When a solid has a hole in it, a plane cross section and thus a slice have a hole in them. The volume of a washer slice is equal to the volume of the disk slice (slice as if it had no hole) minus that of the hole.
Names should be an alphanumeric symbol that is stamped on the respective disk marker. The name that appears on the control point for publication purposes should be the same as the name that actually appears on the mark. Old stations that are reestablished will be given the previous name with...