C 33 3 
IV. 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. 
Read January 29, 1818. 
To determine the distance between the point of suspension 
and centre of oscillation of a pendulum vibrating seconds in 
a given latitude, has long been a desideratum in science. 
Many experiments have been made for this purpose, but the 
attention of all who have hitherto engaged in the enquiry 
(excepting Whitehurst) 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 in practice,) it is not sur- 
prising that the experiments made by different persons should 
have been productive of various results. 
When I had the honour of being appointed one of the 
committee of the Royal Society for the investigation of this 
interesting subject, I imagined that the least objectionable 
mode of proceeding would be to employ a rod drawn as a 
wire, in which, supposing it to be of equal density and dia- 
meter 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 
mdcccxviii. F 
