lays his pasteboard over the whole, and those words wL. are between crotchets [ ] form the intelligence you wish to communicate. For example: suppose you want to express these words,

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"Don't trust Robert: I have found him a villain." [Don't] fail to send my books. I [trust] they will be ready when [Robert] calls on you. [I have] heard that you have [found] your dog. I call [him a villain] who stole him." You may place a pasteboard of this kind three other ways-the bottom at top-the top at bottom, or by turning it over; but in this case you must previously apprize your correspondent, or he may not be able to decipher your meaning.

Secret Correspondence by Music.

FORM a circle like Fig 2, divided into twenty-six parts, with a letter of the alphabet written in each. The interior of the circle is moveable, like that in Fig. 1, and the circumference is to be ruled like music-paper. Place in each division a note different in figure or position.

Within the musical lines place the three keys, and on the outer circle the figures to denote time. Then get a ruled paper, and place one of the keys (suppose ge-re-sol) against the time 2-4ths, at the beginning of the paper, which will inform your correspondent how to place his circle. You then copy the notes that answer to the letters of the words you intend to write, in the manner expressed at the bottom of the figure.

The Magic Vessel.

On the bottom of a vessel, (see Fig. 3, in the Frontispiece) lay three pieces of money, the first at A, the second at B, and the third at C. Then place a person at D, where he can see no further into the vessel than E. You tell him, that by pouring water in the vessel you will make him see three different pieces of money; and bid him observe, that you do not convey any money in with the water. But be careful that you pour the water in very gently, or the

Another.

DISSOLVE bismuth in nitrous acid. When the writing with this fluid is exposed to the vapour of liver of sulphur, it will become quite black.

Another.

DISSOLVE green vitriol and a little nitrous acid in common water. Write your characters with a new pen.

Next infuse small Aleppo galls, slightly bruised in water. tha two or three days, pour the liquor off.

si By drawing a pencil dipped in this second solution over the characters written with the first, they will appear a beautiful black.

Invisible Gold Ink.

PUT as much gold in as small a quantity of aqua regia as will dissolve it, and dilute it with two or three times the quantity of distilled water.

Next dissolve, in a separate vessel, fine pewter in aqua regia, and when it is well impregnated, add an equal quantity of distilled water.

Write your characters with the first solution; let it dry in the shade. To make them visible, draw a pencil or sponge, dipped in the second solution, over the paper, and the characters will appear of a purple colour.

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Invisible Silver Ink.

DISSOLVE fine silver in aqua fortis; and after the dissolution, add some distilled water in the same manner as in the gold ink.

What is written with the above ink will remain invisible for three or four months, if kept from the air; but may be easily read in an hour, if exposed to the fire, air, or sun.

Invisible Yellow Ink.

STEEP marigold flowers seven or eight days in clear distilled vinegar. Press the flowers and strain the liquor, I which is to be kept in a bottle well corked. If you would have it still more clear, add, when you use it, some pure

water.

To make the characters visible, which you write with this ink, pass a sponge over the paper, dipped in the fol lowing solution :

Take a quantity of flowers of pansey, or the common violet, bruise them in a mortar with water, strain the liquor in a cloth, and keep it in a bottle.

Invisible Red Ink.

To the pure spirit of vitriol or nitre, add eight times as much water.

Use the above solution of violets to make visible the characters written with this ink.

Invisible Green Ink.

DISSOLVE salt of tartar, clean and dry, in a sufficient quantity of river water. Use the violet solution to render

it visible.

Another Invisible Green Ink.

DISSOLVE Zaffre, in powder, in aqua regia, for twentyfour hours. Pour the liquor off, add the same quantity of common water, and keep it in a bottle well corked.

This ink will not be visible till exposed to the fire or the sun; and will again be invisible when it becomes cold.

Invisible Violet Ink.

EXPRESS the juice of lemons, and keep it in a bottle well corked. Use the violet infusion to make the writing

visible.

Invisible Grey Ink.

MIx alum with lemon juice. The letters written with this ink will be invisible till dipped in water.

We now present our readers with a variety of amusing experiments, which may be performed by the foregoing inks; and they will, probably, suggest others equally amusing and useful.

A Secret Correspondence by means of Invisible Ink.

A PERSON wishing to carry on a correspondence with another, and who is fearful of having his letter opened or intercepted, can adopt the following plan :

Write any unimportant matter with common ink, and let the lines be very wide apart: then between these lines write the communication you wish to make, with any of the above invisible inks you can most readily procure.

Your correspondent is to be previously apprized of the method of making the characters visible: and writing in common ink will serve to lull the suspicions of those who might intercept the letter, and who, not finding any thing important in it, will either forward or keep it. In either case there can be no danger, as the writing will not be visible without the proper application.

The Mysterious Writing.

WRITE on a piece of paper with common ink any question; then underneath it write the answer either in invisible silver ink, or the invisible green ink, made with zaffre and aqua regia, described in pages 23 and 24.

You give this paper to your friend, and tell him to place it against the wall, or on his dressing-table, keeping the door locked, that he may be sure no person has entered his room: he will next day find the answer written on it.

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The Restored Flowers.

MAKE a bouquet of artificial flowers; the leaves should be formed of parchment. Dip the roses in the red invisible ink, the jonquilles in the yellow, the pinks in the violet, and the leaves in the green ink. They will all appear white; and you show them to the company, observing, that you will restore them to their natural colours, and desiring any person to fix any private mark on them he pleases, that he may be sure there is no deception. You then, unperceived by the company, dip them in the revivifying liquor, used to make the yellow ink visible, described in page 34, and, drawing them gently out, that the liquor may drop, and the flowers have time to acquire their colours, you present them to the company, who will see, with surprise, that they each appear in their natural colours.

Winter changed to Spring.

TAKE a print that represents winter, and colour those parts which should appear green, with the second green invisible ink, described in page 24; observing, of course, the usual rules of perspective, by making the near parts deeper in colour than the others. The other objects must be painted in their natural colours. Then put the print into a frame with a glass, and cover the back with a paper that is pasted only at its extremities.

When this print is exposed to a moderate fire, or the warm sun, the foliage, which appeared covered with snow, will change to a pleasing green; and if a yellow tint be thrown on the lighter parts before the invisible ink is drawn over it, this green will be of different shades. When it is exposed to the cold, it will again resume its first appearance of winter.

The Silver Tree.

DISSOLVE an ounce of fine silver in three ounces of strong aqua fortis, in a glass bottle. When the silver is dissolved, pour the aqua fortis into another glass vessel (a decanter will be best,) with seven or eight ounces of