x 1 ¢ ve - 
7 y° i ¥ aap iS ou < 
2 ~ <0 4 Py 
a ‘ - 
870 DYNAMICAL GEOLOGY. [Boo IIT. 
already dealt with the chemically dissolved ingredients. In deter-— 
minations of the mechanically mixed constituents of river water, it is — 
most advantageous to obtain the proportion first by weight, and then ~ 
from its average specific gravity to estimate its bulk as an ingredient — 
in the water. According to experiments made upon the water of the 
Rhone at Lyons, in 1844, the proportion of earthy matter held in 
suspension was by weight +7455. Harlier m the century the results 
of similar experiments at Arles gave 55 as the proportion when 
the river was low, 54, during floods, and 5,45 in the mean state of 
the river. The greatest recorded quantity is 7 by weight, which 
was found “when the river was two-thirds up with a mean velocity of 
probably about 8 feet per second.” Lombardini gives z}) as the 
proportion by volume of the sediment in the water of the Po. In 
the Vistula, according to Spittell, the proportion by volume reaches a — 
maximum of 7.2. The Rhine, according to Hartsoeker, contains +45 _ 
by volume as it passes through Holland, while at Bonn the experi- 
ments of L. Horner gave a proportion of only yg)oq by volume.? 
Stiefensand found that, after a sudden flooding, the water of the 
Rhine at Uerdingen contained ;¢5 by weight. Bischof measured 
the quantity of sediment in the same river at Bonn during a turbid 
state of the water, and found the proportion z,,, by weight, while 
at another time, after several weeks of continuous dry weather, and 
when the water had become clear and blue, he detected only s7455.4 
In the Maes, according to the experiments of Chandellon, the maxi- 
mum of sediment in suspension in the month of December 1849 was 
xyoq the minimum 77z4gq, and the mean yoJpq.’ In the Elbe, 
at Hamburg, the proportion of mineral matter in suspension and 
solution has been found by experiment to average about 75. The 
Danube, at Vienna, yielded to Bischof about z545 of suspended and 
dissolved matter. ‘Lhe Durance, in floods, contains 7, of suspended 
mud, and its annual average proportion is less than yoy.’ The 
Garonne is estimated to contain perhaps 745.2 The observations of 
Mr. Kverest upon the water of the Ganges show that, during the four 
months of flood in that river, the proportion of earthy matter is z}- 
by weight, or g4, by volume; and that the mean average for the 
year is <4, by weight, or +95; by volume.? According to Mr. Login, 
the waters of the Irrawaddy contain —j,5 by weight of sediment 
during floods, and 755 during a low state of the river.’ In the 
? Humphreys and Abbot, “ Report upon the Physics and Hydraulics of the 
Mississippi,” 1861, p. 147. ; 
2 Ibid. p. 148. 
8 Edin. New Phil. Journ. xviii. p. 102. 
4 « Chemical Geology,” i. p. 122. 
5 Annales des Travaux publics de Belgique, ix. 204. 
® Op. cit. 130. More recent observations by Sir Charles Hartley show that the mean 
proportion of sediment by weight in the Danube water for the ten years from 1862 to 1871 
WAS ip, or (at specific gravity 1°9) x, by volume. a 
7 Payen cited by E. Réclus, “La Terre,” tome i. p. 537. 
* Baumgarten cited by Réclus, op. cit. 
® Journ. Asiatic Society of Calcutta, March, 1832. 
10 Proce. Roy. Soc, Edin, 1857, 

