The effects produced by pouring carbonic acid gas from one vessel to another, have a very singular appearance: if a lighted candle be placed in a jar, and the gas be poured upon it, the flame will be extinguished in a few seconds, though the eye is incapable of distinguishing that anything is poured out. EFFECT OF HYDROGEN ON THE VOICE. Make a hole through a wine cork of sufficient size to admit a smaller cork; through which make another hole, and fix it into the larger one. Tie the corks thus fixed into the neck of a bullock’s bladder, previously exhausted of air; let a tube from a bottle generating hydrogen pass very tightly through the aperture in the small cork, and the gas will distend and fill the bladder. The instant it is full, withdraw the inner cork, and either prevent the escape of the gas by means of the thumb, or cork it closely, till the operator is ready to _breathe the gas_; to do which, he should put the open cork into his mouth, and take _one_ inspiration, when, on immediately speaking, his voice will be remarkably shrill. The effect will pass off in a few seconds. MAGIC TAPER. Provide a piece of copper wire, about ten inches long, and fix at one end of it a piece of wax taper: take a pint bottle of hydrogen, and place the mouth downwards; light the taper, introduce it into the bottle, and the gas will take fire, and burn slowly towards the mouth, where it is in contact with the air. If, however, the taper be passed up into the bottle, it will be extinguished; but, on gently withdrawing it through the burning hydrogen, the wick will be rekindled. This may be done several times in succession with the same portion of gas. THE GAS CANDLE. Provide a strong glass bottle which will contain about eight ounces, or half a pint, into which put a few pieces of zinc; then mix half an ounce of sulphuric acid with four ounces of water, and pour it into the bottle upon the zinc; fit the mouth closely with a cork, through which put a metal tube which ends upward in a fine opening: the mixture in the bottle will soon effervesce, and hydrogen gas will rise through the tube. When it has escaped for about a minute, apply a lighted paper to the tube, and the gas will burn like a candle, but with a pale flame. Its brightness may be increased to brilliance, by sifting over it a small quantity of magnesia. [Illustration] GAS BUBBLES. Provide a bladder, fill it with hydrogen gas, to be made as for the last experiment, and fit the end of a tobacco-pipe closely into the bladder; dip the bowl of the pipe into soap and water, and, by pressing the bladder, soap-bubbles will be formed, filled with hydrogen gas; which bubbles, or balloons, will rise in the air, and keep there for some time. GAS-LIGHT IN THE DAY-TIME. Light a stream of hydrogen gas, and it will be scarcely visible in the day-light; but place in it a small coil of platinum wire, or project a little oxide of zinc through the flame, and it will become very luminous.