NOTES. Vll 



Uerta and Atrevida, under the command of Malaspina, thirteen stations be- 

 longing to the southern hemisphere, and found, on the mean, an ellipticity 

 of 2t ^. 54 . Mathieu also derived from Lacaille's observations at the Cape of 

 Good Hope, and in the Isle of France, compared with Paris, ~- 4 ; but the 

 measuring apparatus of that period did not offer the security afforded by that of 

 Borda and Kater, and the later methods of observation. This is the place for 

 mentioning the fine experiments of Foucault, so honourable to the sagacity of 

 the inventor, which have given a visible proof of the rotation of the Earth on 

 its axis by means of the pendulum, its plane of vibration turning slowly ffom east 

 to west. (Comptes rendus de 1'Acad. des Sciences, se'ance du 3 fe'vrier, 1851, 

 t. xxxii. p. 135.) To obtain deviations to the eastward, as in the experi- 

 ments on falling bodies of Benzenberg and Reich on steeples and in shafts, a 

 very considerable height of fall is required ; whereas Foucault's apparatus 

 renders the rotation of the Earth sensible with a length of pendulum of six feet. 

 Phenomena which are explained by the rotation of the Earth (as the march of 

 Richer's clock at Cayenne, diurnal aberration, deflection of projectiles, and 

 trade winds), are not to be placed in comparison with that which can at all 

 times be called forth by Foucault's apparatus, and of which the members of the 

 Academia del Cimento seem to have had a conception, but not to have pursued 

 it. (Antinori, in the Comptes rendus, t. xxxii. p. 635.) 



( 23 ) p. 30. In Grecian antiquity, two parts of the Earth were pointed out as 

 having, according to inferences drawn from the opinions which then prevailed, 

 remarkable inflation or elevation of surface : the north of Asia and the country 

 under the equator. " The high and naked Scythian plains," said Hippo- 

 crates (De Mice et Aquis, xix. p. 72, Littre), " without being crowned with 

 mountains, spread out and rise to beneath the Bear." The same belief had been 

 attributed to Empedocles at a yet earlier epoch (Plut. de Plac. Philos. ii. 8). 

 Aristotle (Meteor, i. 1 a 15, p. 66, Ideler) says, that the older meteorologists, 

 who "made the sun pass, not under, but round the Earth, considered the swelling 

 of the Earth towards the north to be the cause of the nocturnal disappearance 

 of the sun, and thus of the occurrence of night." Also, in the compilation of the 

 problems (xxvi. 15 ; Pag. 941, Bekker), the coldness of the north wind is 

 attributed to the " height of the ground " in that quarter. In all these passages 

 it is not mountains, but high plains, or general elevation of the land, which are 

 referred to. I have already shown elsewhere (Asie Centrale, t. i. p. 58), that 

 Strabo, who is the only writer who employs the characteristic word opoir&ia 

 for Armenia (xi. p. 522, Casaub.), for Lycaonia, inhabited by the wild ass 

 (xii. p. 568), and for Upper India, and the gold country of the Derdans (xv. 

 p. 706), always distinguishes the difference of climate due to geographical 



