IN THE MEDITERRANEAN. 
249 
idea is supported by the depth of the sea where the volcano appeared, — a depth 
which, according to the most accurate survey, must have been at least 50 or 60 
fathoms. Further, the products examined, whether solid or gaseous, may be 
said to demonstrate that ordinary combustion was nowise concerned in the 
phenomena ; and the absence of inflammable gas in any efficient quantity, (of 
which it appears to me no doubt can be entertained,) seems no less forcibly 
to demonstrate, that the decomposition of water by the metallic bases of 
the earths and alkalies, cannot be admitted as the principal cause. On the 
other hand, if we suppose a state of things in conformity with the hypothesis 
of our globe having been once in fusion, and being still so at a certain depth 
beneath the surface, liable to be acted upon by water flowing in from above, 
the phenomena of the volcano do not seem to be of difficult explanation ; they 
are indeed such as might be expected a priori ; namely, the vast quantity of 
aqueous vapour evolved impregnated with salt ; the porous cinders and ashes 
ejected; the comparatively low temperature of the ejected matters, and the 
apparent absence of any gas in considerable quantity, excepting carbonic acid. 
All the other observations which I have made at different times in the volcanic 
regions of Italy, Sicily and the Lipari Islands have been of the same negative 
character as the preceding, and favourable to the same hypothesis rather than 
to that of the chemical origin of volcanos. The subject however is so myste- 
rious, that what is probable, on further inquiry may not prove true ; and 
other causes may be discovered, which at present are not even imagined. 
Malta, October 25th 1831. 
Explanation of the Plates. 
Plate V. 
A plan of the island, with soundings from a survey by Captain Wode- 
house. Its outline and that of the crater is from observation. The ground 
has been sketched in by Captain Irton, partly from views which accompanied 
the original plan, and partly on supposition. 
Plate VI. 
Fig. 1 — 4. — Profile views of the volcanic island as it appeared on the 
7th August. 
