When light of any kind shines through a dense medium it appears larger, or rather gives a greater glare, at a given distance than when it is seen through a lighter medium. This is more remarkable when the medium holds aqueous particles or vapor in solution, as in a damp or foggy atmosphere. You can see this by standing within a few yards of a street lamp, and noticing the size of the light; on going away to many times the distance, the light upon the atmosphere …