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1 1 o In Col. of Mid. Time corresponding to 4,72032
Lat. - 49 59 N. -
will be proper to repeat the Operation, using the Lat. last found inftead of the Lat. by Account. - H
The Latitude last found, differing only one Mile from that used in the Operation, may be depended on as the true Latitude. Hence it is plain, that the Operation is repeated with very little additional Trouble, but few Alterations being necessary.
Being at Sea in the Latitude of 60° o' North by Account, when the Sun was on the Equator, and consequently ...} no Declination, at I H. o M. P. M. per Watch, his Altitude was 28°53', and at 3 H. o M. P. M. per Watch, it was 20°42'. Required the true Lat.
60 o Latitude
The Latitude by Computation, coming the same with the Latitude by Account, shews that the Latitude by Account was right. From the foregoing Examples it is plain, that the Operation is the same, whether the Sun hath North or South Declination. And it will be the same whether the Ship is in a North or South Latitude. It is also clear, that when the Sun has no Declination, the Secant, rejecting the Index of the Latitude is the Log. Ratio.
Wanting to go through the N. Channel among the Maldives, and
by Account being Latitude 7° 40' N. the Declination being then
22° 47' N. at 7 H. 25 M. 40 S. A. M. the true Altitude of the
Sun's Centre was 22° 30', and at Io H. 31 M. 48 S. A. M. it was found 63° 40'. Required the Ship’s true Latitude : I Times.
N. B. As the Tables are only calculated to 30 Seconds, the Log: for any intermediate Seconds is found by taking the Difference between the Log. next greater and next less, and saying, as 30 Seconds is to that Difference, so is the given Seconds to the Difference of the Logarithms; or, if it be any even Part, take such a Part of the Difference, and apply it to the next less Logarithm; but in these Operations a few Seconds are not regarded. -
The Latitude last found, agreeing with that used in the Operation, it may be taken as the True Latitude; and the Operation is repeated with very little additional Trouble, but few Alterations being ne- cessary.