Suitable buildings as hereinafter provided, and an area of ground appurtenant thereto, of not less than ten acres in one tract, the whole of which shall be prepared and used as a place for gymnastic exercises and healthful recreation by students, except so much thereof as shall be necessarily occupied by the buildings, botanical and other gardens, and such other purposes as shall be plainly promotive of the great objects of the institution.
24 P.S. § 1773