Читать книгу The Natural History of Pliny (Vol. 1-6) - Pliny the Elder - Страница 68

Table of Contents

What we name Rainbows frequently occur, and are not considered either wonderful or ominous; for they do not predict, with certainty, either rain or fair weather. It is obvious, that the rays of the sun, being projected upon a hollow cloud, the light is thrown back to the sun and is refracted435, and that the variety of colours is produced by a mixture of clouds, air, and fire436. The rainbow is certainly never produced except in the part opposite to the sun, nor even in any other form except that of a semicircle. Nor are they ever formed at night, although Aristotle asserts that they are sometimes seen at that time; he acknowledges, however, that it can only be on the 14th day of the moon437. They are seen in the winter the most frequently, when the days are shortening, after the autumnal equinox438. They are not seen when the days increase again, after the vernal equinox, nor on the longest days, about the summer solstice, but frequently at the winter solstice, when the days are the shortest. When the sun is low they are high, and when the sun is high they are low; they are smaller when in the east or west, but are spread out wider; in the south they are small, but of a greater span. In the summer they are not seen at noon, but after the autumnal equinox at any hour: there are never more than two seen at once.