This strange, instinctive act of the natives might form an interesting chapter in optics.
"My Attainment of the Pole"
Frederick A. Cook
But boreal optics play havoc with the eye and the sense of perspective.
"My Attainment of the Pole"
Frederick A. Cook
This is called the entasis of the spire, and belongs to the study of optics in architecture.
"Our Homeland Churches and How to Study Them"
Sidney Heath