COMBUSTION WITHOUT FLAME.

Light a small green wax-taper; in a minute or two, blow out the flame, and the wick will continue red-hot for many hours; and, if the taper were regularly and carefully uncoiled, and the room kept free from currents of air, the wick would burn on in this manner until the whole taper were consumed. The same effect is not produced when the colour of the wax is red, on which account, red wax-tapers are safer than green; for the latter, if left imperfectly extinguished, may set fire to any object with which they are

in contact,

COMBUSTION OF THREE METALS.

Mix a grain or two of potassium with an equal quantity of sodium; add a globule of quicksilver, and the three metals, when shaken, will take fire, and burn vividly.

TO MAKE PAPER INCOMBUSTIBLE.

Take a smooth cylindrical piece of metal, about one inch and a half in diameter, and eight inches long; wrap very closely round it a piece of clean writing paper, then hold the paper in the flame of a spirit-lamp, and it will not take fire; but it may be held there for a considerable time, without being in the least affected by the flame.

SINGULAR EXPERIMENTS WITH GLASS TUBES.

A most remarkable phenomenon is produced in glass tubes, under certain circumstances. When these are laid before a fire in an horizontal position, having their extremities properly supported, they acquire a rotatory motion round their axis, and also a

progressive motion towards the fire, even when their supports declining from the fire, so that the tubes will move a little way upwards to the fire. When the progressive motion of the tubes towards the fire is stopped by any obstacle, their rotation still continues. When the tubes are placed in a nearly upright posture, leaning to the right hand, the motion will be from east to west; but if they lean to the left hand, the motion will be from west to east; and the nearer they are placed to the upright posture, the less will the motion be either way. If the tube be placed horizontally on a glass plane, the fragment, for instance, of coach window glass, instead of moving towards the fire, it will move from it, and about its axis in a contrary direction to what it had done before; nay, it will recede from the fire, and move a little upwards, when the plane inclines towards the fire. These experiments succeed best with tubes about twenty or twenty-two inches long, which have in each end a pretty strong pin fixed in cork for their axis.

water.

AQUATIC BOMB.

Drop about two grains of potassium into a saucer of cold It will instantly burst into flame, with a slight explosion, burn vividly on the surface, and dart about with great violence in the form of a red-hot fire ball.

HEAT NOT TO BE ESTIMATED BY TOUCH.

Hold both hands in water which causes the thermometer to rise to ninety degrees, and when the liquid has become still, you will be insensible of the heat, and that the hand is touching any thing. Then remove one hand to water that causes the thermometer to rise to 200 degrees, and the other in water at thirty-two degrees.

H

After holding the hands thus for some time, remove them, and again immerse them in the water at ninety degrees; when you will feel warmth in one hand and cold in the other. To the hand which had been immersed in the water at thirty-two degrees, the water at ninety degrees will feel hot; and to the hand which had been immersed in the water at 200 degrees, the water at ninety degrees will feel cold. If, therefore, the touch in this case be trusted, the same water will be judged to be hot and cold at the same time.

FLAME UPON WATER.

Fill a wine-glass with cold water, pour lightly upon its surface a little ether; light it by a slip of paper, and it will burn for some time.

ROSE-COLOURED FLAME ON WATER.

Drop a globule of potassium, about the size of a large pea, into a small cup nearly full of water, containing a drop or two of strong nitric acid; the moment that the metal touches the liquid, it will float upon its surface, enveloped with a beautiful rosecoloured flame, and entirely dissolve.

TO SET A MIXTURE ON FIRE WITH WATER.

Pour into a saucer a little sulphuric acid, and place upon it a chip of sodium, which will float and remain uninflamed; but the addition of a drop of water will set it on fire.

WAVES OF FIRE ON WATER.

On a lump of refined sugar let fall a few drops of phosphuretted ether, and put the sugar into a glass of warm water,

which will instantly appear on fire at the surface, and in waves, if gently blown with the breath. This experiment should be exhibited in the dark.

EXPLOSION IN WATER.

Throw very small pieces of phosphuret of potassium into a basin of water, and they will produce separate explosions. The same substance will also burn with great brilliancy, when exposed to air.

WATER FROM THE FLAME OF A CANDLE.

Hold a cold and dry bell-glass over a lighted candle, and watery vapour will be directly condensed on the cold surface; then close the mouth of the glass with a card or plate, and turn the mouth uppermost; remove the card, quickly pour in a little limewater, a perfectly clear liquid, and it will instantly become turbid and milky, upon meeting with the contents of the glass, just as lime-water changes when dropped into a glass full of water.

FORMATION OF WATER BY FIRE.

Put into a tea-cup a little spirit of wine, set it on fire, and invert a large bell-glass over it. In a short time, a thick watery vapour will be seen upon the inside of the bell, which may be collected by a dry sponge.

BOILING UPON COLD WATER.

Provide a tall glass jar, filled with cold water, and place in it an air thermometer, which will nearly reach the surface; upon the surface place a small copper basin, into which put a little live charcoal the surface of the water will soon be made to boil,

while the thermometer will show that the water beneath is scarcely warmer than it was at first.

CURRENTS IN BOILING WATER.

Fill a large glass tube with water, and throw into it a few particles of bruised amber; then hold the tube, by a handle for the purpose, upright in the flame of a lamp, and, as the water becomes warm, it will be seen that currents, carrying with them the pieces of amber, will begin to ascend in the centre, and to descend towards the circumference of the tube. These currents will soon become rapid in their motions, and continue till the water boils.

HOT WATER LIGHTER THAN COLD.

Pour into a glass tube, about ten inches long, and one inch in diameter, a little water coloured with pink or other dye; then fill it up gradually and carefully with colourless water, so as not to mix them apply heat at the bottom of the tube, and the coloured water will ascend and be diffused throughout the whole.

The circulation of warm water may be very pleasingly shown, by heating water in a tube similar to the foregoing; the water having diffused in it some particles of amber, or other light substance not soluble in water.

EXPANSION OF WATER BY COLD.

Thus,

All fluids, except water, diminish in bulk till they freeze. fill a large thermometer tube with water, say of the temperature of eighty degrees, and then plunge the bulb into pounded ice and salt, or any other freezing mixture: the water will go on shrinking in the tube till it has attained the temperature of about forty degrees; and then, instead of continuing to contract till it freezes, (as is the case