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1. Muriatic Acid. — Into a bottle arranged as shown in Figure 1, put a few bits of zinc, and pour a little muriatic acid over them. Effervescence at once takes place, and a colorless gas passes through the bent tube into the jar, which has been previously filled with water, and in

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verted over the trough. When the jar is full of gas, raise it from the water, and apply a lighted taper to its mouth. The

gas takes fire with a slight'explosion, and burns with a pale flame. This gas is called hydrogen, and comes from the muriatic acid.

Pour a little of the muriatic acid into a flask (Figure 2), add a little black oxide of manganese, mix them thor

oughly, and heat gently. A greenish-yellow gas passes into the jar inverted over the water-trough. When the jar is full, close its mouth with a glass plate, remove it from the trough, and set it on the table. Moisten a piece of litmus-paper or colored cotton cloth, and hold it inside the jar. It will be instantly bleached. This gas is called chlorine, and, like the hydrogen, comes from the muri

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atic acid. Chlorine may be recognized by its bleaching power, and also by its color and its suffocating odor.

We have now got from muriatic acid two gases, hydrogen and chlorine.

If a small glass jar be filled with equal parts of these two gases, and a light be applied to its mouth, the mixture will take fire with an explosion. If a little dish of ammonia be standing by, a dense white cloud will appear when the gases burn..

Now this cloud shows that muriatic acid has been produced ; for, if we dip a glass rod in muriatic acid, and hold it over the ammonia, the white cloud at once appears.

Muriatic acid, then, contains nothing but hydrogen and chlorine.

2. Water. — If a bit of sodium be thrust beneath the mouth of an inverted jar, filled with water, as shown in Figure 3, bubbles of gas rise and fill the jar. On raising the jar, and applying a taper to its mouth, we see, by the way in which the gas takes fire, that it is hydrogen.

Fill a tall glass jar with chlorine water (that is, water which has absorbed chlorine gas), invert it, with its

Fig. 3.

mouth in a shallow dish of water, and leave it for ten or twelve hours in the sunshine. Bubbles of gas will be seen to rise, and collect in the top of the jar. If now we set the jar upright, and plunge a lighted taper into the gas, the taper burns much more brightly than in the air. This gas is called oxygen.

We have thus got hydrogen and oxygen from water. If, now, we burn a jet of hydrogen in a jar of oxygen, moisture will collect on the sides. This moisture is water, and comes from the union of the hydrogen and the oxygen.

This shows that there is nothing but oxygen and hydrogen in water.

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