57^2, 



LECTURE XLVl. 



ino- a globe, first entire, and then cnt out according to the terminations of 

 the ditterent countries: or, if still greater precision were required, the greater 

 part of the continents might be divided into known portions of the whole 

 spherical surface, and the remaining irregular portions only weighed. 



The general inclinations and levels of the continents are discovered by the 

 course of their rivers. Of these the principal are, the River of Amazons, the 

 Senegal, the Nile, the River St. Laurence, the Iloangho, the River La- 

 plata, the Jenisei, the Mississippi, the Volga, the Oby, the Amur, tlie Oro- 

 nooko, the Ganges, the Euphrates, the Danube, the Don, the Indus, the 

 Dnieper, and the D\yina; and this is said to be nearly the order of their 

 magnitudes. But if we class them according to the length of country through 

 which they run, the order will, according to Major Rennel's calculation, be 

 somewhat different: taking the length of the Thames for unity, he estimates 

 that of the River of Amazons at 15^, the Kian Kew, in China, 1.54:, the 

 Iloangho 134, the Nile 12-^, the Lena II4., the Amur 11, the Oby 104, the 

 Jenisei 10, the Ganges, its companion the Burrampooter, the rive^ of Ava, 

 and the Volga, each 94-, the Euphrates 84, the Mississippi 8, the Danube 7, 

 the Indus 54, and the Rhine 5^. 



We may form a tolerably accurate idea of the levels-of the ancient continent, 

 by tracing a line across it in such a direction as to pass no river, which will ' 

 obviously indicate a tract of country higher than most of the neighbouring 

 parts. ' Beginning at Cape Finisterre, we soon arrive at the Pyrenees, keep-- 

 ing to the south' of the Garonne and the Loire. After taking a long turn 

 northwards, to avoid the Rhine, we come to Swisserland, and we may ap- 

 proach very near to the Mediterranean in. the state of Genoa, taking care 

 not to cross the branches of the Po. We make a circuit in Swisserland, and 

 pass between the sources of the Danube and of the branches of the Rhine in 

 Swabia. Crossing Franconia, we leave Bohemia to the north, in order to 

 avoid the Elbe, and coming near to the borders of Austria, follow those of 

 Hungary, to the south of the Vistla. The Dnieper then obliges us to go north- 

 wards through Lithuania, leaving the Don wholly to the right ; and the Volga, 

 /to pass still further north, between Petersburg and Moscow, a little above Bjele- 

 sero. We may then go eastwards to the boundary of Asia, and thence northwards 

 to Nova Zembla. Hence we descend to the west of the Oby, and then to the 



