to observe that there are many, and those 
very large caverns or hollows in the bottom 
of the sea, especially where it is rocky ; and 
that the like caverns are sometimes found 
in the perpendicular rocks which form tire 
steep sides of those fisheries. These ca- 
verns are often of great depth, as well as 
extent, and have sometimes wide mouths, 
and sometimes only narrow entrances into 
large and spacious hollows. 
The bottom of the sea is covered with a 
variety of matters, such as could not be 
imagjned by any but those who have exam- 
ined into it, especially in deep water, where 
the surface only is disturbed by tides and 
storms, the lower part, and consequently 
its bed at the bottom, remaining for ages, 
perhaps, undisturbed. The soundings, when 
the plummet first touches the ground, on 
approaching the shores, giye some idea of 
this. The bottom of the plummet is hol- 
lowed, and in that hollow there is placed a 
lump of tallow ; which, being the part that 
first touches the ground, the soft nature of 
the fat receives into it some part of those 
substances which it meets with at the bot- 
tom : this matter, thus brought up, is some- 
times pure sand, sometimes a kind of sand 
made of the fragment of shells, beaten to a 
sort of powder, sometimes it is made of a 
like powder of the several sorts of corals, 
and sometimes it is composed of fragments 
ofrocks ; but beside theseappearances, which 
are natural enough, and are what might well 
be expected, it brings up substances which 
are of the most beautiful colours. 
Dr. Donati, in an Italian work, contain- 
ing an essay towards a natural history of 
the Adriatic Sea, has related many curious 
observations on this subject ; having care- 
fully examined the soil and productions of 
the various countries that surround the 
Adriatic Sea, and compared them with 
those which he took up from the bottom of 
the sea, he found that there is very little dif- 
ference between the former and the latter. 
At the bottom of the water there are moun- 
tains, plains, vallies and caverns, similar to 
those upon land. The soil consist* of dif- 
erent strata, placed one upon another, and 
mostly parallel and correspondent to those 
of the rocks, islands, and neighbouring- con- 
tinents. They contain stones of different 
sorts, minerals, metals, various putrified 
bodies, pumice stones, and lavas formed by 
volcanos. 
One of the objects which most excited 
his attention, was a crust, which he disco- 
vered under the water, composed of crusta- 
ceous and testaceous bodies, and beds of 
polypes of different kinds, confusedly blend- 
ed witlr earth, sand, and gravel ; the differ- 
ent marine bodies which form this crust, 
are found at the depth of a foot or more, 
entirely petrified and reduced into marble j 
these, he supposes, are naturally placed un- 
der the sea when it covers them, and not 
by means of volcanos and earthquakes, as 
some have conjectured. On this account 
he imagines, that the bottom of the sea is 
constantly rising higher and higher, with 
which other obvious causes of increase con- 
cur ; and from this rising of the bottom of 
the sea, that of its leyel or surface naturally 
results; in proof of which, this writer re- 
cites a great number of facts. 
M. Dassie has been at great pains to 
prove, that the sea has a general motion, in- 
dependently of winds and tides, and of more 
consequence in navigation than is generally 
supposed. He affirms, that this rhotion is 
from east to west, inclining towards the 
north, when the sun has passed the equi- 
noctial northward, and that during the time 
the sun is in the northern signs; but the 
contrary way after the sun has passed the 
said equinoctial southward: adding, that 
when this general motion is changed, the 
diurnal flux is changed also ; whence it hap- 
pens, that in several places the tides come 
in, during one part of the year, and go out 
during the other, as on the coasts of Nor- 
way, in the Indies at Goa, Cochinchina, 
&c, where, while the sun is in the summer 
signs, the sea runs to the shore ; and when 
in the winter signs runs from it. On the 
most southern coasts of Tonquin and China, 
for the six summer months, the diurnal course 
runs from the north with the ocean ; but the 
sun having re-passed the line toward the 
south, the course declines also southward. 
There are two principal reasons why the 
sea does not increase by means of rivers, 
&c. falling every where into it. The first 
is, because waters return from the sea 
by subterranean cavities and aqueducts, 
through various parts of the earth. Se- 
condly, because the quantity of vapours 
raised from the sea, and falling on the land, 
only cause a circulation, but no increase of 
water. It has been found, by calculation, 
that in a summer’s day there may be raised 
in vapours, from the Mediterranean Sea, 
5,280,000,000 tuns of water ; and yet this 
sea receivelh not, from all its nine great ri- 
vers, above 1,827,000,000 tuns per day, 
which is but a third part of what is exhaust- 
ed in vapours. 
