WEATHER CHART.--MARCH 14.
Meteorological conditions at noon, Greenwich mean time (7 A. M., 75th meridian time).
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/The_National_geographic_magazine%2C_volume_1_-_p89.png/400px-The_National_geographic_magazine%2C_volume_1_-_p89.png)
Barometer.―Isobars in full black lines for each tenth of an inch, reduced pressure. The trough of low barometer is shown by a line of dashes.
Temperature.―Isotherms in dotted black lines for each ten degrees Fahr. Temperatures below freezing (32° F.) in shades of blue, and above freezing in red.
Wind.―The small black arrows fly with the wind at the position where each is plotted. The force of wind is indicated in a general way by the number of feathers on the arrows, according to the scale given in the following table:
It will be noticed that the Beaufort scale (0-12), in general use at sea, has been converted into the international scale (0-10) for the sake of clearness in plotting data on the chart. The absence of arrows over large areas indicates absence of simultaneous data; at sea, however, this has been partly compensated for in the construction of the chart by information obtained from journals and special storm reports of vessels in the vicinity.