Lives and Opinions of Eminent Philosophers

​And by the friction of clouds that have taken on freezing, this accumulation of snow could receive a rebound. And snow admits of being brought to completion in many other ways as well. "Dew is brought to completion both by the gathering together from the air of particles of such a kind as become productive of such moisture; and by an upward conveyance either from moist regions or from those possessing water—in which regions dew is most of all brought to completion—these particles then receiving a gathering into the same place, effecting moisture, and having an onward conveyance back toward the lower regions, just as similar phenomena are likewise observed to be brought to completion in many instances among us.

​And hoarfrost is brought to completion not differently from dew, when particles of such a kind take on a certain qualitative freezing on account of a certain encirclement of cold air. "Ice is brought to completion both by the squeezing out of the round conformation from the water and the compression together of the scalene and acute-angled shapes existing in the water; and by the adcretion from outside of particles of such a kind, which having been driven together have brought about freezing for the water, having squeezed out some quantity of the round particles. "The rainbow arises from the irradiation by the sun against watery air; or by a peculiar conjunction of light and air, which will produce the peculiarities of these colors either all together or of a single form; from which, as it shines back again, the bordering parts of the air will receive this coloration, such as we observe, by the irradiation against the parts.

​And this visual appearance of roundness comes to be either because the distance is observed by the sight as equal on all sides, or because the atoms in the air, or those borne away from the sun in the clouds, taking on such a compression, this aggregate is deposited into a certain circumference. "A halo around the moon arises both when air is borne toward the moon from all sides, or evenly checks the currents borne away from it to such an extent as to cause this cloudy formation to stand around in a circle and not disperse at all; or also when it checks the surrounding air of the moon symmetrically on all sides so as to cause it to stand around as a round and coarse-particled ring around it.

​This occurs in certain parts either because some current forced its way from outside, or because heat took possession of suitable pores so as to bring this about. "Comets arise either when fire is compacted in certain places at certain times in the upper air through an encirclement taking place, or because the heaven maintains a certain peculiar motion above us at certain intervals, so that such stars appear, or because they themselves shoot forth at certain times on account of some encirclement and come into our regions and become conspicuous. And the disappearance of these occurs through the causes opposite to these.

​Certain stars happen to revolve in the same place not only because this part of the cosmos stands still, around which the rest revolves, as some claim, but also because an eddy of air encircling it stands around it, which acts to hinder its traversing about as the others do; or also because suitable matter does not exist for them adjacent to them, but does exist in this place in which they are observed to lie. And it is possible for this to be brought to completion in many other ways, if one is able to infer what is in agreement with the phenomena. That certain of the stars wander—if it happens that they employ motions in this way—and that certain move uniformly [is likewise explained by various causes].