[ 5^3 3 
The obferver would do well to write down in a book 
the error of adjuftment thus found, and which way 
it is to be applied, whether it is additive or fubtrac- 
tive. 
As it is neceffary to know the exadt time of the 
day, when the diftance of the ftar from the Moon 
is taken, which can only be found at fea, by an al- 
titude of the Sun, or a ftar; and as the altitude of 
a proper ftar cannot always be taken with fufticient 
exa<ftnefs in the night for this purpofe, I would re- 
commend it to the obferver, when he expe&s to ob- 
ferve the Moon at night, to take an altitude of the 
Sun in the afternoon, two or three hours from noon, 
the more the better, provided the Sun be not too near 
the horizon ; noting the exadt time fhewn by his 
watch, at the inftant of obfervation ; which will fhew 
him, by computation, how much his watch is too faft 
or flow for the meridian of the place; whence the 
time fhewn by the watch being alfo noted, when the 
diftance of the ftar from the Moon was taken, he 
will know what the exad: time of the day then was. 
Or if an altitude of the Sun was not taken the evening 
before, an altitude might be taken the next morning, 
after the obfervation of the Moon, provided the inter- 
val of time between the obfervation of the Moon, and- 
the Sun’s altitude did not exceed twelve hours ; for a 
good common watch would hardly vary above a mi- 
nute during that fpace of time, which only makes an ; 
error of a quarter of a degree of longitude. 
The time being determined by an altitude of the 
Sun or a ftar, and the diftance of a proper ftar from 
the Moon’s limb, or the diftance of the Sun and' 
Moon’s neareft limbs in the firft and laft quarter, being 
carefully 
