c>8 Mr. Lax’s Method of finding the Latitude of a Place , 
would then only be necessary to subtract the observed altitude 
from this complement, and we should immediately deduce the 
zenith distance of the sun, when he had arrived at the meridian. 
This being ascertained, we should have no farther difficulty in 
finding the latitude to be adopted in the subsequent computation. 
The exactness of the conclusion which is derived from this pro- 
cess, will necessarily depend upon the degree of certainty with 
which the time is given when the observation is made. An error 
in time may arise, both from an irregularity in the going of the 
clock and a small inaccuracy in estimating the difference be- 
twixt the longitude of the place where the altitude is now taken, 
and that where the time was last determined ; but these causes, 
it is evident, can seldom be very considerable. We may gene- 
rally, I think, be sure of the time within two or three minutes. 
The principle upon which this approximation depends will 
open to us a more compendious way of finding the area gb, and 
which may always be pursued with advantage, when one of the 
altitudes can be taken at a small distance from the meridian. In 
the higher latitudes, indeed, the hour-angle may amount to five 
or six degrees ; but, when the latitude and declination approach 
towards an equality, and are of the same denomination, this angle 
must be restrained within narrower limits. If, instead of deducing 
the meridian altitude from the altitude observed, according to the 
directions before given, we consider it as being actually equal 
to the meridian altitude, and employ the latitude resulting from 
this hypothesis in computing the hour-angle, this angle must 
necessarily be found equal to nothing. We may, therefore, spare 
ourselves the trouble of performing this part of the operation, 
and need only calculate the time belonging to the second obser- 
vation, which is supposed to be made when the sun is at a greater 
