THE HORIZON.

Auckland Star, Volume LXXI, Issue 205, 29 August 1940, Page 11

THE HORIZON.

HOW FAR CAN ONE SEE ? How far away is the horizon is a ques ' .11 that often crops up. The distance which one can see varies with the height of the spectator. The greatest distance at which an object on the surface of the sea, or of a level plain, can be seen by a person whose eyes are at a height of sft from the same level is 2.9 miles. The distance which can be seen from a height of Oft is just over. 3.2.3 miles. At a height of 20ft the range is increased to nearly six miles. . £

An approximate rate fpr finding the range of vision for small heights is to increase the square root of the number of feet that the eye is above the level surface by a third of itself, the result being the distance of the horizon in miles. , Results from this way of calculation are slightly in excess of those in the table below, which is computed by a more precise formula. The table may be used conversely to show the distance of an object of given height that is just visible from a point on the surface of the ea-rth or sea. Refraction is taken into account both in the approximate rule and in the table, which is as follows::—

Height. Pange. "Height. Range. 5ft 2.!> miles 2.000ft 5S.9 miles 20ft Ti.«j miles 3.000ft 72.1 miles SOft 9.3 miles 4,000ft 83.3 miles 100ft 13.2 miles 5,000ft 5)3.1-miles 500ft 20.5 miles 20,000ft 186.2 miles 1,000ft 41.6 miles