All deeds, conveyances, leases and other instruments, which
shall be given by the City, and which to be valid in law must be signed,
sealed and acknowledged, shall be signed and acknowledged by the Mayor,
on behalf of the City, and shall be sealed with the common seal of
the City.
Whenever the amount due and payable on any mortgage belonging
to the City is paid to the City Treasurer, he shall certify the same
to the Mayor, who shall thereupon discharge the mortgage, or may assign
the same, and for that purpose the Mayor shall execute and deliver
all necessary deeds and instruments.