206 xM E M O I R S e/* the 
where it is, for inftancc, two miles deep, will I'ufficd to raifc 
its iurface lo or 12 foot in a tide's time j whereas, if the fame 
quantity of water were to be conveyed upon a channel of 40 
fathoms deep, it would require a very great ftream to efFe<^ it 
in lo large inlets, as are the channels of England and the 
German ocean 5 whence the tide is found to let ftrongeft in 
thole places where the fea grows narroweft, the fame quantity 
of water being to pafs thro* a fmaller paflage 5 this is moft 
evident in the Streighti between 'Portland and Cape le Hogue 
in Norn?andy, where the tide runs like a fluice, and would be 
yet more ib between 'Dover atid Calais^ if the tide coming 
about the ifl and from the north did not check it, and this 
force, being once impreffed on the water, continues to carry it 
above the level of the ordinary height in the ocean, particular- 
ly where the water meets a diredl obftacle, as at St. Afalosj 
and where it enters into a long channel, which running far 
into the land, grows very ftraight at its extremity, as in the 
Severn Sea^ at Cbepfio'X and 'Briftol. From this flioalnefs of the 
fea, and the intercurrent continents, it is, that in the open 
ocean the time of higk-water is not at the moon's appulfe to 
the meridian, but always fome hours after it, as it is obfervcd 
on all the well coaft of Europe ami -Africa, from Ireland 10 
the cape of Good-Hope j in all which a S. W. moon makes 
high-water, and the lame is reported to be on the weft fide of 
j4rn-erka-^ but it would be endlels to recount all the particular 
iolutions, which are eafy corollaries of this hyporhefisj as why 
lakes, fuch as the Cafpian Sea ; and midland leas, fuch as 
the Mediterranean^ the Slack Sea, and 'Baltic, have no fenfi- 
ble tides- for lakes, having no communication with the ocean, 
can neither increafe or diminifli their water, whereby to rife 
and fall^ and feas that communicate by ii.ich narrow inlets, and 
are of fo immenfe an extent, cannot in a few hours time receive 
or empty water fufticient to raife or fink their furface fenfibly. 
Laftly, to dcmonftrare the excellency of this do6trine, the 
example of the tides in the port of ^lonquin in China, which 
are lb extraordinary, and different from all others hitherto 
heard of, may fuffice ^ in this port there is but one flood and 
ebb in 24 hours, and twice in each month 3 viz. when the 
moon is near the Equino^ial, there is no tide at all, but the 
water isftapnant; but with the moon's declination there begins 
a title, which is greatell, when ihe is in the tropical figns j only 
with this diiterence, that when the moon is to the northward 
ot the Eqi'.ator^ it flows when flie is above the earth, and ebbs 
when 
