rater's pendulum. 



143 



geological character ; such as the Azores, the Ca- 

 naries, St Helena, the Isle of France, and various 

 other stations amongst the eastern islands of the 

 Indian and the Pacific Oceans. The advantage of 

 having it swung at the Cape of Good Hope, and 

 especially at the Falkland Islands, (which lie in 

 the correspondent latitude to that of London,) and 

 at various other stations on the mainland, or on 

 large islands, is still more obvious. 



The length of the seconds pendulum at the 

 Galapagos, as determined by our experiments, is 

 395OI717 inches, and the ellipticity or compres- 

 sion of the earth is expressed by the fraction 

 where the numerator expresses the difference be- 

 tween the equatorial and polar diameters of the 

 earth, and the denominator the length of the dia- 

 meter at the equator. 



The details of these experiments have been al- 

 ready published in the Philosophical Transactions 

 for 1823. 



We had no time to survey these islands, a ser- 

 vice much required, since few if any of them are 

 yet properly laid down on our charts. They are 

 in general barren ; but some of the highest have 



