The man who had studied the meteorite of aegospotami, and been put by it on the track of such remarkable inductions, was, naturally, not oblivious to the other phenomena of the atmosphere. Indeed, such a mind as that of Anaxagoras was sure to investigate all manner of natural phenomena, and almost equally sure to throw new light on any subject that it investigated. Hence it is not surprising to find Anaxagoras credited with explaining the winds as due to the rarefactions of the atmosphere produced by the sun. This explanation gives Anaxagoras full right to be called "the father of meteorology," a title which, it may be, no one has thought of applying to him, chiefly because the science of meteorology did not make its real beginnings until some twenty-four hundred years after the death of its first great votary. Not content with explaining the winds, this prototype of Franklin turned his attention even to the tipper atmosphere. "Thunder," he is reputed to have said, "was produced by the collision of the clouds, and lightning by the rubbing together of the clouds." We dare not go so far as to suggest that this implies an association in the mind of Anaxagoras between the friction of the clouds and the observed electrical effects generated by the friction of such a substance as amber. To make such a suggestion doubtless would be to fall victim to the old familiar propensity to read into Homer things that Homer never knew. Yet the significant fact remains that Anaxagoras ascribed to thunder and to lightning their true position as strictly natural phenomena. For him it was no god that menaced humanity with thundering voice and the flash of his divine fires from the clouds. Little wonder that the thinker whose science carried him to such scepticism as this should have felt the wrath of the superstitious Athenians.

Biological Speculations

Passing from the phenomena of the air to those of the earth itself, we learn that Anaxagoras explained an earthquake as being produced by the returning of air into the earth. We cannot be sure as to the exact meaning here, though the idea that gases are imprisoned in the substance of the earth seems not far afield. But a far more remarkable insight than this would imply was shown by Anaxagoras when he asserted that a certain amount of air is contained in water, and that fishes breathe this air. The passage of Aristotle in which this opinion is ascribed to Anaxagoras is of sufficient interest to be quoted at length:

"Democritus, of Abdera," says Aristotle, "and some others, that have spoken concerning respiration, have determined nothing concerning other animals, but seem to have supposed that all animals respire. But Anaxagoras and Diogenes (Apolloniates), who say that all animals respire, have also endeavored to explain how fishes, and all those animals that have a hard, rough shell, such as oysters, mussels, etc., respire. And Anaxagoras, indeed, says that fishes, when they emit water through their gills, attract air from the mouth to the vacuum in the viscera from the water which surrounds the mouth; as if air was inherent in the water."[2]

It should be recalled that of the three philosophers thus mentioned as contending that all animals respire, Anaxagoras was the elder; he, therefore, was presumably the originator of the idea. It will be observed, too, that Anaxagoras alone is held responsible for the idea that fishes respire air through their gills, "attracting" it from the water. This certainly was one of the shrewdest physiological guesses of any age, if it be regarded as a mere guess. With greater justice we might refer to it as a profound deduction from the principle of the uniformity of nature.

In making such a deduction, Anaxagoras was far in advance of his time as illustrated by the fact that Aristotle makes the citation we have just quoted merely to add that "such things are impossible," and to refute these "impossible" ideas by means of metaphysical reasonings that seemed demonstrative not merely to himself, but to many generations of his followers.

We are told that Anaxagoras alleged that all animals were originally generated out of moisture, heat, and earth particles. Just what opinion he held concerning man's development we are not informed. Yet there is one of his phrases which suggests—without, perhaps, quite proving—that he was an evolutionist. This phrase asserts, with insight that is fairly startling, that man is the most intelligent of animals because he has hands. The man who could make that assertion must, it would seem, have had in mind the idea of the development of intelligence through the use of hands— an idea the full force of which was not evident to subsequent generations of thinkers until the time of Darwin.

Physical Speculations