THE SITE AND ORIGIN OF GRAHAM ISLAND. 
257 
is “ tremblingly alive.” But it is reasonable and proper to question such ru- 
mours as have been made without due examination. In the instance before 
us, no endeavour was made to establish the truth by either shortening sail, 
lowering a boat, or even getting a cast of the lead ; moreover, they were three 
or four miles from the supposed object, and opinions on board the Wassanaer 
were not at all unanimous. By similar indecision a teasing knot of perils has 
gained random insertion upon our charts, to the disquietude of sea command- 
ers ; but it is a fault which is fast disappearing, and it may be trusted that 
there are few officers who would not think themselves liable to the imputation 
of culpable carelessness, did they not seek to verify such te dangers” as they 
might accidentally encounter. 
I do not think sub-aqueous volcanic explosions are of such rare occurrence 
as is generally supposed ; and extremely sudden intumescence may arise from 
the expansion of an inferior lava bed. It is not at all improbable that gaseous 
fluids, and ejectamenta, may have been seen, before the accumulation of solid 
matter, protruded from the vent, was sufficient to form a crater of eruption. 
A volcanic apex may become visible, and again be quickly destroyed by tritu- 
ration, the solution of mineral substances, and the repressive force of the co- 
lumn of water over the vent. Now, as there was a chance that something of 
the kind had occurred in the neighbourhood assigned to Larmour’s reef, — 
breakers having been reported near the same spot by the Greyhound frigate, 
and shoals having been immemorially marked there under the names of La 
Ajuga, and B. Scoglio, — I laboriously explored the whole vicinity. In exam- 
ining the chart which resulted from this undertaking, it will be found that a 
knoll, with only seven fathoms upon it, was discovered not far from the site of 
all these reports, and that the Adventure Bank extends from Sicily nearly to 
Pantellaria, where the water deepens at once from 76 fathoms to no bottom 
with 375 fathoms of line. A further inspection will show that the Phlegrsean 
islands of Pantellaria and Linosa have been protruded from the greatest depths, 
where perhaps the fires found the least resistance. 
All these considerations led me to suppose that though the reports were ex- 
ceedingly vague, volcanic agency might still have given grounds for them. I 
therefore made particular inquiries, both in Sicily and Pantellaria, as to 
local earthquakes, and whether any volumes of smoke, ferilli or jets of flame, 
