Vision of a drop

It will now be useful to give an answer to the following question: from what points is a given drop seen and how is it seen from each of them?

For the reasons of symmetry mentioned above, the solutions are obtained from the case of the plane, applying all the aforementioned rotations. For example, for the red color there were two bright directions for the rays \(C_{3}\) which will now correspond in space to a conical surface with a vertex in the center of the drop and the same half-aperture \((42,5^ {\circ})\), of revolution around the straight line joining the center of the drop to the center of the sun. It is for observers situated on such a conical surface, and only for those, that the rays \(C_{3}\) emitted from that droplet are seen to be bright red in color. Similarly for the rays \(C_{3}\) of other colors, now on conical surfaces within the red, as shown in the following figures. The second is an enlargement of a part of the first, only representing seven colors and omitting all the intermediate ones for clarity.

For the rays \(C_{4}\), something similar works, but now with cones outside the first ones and repeating the colors, but in inverted order. The following figures give an idea of the whole and show a detail.