Mike Gunderloy came through, of course, on the ditto sheet and mimeograph topic. He points to the Dead Media Project wherein lies an interesting discussion on “The Difference between Mimeograph, Hectograph, and Spirit Duplication.” It actually lists sources in case you want to delve further into the early magic of duplication. Meanwhile I found a page on antique copying machines, including drawings and photos, at the nifty Early Office Museum.