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Art. XIX. — Results (^‘ C a ptahi Kater's Expa'hneiiis for 
dcternvmmg the Length of the Pendulum, M the principal 
Stations f the Trigonometrical Survey, 
Our readers are no doubt well acquainted with the beautiful 
method of measuring the length of the pendulum which was 
invented by Captain' Henry Kater, and which he so success- 
fully employed in determining the length of the seconds’ pen- 
dulum in the latitude of London. The superiority of this me- 
thod, and the consistency of the results which it yielded, point- 
ed out Captain Kater as the fittest person to extend the experi- 
ments to different points of the meridian ; and in pursuance of 
the resolution of the House of Commons of the 15th March 1816, 
the Royal Society of London requested this active astronomer 
to ascertain the length of the seconds’ pendulum at Unst, Port- 
soy, Leith Fort> Clifton, Arbury Hill, and Shanklin Farm, the 
principal stations of the Trigonometrical Survey. Arduous as 
this undertaking was. Captain Kater did not hesitate to quit his 
family and his scientific pursuits, and devote himself, with his 
usual ardour, to an enquiry in which the scientific character of 
his country was so much concerned. The wise liberality of the 
British Government furnished him with all the requisite instru- 
ments, and every facility which such an undertaking required ; 
and he left London on the 24th J une 1818, accompanied with 
Lieutenant Franks, mth the view of beginning his operations at 
Unst in Orkney, the most northerly station of the survey. He 
arrived at Leith on the 28th June, and reached Unst on the 
9th July, in the Nimrod, commanded by Captain Hailing. Af- 
ter finishing his observations in the Orkneys, he arrived at Port- 
soy on the 1st August ; at Edinburgh on the 28th of August ; 
at Clifton on the 28th September ; at Arbury Hill on the 15th 
October ; and at Shanklin Farm, in the Isle of Wight, about 
the 10th of May 1819, where he completed the series of labo- 
rious operations which he had undertaken. The following are 
the results of these operations, as given by Captain Kater him- 
self in the Philosophical Transactions for 1819, Part III, 
