from the measurement of an arc of the meridian , &c. 509 
If we suppose 3— to be the true compression, let it be 
determined what the value of m^ ought to be to bring out 
that compression ; and by that means to detect the errors of 
the observed degrees, in latitude 9 0 34' 44", and 16 0 34' 42", 
which last may be compared with m ^ . 
Put A = 544433,21 ; a = Sin. a / (2} — Sin. 7 tl} = ,006014, 
radius being unity ; b = (Sin. 3 f 2 Sin. 2 ^ + (Sin. 2 
— Sin.* / (,) ) + (Sin. 3 Z (9) — Sin. * / (,) ) == , 263137. 
Then d = (m^ — m ^ ) = ( A ““ n p, . ,1 ; and (7) = 
from which is deduced m^ 
=60475,47 fathoms. Whence d = (A ^ 3,5192. 
And O — n Q 0 5o ' ^ = 585,17. From these the following table 
has been computed, from which it appears that the first 
degree by measurement, is 2,6 fathoms in defect ; and that 
the one in latitude 16 0 34' 42" is 5,89 fathoms in excess ; 
either of which is too small to affect the elliptic hypothesis ; 
the greatest being only -§• of a second on the earth’s surface. 
