Section 15
SEC. 15. At any time after twenty years from the date of this Act, the Government of the Philippine Islands or any political subdivision thereof to which the right may be assigned, may purchase, and the grantee shall sell thereto all of its plant, poles, wires, buildings, real estate, and all other property used in the enjoyment of this franchise, at a valuation based in part upon the net earnings of the grantee and the actual value on the books, making the proper deduction for depreciation, in part on the present cost of reproduction of said property less depreciation, and in part on the original cost thereof less depreciation, the valuation to be determined, after hearing evidence, by the Supreme Court of the Islands, sitting as a board of arbitrators, whose decision, by a majority of the members thereof, shall be final.