Читать книгу The Circle of Knowledge: A Classified, Simplified, Visualized Book of Answers - Various - Страница 155

Rainbows are arches of prismatic colors, formed by the reflection of rays of light from within drops of water. The rays, which are refracted in entering the drops, are reflected from their posterior surfaces, and again refracted as they re-enter the air, the colors being separated by their unequal refrangibility.

Halos and coronas are circles of prismatic colors which, in certain states of the atmosphere, surround the Sun and the Moon.

Halos are supposed to be occasioned by the presence, in the atmosphere, of small ice crystals which act as minute prisms, decomposing and refracting the light which passes through them.

Coronas are seen when a light mist is floating in the air, and are supposed to be formed by reflection from the external surface of the globules of vapor.