NATURAL 
on other sides by low eminences 
of limestone or a bituminous 
shale, is the immediate situation 
of the springs; they are found in 
three or four different places of 
the morass, appearing as small 
pools; the sides and bottom of 
which are thickly lined with pe- 
troleum, in a viscid state, and by 
agitation, easily raised in large 
flakes to the surface. The most 
remarkable of these pools is 
one circular in form, about fifty 
' feet in circumference, and a few 
feet in depth, in which the petro- 
leum has accumulated to a consi- 
derable quantity. The water of 
the spring, which is doubtless the 
means of conveying the mineral 
upwards to the surface, forms a 
small stream from the pool, sen- 
sibly impregnated with bitumi- 
nous matter, which it deposits in 
parts as it flows through the mo- 
rass ; the other pools are of simi- 
lar character. The petroleum is 
collected generally once in the 
year; and the average quantity 
obtained from the springs is said 
to be about a hundred barrels; it 
is chiefly used for the caulking of 
vessels, not being found to answer 
equally well for cordage. 
THE SIROCCO, 
(From the Same.) 
_ A sudden and violent Sirocco 
came on from the south-east, car- 
rying our vessel forwards eight or 
ten miles an hour; but bringing 
with it, at the same time, all the 
distressing effects which charac- 
terize this extraordinary wind; a 
sense of general oppression, a 
dull head-ache, aversion to mo- 
tion, and lassitude and uneasiness 
HISTORY. 499 
in the limbs. Those who are 
strongly susceptible to electrical 
changes in the air, such as pre- 
cede and attend a thunder-storm, 
will easily understand the effects 
of the Sirocco, as an increased de- 
gree of the sensations which they 
then experience; and, in fact, 
though I am not aware that the 
opinion has been held, there are 
many reasons for believing that 
the peculiarity of the Sirocco wind 
is chiefly an electrical one, and 
not depending either on tempera- 
ture, an undue proportion of car- 
bonic acid, the presence of minute 
particles of sand, or any of the 
causes which have been generally 
assigned to it. That increased 
temperature is not the cause, may 
be inferred from the thermometer 
being little, if at all, raised by the 
access of the wind, and from 
much greater heat often occurring 
without this singularity of effect. 
The air of the Sirocco, as it comes 
from the sea, is not a dry one, 
but in general thick, and loaded 
with moisture; much of which 
appears to be deposited where it 
passes over any considerable ex-' 
tent of land. I have scarcely, in 
any instance, observed this wind, 
in any marked degree, without 
noticing at the same time, some 
electrical phenomena in connec- 
tion with it; to say nothing of 
the effects upon the body, which, 
as mere sensations, may perhaps 
bedoubtfully receivedin evidence: 
In the present instance, off the 
coast of Ithaca, the sky, which 
had been obscuredbytheapproach 
of evening, was suddenly kindled, 
as the wind came on, by broad 
flashes or gleams of electric light, 
which seemed to pervade the whole 
hemisphere, and, at intervals, 
2K2 
