509 
m the Islan d St ‘ MichaeL 
than in any other caldeiraj and distinct loud explosions occur 
at short intervals, which are succeeded by a very perceptible 
elevation of the centre of the body of water within the basin. 
This is attended with a loud hissing noise, and the escape of 
great quantities'of sulphuretted hydrogen gas, steam, and sul- 
phurous acid vapour. On account of the high temperature 
and vast quantities of steam, it is dangerous to approach near 
the spring, except on the windward side. The cattle, however, 
are often seen standing on the opposite side, to free themselves, 
as it is supposed, from vermin. The peasants are in the habit 
of placing baskets filled with lupines, beans, and other vege- 
tables, on the edge of the basin, where they are speedily cook- 
ed. 
From the Great Caldeira, the water is conveyed to two or 
three small buildings, which are used as bathing-houses. The 
temperature of the water being so high, reservoirs have been 
sunk, by removing the earth to the depth of a foot or two, into 
which the hot-water is conducted, and allowed to cool ; it is 
then received into bathing-houses, and its temperature raised at 
pleasure by the admission of more water immediately from 
the caldeira. The water is turbid, from the presence of a large 
quantity of aluminous earth,, but which gives to it a peculiarly 
soft feel. 
A few yards from the principal caldeira, is an elevation about 
fifty feet in height, and probably as many in extent, composed 
of alternate layers, of a coarser variety of sinter, and clay, in- 
cluding grass, ferns, and reeds, in different states of petrifac- 
tion. Not many years since, the side of this hill fell in, and dis- 
covered a deep and frightful cavern; smoke and steam at pre- 
sent issue from it in vast quantity, accompanied by a tremen- 
dous noise. The hill, indeed, appears to be a dome, covering 
an extensive abyss, from which, by another outlet nearer the 
summit, hot mud and stones have been occasionally ejected. 
Looking down through the opening, a body of water is seen 
boiling with great violence. An appalling roar is incessantly re- 
verberated from side to side within the dome, and. is increased, 
at short intervals, by sudden and violent explosions. The sur- 
face of this hill, the sides of the cavern, and the innumerable 
crevices in the ground, are coated with sulphur ; in obtaining 
VOL. VI. NO. IS. APRIL 182S. 
X 
