The fact that the ares of the trade-wind belt of the North Atlantic is estiniated to be 10 million square miles suggests the impracticability of attempting a detailed study of the wind data over the entire region. In the monthly Pilot Charts of the United States Hydrographic Office of the Navy we have a complete set of monthly averages of these winds. Their percentages, including calms, velocities in terms of the Beaufort scale and prevailing directions, within the 8 points of the compass, are given for each 5’ of latitude by 5’ of longitude. Observations from transatlantic and coastwise ships contributed largely, and continue to do so, to the comprehensive mapping of ocean areas. On the other hand, we lack comparative data for different years, a t least in assembled form. The present paper gives a more or less detailed arrangement of the wind data by months and years for one station (San Juan, Puerto Rico) in the trade-wind belt. It includes the variations from year to year in total wind movement; treats of the “trades” as a separate entity; gives the wind velocities and notes the percentage of winds from the east, northeast and southeast. These data also are compared with their normal or average values. Beals has given an interesting survey of “The Northeast Trades of the North Pacific ” from which suggestions have been obtained for the present paper. In referring to the general world pressure system, the following is quoted as applying with equal force to both areas:
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