riddle - separate with a riddle, as grain from chaff screen sift, sieve, strain - separate by passing through a sieve or other straining device to separate out coarser elements; sift the flour
Causing the Civil War. Historically, textbooks have taught that incompatibility between northern and southern economies caused the Civil War. The industrial revolution in the North, during the first few decades of the 19th century, brought about a machine age economy that relied on wage laborers, not slaves.
Events leading to. the American Civil War. Historians debating the origins of the American Civil War focus on the reasons why seven Southern states declared their secession from the United States (the Union), why they united to form the Confederate States of America (or simply known as the Confederacy), and why the North refused to let them go.