| An object appears nearer: |
An Object appears more distant: |
| When looking over water, or a large ravine or depression |
When looking over rolling country |
| When the sun is behind the observer |
When the sun is in front of the observer |
| When the air is clear, especially after a rain |
When the air is not clear, due to fog, smoke, rain, etc. |
| When the background is in contrast with the color of the object |
When the background is similar in color to that of the object. |
| On hot days, esepecially when the ground is moist, an object
will appear more distant if observed from a kneeling of sitting position. This
is due to refraction and heat radiation. Sometimes this refraction renders the
object invisible. |
From: Notes on Training Field Artillery Details by Captain Robert M.Danford
and Captain Onorio Moretti. New Haven: Yale University Press (1917); page
148-149