WEATHER BUREAU. 181 



COLLECTION AND DISTRIBUTION OF DATA. 



The American consuls at 89 of the principal foreign ports have 

 assisted the Bureau in the distribution of marine forms, cloud and 

 ocean charts, and pamphlets of instructions, and in the collection of 

 meteorological observations from vessels. 



The Weather Bureau marine centers are equipped with a standard 

 mercurial barometer, thermometers, and shelter, and have a supply of 

 all ocean meteorological forms, cloud charts, gnomonic charts, and 

 meteorological charts. Assistants have been assigned to special duty 

 in connection with marine work at New York, Philadelphia, and 

 Seattle ; at the latter point the official will have supervision over the 

 entire traffic entering Puget Sound. 



During the year 2,168 vessels of every nationality cooperated with 

 the Weather Bureau in reporting pressure, temperature, wind, and 

 other meteorological data, forwarding to the Marine Division in all 

 about 10,000 weather report books. The data thus obtained are 

 entered in the daily synoptic charts used in making the averages for 

 the meteorological charts issued by the Weather Bureau and in pre- 

 paring the information for the pilot charts issued by the Hydro- 

 graphic Office. 



Calendars containing useful information for captains and observ- 

 ers were distributed to all cooperating vessels, separate calendars 

 being furnished for the Atlantic and Pacific oceans. 



CHARTS PREPARED AND ISSUED. 



Daily synoptic charts. — The daily observations received from the 

 vessels are entered on these charts, which are used in tracing storm 

 tracks and in preparing statements of average conditions of wind 

 and weather for publication in the pilot and meteorological charts. 



Pilot and meteorological cliarts. — The entire data for the North 

 Atlantic charts have been revised and are practically complete. 

 These charts contain normals of pressure and temperature covering 

 a period of eighteen years; wind roses for twenty-five years, per- 

 centage of gales and calms for each 5° square and of fog iov each 1° 

 square of latitude and longitude, and trade-wind limits, all based on 

 a large number of observations. On the back of the meteorological 

 chart for September the origin and course of the West Indian hurri- 

 cane of September 16-21, 1909, are graphically shown and its history 

 briefly given. 



The fog data on the North Atlantic chart have been extensively 

 used by Mr. H. C. Thomson, engineer in charge of the survey for a 

 short-line railway and steamship route to Europe, in his report to the 

 governor-general of Newfoundland and others interested. It is also 

 noted that the English meteorological office has used our fog data and 

 shading to a great extent on their North Atlantic chart. 



The South Atlantic cliarts are published quarterly, and with the 

 charts for the quarter for September-November the data are com- 

 plete, being based on normals of pressure for ten years, of temperature 

 for fifteen years, and of wind roses (direction and force with per- 

 centage of gales and calms) for twenty-five years, and on the average 

 conditions of wind and weather and trade-wind limits. 



The revision of the data for the North Pacific charts has been 

 brought up to the year 1909. The charts now contain normals of 



