Hello, Since I picked up the plate for Macomb yesterday, I decided to do a little research on copper plate engraving of topographic maps so that when we do a display, I will be able to write something about the technique. I found the following article that might be of interest to other libraries that are getting the plates: Phillips, Hugh A. 1997. Copperplate Engraving for the Production of Topographic Maps at the United States Geological Survey 1890-1953. Meridian no. 11: 5-21. Thought others might find it of interest. Linda Zellmer -- Linda Zellmer Government Information & Data Services Librarian Liaison to Natural & Physical Sciences & Agriculture 415 Malpass Library Macomb, IL 61455 [log in to unmask] Phone: 309-298-2723 Fax: 309-298-2791