166 
EARTHQUAKES. 
than mine. On the contrary, in parts of Europe where 
earthquakes are rare compared to America, scientific obser- 
vers are inclined to admit an intimate connection between 
the undulations of the ground, and certain meteors, which 
appear simultaneously with them. In Italy for instance, tb' 
sirocco and earthquakes are suspected to have some Con- 
nection ; and in London, the frequency of falling-stars, and 
those southern lights which have since been often observed 
by Mr. Dalton, were considered as the forerunners of those 
shocks which were felt from 1748 to 1756. 
On days when the earth is shaken by violent shocks, the 
regularity of the horary variations of the barometer is not 
disturbed within the tropics. 1 bad opportunities of verify- 
ing this observation at Cmnana, at Lima, and at Eiobamba ; 
and it is the more worthy of attention, as at St. Domingo, 
(in the town of Cape Francois,) it is asserted, that a water- 
barometer sank two inches and a half immediately before the 
earthquake of 1770. It is also related, that, at the time of 
the destruction of Oran, a druggist fled with his family, 
because, observing accidentally, a few minutes before tide 
earthquake, the height of the mercury in his barometer, he 
perceived that the column sank in an extraordinary manner. 
I know not whether wc can give credit to this story' ; but as 
it is nearly impossible to examine the variations of the weight 
of the atmosphere during the shocks, we must be satisfied 
with observing the barometer before or after these pheno- 
mena have taken place. 
We can scarcely doubt, that the earth, when opened and 
agitated by shocks, spreads occasionally gaseous emanations 
through the atmosphere, in places remote from the mouths 
of volcanoes not extinct. At Cumana, it has already been 
observed that flames and vapours mixed with sulphurous acid 
spring up from the most arid soil. In other parts of the 
same province, the earth ejects water and petroleum. At 
Biobamba, a muddy and inflammable mass, called moya , 
issues from crevices that close again, and accumulates into 
elevated bills. At about seven leagues from Lisbon, near 
Colares, during the terrible earthquake of the 1st of No- 
vember, 1755, flames and a column of thick smoke were seen 
to issue from the flanks of the rocks of Alvidras, and, accord- 
ing to some witnesses, from the bosom of the sea. 
