Section 4
SEC. 4. A sinking fund is created for the payment of the bonds issued under the provisions of this Act, in such a manner that the total amount thereof at each annual due date of the bonds issued shall be equal to the total of an annuity of such a sum, for each million pesos of bonds outstanding, as with interest at the rate of three and one-half per centum per annum, shall be sufficient to retire said bonds at maturity. Said fund shall be under the custody of the Treasurer of the Philippines who shall invest the same in such manner as the Secretary of Finance may approve, in accordance with the provisions of Act Numbered Three thousand and fourteen which governs the investment of sinking funds, shall charge all the expenses of such investment to said sinking fund, and shall credit to the same the interest on investments and other income belonging to it.