[ 1 96 3 
two, three, and fometimes four branches, without 
defcending much lower than thefirft night. I remark- 
ed a kind of intermiflion in the fever of the mountain, 
which feemed to return with violence every other 
night. On the 10th of april at night the lava dif- 
appeared on the fide of the mountain towards Naples, 
and broke out with much more violence on the fide 
next the Torre dell' Annunciata. 
I pa(Ted the whole day and the night of the 1 2 th 
upon the mountain, and followed the courfe of the 
lava to its very fource ; it burft out of the fide of the 
mountain, within about half a mile of the mouth of 
the volcano, like a torrent, attended with violent 
explolions, which threw up inflamed matter to a 
confiderable height, the adjacent ground quivering 
like the timbers of a water-mill; the heat of the lava 
was fo great as not to fuffer me to approach nearer 
than within ten feet of the flream, and of fuch a 
confiftency (though it appeared liquid as water) as al- 
moft to refift the impreflion of a long flick, with which 
I made the experiment; and large ftones thrown on it 
with all my force did not fink, but, making a flight 
impreflion, floated on the furface, and were carried out 
of fight in a fhort time; for, notwithftanding the con- 
fiftency of the lava, it ran with amazing velocity ; I am 
lure, the firft mile with a rapidity equal to that of the 
river Severn, at the paflage near Briftcl. The flream 
at its fource was about ten feet wide, but foon ex- 
tended itfelf, and divided into three branches, fo that 
thefe rivers of fire communicating their heat to the 
cinders of former lavas, between one branch and the 
other, had the appearance at night of a continued flieet 
of fire, four miles in length, and in fome parts near 
two 
