The weather map: How constructed. How distributed. Specimen maps showing differing conditions in California. Winds, velocity and frequency: On-shore. Off-shore. Discussion of air conditions December 20–22, 1914. The international weather map. Relation to weekly forecasts. Cardinal climatic features: Ascending winds and types producing them: Cloud, fog, precipitation. Descending winds: “Northers” and dust-storms. Thermograph and hygrograph traces. Factors in the meteorology of southern California: Influence of latitude: Sea. Mountains. Desert. Path and distribution of storm areas. Knowledge of local climatology necessary in flying. Local winds discussed: “Woollies” (descending wind eddies). “Chubascos” (south coast thunder squall). “Santa Anas” (northeasterly and desiccating). “Wilmingtons” (northwesterly line-squall). “_Practical Meteorology for the Aviator_” (Illustrated by 72 lantern-slides from photographs by the author) Historical: Original work begun in Scotland, year 1749. Characteristics-- English work; Dines’ minute meteorograph. French work; Dr. Berson’s balloon ascent of 6½ miles. German work; detailed data in low altitudes. American work began with Franklin. The Upper Air: Definition: “Stratosphere” is (according to some authorities) the dynamical laboratory of the atmosphere where the main causes of pressure originate. Results in America: Balloon meteorograph (Fig. 3). Charts showing rate of increase in wind velocity with elevation (Chart No. 4). Wind, temperature, pressure, humidity at maximum airplane height of 26,242 feet. Stratosphere: Lower level in winter than in summer. Lower temperature in summer when surface pressure is high. Definition: “Troposphere” is the physical laboratory where cloud and rain are produced by local causes and induced by the effect of the dynamical changes in the upper air. Conditions within 6 or 7 miles of the earth’s surface. Clouds and their Meaning: Cirrus: Height and composition. Formation: Perpendicular shafts of clouds indicate rapid changes in weather. Horizontal layers, no change and clouds will dissipate. Cirro-stratus, threatening in winter. Cirro-cumulus, fair and foul varieties differentiated. Cumulus with strong uplift. Alto-cumulus, cause of parallel rows. Fracto-cumulus, wind indicator, Point Loma “woolly.” Stratus. Alto-stratus, favorable for flying. Strato-cumulus, long shallow rolls, threatening in winter. Cumulo-nimbus, unsafe air conditions for flying. Fracto-nimbus, waterspouts and their causes. Velo cloud, examples, cause, effect, distribution, density.