They had a very efficient system of quickly spreading important
news by relays of special couriers, who took the news to the
first stations or tribes in different directions, where others
took the verbal dispatches and ran to the next station, and so
on, so that all tribes within an area of a hundred miles would
get the good or bad tidings within a few hours. In this manner
important communication was kept up between the different tribes.
They also had well organized signal systems, by fires in the
night and smoke by day, on high points of observation--variations
in the lights (either steady, bright or flashing) indicating
somewhat the character of the tidings thus given.