1911 Encyclopædia Britannica/Beaufort Scale

6851721911 Encyclopædia Britannica, Volume 3 — Beaufort Scale

BEAUFORT SCALE, a series of numbers from 0 to 12 arranged by Admiral Sir Francis Beaufort (1774–1857) in 1805, to indicate the strength of the wind from a calm, force 0, to a hurricane, force 12, with sailing directions such as “5, smacks shorten sails” for coast purposes, and “royals, &c., ‘full and by’ ” for the open sea. An exhaustive report was made in 1906 by the Meteorological Office on the relation between the estimates of wind-force according to Beaufort’s scale and the velocities recorded by anemometers belonging to the office, from which the following table is taken:—

 Beaufort scale.   Corresponding wind.   Limits of hourly velocity. 
Numbers. Miles per hour.
0  Calm  Under 2
1–3  Light breeze 2–12
4–5  Moderate wind 13–23
6–7  Strong wind 24–37
8–9  Gale 38–55
10–11  Storm 56–75
12  Hurricane Above 75