_Nimbus_

TYPES OF RAIN CLOUDS.]

[Illustration: KITE-FLYING--THE NEW WAY.

_Courtesy of U. S. Weather Bureau._]

[Illustration: KITE-FLYING--THE OLD WAY.

Benjamin Franklin performing his famous experiment, whereby he proved
that a flash of lightning was an electric discharge.]

[Illustration: THE EXPLORER OF THE UPPER AIR.

Weather box kite being released at the Drexel Aerological Station, with
equipment to tell altitude, pressure of atmosphere, velocity of wind,
and temperature, in a continuous record.

_Courtesy of U.S. Weather Bureau._]

[Illustration: SNOW-FLAKES FROM THE UPPER REGIONS OF THE AIR.]

[Illustration: SNOW-FLAKES FROM THE MIDDLE REGIONS OF THE AIR.]

[Illustration: SNOW-FLAKES FROM THE LOWER REGIONS OF THE AIR.

Note the gradual progression from solid to feathery forms, and
especially that every elaboration maintains the six-pointed crystal
type.

_Courtesy of J. Wilson Bentley._]

[Illustration: RINGING THE FROST ALARM!

Thermometer with electric attachment which wakes the neighborhood when
the grip of a cold wave menaces ruin to a fruit crop.

_Courtesy of U.S. Weather Bureau._]

[Illustration: FIGHTING FROST IN AN ORCHARD--NIGHT.]

[Illustration: FIGHTING FROST IN AN ORCHARD--DAWN.

The pall of smoke prevents evaporation and keeps the air near the ground
from freezing temperatures.

_Copyright by J. Cecil Alter, U.S. Weather Bureau, Cheyenne, Wyo._]

[Illustration: BUCKING A SNOW DRIFT.]

[Illustration: CLEAR THE WAY!

Even an avalanche cannot stop Man, backed with the resources of modern
snow-fighting machinery.

_Courtesy of Northern Pacific Railway Co._]

[Illustration: MEASURING THE BLIZZARD'S RAGE.

Shielded snow gauge in the Northwest to register the amount of
snow-fall.

_Courtesy of U. S. Weather Bureau._]

[Illustration: SIGNALS ON DELAWARE BREAKWATER.

_Courtesy of Geo. S. Bliss, U.S. Weather Bureau, Philadelphia, Pa._]

[Illustration: SIGNAL TOWER FOR STORM WARNINGS.

Flags used by day, lanterns by night.

_Courtesy of U.S. Weather Bureau._]

[Illustration: THERMOMETERS AND RAIN-GAUGE.

Instruments in shelter, as supplied to each co-operative observer.

_Courtesy of the U.S. Weather Bureau._]

[Illustration: PENCIL DRAWINGS OF TORNADO IN DAKOTA.

For many years this was an authoritative series of pictures, and
shows:--(A) Tornado becoming a waterspout;--(B) Tornado wrecking a
farm