This act shall apply to any cemetery district, not within any incorporated city, which constitutes a group of four (4) cemeteries and which district is located in a county having a population of not less than two hundred fifty thousand (250,000). If a majority of the qualified electors of said district present at the annual cemetery district meeting shall determine the amount of additional tax necessary to be levied, not to exceed one (1) mill on all the taxable property of the district, for the purchase of additional land for said cemetery and for the improvement thereof, the directors may submit same to the board of county commissioners of such county and said tax shall be levied on all the taxable property of said cemetery district: Provided, Such tax shall not be levied more than two (2) years.