The proceeds of that portion of lot No. 14, in square No. 263, which was authorized to be sold by an Act of Congress dated June 4, 1872, shall be invested by the authorities of the District in another lot or part of a lot in the City of Washington, and in improvements thereon; and the property so purchased shall be used for the purpose of the public schools, and for no other purpose.
D.C. Code § 38-405