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Diagrams of Experiments: Winter

An Experiment with Sympathetic Ink, called Winter changed to Spring.

Take a print which represents winter, and trace over the trees, plants, and ground, with the green sympathetic ink; observing to make some parts deeper than others, according to their distance. When those parts are dry, paint the other objects in their natural colours; then put the print into a glazed frame, and cover the back of it with a paper, pasted over its border only. When this print is exposed to the heat of a moderate fire, or to the warm rays of the sun, all the grass and foliage will turn to a pleasing green; and if a yellow tint be given to some parts of the print, before the sympathetic ink be drawn over it, the green will be of different shades, and the scene, that a minute before represented Winter, will now be changed into Spring. When this print is placed in the cold, Winter will appear again, and be again driven away by the warm rays of the sun; and this alternate change of seasons may be repeated as often as you please, provided the print be not made too hot. appe 5 Q の APPENDIX.

A remarkable Experiment, called the Revivified Rose. Take a rose that is quite faded, and throw in some common sulphur in a chafing dish of hot coal. Hold the rose over the fumes, and it will become quite white; then dip it into a basin of water, and giving it to any one, tell him to put it into his box or drawer, and after locking it, to give you the key. About five or six hours afterwards, return him the key, and when he unlocks his drawer, instead of the white rose he put into it, he will find one perfectly red.

How to Write on Glass by means of the Rays of the Sun. Dissolve chalk in aqua-fortis, to the consistence of milk, and add to it a strong solution of silver; keep this liquor in a glass decanter, well stopped, and cutting out from a paper the letters you wish to appear, paste it on the decanter, and place it in the sun, in such a manner, that its rays may pass through the spaces cut out of the paper, and fall on the surface of the liquor; then will that part of the glass through which the rays pass be turned black, while that under the paper will remain white; but particular care must be taken that the bottle be not moved during the time of the operation. To produce different Colours, by pouring a colourless Liquor into a clean Glass.

Take a strong solution of quicksilver, made with spirit of nitre; dilute it with water, and pour it into a hot glass, rinsed in strong spirit of sea-salt, and it will instantly become coloured. Or, if a solution of silver, made with spirit of nitre, considerably diluted, be poured into a glass, prepared in the manner above-mentioned, it will produce the same effect. And if you pour hot water upon new-made crocus metallorum, and put it into a clean glass, rinsed with any acid, it will produce an orange colour. To produce a Colour which appears and disappears by the Influence of the Air.

Put into a decanter some volatile spirit, in which you have dissolved copper filings, and you will have a fine blue tincture; and if the bottle be stopped, the colour will soon return again; and this experiment may be repeated a considerable number of times.

APPEN To turn a colourless Liquor Black, by adding a White Powder to it.

Put a hot weak pellucid infusion of galls int a glass, and throw into it a grain of the vitriol of iron, calcined to whiteness, and considerably heated; then, as it falls to the bottom, it will make a black cloud, which will uniformly diffuse itself through the transparent liquor, and gradually turn it black. The same effect may also be produced by the addition of a little vitriol of iron calcined to a yellow colour, or by the colcothar of vitriol calcined to redness. The black liquor, produced as above, may be rendered pellucid again, by pouring the liquor hot into a glass rinsed with the pure acid of vitriol. And to make this transparent liquor black again, pour to it as much hot oil of tartar per deliquium as will saturate the acid, which has attracted the metallic matter.

Freezing Mixture.

In the time of snow, a freezing mixture may easily be made, by mixing a little snow and common salt in a basin near the fire. If water in an iron cup or phial be put into this mixture, it will immediately be frozen; and if pounded ice and common salt be added, it will have a still more powerful effect. Experiments with the Microscope.

They who possess this amusing instrument, may easily per form with it a variety of pleasing experiments; among others, the following:-Leave some vinegar exposed in a saucer, for a few days, to the open air; then place a drop of it, by means of a clean pen, or a camel's hair brush, on the transparent objectplate of the microscope; and if the object-plate be properly illuminated from below, you will observe in this drop of liquor animals resembling some small eels, which are in continual motion. If you slightly bruise some pepper-corns, and infuse them in water for a few days, and then expose a drop of it to the microscope, a number of animals of a different kind will be visible. These are of an oblong shape, and, like the others, in continual motion, going backwards and forwards in all directions, turning aside when they meet each other, or when their passage is stopped by some obstacle.

In otner infusions, as in that of new hay, differently shaped animalcules will be found. When the drop in which they swim, and which to them is like a pond, becomes diminished by evaporation, they gradually retire towards the middle.