90 An Account of Experiments for determining the Length of 
think proper to dispute the accuracy of my foregoing computa- 
tion, or the justice of my disapproval, (and that you will be 
pleased to afford me your pages as the medium,) I shall enter 
without hesitation into all the minutie of the question. 
I am, sir, 
Your most obedient servant, 
St. Finbars, Cork, July 15, 1818. WILLIAM GUTTERIDGE. 
XIV. An Account of Experiments for determining the Length 
of the Pendulum vibrating Seconds in the Latitude of London. 
By Capt. Henry Kater, F.R.S.* 
A iM determine the distance between the point of suspension and 
centre of oscillation of a penduluin vibrating seconds in a given 
latitude, has long been a desideratum in science. Many experi- 
ments have been made for this purpose ; but the attention of all 
who have hitherto engaged in thé inquiry (excepting White- 
hurst) appears to have been directed to the discovery of the 
centre of oscillation. The solution of this problem depending, 
however, on the uniform density and known figure of the body 
employed, (requisites difficult if not impossible to be ensured ia 
practice,) it is not surprising that the experiments made by dif- 
ferent persons should have been productive of various results. 
When I had the honour of being appointed one of the com- 
mittee of the Royal Society for the investigation of this interest- 
ing subject, I imagined that the least objectionable mode of pro-~ 
ceeding would be to employ a rod drawn as a wire, in which, 
supposing it to be of equal density and diameter throughout, the 
centre of oscillation, as it is well known, would be very nearly 
at the distance of two-thirds of the length of the rod from the 
point of suspension; and I purposed by inverting the rod, and 
taking a mean of the results in each position, to obviate any 
error which might arise from a want of uniformity in density or 
figure. After numerous trials however, and as frequent disap- 
pointments, I was at length convinced of the impracticability of 
obtaining a rod sufficiently uniform ; and I was besides aware, 
that under certain circumstances errors might arise from this 
cause which it would be impossible by any method to detect. 
Not feeling at all satisfied with the prospect which the use of 
a rod presented, I endeavoured to discover some property of the 
pendulum of which 1 might avail myself with greater probability 
of success; and I was so fortunate as to perceive one, which 
* Fyom the Transactions of the Royal Society for 1818, part i. 
‘ins promised 
