The vibrating-plate viscometer enable use to measure the change in viscosity of slurris (clay slips) as it sets up in the plaster mold. The phenomenon of the dehydration of slurries by the plaster mold is similar to that is the flow of fluid through packings. We studied the relation of setting time t and x the distance from wall. It is seen that on a log-log chart the experimental points fall close to a straigt lime. We obtained an equation as follows :
log t= 2 logx-A (A= constant)
When t is the setting time of slurries and x is the distance from wall of the plaster mold