The income of the school fund shall be paid into the general fund of the state treasury, and shall be used for the support of public schools, the payment of salaries of county superintendents and the payment of accrued interest on bonds purchased for the fund, the payment of interest on, and the purchase of, bonds issued locally for school purposes to the extent and within the limits provided by law, and for no other use or purpose whatsoever. The payment of premiums on bonds purchased shall be made out of the investment account.
N.J.S. § 18A:56-15