The board of commissioners, city manager, or mayor and council of any city of the second or third class may appoint a policeman or policemen to serve at the pleasure of the appointing authority or for a stated period and for stated hours per day, at such compensation as shall be agreed upon: Provided, That such policeman or policemen shall be residents of the county in which said city is located or of an adjoining county of this state: Provided, That in commission cities and mayor-council cities the mayor may make temporary appointments hereunder, but such appointments shall in no case extend beyond the next regular, adjourned or special meeting of the commission or council unless confirmed by a majority of the commission or council. Such policeman shall have the powers of assistant marshal or policeman, after having taken the oath or oaths as required by statute and the giving of bond if a bond be required. All such appointments shall be in writing and a copy filed in the office of the city clerk.