a bottle, which must be kept closely stopped. Every time the bottle is unclosed, the liquor will appear luminous. This experiment must be performed in the dark.