290 E W. Hilgard—Silt analysis of Soils and Clays. 
elutriator (inverted) cone. The smallness of the lower orifice 
of the latter renders the current there sufficiently rapid to pre- 
vent any portion of the sediment concerned at a given velocity 
from falling into the relay; and whatever sediment does aceu- 
The obvious remedy was to adapt to the wide (upper) end of 
the eaercieiy: tube a cylindrical portion, as shown in the dia- 
factory, and apparently inconsistent, especially as regards the 
finer sediments 
the elutriating vessel, the same phenomenon recurred ; an 
repeated “cohobation,” I finally succeeded in getting about 
four-fifths of the whole quantity of sediment settled into the 
relay reservoir | 
On examination I found this coarse sediment to consist of 
flocculent aggregates of from a few to as many as 30 fine par 
ticles of siliceous silt. When violently shaken, they part com” 
pany and become diffused, singly, through the liquid, which 
then presents simply a general turbidity; the particles then 
