Provide a large tin box, of the size of a large snuff-box, and in this place eight other boxes, which will go easily into each other, and let the least of them be of a size to hold a guinea. Each of these boxes should shut with a hinge, and to the least of them there must be a small lock, that is fastened with a spring, but cannot be opened without a key;—observe, that all these boxes must shut so freely, that they may be all closed at once. Place these boxes in each other, with their tops open, in the drawer of the table on which you make your experiments; or, if you please, in your pocket, in such a manner that they cannot be displaced.
Then ask a person to lend you a new guinea, and desire him to mark it, that it may not be changed. You take this piece in one hand, and in the other you have another of the same appearance, and putting your hand into the drawer, you slip the piece that is marked into the least box, and shutting them all at once, you take them out; then showing the piece you have in your hand, and which the company suppose to be the same that was marked, you pretend to make it pass through the box, and dexterously convey it away.
You then present the box, for the spectators do not yet know there are more than one, to any person in company, who, when he opens it, finds another, and another, till he comes to the last, but that he cannot open without the key, which you then give him, and retiring to a distant part of the room, you tell him to take out the guinea himself, and see if it be that which he marked.
This amusement may be made more surprising, by putting the key into the snuff-box of one of the company, which you may do by asking him for a pinch of snuff, and at the same time conceal the key, which must be very small, among the snuff; and when the person, who is to open the box, asks for the key, you tell him that one of the company has it in his snuff-box. This part of the amusement may likewise be performed by means of a confederate.
To make Pictures of Birds with their Natural Feathers.
First take thin board or panel, of deal or wainscot, well seasoned, that it may not shrink; then paste white paper smoothly on it, and let it dry; if the colour of the wood show through, paste a second paper over it. When the paper is dry, get ready any bird that you would represent, and draw the outline as exact as you can on the papered panel. You then paint the ground-work, stump of a tree, the bill and legs, their proper colour, with water-colours, leaving the body to be covered with its own natural feathers. In the space you have left for the body, you lay on very thick gum-water, letting each coat dry before you lay on another, and so continuing until the gum is as thick as a shilling. Then take the feathers off the bird; and, as you proceed, draw a camels'-hair pencil, dipped in gum-water, over the coat of gum that you have laid on the paper, that it may more readily adhere. As you strip the bird, you must fix the feathers in their proper places on the board, and you shave the shafts or stems of the larger feathers, that they may lie flat. The most ready way to perform the operation, is to provide yourself with a pair of steel pliars to take up and lay on the feathers with. You should prepare some small leaden weights to lay on the feathers, that they may more readily adhere to, and lie flat on, the gum. The part where the eye is must be supplied by a small piece of paper, coloured and shaped like one; or you may, probably, be able to get a glass bead that will answer the purpose better. In order that the feathers may lie smooth and regular, when the whole is perfectly dry, lay a book, or a flat board, with a weight on it.
The Art of Bronzing.
Bronzing is that process by which figures of plaster-of-paris, wood, &c. are made to have the appearance of copper or brass. The method is as follows:
Dissolve copper filings in aqua fortis. When the copper has impregnated the acid, pour off the solution, and put into it some pieces of iron, or iron filings. The effect of this will be to sink the powder to the bottom of the acid. Pour off the liquor, and wash the powder in successive quantities of fresh water. When the powder is dry, it is to be rubbed on the figure with a soft cloth, or piece of leather; but observe, that previously to the application of the bronze powder, a dark blackish sort of green is first to be laid on the figure: and if you wish the powder to adhere stronger, mix it with gum-water, lay it on like paint, with a camels'-hair brush, or previously trace the parts to be bronzed with gold size, and when nearly dry, rub the powder over it.