LXXVIII. He admits, however, that it is infinitely divisible, and that its concretions take place over the whole of it, as he explains in the third book of his Physics, and not according to any circumference or juxtaposition; for a little wine when thrown into the sea, will keep its distinctness for a brief period, but after that, will be lost. LXXIX. They also say that there are some Dæmones, who have a sympathy with mankind, being surveyors of all human affairs; and that there are heroes, which are the souls of virtuous men, which have left their bodies. LXXX. Of the things which take place in the air, they say that winter is the effect of the air above the earth being cooled, on account of the retirement of the sun to a greater distance than before; that spring is a good temperature of the air, according to the sun’s approach towards us; that summer is the effect of the air above the earth being warmed by the approach of the sun towards the north; that autumn is caused by the retreat of the sun from us … to those places from which they flow.[92] LXXXI. And the cause of the production of the winds is the sun, which evaporates the clouds. Moreover, the rainbow is the reflexion of the sun’s rays from the moist clouds, or, as Posidonius explains it in his Meteorology, a manifestation of a section of the sun or moon, in a cloud suffused with dew; being hollow and continuous to the sight; so that it is reflected as in a mirror, under the appearance of a circle. And that comets, and bearded stars, and meteors, are fires which have an existence when the density of the air is borne upwards to the regions of the æther.