Lieutenant Maury has said that the atmosphere makes the whole world akin. The breezes that blow over our land may in turn visit every other, carrying bane or blessing. Alas! we fear, to-day, that the feverish breath which poisons the air of Italy may spread its pestilence to our shores. One lesson we learn from this is, that the misery or prosperity of any one portion of the earth may affect every other; and that which benefits a part, contributes in this way a blessing to the whole.
NITROGEN.
In our first article of this series somewhat extended reference was made to oxygen, and we shall therefore not dwell upon that element at this time.
Nitrogen, which constitutes by measure 79.04, and by weight 76.8 of the air, is remarkable for the absence of positive qualities. It is a colorless, tasteless, odorless gas, will not burn, nor support life or combustion. Its chief office is that of a diluter. Without it we should live too fast; even as it is we live too fast! With oxygen alone to breathe, ours would be a short and fevered existence. All flames and fires would be kindled into furious combustion, stoves themselves would burn, and the very “elements melt with fervent heat.”
MERCURY DISSOLVING IN NITRIC ACID.
We can prepare air artificially, by mixing one part of O with four parts of N, thoroughly shaking them together. Nitrogen can easily be obtained in the following manner: Make a small cavity in a piece of cork; line this by sifting into it a little plaster or crayon dust. Place the cork on some water in a deep plate. Insert now in the cavity a piece of dry phosphorus (always handle phosphorus with care), touch the P with a heated wire, and quickly place over it an inverted jar. White fumes will instantly rise, which are phosphoric anhydride, P₂O₅. These will be quickly absorbed by the water, and the water will rise and fill one-fifth of the jar. It will be necessary to add water as that in the plate rises. The remaining four-fifths of the jar will be occupied by nitrogen.
The following is an instructive experiment: Take two jars of equal size (one open at both ends), one of which is fitted with a stopper; fill one with O and the other with N. Place a smooth glass plate under each before removing the pneumatic trough, and holding the plates closely over the top, invert one jar on the other—plate to plate—the jar of O being below. Now carefully remove the plates, and also the stopper from the jar of N, and quickly insert a lighted taper with a long snuff. As it descends through the N it will be extinguished, but as it enters the O it will be rekindled. This may be repeated many times by raising and lowering the taper. N does not seem to be strongly attached to anything; that is, it has but slight affinity for the substances with which it combines. Strange enough, from this sluggishness results a marvelous activity. Being held with such little force it is liable at any time to be liberated in the form of a gas, and the decomposition of the whole compound of which it formed a part will take place. Hence, instability is the most marked characteristic of N. It reminds one of some loafer, without steady occupation or aims, restless, vacillating, but always a factor in every turbulence or outbreak.
BISMUTH DISSOLVING IN NITRIC ACID.