of the Pendulum made by Capt. Kater, M. Biot, Sfc. 19 



the former only O'^'OOOOQi, or about rr— -„ part of an inch. 



These approximating rules, when A N is great, cannot be em- 

 ployed where extreme accuracy is required. They will be 

 sufficiently correct when aN is small, as in the case of deter- 

 mining the length of the pendulum at various points on an 

 arc of the meridian not differing above a degree or so from 

 each other. If, however, the mean of the numbers of oscilla- 

 tions at the two places be used, the results would in general 

 be more correct; and formulae (1) and (4) may always be em- 

 ployed when the difference of the numbers of oscillations at 

 the two places does not exceed 30 or 40. 



To render the results accurate in all probable cases when 

 the formulae are used, we have computed the following Table 

 of corrections for various differences in the number of oscil- 

 lations. 



C2 



\ ariation 



