When the air is clear bad seeing is due to atmospheric inequalities which the free mixing caused by winds will eliminate. When the moon's horns, then, appear sharp, that is, when the seeing is good, we know that these inequalities do not exist, and the natural inference is that they have been smoothed out by strong overrunning winds, which later may reach the surface of the earth.
Stars
"The prudent mariner oft marks afar
The coming of tempests by Boötes's star."
—Aratus.
The stars, like the sun and the moon, have furnished a number of proverbs concerning the weather, and, while most of them are only nonsense, a few have decided merit, as, for instance:
"When the stars begin to huddle,
The earth will soon become a puddle."
This proverb furnishes, in general, a correct forecast. It also affords a curious illustration of the ignorance that once was—perhaps it would not be far wrong to say still is—so prevalent in regard to stars.
When a mist, due to the beginning of condensation, forms over the sky the smaller stars cease to be visible, while the brighter ones shine dimly with a blur (really a faint corona) of light about them, each looking like a small confused cluster of stars. Hence the idea, as above expressed, that stars can huddle together at one time—before a rain—and be scattered asunder at another.
There is also some ground for the proverb that declares the number of stars within a lunar halo to be the number of days before a storm, for the nearer the storm the denser the condensation, and therefore the smaller the number of stars seen through it. However, as an entire day is a pretty long unit of time to use in sign forecasting, it would be better simply to say that the fewer the stars within the ring the nearer the rain; though even in this form it is not very trustworthy, owing to the fact that the brighter stars are unevenly distributed.
An entirely different star phenomenon that has given rise to a few proverbs is twinkling, or the irregularities with which they shine. This fluctuation in their light is caused mainly by irregular refraction due to numerous inequalities in the distribution of temperature, such as necessarily accompanies the over and under running of air currents of different temperatures and different humidities, a condition that often precedes a storm. Hence the justification of the prosaic proverb that says:
"When stars flicker in a dark back-ground rain or snow follows soon."
