The Board of Finance and Revenue shall determine the amount of money necessary for the payment of interest on the bonds and the principal thereof, if any, for the two fiscal years beginning June first, one thousand nine hundred forty-nine, and the times and amounts of such payments, and the amount so determined shall be transferred from the Toll Bridge Fund to the toll bridge sinking fund, and for such purpose, as much of the money in the Toll Bridge Fund as may be necessary is hereby appropriated.