When and as often as the Board or Vestry are enabled and think it expedient to pay off One or more of the said Mortgages, they shall cause the several Numbers of such Mortgages to be written upon distinct Slips of Paper of an equal Size, and all such Slips shall be rolled or folded up in a similar Form, and put in a Box, and the Clerk of the said Board or Vestry shall, at a Meeting of the Board or Vestry, draw separately out of the said Box One of the said Slips, and thereupon the Mortgage corresponding with the Number so drawn shall be paid off by the Board or Vestry; and after every such Ballot the Board or Vestry shall cause a , Notice, signed by the Clerk, to be given to the Person entitled to the Money to be paid off, and such Notice shall express the Principal Sum proposed to be paid off, and that the same will be paid, together with the Interest due thereon, at a Place to be specified in such Notice, at the Expiration of Six Months from the Date of giving such Notice; and at the Expiration of such Period the Interest of the Principal Money to be paid off shall cease, unless such Principal Money and Interest be not paid, on Demand, pursuant to such Notice; but such Principal Money, and the Interest thereof to the End of the said Six Months, shall nevertheless be payable, on Demand.