184 Description of a Lake of Sulphuric Acid. 
hy means of ropes with knots fixed to the summit of tlie 
precipice, because all the rocks, being calcined and reduced 
to the state of lime, are not to be trusted. If one of these 
rocks was to be detached by the weight of the persons upon 
the ladders, it would roll down to the bottom of the gulf, 
sweeping every thing before it. In our case however all 
necessary precautions were taken, and we arrived without 
any accident at the bottom of the voleano, im the part 
where the smoking vents are situated. 
This was the iirst time that I saw so near me those 
frightful laboratories in which nature prepares the revolu- 
tions which change the surface of the habitable globe. I 
cannot tell you which sentiment most prevailed, that of 
terror or admiration: whatever be the courage with which 
men are armed, they are actuated by the intimate and na- 
tural sentiment of their preservation when every thing 
around them threatens them. Rocks suspended over our 
heads, and which seemed continually falling under our 
feet ; the shaking and heat of boiling substances, from which 
we were separated only by a crust of hard ashes; the 
hissing of these substances, similar to the noise of breakers 
at sea; an inflamed and pungent air which we breathed, 
all contributed to astonish and stupefy my senses. When 
the tranquillity necessary to observation returned, I ad- 
vauced from the side of the volcanic issues which give 
passage to the smoke: they are fourin number, and all are 
situated in the eastern part of the volcano. The aperture 
which we first meet with is the largest; it is a perfectly 
round hole, about seven feet in diameter; beside tne 
there is another which imperfectly resembles a grotto, from 
the bottom of which a thick smoke issues: these two 
apertures are surrounded to some distance by an efflores~- 
cence of sulphur resembling gold dust: the sides of the 
anertures~are fringed with very brilliant sinall crystals of 
sulphur. We may approach close to these two apertures. 
M. Vikerman and’ M. Lisnet, being ignorant how dangerous — 
and pungent sulphurous vapours are, were bold enough to 
enter the grotto which précedes the second aperture; they 
were seized by the exhalations, and had barely time to 
retire: but they might have been suffocated betore it was 
possible to give them any assistance. Amid the vapours 
which surrounded us, our hands and faces appeared of a 
blood red. 
The other two mouths to the eastward of the latter are 
both adjoining to and placed against the eastern flank of 
the volcano, They appear to be over the most ardent fire ; 
for 
