four feet and a half, which being kept between the Com- 
pafses, naturally divide jthe faid Circles in the points 
t^l[€9<S^ through the which points if you draw lines 
parallel to the bale A B they ftiall cut the j5?^r/>^;2^/^:2^/^r 
CD, in the hightsof the high and£(?2i? water marks, which 
will be at the entrance of the ISlcon into the i^iAJigns, So 
the greateft depth of the high water ^ when the Moon enters 
^3^^, is but ly^ feet, and the leaft 2X Low wateml 
feet : but when fhe Enters 11,^.-^»,^, the high-water depth 
is 21 1 feet, the Low-water but ^ \ feet 5 as appears by the fi- 
gure. And this Hypothefi's not only agrees with all that 
M.^. Davenport hath obiervcd hirafelf, or collected from 
the Natives^ but hath been found to hold true fince in the 
year 1(^82 by the Ingenious Capt. i^;^^?^^, in his Voiage to 
t\\nport i fo that there is no room to doubt of the truth 
thereof'By this method may the time and hight of the Tides 
be with fufficient certainty computed, but to philofopbi^^e 
theron, and to attempt to ailign a reafon, why the Moon 
ihould in fo particular a manner influence the waters 
in this one place, is a task too hard for my undertaking, 
efpecially when I confidcr how little we have been 
able to eftablilh a Genuine and latisfad:ory T^e^^ry of the 
Tides ^ found upon our own Coafis^ot which wee have had 
fo long Experience. It would be however a very acceptable 
thing if fome curious Navigators would inform us, what 
tides or Currents are found at Macao, ^tiemoy, and other 
places on the Coajl of China and on Formoja ; it being molt 
probable that this flood cometh out of the North Eafi, a- 
iongft theCoaft China, for that the Northerly Moo?isoo?i 
is found to occafion the higheft fpring-tides. There is 
yet another thing well worch Inquiry, that feeing that 
this motion of the5^a is more or lefs as the Moon is far- 
ther from or nearer to the Equino^liall, it is not unlikely, 
that fome years may have much higher Spring-tides 
than others, according to the Various Obliquity of the 
Moons orbite to t\\c Equinoctiall, for when the alcending 
Nodeis in Y, ( as it was anno i(57 1 and will be anno 1^90) 
■ ■ ■ ■ N the 
