The 1850 map shows how the european powers had been trading and colonizing the what?

This shift in trading patterns entailed in the long run changes in colonial policy ... However disruptive these changes may have been to the societies of Africa, South ... the 19th century were distinguished by the spread of the colonizing powers, or of German, and Irish—composed the largest group of migrants in the 1850s.

in 1897, pershing became a tactical officer at west point, and that's where he was given the nickname "black jack." pershing's first name is "john," for which "jack" is a nickname, and he was a white man who commanded black troops. hence "black jack".