I've tried to copy/scan but it is not coming out readable. I don't want to try again. The note was found folded and I don't want the flatten it again. I did reread and the word "fire" looks like the second letter is "r" not "i". So that sentence reads, "Pass Mr. Chas a. Trowbridge to these ???? and return, fr??, over the military railroad from Washington City."

There is a name then a signature. Looking more closely there are two initials, I can't believe I didn't realize but the what I thought was an "N" is a "U" and the "L" is and
"S". I think it's US Grant!!!!

I wouldn't had thought to look at each letter on the note if you had not mention what you did about the word "fire" that was one word I was certain of.