Experiments were conducted according to the following procedure: 7 cc. of
the material to be tested was introduced into each of several celluloid centrifuge
tubes. This material was centrifuged at room temperature for a period of 4 hours,
comprising an acceleration period of approximately 30 minutes, 3 hours at 27,300
R.P.M., and a deceleration time of approximately 30 minutes. The tubes were
then removed from the centrifuge with a minimum of agitation and placed, one
at a time, in the sampling instrument described above. The valve on the plunger
was opened and the celluloid tuberaised until thetip of theplunger just contacted