The Weather Bureau furnishes, when practicable, for the benefit of all interests dependent upon weather conditions, the "Forecasts" which are prepared daily at the Central Office in Washington, D. C, and certain designated stations. These forecasts are telegraphed to stations of the Weather Bureau, railway officials, postmasters and many others, to be communicated to the public by means of flags or steam whistles. The flags adopted for this purpose are five in number, and of the forms and colors indicated below: