Quote:
They are not stamps at all.
That was true, but not if Azariah Harris had had his way in 1879. He proposed issuing a coupon bond with pages of three cent coupons/stamps which would become valid for postage day by day as the bond matured.

Each coupon had the year date and a blank space for adding the date of the month and day. Unfortunately too many things could go wrong with such an arrangement if the bondholder held it after maturity or cashed it in early. Applying all the dates might have proved cumbersome and time consuming, and verifying the stamps once applied to mail matter would have been an invitation to do-it-yourself postage.
The idea didn't fly.