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 APPARENTLY 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. If the paper be strained over a cylinder of wood, it is quickly scorched.
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 to the heat, and that the hand is touching anything. Then remove one hand to water that causes the thermometer to rise to two hundred degrees, and the other in water at thirty-two degrees. After holding the hands thus for some time, remove them, and again immerse them in the water at ninety degrees; when you will find 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 two hundred degrees, the water at ninety degrees will feel cool. 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-COLORED FLAME UPON WATER.
Drop a globule of potassium, about the size of a large pea, into as 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 rose-colored flame, and entirely dissolve.