Appendix. 305 
During the winter months, or at least during the seventy-one days 
that the sun remained constantly below the horizon, the diurnal 
variations of the thermometer and barometer were scarcely perceptible, 
being almost, if not quite, concealed by the oscillations due to the 
passage of storms. 
The intensity of solar radiation was measured with the black 
bulb thermometer zz vacuo. This instrument was freely exposed to 
the sun by fixing it horizontally above the ground at the same height 
as the thermometer screen, viz., 4 ft. 6 in. A temperature above 
80° F. was frequently recorded by this thermometer, whilst the 
temperature in the shade remained below freezing-point. These 
high readings were probably due to the hygrometric conditions of 
the atmosphere, the air, on account of the intense cold, being 
extremely dry. 
Table IV. gives some of the highest readings with the solar 
radiation thermometer, and the temperature of air in the shade 
observed at the same time. 
TABLE IV. 
Solar Temperature 
Date. Thermometer. in fem 
Marca gral o . 3 o o o o BO I 24:0? Е. 
o ОШ . s ə ə s s. o ODOT, 22:4? Е, 
» Tü o o o o o o а Ges". 20:9? Е. 
x ПОШ e o o o «e o °2 M, 24°5° Е. 
o Z a a o o s s. o nonem Soo” IF, 
Relative humidity between 40° and 50°. 
The most remarkable feature in the meteorological conditions of 
the Antarctic is the wind. 
The prevailing E.S.E. and S.E. winds at Cape Adare, which is 
within the area of abnormally low pressure, tend to prove the existence 
of a great anti-cyclone stretching over the polar area, which in its 
turn necessarily implies the existence of upper currents from the 
northward, blowing towards and in upon the polar regions to make 
good the drain caused by the surface outblowing S.E. winds. 
The frequency and force of these gales, and the persistency with 
which they blew—always from the same direction, E.S.E.— the 
invariably high rise in the temperature, and the sudden fall and rise 
of the barometer, the dryness of the winds—the relative humidity 
generally between 40° and 5o^—-and the motion of the upper clcuds 
from the N.W., point to the fact that the South Pole is covered by 
what may be regarded practically as a great permanent anti-cyclone, 
more extensive in the winter months than in the summer. 
X 
