68 Objervations on the Fog of 1783. 
year by our domicftic as well as foreign gazetiess and we 
may conclude fo from the minute obfervations. of the cele- 
brated Van Swinden, and the tables publifhed by Toaldo,; 
Cotte, Beraud, Besuclin de Romily, &c. Sometimes, in- 
deed, rain took place in one country or other; but in gene- 
tal, till the preceding winter, an extraordinary drought pre- 
vailed. It began about 1774, and in the month of June 1782 
was extremely great in Italy and in our fouthern provinces. 
We experienced at that period a fuffocating heat; the earthy 
as we may fay, feemed to be on fire, and, m the Plain of 
Camargue, fcorched the feet of the reapers to fuch a degree 
that they were obliged at length to walk upon ftraw: feveral 
died of heat with the fickles in their hands, and there were 
a great many fick. Ina word, the drought and heat were fo 
exceflive, that, at two leagues from Sallon, the fpiders, whick 
im general are not venomous, occafioned by their bite violent 
difeafes, which had a great affinity to thofe occafioned by the 
bite of the tarantula. 
In confequence of this great drought, the exhalations of 
the earth, fpecifically heavier than the air, and deprived of 
that humidity which ferves them as a yehicle, remained in 
the bofom of the earth, where they muft have formed im- 
menfe accumulations. ‘The winter of 1782-1783 was rainy, 
particularly in Calabria and Sicily; and the Alps were 
covered with a great deal of fnow. The fpring alfo was in 
general rainy. The water then being filtered into the bowels 
of the earth, was at firft abforbed by the very dry exhalations 
there confined. , This humidity, added to the warmth of the 
fpring, no doubt occafioned effervefcences and fermentations; 
fo that the exhalations, difengaging themfelves with violence, 
in certain places convulfed the earth, as was the cafe in Ca- 
labria and Sicily. In proportion as the water filtered into the 
earth by its own weight, it found new exhalations, which, 
by difengaging themfelves, occafioned new convulfions, but 
lefs confiderable on account of the lefs abundance of thefe 
exhalations. In places where they were heated by their 
mixture, they liquefied ftones, and threw up volcanic iflands, 
asin Iceland. In the laft place, thefe fubtle exhalations 
rifing into the atmofphere from all I parts, with the vapours, 
whielz 
. 
