Section 271. Sinking fund of the city of New York

There is hereby continued
  the fund known as the "sinking fund of the city of New York" which shall
  have for its purpose the amortization and redemption of the principal of
  the  debt of the city of New York incurred on and after the first day of
  January, eighteen hundred ninety-eight, and evidenced by corporate stock
  of the city of New York, excepting that issued to provide for the supply
  of water and that issued  since  the  first  day  of  January,  nineteen
  hundred ten, for rapid transit or rapid transit unification purposes and
  that  issued  since  the  first  day of July nineteen hundred eighty-one
  which is redeemable from the general sinking fund or any  other  sinking
  fund established pursuant to chapter 11-A of this charter.