There is a logarithmic relation between visibility and the graduation of “Wigand Sichtmesser, ” and the curve showing this relation changes its shape according to (a) the weather condition, (b) the distance and (c) the form of the object. In this report the author constructed the “visibility table” after his observations under various conditions such as:
(a) (i) clear, (ii) mist or haze, (iii) rain of fog.
(b) (i) object in the distance, (ii) object situating near.
(c) (i) object visible cle_??_rly, (ii) object visible dimly.