the |)lace where you arc muft be known fas hath beenfaid 
above) yoa muft have a care to obferve that time as precifc- 
ly a;S is poffible. For every minute of time , that you roifrcck- 
on J makes a 4th part of a degree in longitude, which amounts, 
near the iEquator, toabove 15, Englifh miles, but lefs elfc- 
where. Wherefore to find the time of the day with certainty, 
you are not to truft to the Obfeivation of the Suns greateft 
Altitude 5 thence to conclude that 'tis juft Noon , or that the 
Sun is in the South, unleft, being betwixt the Tropicks^ you 
have it juft in the zenith. For elfethe Sun being near the Me- 
ridian, remains for fome time without any fenfible alteration of 
its Altitude. Wherefore, though the Meiidian Ahrrtude nnray 
ferve vvell enough for knowing vhc Latitude or the Hight of 
the Pole upon occafion 5 yet it will not ferve for finding pre- 
cifely the Longitude of that place. Much lefs are you to rely 
upon the Se3,'Compajfes ^ thereby to find the prccife time of 
Noon. Neither are the Aftronomical Rings or other forts of 
Sundyals furc enough for (hewing the time to mmtes and fe- 
conSs, But it is better to obferve the Suns Altitude , whea 
*tis in the Ea(i or Weft , (the nearer, the better : ) for being there. 
Altitude changes inaftort time, more fenfibly than before 
or after ^ and thus from^ iht Hight of th Pok, and the Decli- 
mtion of the Sun the Hour may be calculated 5 the manner 
whereof is fuificicntlv taught by others yyet by reafonthat this 
Calculation is fomewhac troublefomc,and that alfo there may be 
fome Errors m the taking of the Suns Altitude,^ Iiere follows 
in eaffer way. 
Hmbj Ohfervi}^gthe Rifing dnd Setting of the 
Suny and the Time hpheWMches ^ the 
LongitudeaP Sea tmybtfonnd: - 
This/Way doth neither require the Encwledg; of the Hight 
ef the Pa/< > nor of the Declirjation of the Sm , nor thtUfe of any 
ji[hon6micat Tnftruments : Neither can the Refractions of the 
Sun or Stars caufe any confiderable Error 5 the refradion of 
the Morning differing b^t Uttkof noihing ffom that of the 
Evening, of one arid.the fameiay, efp cciaI%at,S^^ Thuj-then 
you' arc to proceed 5 * ^ At 
