From the 1904 transitional period, soon after the Universal Talking Machine had been purchased by Victor’s Eldridge R. Johnson but was still marketing its own (pre-Victor) phonographs. The “Zonophone Company” name on the inner panel was used only briefly, dating this piece to fairly early in the year. (Many thanks, Jorge – I owe you a finder’s fee!)
Mainspring’s American Zonophone discographical data — now including all general-catalog 7″, 9″, 10″, 11″, and 12″ pressings — can be found on the free Discography of American Historical Recordings website, hosted by the University of California–Santa Barbara. If you prefer books, Bill Bryant’s 10″ / 12″ American Zonophone discography is still available on the Mainspring Press website at special close-out pricing (but quantities are very limited).