Ring;—The Suspension of Solids in Fluids. 283 
But more strange than this is the fact that the Mississippi, 
.after winding back and forth some 1,100 miles upon a flood 
plain which falls but one inch in 40 rods, delivers in suspension 
into the Gulf more than 11 tons of sediment per second, 2.65 
times heavier than the water and yet drops this load almost at 
once on commingling with the denser water of the sea. Almost 
equally strange is the movement along the bottom of more 
than one additional ton per second of coarser sediment, making 
an aggregate per annum of 392 million tons or more than 
224,000 acre-feet. By what process or mechanism is this enor¬ 
mous load of rock particles sustained so long and borne so far 
across a plain so nearly level and then dropped at once in the 
stiller, heavier salt water? And when the question is solved 
for silt in suspension in water, the solution must also include 
the suspension of dust particles in the atmosphere whose spe¬ 
cific gravity must exceed that of the air itself some 2,049-fold. 
If it is true that solid particles, when immersed in water, 
air or other fluid, become invested with a layer of the suspen¬ 
sion medium and that this is compelled to traved with them, 
such a layer must increase the effective diameter of the particles 
by twice the thickness of the retained layer. It must increase 
the effective volume of the particles in the ratio of the cubes 
of the actual and effective diameters, and it must augment the 
head resistance to motion very nearly in the ratio of the squares 
of the actual and effective diameters. At the same time it 
must materially reduce the effective, specific gravity to a value 
approaching that of the medium of suspension. These being 
true it is clear that when the retained fluid layer has sufficient 
thickness to reduce the specific gravity nearly to that of the 
fluid of suspension its power to float the particles becomes 
relatively very great. 
The diameter of the finest clay particles ranges all the way 
from .001 millimeter down to and below .0003 millimeter, 
and observations indicate that particles of gold just beginning 
to precipitate possess diameters as small as .0002 to .00005 
milimeter; while it is claimed that the diameters of collodial 
particles are as small as .000011 millimeter to .000004 milli- 
