He is not a true man of science who does not bring some sympathy to his studies, and expect to learn something by behavior as well as by application. It is childish to rest in the discovery of mere coincidences, or of partial and extraneous laws. The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one. Mathematics should be mixed not only with physics but with ethics; that is mixed mathematics. The fact which interests us most is the life of the naturalist. The purest science is still biographical.
Books, not which afford us a cowering enjoyment, but in which each thought is of unusual daring; such as an idle man cannot read, and a timid one would not be entertained by, which even make us dangerous to existing institution - such call I good books.