Illustrated as Figure VI in Russ Logan's article about off-center half dollars in Volume 9, Issue 3 of the Journal. Russell Logan was not only a collector, but was a student of the early coinage. He considered error coins to be important windows into the technology of our first Mint. Many of the coins in his collection were struck off-center, and the present offering may be the single largest gathering of these coins ever to be sold at public auction. His article about the study and descriptive methodolgy for these off-center coins was well-thought out and very well written. He used calculus to determine the magnitude of off-centering, and prepared a simple chart to provide the theoretical percentage off-center of any coin, based on two simple measurements. In the course of his article, he provided all of the necessary details for describing an off-center coin, including the magnitude, direction, flatness (or lack thereof), doubling of strike, and edge description.