them from each other are not distinguished, their mere distance from the observer prevents discrimination of them. By and by instead of individual drops there is seen a single blurred mass that contains them all. Aristotle agrees with this opinion. His words are: Beams of light are reflected by sight from every smooth surface. Now, nothing is 8 smoother than water and air. Therefore, our sight is reflected back on us from thick air. Indeed, where the vision is dull and feeble, the slightest stroke of air checks it. Some people suffer from an affection which causes them to think that they are meeting their own image, and they see everywhere the reflection of themselves. And why? Because the power of their eyes is so weak that it cannot overcome the resistance of even the nearest layer of the atmosphere. What dense air effects in ordinary cases, any kind of air is sufficient to effect in the cases referred to by Aristotle. For whatever the nature of the air, it is strong enough to defeat weak sight. Now, much more is our vision reflected upon us by water because it is denser and cannot be pierced; it absolutely stops the rays from our eyes, and turns them back to the source whence they proceeded. Well then, when there are numerous 9 raindrops, they are just so many mirrors. But on account of their smallness they express the sun’s colour without distinct shape. By and by when the same colour is reflected in the countless drops that fall without intermission, it begins to take on the appearance not of numerous images with intervals between, but of a single, long, uninterrupted image.