Corporations were really different back then and were only created strictly for their purpose and rarely allowed to be created. Like the NYC water system is one of those old corporations. Now we can create a corp in another state for practically no money.
Michael Meyer's recent book Benjamin Franklin's Last Bet details the origin and fate of his bequests to Philadelphia and Boston.
The funds were intended to be loaned to aspiring tradesmen, who would repay their loans with interest over ten years. The two cities would receive some of the funds for public works after 100 years and the balance after 200 years. Both cities failed to manage the funds as Franklin intended.
From Meyer's book, I learned more about Benjamin Franklin's life, about the challenges of fund management, and about the difficulty of controlling events from beyond the grave.