Gunpowder, gun-cotton, nitro-glycerine, and dynamite all contain N, and their explosive character depends largely upon its presence. Nitrogen and chlorine form a compound, which explodes with such terrific violence that its manufacture should never be attempted by students.
Nitrogen iodide is another of these dangerous combinations. It can be made in very small quantities, however, in the form of a black powder, which may be handled with impunity while it is damp. The touch of a feather, or a zephyr, will sometimes explode it when dry. It is almost impossible to keep it; the jar of a foot-fall or slamming of a door is often sufficient to liberate the unstable nitrogen, and the substance disappears with a loud report. The tremendous rending force of dynamite is well known. A small charge in a torpedo will sink a ship. The Greely Relief Expedition used it to open their way through the arctic ice fields. Its atoms rush apart with such frightful velocity that if a pound of it be exploded upon a naked bowlder, of many tons weight, the rock is shivered into fragments.
COMPOUNDS OF N AND O.
At every breath we take into the lungs a mixture of N and O. The operation is not only harmless, but essential to life. When, however, N and O are compounded, the resulting substances are very different. Nitrous oxide (N₂O) forms the well known laughing gas, which breathed, produces for a time a species of intoxication, and if its inhalation is continued, results in insensibility. Nitric oxide (NO) when first formed consists of suffocating red fumes, while nitric acid (HNO₃) is a very corrosive liquid which will cauterize flesh, and acts with great energy upon most of the metals. It is sometimes termed aqua fortis, and is much used in etching upon copper. The surface of the metal plate is covered with varnish or wax, upon which the design is then traced by a sharp pointed instrument. The acid is then applied and remains until, in the judgment of the artist, the impression is deep enough. Any one can easily etch his name, in this way, on a knife blade, or make a stencil plate from a thin strip of brass or copper. Silver, copper, mercury, lead, zinc, iron, bismuth can all be dissolved by nitric acid.
The five compounds of N and O admirably illustrate the laws of atomic combination. Their symbols are as follows: Nitrogen monoxide, N₂O; nitric oxide, NO; nitrogen trioxide, N₂O₃; nitrogen peroxide, NO₂; nitrogen pentoxide, N₂O₅. A careful examination of the weights of these substances, which may be made by consulting some good chemical manual, will show that there is an exact ratio of combination, their proportional weights being respectively as 1¾ to 1, 1¾ to 2, 1¾ to 3, 1¾ to 4, 1¾ to 5. Since atoms can not be divided they must combine atom for atom, or in multiples. This principle has been more fully stated in the form of six
LAWS OF COMBINATION.
The first law of weights says that the elements of a given compound always unite in the same proportions, by weight. The second law is, that if two or more substances unite to form several compounds, their highest combining proportions will always be multiples of their lowest combining weights. The third law announces that the combining weight of a compound is the sum of the combining proportions of its constituents. The volumetric laws are as follows: 1, If two or more elements unite to form a compound, their proportion by volume will always be the same; 2, if they unite to form a variety of compounds, these proportions will always be multiples of the lowest combining volumes. 3. The third law is most curious of all; that the combining volume of a gaseous compound is always 2. For example, if two elements represented by x and y unite in proportion of one volume of x to one of y, there would be formed two volumes of the compound. If there should be two volumes of x and one of y there would be two volumes of the compound, and if they should unite three volumes of x and one of y, again there would be but two volumes of the product. Just why two should be such a favorite number is difficult to explain. No one can carefully study these interesting laws without perceiving the necessity for a rare intelligence in arranging all materials with such mathematical exactness.
How absurd to ascribe to atoms the power to count, to weigh, to measure, to arrange themselves in orderly combinations which surpass the most skilful marshaling of battalions on a great battle field. It would be to make gods of atoms.
AN ALLEGORY—THE FOUR KINGS.
