Description: A world map from 1915 showing typical global isobars and winds during July. This map is color–coded to show the areas of high barometric pressure in tans, and areas of low barometric pressure in blues. The dark blue color indicates areas of pressures below 30 inches. Barometric pressures are shown on the isobar lines. Typical wind directions are shown flying with the arrowheads, away from high pressure and towards low pressure areas.