more general, much more splendid, and, we may add,
much more familiar to those who live on our coasts. There must be many
in the British Isles who have never had the opportunity of seeing the
light of the glow-worm, but there can be few of those who have
frequented in summer any part of our coasts, who have never seen that
beautiful greenish light which is then so often visible, especially on
our southern shores, when the water is disturbed by the blade of an
oar or the prow of a boat or ship. In some cases, even on our own
shores, the phenomenon is much more brilliant, every rippling wave
being crested with a line of the same peculiar light, and in warmer
seas exhibitions of this kind are much more common. It is now known
that this light is due to a minute living form, to which we will
afterward return.

But before going on to speak in some detail of the organisms to which
the phosphorescence of the sea is due, it will be as well to mention
that the kind of phosphorescence just spoken of is only one mode in
which the phenomenon is exhibited on the ocean. Though sometimes the
light is shown in continuous lines whenever the surface is disturbed,
at other times, and, according to M. de Quatrefages, more commonly,
the light appears only in minute sparks, which, however numerous,
never coalesce. "In the little channel known as the Sund de Chausez,"
he writes, "I have seen on a dark night each stroke of the oar kindle,
as it were, myriads of stars, and the wake of the craft appeared in a
manner besprinkled with diamonds." When such is the case the
phosphorescence is due to various minute animals, especially
crustaceans; that is, creatures which, microscopically small as they
are, are yet constructed more or less on the type of the lobster or
cray-fish.

At other times, again, the phosphorescence is still more partial.
"Great domes of pale gold with long streamers," to use the eloquent
words of Professor Martin Duncan, "move slowly along in endless
succession; small silvery disks swim, now enlarging and now
contracting, and here and there a green or bluish gleam marks the
course of a tiny, but rapidly rising and sinking globe. Hour after
hour the procession passes by, and the fishermen hauling in their nets
from the midst drag out liquid light, and the soft sea jellies,
crushed and torn piecemeal, shine in every clinging particle. The
night grows dark, the wind rises and is cold, and the tide changes; so
does the luminosi