A strong mind sees things in their true proportions; a weak one views them through a magnifying medium, which, like the microscope, makes an elephant of a flea: magnifies all little objects, but cannot receive great ones.
Notes from Wikiquote
Sometimes quoted as: "A weak mind is like a microscope, which magnifies trifling things but cannot receive great ones." The first publication of this form yet located is in a section of proverbs called "Diamond Dust" in Eliza Cook's Journal, No. 98 (15 March 1851)