The Paper Oracle.
Some amusement may be obtained among young people by writing, with common ink, a variety of questions, on different bits of paper, and adding a pertinent reply to each, written with nitro-muriate of gold. The collection should be suffered to dry, and put aside, until an opportunity offers for using them. When produced, the answers will be invisible; desire different persons to select such questions as they may fancy, and take them home with them; then promise, if they are placed near the fire during the night, answers will appear written beneath the questions in the morning; and such will be the fact, if the paper be put in any dry, warm situation.
The Mimic Gas-House.
This shows a simple way of making illuminating gas, by means of a tobacco-pipe. Bituminous coal contains a number of chemical compounds, nearly all of which can, by distillation, be converted into an illuminating gas; as with this gas nearly all our cities are now lighted in the dark hours of night. To make it, obtain some coal-dust (or walnut or butternut meats will answer), and fill the bowl of a pipe with it; then cement the top over with some clay; place the bowl in the fire, and soon smoke will be seen issuing from the end of the stem; when that has ceased coming apply a light and it will burn brilliantly for several minutes; after it has ceased, take the pipe from the fire and let it cool, then remove the clay, and a piece of coke will be found inside: this is the excess of carbon over the hydrogen contained in the coal, for all the hydrogen will combine with carbon at a high temperature, and make what are called hydrocarbons—a series of substances containing both these elemental forms of matter.
Alum Basket.
Make a small basket, about the size of the hand, of iron wire or split willow; then take some lamp-cotton, untwist it, and wind it around every portion of the basket. Then mix alum, in the proportion of one pound with a quart of water, and boil it until the alum is dissolved. Pour the solution into a deep pan, and in the liquor suspend the basket, so that no part of it touch the vessel or be exposed to the air. Let the whole remain perfectly at rest for twenty-four hours; when, if you take out the basket, the alum will be found prettily crystallized over all the limbs of the cottoned frame.
In like manner, a cinder, a piece of coke, the sprig of a plant, or any other object, suspended in the solution by a thread, will become covered with beautiful crystals.
If powdered tumeric be added to the hot solution, the crystals will be of a bright yellow; if litmus be used instead, they will be of a bright red; logwood will yield them of a purple, and common writing-ink, of a black tint; or, if sulphate of copper be used instead of alum, the crystals will be of fine blue.
But the colored alum crystals are much more brittle than those of pure alum, and the colors fly; the best way of preserving them is to place them under a glass shade, with a saucer containing water. This keeps the atmosphere constantly saturated with moisture, the crystals never become too dry, and their texture and color undergo but little change.