The Atlantic Monthly, Volume 06, No. 33, July, 1860 eBook

This eBook from the Gutenberg Project consists of approximately 298 pages of information about The Atlantic Monthly, Volume 06, No. 33, July, 1860.

The Atlantic Monthly, Volume 06, No. 33, July, 1860 eBook

This eBook from the Gutenberg Project consists of approximately 298 pages of information about The Atlantic Monthly, Volume 06, No. 33, July, 1860.

The atmosphere absorbs some portion of the light which it receives.  It is not all reflected or refracted or even penetrative.

Objects seen under various degrees of light, either convected or retarded by different media, appear near or distant, distinct or confused.  Thus, we are often surprised at the apparent nearness and brightness of an opposite shore or neighboring island, in some conditions of the air, while at other times they seem distant and lie in shadowy obscurity.

The looming up of a vessel on the water is another common instance of the principle of refraction.

It has been noticed by almost every one, that, during the warm and moist nights of summer, the moon, as she rises above the horizon, appears much larger than when at the zenith.  So the setting sun is seen of apparently increased size.  Sir John Herschel asserts that the appearance is an illusion, and so do some others.  Professor Carey says, that, if we look through a paper tube at the moon when on the horizon, the paper being folded so as to make the aperture of its exact size, and then look again at it when it reaches the zenith, we shall find there is no difference.

On the other hand, an experiment is offered by a German Professor, of the name of Milo, of this kind:  If we look through a tube so constructed as to have one side filled with spirits of wine and the other with common air, the half of the object seen through the former will be found to appear much larger to the eye than the other half seen through the latter.

It is laid down, that, where extraordinary refraction takes place laterally or vertically, the visual angle of the spectator is singularly enlarged, and objects are magnified, as if seen through a telescope.  Dr. Scoresby, a celebrated meteorologist and navigator, mentions some curious instances of the effects of refraction seen by him in the Arctic Ocean.

Many remarkable phenomena attend this state of the atmosphere, known as the Fata Morgana of Sicily, the Mirage of the Desert, the Spectre of the Brocken, and the more common exhibitions of halos, coronae, and mock suns.  The Mountain House at Catskill has repeatedly been seen brightly pictured on the clouds below.  Rainbows are also due to this condition of the atmosphere.

We might occupy the remainder of the space allowed us by enlarging on various topics which belong to this part of our subject.  The twilight gray, the hues of the evening and morning sky, the peculiarity of the red rays of light, the scintillation of stars, their flashing changes of colors, are all meteorological in their character, as well as strikingly beautiful and interesting.

* * * * *

Polarity of light is another of the wonders of which Meteorology takes cognizance.  The celebrated Malus, in 1808, while looking at the light of the setting sun shining upon the windows of the Luxembourg, was led to the discovery that a beam of light which was reflected at a certain angle from transparent and opaque bodies, or by transmission through several plates of uncrystallized bodies, or of bodies crystallized and possessing the property of double refraction, changed its character, so as to have sides, to revolve around poles peculiar to itself, and to be incapable of a second reflection.  The angle of polarity was found to be 54 deg..

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The Atlantic Monthly, Volume 06, No. 33, July, 1860 from Project Gutenberg. Public domain.