15. In any legal proceeding, whether civil, criminal or otherwise, a copy of a declaration attested in the manner prescribed in section 14 and a copy of the newspaper having the name of a person printed thereon as its editor, shall be sufficient evidence, unless the contrary is proved, as against the person whose name has been subscribed to such declaration, or printed on such newspaper, as the case may be, that the said person was printer or publisher, or printer and publisher (according as the words of the said declaration may be) of every portion of every newspaper whereof the title corresponds with the title of the newspaper mentioned in the declaration or the editor of every portion of that issue of the newspaper of which a copy is produced.