Page:Popular Science Monthly Volume 17.djvu/792

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of these bones are found occasionally in birds, reptiles, and amphibia. We meet a few other marks of the reptiles in the ornithorhynchus: for example, some ribs are partly or wholly separated from the spine; the hollow called the acetabulum, in which the thigh-bone is attached to the pelvis, is not perfect; the ear is formed very simply, the auditory canal not being wound spirally, and the outer ear being wanting.


THE author of an essay on "The Empire of Tones," which was published at Brunswick a few years ago, wrote: "The globe is played upon around its whole circuit by the billows of the mighty ocean; it is encompassed by the strata of the atmosphere ever moving in sound-waves; and is swept from pole to pole by a flood of the most diversified tones which have their origin in nature. Over the eternal snow-peaks of the mountains, where all life has long since been made stark by the cold, howl icy storms like the voice of a gigantic organ. In the deep bosom of the earth the miner hears the murmur of the subterranean waters, the whistling of the jets of escaping gases, and the monotonous trickling of the gathered dampness. The human race has heard the voices of creation for thousands of years, from its childhood; but how incompetent has science been till now to explain the origin and meaning of these innumerable sounds!" A notice of some of the most remarkable of the sounds which are produced by the acoustic forces of nature will be of interest.

It should be borne in mind that waves of sound produced by a single impulse have the property of putting other waves in motion, so as to prolong the effect and produce a tone from the combination of the wave-movements. From this we may understand how resonances may be caused and harmonies may be heard in nature, the real origin of which may not be perceived by the common observer, or even by the learned investigator. Of such are the mysterious noises heard in the woods of Ceylon, on the banks of the Orinoco, and on the peninsula of Sinai. The rustle of the woods, the roll of the thunder, the crash of the storm, the murmur of the waterfall—all those sounds of the earth and the air of which the poets are so fond, and in which the ancients recognized the prophetic voices of the gods—sober science seeks to trace back to the same law whose operation is perceived when the bullet whizzes through the air, when the wind whistles through the crack of the door or window, when the burning wood snaps in the fireplace, when the stove-door crackles in cooling, when the teakettle sings that the water is boiling. Most of these sounds, which are pro-