d
turn of the gradient in high southern latitudes, as shown by the
_Discovery_ Expedition. This bears of course on the theory which
places an anticyclone in the South Polar region. Lockyer's theories
came under discussion; a good many facts appear to support them. The
westerly winds of the Roaring Forties are generally understood to be a
succession of cyclones. Lockyer's hypothesis supposes that there are
some eight or ten cyclones continually revolving at a rate of about
10 deg. of longitude a day, and he imagines them to extend from the 40th
parallel to beyond the 60th, thus giving the strong westerly winds
in the forties and easterly and southerly in 60 deg. to 70 deg.. Beyond 70 deg.
there appears to be generally an irregular outpouring of cold air from
the polar area, with an easterly component significant of anticyclone
conditions.

Simpson evolved a new blizzard theory on this. He supposes the surface
air intensely cooled over the continental and Barrier areas, and the
edge of this cold region lapped by warmer air from the southern limits
of Lockyer's cyclones. This would produce a condition of unstable
equilibrium, with great potentiality for movement. Since, as we have
found, volumes of cold air at different temperatures are very loath
to mix, the condition could not be relieved by any gradual process,
but continues until the stream is released by some minor cause, when,
the ball once started, a huge disturbance results. It seems to be
generally held that warm air is passing polewards from the equator
continuously at the high levels. It is this potentially warm air
which, mixed by the disturbance with the cold air of the interior,
gives to our winds so high a temperature.

Such is this theory--like its predecessor it is put up for cockshies,
and doubtless by our balloon work or by some other observations it
will be upset or modified. Meanwhile it is well to keep one's mind
alive with such problems, which mark the road of advance.

_Sunday, August_ 6.--Sunday with its usual routine. Hymn singing has
become a point on which we begin to take some pride to ourselves. With
our full attendance of singers we now get a grand volume of sound.

The day started overcast. Chalky is an excellent adjective to describe
the appearance of our outlook when the light is much diffused and
shadows poor; the scene is dull and flat.

In the afternoon the sky cleared, the moon over Erebus gave a straw
colour to the dissipating c