Some minds improve by travel, others, rather, resemble copper wire, or brass, which get the narrower by going farther.

Hood contrasts two kinds of travelers: those whose intellects broaden through exposure to new places and ideas, and those whose thinking actually constricts. The simile of copper or brass wire evokes the physical process of drawing metal through a die: the farther it is drawn, the thinner it becomes. Applied to character, the image suggests that mere movement and novelty do not guarantee growth; without curiosity, humility, and reflection, travel can harden prejudices, reduce complexity to stereotypes, or turn experience into a narrow set of anecdotes. The aphorism is also a satirical warning against mistaking cosmopolitan mileage for genuine cultivation.