Whenever any grant, gift, donation or legacy of real or personal property has been or shall be, directly or indirectly, made to or for the use of any public school district or attendance center and the deed, will or other instrument by which such grant, gift, donation, or legacy is made declares in terms or in substance that such property shall be held, managed, improved and invested or otherwise disposed of for the use and benefit of the public schools in such district or an individual attendance center, the title to such property shall be vested in the school board of such district for use in whatever manner the board shall choose and shall be held, managed, improved, invested or disposed of by such board in such manner as the board, in its discretion, sees fit; provided, however, when the person making such a grant, gift, donation, or legacy expresses in the instrument by which it was made an intention that it shall be used for a certain purpose, the school board shall promote and carry into effect such intention until the board determines in its discretion that it is no longer possible, practical or prudent to do so.
     This Section does not apply in any case where the deed, will or other instrument effectively vests the title and control of such property in a trustee or grantee named in such instrument unless the trustee or grantee is incapable of taking or administering the trust, or refuses or fails to accept the trust, in which case the title and control thereof shall vest as provided in the preceding paragraph.
     This Section does not validate any legacy which but for this enactment would have been invalid.