In one part becomes obscured. The obscuration increases
In Rome, at one time, to talk publicly of their being due to natural causes was an offence punishable by law So strong a hold had this superstition on the popular mind that, even after it came to be generally believed that eclipses of the sun were caused by the moon coming between the earth and the sun, eclipses of the moon were still considered to be due to some supernatural power. When the moon was in eclipse, the people turned out and made a great noise with brazen instruments the idea being that by doing so they gave her ease in her affliction. Similar notions have prevailed among all barbarian tribes. The Chinese imagine eclipses to be caused by great dragons trying to devour the sun and the moon, and accordingly they beat drums and brass kettles to terrify the monsters into letting go their prey. Even in modern India, the ignorant country people still believe that an eclipse, like a comet, is an omen of coming disaster.
The sun may be partially or wholly eclipsed. A partial eclipse is caused by the moon passing over part of the face of the sun. The sun’s disc loses its circular form; one part becomes obscured. The obscuration increases for a time and then diminishes until it disappears altogether. A total eclipse takes place when the moon comes between the sun and the earth, and the whole sun becomes slowly darkened and finally disappears for a time.
It is observed that solar eclipses always happen at the time of a new moon, when the sun and moon are on the same side of the earth. Astronomers can calculate when the moon will come between the earth and the sun, and so can predict exactly when an eclipse will take place and how long it will last. Eclipses of the sun are of great value to astronomers, because when the sun itself is blotted out from sight by the dark mass of the moon, the sun’s corona, invisible to us in full sunlight, becomes visible, and can be examined by the telescope, and its composition determined by the spectroscope. The almost instantaneous darkening of the sun, particularly when it is unlooked for, is calculated to impress a spectator with vague terror; even when expected, it fills the mind with awe. The sudden darkness is impressive from its strangeness, as much as from occurring by day; it resembles neither the darkness of night nor the gloom of twilight. The cone of the moon’s shadow, though it completely envelops the spectator, does not enclose the whole atmosphere above his horizon.
The mass of unenclosed are, accordingly, catches the sunlight, and reflects it into the region of the total eclipse, making there a peculiar twilight. Stars and planets appear, and all animals are dismayed by the dismal aspect of nature.