The board may invest any of the surplus or reserve belonging to the fund in such securities and investments as are authorized for investment by savings banks. All such securities or evidences of indebtedness shall be placed in the hands of the State Treasurer who shall be the custodian thereof. He shall collect the principal and interest thereof when due and pay the same into the fund. The State Treasurer shall pay for all such securities or evidences of indebtedness by check issued upon requisition of the secretary. All such payments shall be made only upon delivery of such securities or evidences of indebtedness to the State Treasurer. To all requisitions calling upon the State Treasurer to pay for any securities or evidences of indebtedness there shall be attached a certified copy of the resolution of the board authorizing the investment. The board may, upon like resolution, sell any of such securities.