[ i$8 ] 
are too near, the fpiral Motion is interrupted, and 
the Continuity of the Water broke; which, rufhing 
in on all Sides, immediately fills up the Cavity, and 
enables them to go over it fafe. Hence in blowing 
Weather, or when there is a breaking Sea, tho' there 
may be a circular Motion in the Water, there can 
be no Cavity. 
When there is a fteep funk Rock near the Con- 
courfe of fuch ftrong 1 ides, and not very deep below 
the Surface, a mod amazing ‘Phenomenon wil hap- 
pen : For, the Stream being interrupted in its C o »ne, 
and falling fuddenly over the Rock, is reflected t cm 
the Bottom upwards, fwelling and bubbling on the 
Surface like boiling Water, and carrying Sand, Shells, 
Flfhes, or other loofe Bodies along with it ; which, 
with Boats, or whatever elfe is near, are driven wi h 
great Force from the Center all around toward the 
Circumference, upon which, a Gyration of the V\ ater 
enfuing, a Whirlpool begins, which is carri d along 
with the Stream, as was faid above, lefltnmg gradu* 
ally till it is quite extinguifhed : In a little rime a new 
Eruption and Ebullition, like the former, begins, 
which proceeds in the fame manner, till the Swift- 
nefs of the Stream abates, or the 1 idc rifes or falls 
too much above the Rock, 
* 
Queries concerning the Tides in a large Ocean ; 
which, it r^Johed from Observation, would ren- 
der the Theory more pi rfeEt. 
i. Smce the A traftion of the Moon ra ; fes the 
W ater directly below; her, by d minifhing its Gra- 
vity toward the Earth's Center, and, at that very 
fame 
