That the twenty-fifth day of May and the thirtieth day of September in each year be and hereby are set apart and designated as “Memory Days”; said days to be used for the purpose of improving and beautifying the various cemeteries throughout the state and of the graves therein; that all may thus show forth on these days by these appropriate acts a loving and tender remembrance for the dead: Provided, however, That if either of the days herein designated shall fall on Sunday, the next Monday following shall be deemed “Memory Day” for all or any of the purposes of this act.