| http://www.w3.org/ns/prov#value | - The edge of the disk is appropriately thin and is preferably beveled to essentially a knife edge as shown in FIG. 2 so that when greased with petroleum jelly or other such amorphous grease or oil and coated with a powder sample, the adhering rim of powder (9) is of narrow dimensions, suitably about 0.05 mm in thickness.
|
