17 +11.5 +8.8 +7.80
30 +1.0 -1.8 -0.27 18 +9.2 +6.2 +7.52

The figures in the maximum column, it will be seen, are by no means
very high. That the enormous covering of snow, which the north winds
had heaped on the beach, could disappear so rapidly notwithstanding
this low temperature probably depends on this, that a large portion
of the heat which the solar rays bring with them acts directly in
melting the snow without sun-warmed air being used as an
intermediate agent or heat-carrier, partly also on the circumstance
that the winds prevailing in spring come from the sea to the
southward, and before they reach the north coast pass over
considerable mountain heights in the interior of the country. They
have therefore the nature of _foehn_ winds, that is to say, the whole
mass of air, which the wind carries with it, is heated, and its
relative humidity is slight, because a large portion of the water
which it originally contained has been condensed in passing over the
mountain heights. Accordingly when the dry _foehn_ winds prevail, a
considerable evaporation of the snow takes place. The slight content
of watery vapour in the atmosphere diminishes its power of absorbing
the solar heat, and instead increases that portion of it which is
found remaining when the sun's rays penetrate to the snowdrifts, and
there conduce, not to raise the temperature, but to convert the snow
into water. [261]

The aurora is, as is well-known, a phenomenon at the same time
cosmic and terrestrial, which on the one hand is confined within the
atmosphere of our globe and stands in close connection with
terrestrial magnetism, and on the other side is dependent on certain
changes in the envelope of the sun, the nature of which is as yet
little known, and which are indicated by the formation of spots on
the sun; the distinguished Dutch physicist, VON BAUMHAUER, has even
placed the occurrence of the aurora in connection with cosmic
substances which fall in the form of dust from the interstellar
spaces to the surface of the earth. Thus splendid natural phenomenon
besides plays, though unjustifiably, a great _role_ in imaginative
sketches of winter life in the high north, and it is in the popular
idea so connected with the ice and snow of the Polar lands, that
most of the readers of sketches of Arctic travel would certainly
consider it an indefensible omission if the author did not give an
account of the aurora as seen from hi