Section 4-102. Loss of certain lands; by reversion

The lands situate in the
  county of Westchester which were taken by the city, by virtue of the act
  entitled "An act to provide for supplying the city of New York with pure
  and wholesome water" passed May second,  eighteen  hundred  thirty-four,
  shall  be  held  and appropriated by the city for the use and purpose of
  introducing water into the city, and for purposes  necessarily  incident
  thereto,  and  for  no other uses or purposes whatever. In case the city
  should use any of such lands situate in the county  of  Westchester  for
  purposes  other  than  in  this  section permitted, or in case such land
  should not be required for the purpose of  introducing  water  into  the
  city,  such  lands  so improperly used, or not so required, shall become
  vested in the individual from whom such city obtained it,  as  full  and
  perfectly  as  though  such act had never been enacted, upon repaying to
  the city the amount originally paid for the same, after  deducting  from
  such  amount  the  damages sustained by such individual by reason of any
  alteration or work which the city may have made upon such land.