No corporation or limited partnership association organized for manufacturing purposes, whose manufacturing plant or plants, in whole or in part, are or may be leased to another corporation, limited partnership, individual or individuals, shall, by reason of such leasing, be deprived of the exemption from taxation upon its capital stock or any part thereof, to which under existing laws it would be entitled if such lease had not been made. All acts or parts of acts inconsistent herewith are hereby repealed.
72 P.S. § 1893