John C. Fremont. Explorer
of the Rocky Mountains, the "Pathfinder", Senator from California, free
frank "Free J.C. Fremont/U.S. Senate" on cover addressed in his hand
to Charles F. Mayer in Baltimore Md., red "Panama" straightline
handstamp and "Steam Ship 30 Cts" in circle with rate crossed out in
blue pen and matching "Free"VERY FINE. ONE OF TWO RECORDED COVERS FRANKED BY FREMONT AND HANDSTAMPED WITH THE "PANAMA" STRAIGHTLINE AT THE UNITED STATES POSTAL AGENCY IN PANAMA.
Charles F. Mayer was a member of the Konig family and principal in the Baltimore firm of Mayer & Konig, a prominent importer and dealer in fancy goods. A similar cover (except bearing the "Steam/Ship" marking in two lines) was offered in our 1996 Rarities of the World sale and realized $7,500 hammer. (Image)
Alpheus Felch. Free frank
"Free A. Felch" as Senator from Michigan on blue cover from
California to Michigan via New York, clear strike of red boxed "Via
Nicaragua Ahead of the Mails" handstamp, also strikes of "Steam/Ship"
and "Free" handstamps, minor wear, Very Fine, scarce usage, probably sent
in early 1853, ex Knapp, Wiltsee and Grunin
(Image) 
James William Denver.
Commissioner of Indian Affairs, three covers addressed to him and sent free
of charge under his franking privilege, including one with designation
"Via Tehauntepec", two sent to Washington D.C., last sent to Kansas
Terr., fresh and Very Fine (Image)