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
Causes of the Civil War: Abolitionism. The issue of slavery was further heightened by the rise of the Abolitionist movement in the 1820s and 1830s. Beginning in the North, adherents believed that slavery was morally wrong rather than simply a social evil.
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. At the same time, the warmer Southern states continued to rely on slaves for their farming economy and cotton production.