A ray of light falling slantingly upon a window, in passing through it is slightly brought to the perpendicular; and if it then falls upon the surface of water, it is still further brought to the perpendicular in passing through the water.
475. Is light refracted in passing from a dense medium to a thinner one?
It is; but the direction of the refraction is just the opposite to the instance just given; a ray of light passing through water into air, does not take a more perpendicular course, but becomes more oblique.
Fig. 11.
476. Why, if a rod or a spoon be set in an empty basin, will it appear straight, or of its usual shape?
Because the rays of light that are reflected from it all pass through the same medium, the air.
477. Why if water be poured into the basin will the rod or spoon appear bent?
Because the rays of light that pass through the water are reflected in a different degree to those that pass through the air.