Quinine is efficient in its natural state, but it has[p. 156] been made infinitely more effectual by the breaking up or changing of the molecules with acids. Sulphate of quinine is made by the use of sulphuric acid as a solvent.
Explosions.—Explosions depend on oxygen. While this element does not burn, a certain amount of it must be present to support combustion. Thus, the most inflammable gas or liquid will not burn or explode unless oxygenized. Explosives are made by using a sufficient amount, in a concentrated form, which is added to the fuel, so that when it is ignited there is a sufficient amount of oxygen present to support combustion, hence the rapid explosion which follows.
Vibration in Nature.—The physical meaning of vibration is best illustrated by the movement of a pendulum. All agitation is vibration. All force manifests itself in this way.
The painful brilliancy of the sun is produced by the rapid vibrations of the rays; the twinkle of the distant star, the waves of the ocean when ruffled by the winds; the shimmer of the moon on its crested surface; the brain in thinking; the mouth in talking; the beating of the heart; all, alike, obey the one grand and universal law of vibratory motion.
Qualities of Sound.—Sound is nothing but a succession of vibrations of greater or less magnitude. Pitch is produced by the number of vibra[p. 157]tions; intensity by their force; and quality by the character of the article vibrated.
Since the great telephone controversy which took place some years ago there has been a wonderful development in the knowledge of acoustics, or sounds. It was shown that the slightest sound would immediately set into vibration every article of furniture in a room, and very sensitive instruments have been devised to register the force and quality.
The Photographer's Plate.—It is known that the chemical action of an object on a photographer's plate is due to vibration; each represents a force of different intensity, hence the varying shades produced. Owing to the different rates of vibrations caused by the different colors, the difficulty has been to photograph them, but this has now been accomplished. Harmony, or "being in tune," as is the common expression, is as necessary in light, as in music.
Some chemicals will bring out or "develop," the pictures; others will not. Colors are now photographed because invention and science have found the harmonizing chemicals.
Quadruplex Telegraphy.—One of the most remarkable of all the wonders of our age is what is known as duplex and quadruplex telegraphy. Every atom and impulse in electricity is oscillation.[p. 158] The current which transmits a telegram is designated in the science as "vibratory."
But how is it possible to transmit two or more messages over one wire at the same time? It is by bringing into play the harmony of sounds. One message is sent in one direction in the key of A; another message in the other direction in B; and so any number may be sent, because the electrical vibrations may be tuned, just like the strings of a violin.