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It is now high time that I ran over the other varieties of celestial fires, whose forms are diverse one from the other. Sometimes there is a shooting star, sometimes there are glowing lights, which are occasionally stationary, sticking to one spot, and at times able to rush through the air. Several species of these may be observed. There are, for example, Bothynae (cave-like meteors) when within an outer circle there is a blazing gulf in the sky like a circular grotto excavated in it. Then there are Pithitae (barrel-shaped meteors) when a vast circular mass of fire like a cask either rushes through the sky, or blazes away in one spot. There are Chasmata (chasms), too, when there is a subsidence of some portion of the heavens, which sends out hissing flame, as it were, from its hidden recesses. There are also a great number of colours in all these. Some are of brightest red, some of light insubstantial flame, some of white light, some glittering, some with a uniform glow of orange without sparks or rays. We see, therefore,
The stars’ long tracks that gleam white behind.
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These stars, for so they appear to be, dart forth and flit across the sky, and by reason of their extraordinary rapidity seem to leave a long trail of fire. Our sight cannot follow their course, and wherever their career leads we imagine the heaven is all on fire. Such is the swiftness of their flight that its separate portions are not distinguished and it can be grasped only as a whole. We are aware rather of the quarter in which the star appears than of its route. It, therefore, seems to mark its entire course with a line of continuous fire, because the slowness of our vision fails to keep pace with the stages of its career and sees at the same moment the start and the finish; as happens in a flash of lightning, the fire seems a long train because the meteor traverses its path rapidly and the space through which it falls presents itself to our eyes as a whole. But, as a matter of fact, the fire does not extend itself all through the space crossed by the meteor. Nor have such long thin bodies strength enough for the effort. How, then, it may be asked, do they issue forth? The answer is, the fire is kindled by the friction of the atmosphere and is urged headlong by the wind. Still, it does not always arise from wind or friction. Sometimes its origin is due to certain peculiar conditions in the atmosphere; for on high there are many elements, dry and hot and earthy, among which fire is generated. It then streams down in pursuit of fuel to sustain it, and therefore is hurried rapidly along. The reason for the differences of colour it presents lies in the nature of the material set on fire and in the degree of violence of the conflagration. A falling body of this kind betokens wind, which may be looked for in the quarter in which the meteor has burst out.