Many will probably ask: how can divers working in their spacesuits, 't see anything under water, if our eyes in the water almost does not refract the rays of light? After all, diving helmets are supplied flat and not convex glass... Then, could the passengers Jules-vernova Nautilus to admire through the window of his underwater cabins landscape of the underwater world?
We are facing a new question, however, it is easy to answer. The answer will become clear if we take into account that when we are under water without diving suit, the water is directly adjacent to our eye; same in a diving helmet (or in the cabin of the Nautilus eye is separated from the water layer of air (and glass). This significantly changes the whole thing. Rays of light leaving the water passing through the glass, get first in the air and only here get into the eyes. Falling out of the water on plane-parallel glass at any angle, the rays, according to the laws of optics, out of the glass without changing direction; but then, at the transition from air in the eye, the rays, of course, are refracted, and the eyes under these conditions, acts in the same way as on land. In this lies the secret of the Smoot us contradictions. The best illustration of it is that we are quite well-see fish swimming in the aquarium.