I 
[ 12 + ] 
however, liable to the leaf! error, when the meridian 
cuts the arc to be meafured at right angles in the 
middle of it ; but this makes fo very frnall a difference, 
that it is not worth regarding; nor is it indeed necef- 
fary, that the arc fhould not deviate two or three de- 
grees from right angles with the meridian, at that end 
where it cuts it molt nearly at right angles, in cafe the 
fituation and circumffances of the country fhould 
make this more convenient, the errors, that would be 
occafioned by fuch a deviation, being too fmall to affedt 
the conclufion. And if this deviation was rbiil much 
greater, and the length of a degree of the meridian at 
the fame place was known, it would be very eafy to 
make the neceffary corre&ions. 
It will perhaps be objected, that the method above 
propofed depends, in fome meafure, upon time, as 
well as others, the finding of the meridian not being 
to be performed without it; but I muff obferve, that 
the motion of the pole ffar, by which I propofe to find 
the meridian, being flower than that of a ffar at the 
equator, nearly in the proportion of 30 to 1, this 
method will admit of an exadtnefs greater in the fame 
proportion (except the reduction of the Sin. to the R. 
before mentioned) than thofe obfervations, by which 
we endeavour to find the difference of the longitude 
of two places, by the difference of the time of the fun, 
or a ftar’s coming to their refpe&ive meridians. 
The method above propofed will likewife require 
different inffruments from thofe commonly in ufe; 
but admitting, that inffruments of equal radius are 
capable of equal exadlnefs, this method will admit of 
the fame exadtnefs with the obfervations of a degree 
of the meridian, except the before-mentioned limita- 
4 tion. 
