All deeds and other legal documents made, given or entered into
by the City requiring a seal shall be sealed with the City Seal and
shall be signed and acknowledged in behalf of the City by the Mayor.
All motor vehicles owned by the City and under the charge of
any department thereof shall have affixed on the outside thereof a
facsimile of the City Seal not less than eight inches in diameter
and shall also have so designated, in letters not less than two inches
in height, the name of such department.