As generation followed generation, the 100 or so outstanding notes with a combined face value of $66,000 have all but been forgotten, aside from an occasional newspaper account. But the Bank of New York Mellon, which administers the bonds for the city, has a record of the 39 bondholders who own them and has been mailing them interest checks twice a year.

Two of the active bonds are in the Museum of the City of New York, which has held them since 2001. They were a gift from Mr. Lebenthal, who had held them for 30 years after buying them through a broker from the Poughkeepsie Rural Cemetery. The cemetery had gotten them from Martha B. Jones in 1914. She took possession of them in 1881.

City officials declined to identify the other bondholders, citing privacy concerns, so it is hard to say how they have kept track of a flimsy piece of paper that would not pay off for several lifetimes.

But the difficulty of the task can be seen in the fact that city officials can no longer locate the heavy bound ledger in which, in neat Victorian script, their predecessors kept track of the bonds by serial number and purchaser name.

The ledger, which the city displayed as recently as 1980, became superfluous when record keeping for the bonds was transferred to computers.

Not all the ledgers are missing: “We do have some dating back to the early 1900s,” Regina Fleszar, the director of investor relations for the city comptroller, wrote in an e-mail message. “But at the moment cannot find the one containing the 1868 bonds.”

Image Credit... The New York Times

What is known about the bonds is that they were the handiwork of a wily 19th-century financier and a couple of cash-strapped towns that schemed to implement a public work at the expense of their wealthy, gleaming neighbor.