410 Messrs. Lamprey and Schaw on Pendulum 



then will the product of uvw be capable of being determined by 

 means of the solution of a quadratic equation, of the square root^ 

 of whose roots the coefficients of uvw will be known linear func- 

 tions. Thus by an affected quadratic, a pure quadratic, and a 

 cubic equation, the values of u, v, w may be completely ascertained. 

 The discussion of this theoiy, and of a general inverse method for 

 assigning the true (in the sense of the most manageable) Ca- 

 nonical Form for functions of any even degree, will form the 

 subject of a subsequent communication. 



=*=«= 



LXI. An Account of Pendulum Experiments made at Ceylon, 

 By Jones Lamprey, A.B.y M.B., Assistant Surgeon, 16th 

 Refft., and Lieut. H. Schaw, R.E. 



' ' ih ike Editors of the Philosophical Magazine and Journal. 



Colombo, Ceylon, 

 Gentlemen, September 15, 1851. 



AS the following pendulum experiment made in this latitude 

 (6^ 56' 6" N.) may prove of value to those interested in 

 similar experiments in Europe, we beg leave to communicate it; 

 to you, together mth the results of our observations thereon. 



The recent publications on this subject which have appeared ia, 

 your valuable Magazine afforded us much interest, and induced^ 

 us to repeat the experiment here ; thinking that if the law holds,; 

 good at a place so near the equator, its truth will be confirmed 

 beyond doubts. 



The building in which the experiment was conducted was a 

 large church belonging to the Dutch Presbyterians of Colombo, 

 and from its height was the only one at all applicable for such a 

 purpose. The principal timbers of the roof are sixty-eight feet 

 above the floor ; between two of these was secured a small beam^, 

 from which our pendulum was suspended. ,^j ..j.j,^ fjuvi^^iln^. ■'; 



The ball of the pendulum was of lead, cast in a mbma, ancl 

 afterwards turned true in a lathe, and was nearly a sphere ; it 

 weighed 30^ lbs. The wire by which it was suspended was gj-th 

 of an inch in diameter, and 66 feet 6 inches long ; to its upper 

 extremity were attached a number of fibres of raw silk, which 

 were evenly drawn through a small hole in an iron plate and 

 carefully secured on its other side ; this plate was screwed to the 

 under side of the small beam before mentioned. 



The circle over which the pendulum was made to oscillate, was 

 in the experiments here recorded only 6 feet in diameter, there 

 being evidently less inclination to ellipticity when small arcs 

 were used, and the ellipticity, when it does occur, having less 

 tendency to cause apsidal motion. 



J 



