The great city can teach something that no university by itself can altogether impart: a vivid sense of the largeness of human brotherhood, a vivid sense of man's increasing obligation to man; a vivid sense of our absolute dependence on one another.

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In 1902 Low resigned as president of the university to become the second mayor of the newly consolidated City of New York. McClellan Jr. Low & Brothers which had been founded by his father in New York.

He was a leading municipal reformer during the Progressive Era.