Part 32 (1/2)
The way to find which way the wind is blowing, if there is only very light breeze, is to throw up little bits of dry gra.s.s; or to hold up a handful of light dust and let it fall, or to suck your thumb and wet it all round and let the wind blow over it, and the cold side of it will then tell you which way the wind is blowing.
Weather Bureau
The U. S. Department of Agriculture Weather Bureau publishes a ”Cla.s.sification of clouds,” in colors which may be had for the asking. If you are near one of the weather signal stations daily bulletins will be sent to camp upon request, also the weather map.
A set of flag signals run up each day will create interest. The flags are easily made, or may be purchased.
Keep a daily record of temperature. A boy in charge of the ”Weather Bureau” will find it to be full of interest, as well as to offer an opportunity to render the camp a real service. He will make a weather vane, post a daily bulletin board, keep a record of temperature, measure velocity of wind and rainfall.
If you have lost your bearings and it is a cloudy day, put the point of your knife blade on your thumb nail, and turn the blade around until the full shadow of the blade is on the nail. This will tell you where the sun is, and decide in which direction the camp is.
Points of Compa.s.s
Face the sun in the morning, spread out your arms straight from body.
Before you is the east; behind you is the west; to your right hand is the south; to the left hand is the north.
A Home-made Weather Prophet
For a home-made barometer you need a clean, clear gla.s.s bottle. Take one drachm[1] each of camphor gum, saltpetre and ammonia salts, and dissolve them in thirteen drachms of pure alcohol. Shake till dissolved. Then pour in bottle and cork tightly. Hang the bottle of mixture against the wall facing north, and it will prove a perfect weather prophet. When the liquid is clear it promises fair weather. When it is muddy or cloudy it is a sign of rain. When little white flakes settle in the bottom it means that the weather is growing colder, and the thicker the deposit the colder it becomes. Fine, starry flakes foretell a storm, and large flakes are signs of snow. When the liquid seems full of little, threadlike forms that gradually rise to the top, it means wind and sudden storm.
[Transcriber's Footnote 1: Dram, drachma; drachm; U.S. Customary System equal to 1/16 of an ounce or 27.34 grains (1.77 grams). Apothecary weight equal to 1/8 of an ounce or 60 grains (3.89 grams).]
U. S. DEPARTMENT OF AGRICULTURE WEATHER BUREAU. EXPLANATION OF FLAG SIGNALS,
[Ill.u.s.tration: Flags]
No. 1, alone, indicates fair weather, stationary temperature.
No. 2, alone. Indicates rain or snow, stationary temperature.
No. 3, alone, indicates local rain, stationary temperature.
No. 1, with No. 4 above it, indicates fair weather, warmer No. 1, with No. 4 below it, indicates fair weather, colder.
No. 2, with No. 4 above it, indicates warmer weather, rain or snow.
No. 2, with No. 4 below it, indicates colder weather, rain or snow.
No. 8, with No. 4 above it, indicates warmer weather with local rains.
No. 3, with No. 4 below it, indicates colder weather with local rains.
No. 1, with No. 5 above it, indicates fair weather, cold wave.
No. 2, with No. 5 above it, indicates wet weather, cold wave.
Forecasts made at 10 A.M., and displayed between 12 and 1 P.M., forecast the weather for the following day until 8 P.M.
FORECASTING THE WEATHER 245
Plant Barometers
The dandelion is an excellent barometer, one of the commonest and most reliable. It is when the blooms have seeded and are in the fluffy, feathery condition that its weather prophet facilities come to the fore.
In fine weather the ball extends to the full, but when rain approaches, it shuts like an umbrella. If the weather is inclined to be showery it keeps shut all the time, only opening when the danger from the wet is past.