The said Trustees may:sell all the real estate situate in the City of Baltimore, heretofore purchased by the Trustees of the McDonogh Educational Fund and Institute; and invest the proceeds in real estate in the vicinity of Baltimore, of such dimensions and at such distance from said City as to them may seem most judicious for the purpose of establishing a school farm, as directed under the will of the said John McDonogh, which real estate shall be in fee simple and adapted to agricultural purposes. In addition to the proceeds arising from the sale of the real estate aforesaid, the said Trustees are authorized to use all the interest which may accrue from the investment of the sum of $500,000, in the purchase of said real estate and erection of such buildings and improvements thereon as may be necessary for such school farm, until the purchase money of the land and the erection of said buildings shall have been fully paid. Provided, nevertheless, that the principal sum of said fund shall at no time be less than $500,000, which the said Trustees are required to have well secured at all times. City Code, 1879, art. 34, §5 1893, art. 34, §5 1927, art. 26, §5 1950, art. 20, §4 1966, art. 1, §63 1976/83, art. 1, §58 Ord. 1868-068