a coign of vantage

a coign of vantage

A beneficial spot or position, especially for viewing something. "Coign" is a variant spelling of "quoin," the outside corner of a building or wall. My office affords me a fine coign of vantage, as I can watch everyone on the floor without them knowing,
See also: coign, of, vantage
References in classic literature ?
If one has a taste for that kind of thing the merest starting-point becomes a coign of vantage, and then by a series of logically deducted verisimilitudes one arrives at truth--or very near the truth--as near as any circumstantial evidence can do.