dined, but the remainder very steep. Many 
parts of this internal descent appeared to 
be incnisted with yellow substances, which 
he supposed to be the muriate of ammonia 
(sal ammoniac) or sulphui'. 
Fluid lava, resembling melted brass, red- 
hot, and liquid, filled the crater to a certain 
height, and this matter appeared to be in- 
fluenced by two distinct impelling powers, 
the one whirling and agitated, and the 
other upwards ; at times it rose rapidly, and 
when the surface had reached within thirty 
feet of the edges of the crater, an explosion 
took place like a short clap of thunder, and 
at the same instant, a portion of the lava 
was hurled with inconceivable swiftness in- 
to the air, which was as instantaneously se- 
parated into numerous fragments, and those 
w'ere accompanied by a copious discharge 
of sand, ashes, and smoke. Imihediately 
before the eruption occurred, the lava ap- 
peared inflated, and large bubbles, some se- 
veral feet in diameter, rose and burst, the 
detonation followed, and the lava sunk, till 
a repetition of this operation was com- 
menced ; during tlie rising, a sound issued 
from the crater like that produced by a li- 
quid boiling violently in a cauldron. Blany 
of the eruptions were so inconsiderable, 
that their effect could not be visible ai a 
small distance from the mountain ; in those 
the fragments constantly fell back into the 
gulph, with a sound, on their collision with 
the great mass of matter, similar to that 
produced by water when forcibly struck 
with flat staves : in the greater explosions, 
many of the pieces returned into the cra- 
ter, some falling on the sides and rolling 
down, but many descended a precipice, 
formed by one. side of the mountain, to the 
sea. 
The pieces of scoriaceous lava, as they 
moved in the air, retained their red-hot ap- 
pearance, though the sun shone clear; 
many of them came in contact during their 
progress, and, according to the degree of 
heat they possessed, they adhered, or were 
broken. The smoke seemed to be foreign 
to the lava, as none attended the fragments 
thrown into tlie air, and that which escaped, 
passed through fissures, and at the mo- 
ment the lava burst. According to Spal- 
lanzani’s conjectures, the crater may be 
about twenty-five or thirty feet in depth, 
when the lava is raised to its greatest 
height, and upon its subsiding, forty or fifty. 
There are no visible marks of its ever hav- 
ing overflowed so as to descend like those 
pf ./Etna and Vesuvius. 
“ Though the ejections of the larger and 
heavier stones have short intermissions, 
those of the lesser and lighter have scarcely 
any. Did not the eye perceive how those 
showers of stones originate, it would be 
supposed that they fell from the sky : the 
noise of the more violent eruptions, resem- 
bling that of thunder, and the darkness oc- 
casioned by the mounting cloud of smoke, 
present the image of a tempest.” 
While this naturalist was employed in 
intense observation, the eruption suddenly 
ceased, the lava sunk to a greater depth 
than )isual, and remained thus depressed ; 
the fierce light subsided, and at tlie same 
instant the various streams of smoke, issuing 
before silently from the apertures west of 
the crater, began to rush forth with a loud 
hissing noise, and the apertures to shine 
with a bright colour of fire. “ I know no- 
thing,” says Spallanzani, “ to which the 
sound produced by the issuing of these 
fumes can be more properly compared than 
the blowing of large bellows into a furnace 
by which metals are melted ; such as I have 
seen at Zalatna, in Transylvania, and Schem- 
nitz and Kremnitz, in Hungary, except that 
those volcanic bellows roared a lumdred 
times louder, and almost deafened the ear.” 
We cannot conclude this article more 
properly than by giving an account of the 
crater of iEtna, as it was examined by the 
above author, to whicli he ascended with 
equal danger and difficulty, and where he 
was compelled to sit nearly two hours ere he 
could commence his observations s he then 
says, “ I viewed with astonishment the 
configuration of the borders, the internal 
sides, the form of ttie immense cavern, its 
bottom, an aperture wbicli appeared in it, 
the melted matter which boiled within, and 
the smoke which ascended from it. The 
whole of this stupendous scene was distinctly 
displayed before me; and 1 shall now pro- 
ceed to give some description of it, though 
it will only be possible to present the rea- 
der with a very feeble image, as the sight 
alorie can enable him to form ideas at all 
adequate to objects so grand and astonish- 
ing. 'Fhe upper edges of the crater, to 
judge by the eye, are about a mile aud a 
half in circuit, and form an oval, the longest 
diameter of wliich extends from east to 
west. As they are in several places broken, 
and crumbled away in large fragments, they 
appear as it were indented, and these in- 
dentations are a kind of enormous steps, 
formed of projecting lavas and scorire. The 
internal sides of the cavern, or crater, are 
