in Derwent Lake, Keswick. 67 
the 7th of September ; but only of small ex- 
tent, about twelve yards in length; and 
although its height above water never ex- 
ceeded seven or eight inches, yet when the 
lake rose about three feet perpendicular, part 
of the island still remained above the surface, 
and continued so till the latter end of October, 
when it disappeared, and has not been seen 
above water since. 
In the year 1808, an anonymous letter ap- 
peared in the Carlisle Journal, describing this 
island, attributing its ascent to the rarefaction 
of air under it by heat, and stating that when 
it first appeared, no water could be disco- 
yered beneath it, nor any thing but confined air. 
“This not corresponding with my observa- 
tions, I took the liberty of enquiring through 
the same medium, who had ever examined 
the island, when no water but only confined 
air could be discovered beneath it: and at 
the same time submitting as my own opinion 
that the earth was rendered buoyant by its being 
impregnated with akind of gas, produced un- 
der or rather within its substance. The subject 
wasthen taken up bya third person, who in con- 
currence with a formerly received opinion, as- 
cribed its ascent to a small brook, or rill of 
water, which falling from the mountain op- 
posite the place, meets with a subterraneous 
passage, by which it enters the lake unper- 
