[Illustration: FOREST RANGER IN IDAHO. [Illustration: OBSERVER AMONG THE QUAKING ASPENS. SNOW SURVEY WORK. _Courtesy of U. S. Weather Bureau and of J. Cecil Alter._] [Illustration: NO PEAK TOO LOFTY FOR A WEATHER STATION. Taking recording instruments up a mountainside where there has never been a trail. _Copyright by J. Cecil Alter, U. S. Weather Bureau, Cheyenne, Wyo._] [Illustration: WALL SUN-DIAL AT SANTA BARBARA, CAL., ON OLD SPANISH MISSION.] [Illustration: SUN-DIAL AT HILLSIDE, N.Y., DUPLICATE OF THAT OF SIR WALTER SCOTT AT ABBOTSFORD.] [Illustration: THE FIRST LINE OF DEFENCE AGAINST THE TEMPEST. Headquarters of the U. S. Weather Bureau, at Washington, D. C., where every wind and cloud that passes over the United States is chronicled and watched; the greatest forecast office in the world. _Courtesy of U. S. Weather Bureau._] [Illustration: SOLAR HALO SEEN IN THE UNITED STATES. This halo was seen over a wide area, and was especially bright in Virginia. _Courtesy of Scientific American._] [Illustration: SOLAR HALO SEEN IN RUSSIA. (By permission from Camille Flammarion's "Meteorologie.")] [Illustration: THE DUST THAT MAKES RED SUNSETS. The volcanic eruption of Lassen Peak, Cal., on October 6, 1915, taken at intervals, the first three photos five minutes apart, the fourth, ten minutes later, showing the beginning of the second cloud. _Copyright by Chester Mullen. Courtesy of U. S. Weather Bureau._] [Illustration: AN ARMY DESTROYED BY WEATHER. Napoleon deserting his troops during the retreat from Moscow, when the emperor defied the winter, and left a quarter of a million men dead on the snows of Russia.] [Illustration: _Cirrus Implexus_ _Alto-Strato-Cumulus_ TYPES OF UPPER CLOUDS.] [Illustration: _Cumulus_ _Stratus_ TYPES OF LOWER CLOUDS.] [Illustration: _Cumulo-Nimbus_ _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._]