This is getting interesting! I found out from the friendly librarian in Springfield, IL that Brown University, in Rhode Island, has the largest collection of EE letters going. So, I guess I have to go to Providence, RI at some point.
I had planned to try to go to Springfield this summer, and may still be able to afford it, if the checks for a variety of things I have done come through.
DONATIONS GRACIOUSLY ACCEPTED, btw.
The way this seems to be going, I will become the world's greatest expert on Colonel Ellsworth. He is my book, most of my Master's thesis (I hope!) and now I may have to do a book on his letters.
That way, fifty years from now, when the next writer falls for EE, there will be a lot more out there.