Torrents of Hot Water ^ Air-Volcanoes^ and Cold-Springs. 31 S 
inhabitants, of the districts use it in place of fuel. The moya 
which was thrown out after the terrible earthquake of 1797^ 
and which inundated the country of Pelileo, and destroyed the 
village of that name, was remarkable for its abundance of in- 
flammable matter. Very often these streams of mud from the 
interior of the mountains, bring along with them fishes about 
four inches in length, named by Humboldt Pimolides Cyclopum^ 
and the quantity is sometimes so considerable, that their putre- 
faction occasions diseases in the country. Humboldt remarks, 
that they are of the same species as occur in the rivulets of the 
neighbouring country, and appear to find their way into the 
subterranean lakes by means of fissures in the rocks. This 
mud or moya, so remarkably distinguished by its inflammable 
ingredient and imbedded fishes, is further interesting, by its con- 
taining traces of glassy felspar, and imbedded portions of a fibrous » 
substance somewhat resembling pumice. It is probable that it 
is an altered porphyry ; and we are of opinion, that when com- 
pletely indurated, it will exhibit characters of the same general 
nature with those observed in some porphyries, said to be of 
volcanic and igneous origin. 
4. RocJcs formed hy Air or Mud Volcanoes. 
In some countries, jets or great bubbles of water, highly im- 
pregnated with mineral matter, are thrown out of the earth by 
means of gas. The earthy matter is deposited in the state of 
mud, principally around the mouths of the cones from whence 
it is expelled ; and as these cones somewhat resemble volcanoes 
in form, they have been named Air-volcanoes. One of the most 
remarkable of these air-volcanoes hitherto described, is that of 
Macalouba in Sicily, of which an account has been published by 
Dolomieu. It consists of a hillock of hardened mud, about one 
hundred and fifty feet in height. Its superior part forms a 
plain more than half a mile in circumference, and rising from it 
are numerous small cones not more than three feet in height, each 
of which has a crater or hollow filled more or less deeply with a 
liquid mud, which is in a state of perpetual agitation, owing to 
the constant passage of great bubbles of air through it Por- 
tions of the mud are constantly thrown out, and thus add to the 
bulk and height of the cones. 
VOL. II. NO. 4. APRIL 18^, 
X 
