(P4J) 
jE^uation of thefe days, taken out of the Table*, And if the 
Aggregate doe luft make i a.hours^the Watch is fet adjufted to 
the right meafure 5 but if it differ, you are to divide the mi- 
nutes and feconds of that difference by the nua>ber of the days 
between both the Obfervations, to get the daily difference. 
Let us fuppofe 5 this fecond Obfervation to have been made 
the 20. of Marchy viz. 8. days after the firft, and finding, that 
the Middle of theSun being feen in the Meridian in the fame line 
h. m. fee. 
with the two threds, as before ,the Watch pointsii — 51 — j 
The ^Equation of the 20 of Mdrch,hy the Table, is— o — 10 -4® 
Which being added to the time , fhow'd by the 
Watchj^gives 12— i--47 
If this had been luft x 2 hours^the Watch would have been well 
adjufted, but being i.min.47. fee. more than 12, it hath gone 
fo much too faft in S.days. And thefe i min. 47. fee. that is, 107, 
fee. being divided by S^there comes i^f fee. for the difference of 
every 24. hours 5 which difference being known, if you 
want time, or have no mind to take the pains to adjuft the 
Watch to its right meafure (this being not neceffary , fince you. 
may bring itthuson lliip-board) note onely the dailydifference^ 
and regulate your felf accordingly, as hath been mentiou'd. But if 
you will adjuft it better, you muft remove the lefs weight of the 
Pendulum a little downwards, which will make it goe flower 5 
and then you muft begin to obferve anew by the Sun, as be- 
fore. If it had gone^^oo flow, you muft have remov'd the 
mention'd weight fomewhat upwards. And this is of that 
importance in the finding out of Longitudes^ that, if it be not 
obferv'd, you may fometimes in the fpaceof 3 months mif- 
reckon 7. degrees and more (yet without any fault in the 
Watches > J which under the T'repcks WiW araout to above 400 ^ 
Englifh miles, 
Hivin^t fhew'd; How the Watches may be adjufted at^ 
Land, or how their daily difference may be known-, nextflaall ; 
follow , How the fame may be done, when a Velfel rides at 
anchor , it being hardly fefible when ilie is under faile. 
in the morning then, wl en the .' urns juft half above the ;^i?V" 
rizan ^ note^» what hoor^ min^ and fee, the Watch points at ^ 
