6

Atmosphere

(a) WEATHER WISDOM

THE general theory of wind depends upon two factors — heat and the earth's motion. The air near the equator, being heated and becoming lighter, gives way to a periodical inrush of heavier air from the colder regions, that of the poles pressing against that of the equator; when the air of the poles meets the air of the equator moving northward they counterbalance each other, producing calms and variable winds, such as the equatorial doldrums.

Such is the general idea of the motion of the atmosphere, which is modified by certain local manifestations, the monsoons of the Indian Ocean, and the north-east and south-east "trade winds," where the wind blows from the same quarter for days at a time.

Cirrus or "Mare's Tails." — Clouds which consist of wisp-like streaks and streamers.

Cumulus. — A cloud composed of dense convex mounds or masses.

Stratus. — A continuously extended sheet of cloud.

Cirro-cumulus or "Mackerel Sky." — Well defined, small rounded masses of clouds separated by intervals of sky.

Cirro-stratus. — Clouds which partake of the char­acteristics of both cirrus and stratus clouds in combina­tion.

Cumulo-stratus. — Clouds formed by the blending of cumulus and stratus.

Cumulo -cirro -stratus or Nimbus. — The rain cloud — a combination consisting of a sheet of cirro-stratus, under which a cumulus cloud drifts.

Soft or delicate clouds foretell fine weather, a dark, gloomy blue sky presages wind, but a light blue sky indicates fine weather. Generally speaking the lighter and softer the clouds the less wind (though there may be rain), and the harder and more ragged the clouds the stronger the wind to follow.

Sky Colours. — The colour of the sky, caused by moisture or clouds, is a sure indication of the weather, the principal effects being noted at sunrise or sunset. A deep blue colour of the sky, even when seen through clouds, indicates fair weather; a growing whiteness, an approaching storm.

Sun Colours. — A red sunrise, with clouds lowering later in the morning, indicates rain. A gray lowering sunset, or one where the sky is green or yellowish-green, indicates rain. A light yellow sky at sunset presages wind. A gale, moderating at sunset, will increase before midnight, but if it moderate after midnight the weather will improve.

If the full moon shall rise red, expect wind.

Halo. — By a "halo" is meant one of the large circles, or parts of circles (also called Sun Dogs), about the sun or moon. A halo occurring after fine weather in­dicates a storm.

Corona. — By a "corona" is meant one of the small coloured circles frequently seen around the sun or moon. A corona growing smaller indicates rain; growing larger, fair weather.

Rainbows. — A morning rainbow is regarded as a sign of rain; an evening rainbow, of fair weather.

Fogs. — Fogs indicate settled weather. A morning fog usually breaks away before noon.

Three foggy mornings will be surely followed by a rain storm.

Haze. — Haze is believed to prognosticate frost in winter, snow in spring, fair weather in summer, and rain in autumn.

Clearness. — Unusual clearness of the atmosphere, un­usual brightness or twinkling of the stars, indicates rain.

Friday's weather shows what may be expected on the following Sunday; that is, if it rains on Friday noon, then it will rain on Sunday, but if Friday be clear, then Sunday will be fine as well.

The twelve days immediately following Christmas denote the weather for the coming twelve months, one day for a month. The day of the month the first snow­storm appears indicates the number of snowstorms the winter will bring. For example, the first snowstorm comes on November 29 — look out, then, for twenty-nine snowstorms.

When you see northern lights you may expect cold weather.

Storms that clear in the night will be followed by a rain storm.

When the sky is full of stars expect rain.

No weather is ill, if the wind is still.

The sharper the blast the sooner it is past.

If a cat washes herself calmly and smoothly the weather will be fair. If she washes herself "against the grain" take your mackintosh with you. If she lies with her back to the fire there will be a squall.

Cats with their tails up and hair apparently electrified indicate approaching wind.

If pigs are restless there will be windy weather. Pigs are said to be able to see the wind.

The direction in which a loon flies in the morning will be the direction of the wind the next day.

Magpies flying three or four together and uttering harsh cries predict windy weather.