A period of about twelve years measured the beat of the pendulum. After the Declaration of Independence, twelve years had been needed to create an efficient Constitution; another twelve years of energy brought a reaction against the government then created; a third period of twelve years was ending in a sweep toward still greater energy; and already a child could calculate the result of a few more such returns.

A History of the United States of America During the First Administration of James Madison (1890), Vol. II, Ch. VI: Meeting of the Twelfth Congress; 1921 edition, p. 123