Hodgson the photographic apparatus at Kew registered a marked
disturbance of all the three magnetic elements; while shortly after
the ensuing midnight the electric agitation culminated, thrilling
the whole earth with subtle vibrations, and lighting up the
atmosphere from pole to pole with coruscating splendors which
perhaps dimly recall the times when our ancient planet itself shone
as a star.

If this amazing occurrence stood alone, and as I have already said it
has never been exactly duplicated, doubt might be felt concerning some
of the inferences drawn from it; but in varying forms it has been
repeated many times, so that now hardly anyone questions the reality
of the assumed connection between solar outbursts and magnetic storms
accompanied by auroral displays on the earth. It is true that the late
Lord Kelvin raised difficulties in the way of the hypothesis of a
direct magnetic action of the sun upon the earth, because it seemed to
him that an inadmissible quantity of energy was demanded to account
for such action. But no calculation like that which he made is final,
since all calculations depend upon the validity of the data; and no
authority is unshakable in science, because no man can possess
omniscience. It was Lord Kelvin who, but a few years before the thing
was actually accomplished, declared that aerial navigation was an
impracticable dream, and demonstrated its impracticability by
calculation. However the connection may be brought about, it is as
certain as evidence can make it that solar outbursts are coincident
with terrestial magnetic disturbances, and coincident in such a way as
to make the inference of a causal connection irresistible. The sun is
only a little more than a hundred times its own diameter away from the
earth. Why, then, with the subtle connection between them afforded by
the ether which conveys to us the blinding solar light and the