469 



lake of Thrasimene. The Arno, in the cele- 

 brated voltata which it makes toward the south, 

 the west, and the north, between Ribiero and 

 Ponta Sieve, divided itself near the Arazzo into 

 two branches, one of which went to the sea 

 by Florence and Pisa, as at present ; and the 

 other, after having followed the Val de Chiana, 

 mingled it's waters with the Tiber, either imme- 

 diately, or after having confounded them with 

 those of the Paglia. Mr. Fossombroni has shown 

 how in the middle ages, from the effect - of de- 

 posits of earth from the river, a point of parti- 

 tion was formed in the Val de Chiana ; and how 

 the northern part of the Arno Teverin now flows 

 (on a counterslope) from south to north, from the 

 little lakes of Montepulciano into the Arno*. 

 The classical soil of Italy contains then, among 

 so many prodigies of nature and of art, one of 

 those bifurcations, of which the forests of the 

 New World display another example on a much 

 larger scale. 



I have been often asked since my return from 

 the Oroonoko, whether I were inclined to be- 

 lieve, that the channel of the Cassiquiare would 

 be choked up by successive accumulations of 

 earth ; and whether I did not think, that the two 



* Carte d'ltalie de Bacler Dalbe, No. 18, 23,24. Fossombroni, 

 Manor ia idraulica sopra la Val de Chiana, 1789, p. 17. 

 Prony, on the hydraulic system of Italy, in the Journal de 

 VEcole Poly technique, vol. 4, p. 62. 



