The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1842-09-20 00:00:00

THE FLOATING ISLAND IN DERWENT LAKE
NEAR KESWICK. .

'lbis most extraordinary phenomenon is situate not far
from Lowdore, at the south-east extremity of the lake, and
a little more than 150 yards from the land, where the depth
of the water does not exceed six feet in a mean state of thd
lake.
During the last forty years it has appeared thirteen times.
In the year 1808, from July 20 to the beginning of October
in the same year; in 1813, from the 7th of September to the
end of October following ; in 1815, from August sto the
end of the month;. in 1819, from August 14 to the end of
the same month ; in 1824, from June 21 to the end of Sep-
tember ' • in 1825, it was above the water from the 9th to the
23rd of September ; and from the 11th of July to the end of
September in 1826. " The circumstance of its appearing in
three successive years," says Mr. Otley, " may be attributed
to the extraordinary warmth of the season." It made its
appearance again on the 10th of June, 1831, and remained
uncovered until the 25th of September. In 1834 and 1835
it was visible for a few weeks in August and September. In
1837 it appeared in July and August. It appeared again on
the 19th July, 1841, and remained till the end of August.
And it made its appearance in the latter end of last or the
beginning of the !present month (September,) but it is not
yet quite so large as on sore of the former occasions of its
appearance.
We will not undertake to investigate the great number of
hypotheses which have been advanced relative to the cause
of this singular phenomenon, nor examine into any of the
arguments which have been adduced, but will merely give
the opinion of Mr. Otley, who is well versed in the geological
and meteorological properties of the lake district, who is
resident at Keswick, and who ,for the last thirty years has
watched with much attention the operation of it. Mr.
Otley says—
" That it generally rises after an interval of a few days,
and after a continuance of fine weather. Its figure and dimen-
sions are variable ; it has sometimes contained about half an
acre of ground, at other times only a few perches; but ex-
tending in a gradual slope under water, a much greater por-
tion is raised from the bottom than reaches the surface of the
lake. Several large rents•or cracks may be seen in the earth
about the place, which appear to have been occasioned by its
stretching to reach the surface. It never rises far above the
level of the lake, but having once attained the surface, it for
a time fluctuates with the rise and fall of the water, after
which it'sinks gradually. When at rest in the bottom of the
lake it has the same appearance as the neighbouring parts,
being covered with the same vegetation, consisting princi-
pally of litterella lacustris and lobelia dorimanno, inters-
persed with isoetes lacustris, and other plants common in
this and all the neighbouring lakes ; after remaining some
time above the water, its verdure is improved. For a few
inches in depth it is composed of clayey or earthy matter,
apparently deposited by the water, in which the growing
plants have fixed their roots ; the rest is a congeries of de-
cayed vegetable matter, forming a stratum of loose peat earth,
about six feet in thickness, which rises from a bed of very
fine soft clay. A considerable quantity of air is contained in
the body of the island, and may be dislodged hy probing the
earth with a poll. This air was found by Dr. Dalton to con-
sist of equal parts of carbureted hydrogen and azotic gases,
with a little carbonic acid.
Mr. Otley further adds—
" That one material circumstance, has however, generally
escaped observation—namely, that the air to which the rising
of this island has been attributed, is not collected in a body
underneath it, but interspersed through the whole mass.
And the most probable conclusion seems to he, that the air
or gas is generated in the body of the island by decomposition
of the vegetable matter of which it is formed ; and this gas
being produced most copiously, as well as being rarified in
hot weather, the earth at length becomes so much extended
therewith as to render the mass of less weight than an equal
bulk of water. The. water then insinuating itself between the
substratum of clay and peat earth forming the island, bears
it to the surface, where it continues for a time, till partly by
escape of the gas, partly by its absorption, and partly by its
condensation consequent on a decrease of heat, the volume is
reduced, and the earth gradually sinks to its former level,
where it remains till a sufficient accumulation of gas again
renders it buoyant. But as the vegetable matter of which
the island is principally composed appears to have been
amassed at a remote period, when the lake was of less depth
than at present, receiving very little addition from the decay
of plants recently grown upon the spot, it is reasonable to
suppose that the process of furnishing the gas cannot from
the same materials be continued ad infinitum ; but that
there must be a time when it shall have arrived at its maxi-
mum, after which the eruptions will become less extensive
or less frequent." •