68 Account of the Floating Island 
ceived: which passage he supposes may be 
continued to this place, and_ that during a 
dry season its outlet may be so far choked. up, 
that on the commencement of rain, the con- 
fined water may force up this island, but what 
I think militates against this opinion is, that 
the earth in its rising, not admitting of the 
required, extension, is frequently rent quite 
through; so that the water under it has a free 
communication with the lake; and on ex- 
amining the place at different periods of the 
late severe frost, in expectation of discover- 
‘ing by some difference of temperature, the 
place where the beforementioned brook dis- 
charged itself; the only appearance of a 
spring that I could perceive, was in the very 
edge of the lake. And admitting it possible, 
that the ascent of this island may be aided by 
some spring underneath; yet I am of opinion 
that its continuance upon the surface, must 
be attributed to the quantity of gas pro- 
duced within its substance (by a decomposi- 
tion of the vegetable matter of which it is 
formed), and which the clayey coating I 
think assists it in retaming; and I have ven- 
tured to suggest, that at a certain stage of 
this decomposition, the effect must be at its, 
maximum ; after which the eruptions will be- 
come less extensive or less frequent. 
