From Houghton Mifflin Word Origins:
(Origin 1684) Describing a farmhouse in a snowstorm in the 1770s, Hector St. John de Crèvecoeur mentions "an enormous back-log, without which a fire is supposed to be imperfectly made and to be devoid of heat." A thorough description of a fire properly laid is found in Knickerbocker Magazine for February 1852: "The 'log' has been placed; the 'back-log' has surmounted it; the 'top-stick' crowns the apex; the 'forestick' rests against the 'and-irons'; and the intermediate 'cob-house' of timber, fired by the faithful 'kindling-wood,' is all ablaze, and roaring up the chimney."
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