0*5 7) 
out to be fomewfiat ffiorter and ffiorter, from the New and FuM 
Moone unto the Quarters $ yet not in znjqvall manner, neither 
gradually decreafing from the New and Moone untill the 
Quarters % but rather , that there was fome little difference of 
alteration both at the New and Full Moones, and alfo at the 
Quarters % and that the greateft difference fell out in the midft 
between them, agreeing very well to a Circular proportion^ after 
this manner: (See Fig. 5.) 
Firfc Divide a Circle into 12 Equal parts, or hours ? accor- 
ding to the Moones motion or diftance from the Sun^ from the 
New Moone to the Full. 
Secondly ^ Let the Diameter of the Circle be divided into 90 
parts or min. that is, according to the time of the difference of 
Tides between the New or Full Moone, and die garters $ which 
is one hour and an halfe. 
Thirdly, Make \ perpendicular lines crofs the Diameter of the 
Circle, from hour to hour. 
Fourthly 0 Reckon the time of the Moones coming to the 
South in the circumference of the Circle, and obferve the Per- 
fendicular-Line, that falls from that point upon the Diameter % 
and the proportionall Minutes^ cut thereby, will (hew, how many 
Heures 0 or Minutes are to be fubftra&ed from the time of High- 
tides at the New and Full Moone, that fo you may have the true 
time of Strides that prefent day. 
For Example 5 At London, on the day of New and Full Moone* 
it is High-Tide at London at 3 of the Clock, that is, when the 
Moone is three hours paft the Meridian : and fo by the Common 
Rule, the Moone being about four dayes old, it will be South a- 
bout three of the Clock, and it will be High-tide three houres af- 
terwards, that is, at <5of theC lock. But now by this Rule, if 
you count this time of the Moones coming to the South in the 
Circumference^ the perpendicular-line, which comes from 3 to 9^ 
cuts the Diameter in the halfe 5 at 45 min. which fhews, that fa? 
much is to be abated from the time of High-tide in the New and 
Full Moones So that it is High-tide 4s min. before 6 of the. 
Clocks, that is, at 5. hours 1 5 min. and not at 6 of the clock * 
according to the common- Rule, 
The like youmay do for any other Porter place^ knowing the 
