114 Mr. Lax's Method of finding the Latitude of a Place , 
minutes of time ; and Z the whole error in the time computed 
with the greater altitude ; then will the error in the result be 
to the whole correction of the latitude (L) : : - z ~ tz : tz : : 
tx t L 
2 ' 15 T* 
tx . lyo — d\ 
2 * 15^7^ 
L : : 7 ,5 x Jz : ^ - 
L. This 
error will consequently be equal to - 7 ’ 5 ** ■■ ; and hence it ap- 
y 
pears that, if we had pursued this method in the last example, 
and there had been an error of a minute in the time given by 
the clock, there would not have been an error of a single se- 
cond in the conclusion. 
4. If the time were determined by equal altitudes, and one 
of them were to be employed in computing the area g b, it is 
manifest that we should entirely exclude the error which has 
just been considered. It would be necessary, however, in 
order to correct by the second observation any inaccuracy that 
may have occurred in reading off at the first, to move the index, 
and then bring it apparently to the same position again, before 
we proceeded to take the second altitude. 
EXAMPLE V. 
On the 30th of January, 1799, the following altitudes of the 
sun's lower limb were taken in Trinity College, Cambridge ; 
the height of the barometer being 29,6 inches, and of the 
thermometer 31 degrees. 
