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is one of the purest and most refined of our sensitive pleasures. It possesses the power of charming our ears, soothing our passions, and affecting our hearts ; it dissipates the gloom of melancholy, animates the vital spirits, and gives sublimity to our thoughts and sentiments. When a lady tunes her melodious voice, or touches with her fingers the keys of the pianoforte, or the strings of the lyre, the air distributes every musical variation and every note, with the utmost precision. It conveys its message with the greatest impartiality to the ear of every listener. Though many instruments may be employed, and a thousand persons be present, and placed in every direction, it distributes the harmony alike to every
It keeps the most exact time—it conveys the slightest inflections of the voice, and the smallest variation of a tone. It runs through the whole compass of music, swells the sounds, and makes them even thunder in our ears. The next moment, it makes them flutter and melt into dying strains. After this, it swells the notes again, and sinks them in their turns. Thus it expresses, in the most lovely manner, every passion and emotion of the soul, and charms every heart with its persuasive sounds.
That all the effects now stated are owing to the ministration of the atmosphere, is proved by one decisive experiment.
Place a small bell under the receiver of an air-pump; let it be rung, and the sound will be heard at a
considerable distance. Exhaust the air from the receiver, and the sound can scarcely be heard by the nicest ear. Even in places where the air is not excluded, but only highly rarefied, as in the higher regions of the atmosphere, sounds are scarcely heard. Fredlichius, a gentleman of Hungary, informs us, that when he was on one of the loftiest tops of the Carpathian mountains, he fired a pistol, which at first made no greater noise than if he had only broken a stick or a staff; but after a little time there was a murmuring for a while which filled the valleys and woods below. Descending to the lower valleys and the rugged rocks, he fired again, which made a dreadful sound, as if great guns had been discharged, and as if the whole mountain had begun to tumble about his ears. The sound lasted for half a quarter of an hour, till it had reached the most secret caverns, where the sound was enlarged and reflected back in every direction. These facts show that the elasticity of the air, which is always greatest where the air is densest, is essential to the propagation of sound.
10. The atmosphere is the cause of that splendour and universal light around us, which lays open to our view the landscape of the world." Were this atmosphere destroyed, we might see the sun without enjoying the light and brilliancy of day. That luminary would, indeed, strike our eyes with a vivid brightness when we turned round to behold his flaming orb; but it would appear only as a blazing fire during night in a spacious plain, where all is gloom and darkness around. It would suddenly burst on our view in the eastern horizon, in the morning, and would not change its aspect in the least, during its course through the heavens, till it suddenly disappeared in the western sky. The objects immediately around us would be partially visible; but the rays of the sun which fell on distant objects would be for ever lost in the expanse of the heavens; and when we turned our back to the sun, nothing would present itself, but an abyss of darkness, and the whole horizon involved in a dismal gloom. The number of objects in the heavens would, indeed, be augmented, for the stars would shine through a canopy as black as ebony, even when the sun was above the horizon ; but all the gay colouring of the terrestrial landscape, which now delights the eye and the imagination, would be for ever veiled from the inhabitants of the world. In such a state of things, it would be always night; and the difference between such a night and that which we
now enjoy, would be, that the celestial orbs, instead of being grounded on a beautiful azure sky, would appear on a black canopy, like so many white points on a dismal mourning carpet.
But the Almighty, whose arrangements have all a respect to the happiness of his creatures, has enveloped our globe with an atmosphere, and has endowed it with a capacity of reflecting and refracting the rays of light in all directions.
This atmosphere, too, is charged with innumerable myriads of watery particles, exhaled by evaporation from every region of the sea and land. In the serenest days of summer,
when no clouds nor vapours are to be seen, these rarefied particles of water, which are imperceptible to the keenest eye, fill the whole sphere of the atmosphere around us, both above and below the region of the clouds. It is among these rarefied waters in the higher regions of the air that the rays of light reflected from the surface of the land meet, and are again reflected in every direction to the earth; and hence is produced that beautiful azure colour which distinguishes the aspect of the heavens. This azure is sometimes lighter, according to the quantity of rays which enter the atmosphere, and sometimes darker, when the absence of the twilight heightens the blue of the celestial concave, by means of that black and void space which lies beyond the limits of the atmosphere. In corroboration of these remarks, it may be noticed, that the higher we ascend above the surface of the earth, the darker does the sky appear. And hence all travellers affirm, that, on the tops of lofty mountains, it sometimes appears as black as ebony, which causes the milky way to appear like a pure flame shot across the heavens, and the stars to shine with a greater brightness, and to appear far more numerous than in the plains below.
11. The atmosphere is the cause of the morning and evening twilight. We all know
that the day is gradually ushered in after the darkness of the night. More than an hour before the rising of the sun, in this part of the world, a streak of light appears in the eastern horizon. This light increases in brilliancy every moment—the landscape of the earth, which had been previously covered with a mantle of blackness, appears gradually to emerge from an abyss of darkness, like the light at the first creation—the circle of the horizon becomes inflamed with a bright vermilion—the mountain tops are tinged with purple ; and at length appears the most beautiful and sublime object in nature, the sun rising in his might and glory. And, when this luminary has described the circuit of the heavens, and passed the verge of the western horizon, darkness does not come on instantaneously, but by slow and imperceptible degrees, so as to warn us to prepare for its approach. The season of twilight, particularly that of a summer evening, is perhaps one of the most agreeable and interesting periods of the day. How many delightful walks and excursions-how many cheerful and solemn musings-how many endearing intercourses of love and friendship does it recall to our recollection, when we strolled along the solitary walks, or reclined in the bower of friendship, till the rising moon and the twinkling stars called us to our nightly repose !
Now, all such pleasures and advantages derived from the twilight, are owing to the agency of the atmosphere. When the sun