FREQUENCY OF HIGH WINDS 321 
result is entirely different from that obtained for Yarmouth. At 
Framheim calms were of frequent occurrence and the wind blew 
at 4 miles an hour or less during 42 per cent. of the total time. 
From this high percentage of calms winds of higher velocity fell 
off rapidly and regularly. It is important to notice that the shape 
of the curve for Framheim is similar to that of the curve for 
Yarmouth from its highest point to its end. This shape is fre- 
quently met with in scientific work, and indicates that the change 
from maximum to minimum is regular without any outside factor 
influencing the natural change from stage to stage. It is the shape 
of the ‘ probability curve,’ that is, the curve which indicates the 
probability that anything will occur when it departs from a most 
probable value. The wind conditions shown in the Framheim 
curve are the ideal ones for polar work, for the most probable 
wind is a calm, and the frequency with which higher velocities 
occur decreases rapidly and regularly as the velocities increase. 
We will now turn to the results of a similar analysis for the 
winds recorded at Cape Evans. Column 4 of Table I. contains 
the data, and they are plotted on the thick curve of Fig. 1. Here 
we have a curve which commences in a manner similar to that 
of Framheim: the most frequent winds are those with a velocity 
of less than 4 miles an hour, and higher winds are less frequently 
met with. In fact if one had the whole of the Framheim curve 
and only the first part of that for Cape Evans—as far as winds 
of 14 miles an hour—one would say they were similar and would 
complete the Cape Evans curve along the thin dotted line indi- 
cated in the figure, making it run parallel with the other two 
curves. 
But that would be assuming that there was nothing abnormal 
in the region in which Cape Evans was situated, and that the 
winds were governed by the same laws as at Framheim. The 
real curve does not follow this ideal curve, but takes an entirely 
different shape. The frequency of winds greater than 15 miles 
an hour does not decrease with the velocity, for all winds with 
velocities between 15 miles an hour and 34 miles an hour occur 
with practically the same frequency. It is not until we reach 
higher velocities than 35 miles an hour that a decrease in fre- 
quency accompanies an increase in velocity. This shape of the 
curve indicates that there is some factor affecting the winds at 
Cape Evans which is not present at a normal station. 
VOL. II—2I 
