grey color. I met with only one patch of
it, intermixed with Trickostomum canescens,
in a rocky situation. From these hills,
though at a considerable distance, I could
perceive the steam from the hot spring, and,
taking a different route from what I had
done when I made a former attempt, I at
length, with some difficulty, arrived at it.
While yet full a mile from the spot, the superior
verdure of the grass, that was within
the influence of the heat, was very remarkable.
What struck me as most extraordinary
in this spring, though I afterwards found it
not to be uncommon in Iceland, was the
circumstance of its being actually situated in
the middle of a cold stream, bubbling up
from some little cavities, which were formed
in a whitish siliceous incrustation, that covered
a considerable portion of the bed of
the river, and extended on one side of it,
even as far the shore, where its surface was
covered with numerous minute mammillæ.
This incrustation is a deposit from the water,
and the mammillæ are probably caused by
the irregular faffing of the water upon it in
drops. On dipping in the water my little
pocket thermometer, which was graduated to
tlO T SPRING. 49
fto more than 120° of Fahrenheit’s scale, but
was the only one I had with me at the time,
the quicksilver instantly rose to the top of
the tube. I found lying dead in the hot water
a number of eels*, not more than four or five
inches long: these had, doubtless, been conveyed
down by the rapidity of the current
to the heated part of the water, which, as it
affects the whole width of the stream, must
be an effectual barrier to the migration of
fish, and of other aquatic animals. I remarked,
however, no others in this water, except
one or two specimens of a iJyticus, which I
was not able to catch, but which appeared
to be the same as our D. acuductus. Almost
in the hottest part of the water, I gathered
Conferva spiralis Dillw.; but it had lost all
its color, and had probably only floated into
that situation, not being really a native of it:
a species, also, which appeared to me to be
new, grew attached to the banks, at a very
* Povelsen and Olafsen have mentioned the circumstance
of small eels being found dead near the heated
waters of Iceland, and remark that, although large eels
are known to exist in the river, they have never been
»net with lying dead, as the smaller ones,
von. 1. e