I've found one of the most difficult things to transcribe on letters is signatures. For those who are interested, I would like to share how I've been finding the names for the signatures on James A. Garfield correspondence.
PART 1: Download the index to the James A. Garfield Papers
1) Go to this URL https://www.loc.gov/item/73009594
2) Find "Download PDF (Complete"). Click "Go"
3) If prompted, click "Save file"
4) Look in your downloads folder. There should be a file called service-gdc-gdclccn-73-00-95-94-73009594-73009594.pdf. This is the correspondence index.
5) If you don't have it already, download Adobe Acrobat Reader (free) https://get.adobe.com/reader/ This program will allow you to open and read the file.
PART 2: Look up signatures
1) Find the volume number of the volume you are working in. If you don't know what the volume number is, hover over the last link in the header above your document. The volume number is contained in that link. Example: https://imgur.com/E0uyxaJ
2) Find the sequence number. This is the hand-written number on the top/bottom/middle of the page. Example: https://imgur.com/XaqfTBt Ignore any crossed-out numbers and ignore any typewritten numbers.
3) Search for the combination of volume/sequence number in the index. Pad both volume and sequence numbers to three digits with leading zeroes. Put a slash between the volume number and the sequence number: https://imgur.com/fmsq5Rd
If on rare occasion this doesn't work, you can also search by date (pay attention to the date format used in the pdf document when searching).
By using this method I've been able to find at least 99 percent of the signatures on Garfield letters I've worked on. I hope this can be helpful to someone else.
