XIV
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Some of your friends the philosophers, a critic may say to me, in giving an explanation of shooting stars have told us that some parts of the atmosphere contract fire which is drawn from these same higher regions, and that the fires are kindled by the glow of the ether. Yes, but I reply that it makes all the difference whether the fire is alleged to fall from the ether, which is incompatible with its nature; or whether it is asserted that from its fierce glow the heat leaps the boundary between it and the lower regions, firing them by its power. For on the latter assumption, the fire does not fall from the upper region, which is impossible, but is kindled in the lower. Surely, too, when a widely spread conflagration occurs in one of our cities, we see detached blocks which have for long been heated by the fire from a distance at last catch fire of themselves. So in the upper atmosphere, which is endowed with the power of drawing fire, in all probability there are cases of ignition from the heat of the superposed ether. In nature there is never a sudden transition from one element to a totally different one. Hence there must be some congruity between lowest ether and highest atmosphere; conversely highest atmosphere cannot be wholly dissimilar to lowest ether. On the confines the two elements pass so imperceptibly into one another that at a particular point there might well be doubt whether one is in atmosphere or in ether.