We observe much of the world through the eyes. Choose a type of observation that cannot be perceived with the eyes. The force field of a magnet radiating out in all directions. A magnetic compass pointing north. A magnet picking up a steel paper clip. A magnet having no effect on a plastic paper clip.

Thats where they was ported and the fields that noone really knew much about needed tended, so they put slaves out there do free work and huge profits and so on the north decided to hold its own and was more different way of survival did not have same climate conditions to afford protecting slaves from winter so expenses be diff from south