On the Annual Water-discharge of Large Rivers. 265 
This proposition may be illustrated by the following observa- 
tions made on the Parana and on the Uruguay :— 
I—Cross Section of the Parana, made near Rosario, on the 
25th January, 1871. 
Let v = the mean velocity from surface to bottom at any point, ex- 
pressed in feet per minute. 
d = the depth at any point, expressed in feet.. 
The mean velocities and depths were taken at nine stations 
across the river, with the following results :-— 
Station. ‘o | d oi 
1° 108-4 ft. per minute. 24-4 feet. 4-44 
2 2538 5 ete o, 371 
3 255°3 a4 DS'Di 5; 4:37 
4 241°0 ~ Doin ss 4:49 
5 215°3 5, 49:00 5 4:39 
6 195-0 ? 42:0 ,, 4-64 
7 172-2 7 400 ,, 4°33 
8 129-2 7 33:0, 3:92 
9 89°5 v ZO 49 4-44 
Mean ratio, . ; . . “ 43033 
IlL—Cross Section of the Uruguay, made near Salto, on the 
3rd February, 1871 :— 
Station. v | d | 5 
19 79°6 ft. per minute. 13:1 feet. 7-45 
2 234-2 a 22°0 ,, 10°64 
3 261-4 “p 25:0 ,, 10°45 
4 281°7 + 29:0 ,, 9-71 
5 3013 7; 298 ,, 10°11. 
6 329°8 ~ 33:0 ,, 9-99 
di 3175 fe 300 ,, 10°25 
8 319°5 os SlsOe.; 10:03 
9 333°1 5 OU 11:19 
Mean ratio, 
