1 14 CAUSES which affett the ACCURACY 



introduced, and the formula will become fimilar to that which 

 was formerly iiiveftigated. For , or 



i 



" n 1 2 n 3 "3 



P - i nlog.$ + (%.*) -- - (log.b} + &c. When n 



is very fmall, as in the prefent cafe, this feries converges with 

 extreme rapidity ; and the terms involving 3 , &c. may fafely 

 be rejected. . Therefore, 



n 2 



-- - = I nlog.$-\ -- (%.(3) I + nlog.b -- (log. b} = 

 /3 b 



I +" / 2 n 2\ 



q g (H h}(log. b log. ( log. b} + ~- (log. (3) j 



* 2 



Hence, z= - H -r 



/ 



(i ffz) (i z) 



29. WHEN n vanifhes altogether, the value of s, affigned by 

 this formula, coincides, as it ought to do, with that which was 

 inveftigated, on the fuppofition of the denfity being precifely as 

 the compreflion j for by applying the reduction of 'art. 17. we 

 have, 



But when , though very fmall, does not vanifh altogether, by 

 the fame reduction, 



z = q 



If, therefore, we fuppofe 7 to be equal to p y or to 4343 



fathoms, 



