i 
{ 
E. W. Hilgard—Silt analysis of Soils and Clays. 291 
ways, Even when a central core is introduced in the axis of 
the conical tube, so as to force up the current close to the sides, 
return currents will form, and with them these miniature 
avalanches. 
Nobel’s apparatus, or those of Schultze and Fresenius; or even 
the later ones of Miiller, and of Schéne ;* in all of which the 
e 
Fig. 1 of the diagram shows, on a somewhat enlarged scale, 
the instrument I have devised, with this end in view. 1! 
of 34°8™™ inside diameter at its 
may be imparted by clockwork, or a turbine. ries 
8 the whirling agitation caused by the rotation 0 the 
dasher would gradually communicate itself to the whole column 
: Pee having been unable to obtain, for reference, the original papers of 
the 
aden r authors; the most thorough, probably, heretofore published on this 
