(2071 ) 
Iftherefore there be no other Periods of Tydes but thefe 5 or 
no other remarkablcjOiy work is done, and I need not be furthes! 
folicitous.' For, then there will feem to be either no other ine- 
quality ofmotionsjOr none confiderable, But^if there be alfo ob- 
fervable an Annud period, (as very many think there is 5 ) or any 
other fuch period j (as perhaps there may be,) then are we to ftek 
for the Caufe thereof in foniewhat of Inequa!ity,which doth (for 
the -^/z/;^^/ Period Annually xtcm > or (for any other Period,) 
which doth recur in fuch a time as that other Period doth re- 
quire* 
Now forafmochasthe three Motions above mentioned are nei* 
ther (as was above fuppofed) each Equal in it felfj or perfedtly 
Circularjnor all 00 Parallel Axes 5 thereisjbothas to the Sun5and 
as to theMooo,at leaft a double Inequality ; the one^hy reafon of 
the ^^^e«^r/Vi/^,and (which depends thereon) the Apog£um and 
Ter7g£um , the other Jjy reafon of the Obliquity of the Zodiack and 
the Mooo^s Orbite, with the iEquinoftial, and with each other. 
From every of which doth proceed fome little Inequality of Mo- 
tion in the Earth's Surface : But whether fo much as to make any 
remarkable alteration in the Tydes, is hardly determinable than 
by obfervation. 
Now for that of the Moon ^oth as to its Apog^um and Terigmm^ 
(with the Inequality of Motion depending on it ^ ) and as to the 
Obliquity of its Orbe both with the ZW/^^r^ the Mquator 
(which caufeth another Inequality both in the Motion of Longi* 
fndeand Right Afcenjion^^) I have hitherto contented my felf to in- 
finuate itjin one of my Letters on thisfubjeft^ v»athout further in- 
iifling onit 5, becaufe 1 did not know of any Periodical Viciffi- 
tude of Tydes confonant thereunto. When any fuch Chall be dif- 
GOveredjWe have here a Foundation ready for the Salving of ir. 
But as to any Amual Viciffitude^itis not ofuC; .,hecaufe it doth not 
Annually recur. 
iC But,becau(e it hath been almoft generally received5That there 
is an Obfervable A^nualPeriod '-^ I did^ for the falving of that5ap- 
,"ply not the Inequality of the Natural Uayesj butthofe caufes from 
owhence that proceeds^the Excentricity \oi the iSun or Earth s Orbj, 
and the Obliquity of the ZQdiack»Thej^rw£?rof tbefe,if fingly con- 
fideredjwould caft thofe Annual Tydes in June ^ind December (j:he 
timcs o(thQ.SunsApogmm and Ferig^fim^ or rather the Earth s 
Af helium. 
