Frank J. Wilstach, comp. A Dictionary of Similes. 1916.
Learning
Learning is like a lark, that can mount, and sing, and please herself, and nothing else; but may know that she holdeth as well as the hawk, that can soar aloft, and can also descend and strike upon the prey. Francis Bacon
Learning is like mercury, one of the most powerful and excellent things in the world in skillful hands; in unskillful, the most mischievous. Alexander Pope