Procedure when service cannot be effected as before provided

Procedure when service cannot be effected as before provided.-If service in the manner mentioned in section 69 and 70 cannot by the exercise of due diligence be effected, the serving officer shall affix one of the duplicates of the summons to some conspicuous part of the house or home-stead in which the person summoned ordinarily residues; and thereupon the summons shall be deemed to have been duly served.