Words and terms have, to different minds, various significations; and weoften find definitions changing in the progress of events. Bailey sayslearning is "skill in languages or sciences." To this, Walker adds whathe calls "literature," and "skill in anything, good or bad." Dr. Websterenlarges the meaning of the word still more, and says, "Learning is theknowledge of principles or facts received by instruction or study;acquired knowledge or ideas in any branch of science or literature;erudition; literature; science; knowledge acquired by experience,experiment, or observation." Milton gives us a rhetorical definition ina negative form, which is of equal value, at least, with any authorityyet cited. "And though a linguist," says Milton, "should pride himselfto have all the tongues that Babel cleft t