niotion o f waters or rivers has been the caufe of the
roundnéfs of ftones, for who can have refolution to embrace
a.fyftem which would engage him to hold that the
Rhone for inftance had traverfed the fummit o f the
mountain of Credo, one o f the higheft in the world, all
conipofcd of fuch pebble ; and the fame, reafoning mull
be allowed to many other mountains with Gmilar appearances
in different parts of the world.
Sometimes, it is true, ftones and pieces of rock are
hurried forward in rivers, and brought down by torrents
after florins ; the fame may happen in ftreets and cities,
but this is not extraordinary, when the declivity of the
fituation is coniidered, which gives additional power and
force to the water, occaGoning a natural effexft, which
ceafes when fuch bodies come to a place where they will
be at reft. This will account for fuch ftones as have
been rolled down into the beds o f rivers by their natural
weight, when the earth which fupported them has
given way;
SuppoGng then this notion to be exploded, the difficulty
ftill remains to account for their fmoothnefs and
roundnefs, which is no eafy matter to explain, being involved
with many perplexing circumftances, which I ihall
leave to be elucidated by others more intelligent than
myfelf. It is certain that water and time are two powerful
ful agents that can bring about furprifing effeils. The
world is full of thefe roqnd ftones of various Gzes and
appearances, they are found in vallies, on hills, and at a
conftderable depth in the earth, as well as on the fummit
of the higheft mountains. I have feen round diamonds
covered with a light fcurf, fapphires and oriental topazes
found like cornelians. T h e cryftal o f the Rhine never
becomes round, becaufe in its natural ftate it is not
angulai, and forms a mafs already round, the reverfe of
common rock cryftal, compofed of lamina of a regular
fhape. Many o f the learned have been deceived by
thefe cryftals of the Rhine, thinking, becaufe they found
them at two leagues diftance from Straiburg, in the
midftof the Gelds, that the river has altered its bed, entertaining
that fond notion, of the waters carrying them
along; at the fame time, they did not conGder that they
are not to be found a few leagues above Dieux Brifac,
nor any where below Straiburg. Therefore if thefe river?
carried fuch pebbles in their courfc, they would have
them at their mouth, where they enter the fea, and therp
would be no fand banks at thefe places, for the ftones
would Gil up the cavities, and the waters would roll over
them, which certainly is not the cafe. , The very bottorp
of the fea would fuffer fome change from tjie great quantities
of ftones brought down, by fo many riyers, and
forced into its bed, from whence it would follow, thattlje
E e e 2,,;, j, , obfervapors