An entirely opposite method is used by the Jesuit Father Kircher.
He starts from the point of view that the principal object of nature is man and that all the rest is created for him. The planets are uninhabited because, apart from man, there could be no reasonable beings. But since they have upon man an influence determined by their astrological value, he finds the planets to be such as astrology represents them to be in their action upon us without considering their position with regard to the Sun.
On Mercury, everything takes place gaily and joyously, since all those who are born under its influence are inclined to lightness and mischief. On Venus, everything is even better—or worse: he finds everything gracious and charming; a soft rosy light is spread over the planet, perfumes are wafted about everywhere, zephyrs mingle their murmurings with those of the brooks, and gold and precious stones sparkle everywhere. Jupiter having, like Venus, a beneficent influence upon man, everything there is perfect: the air is pure and wholesome, the waters crystal-clear, and the soil itself as bright as silver. On Mars, on the other hand, everything is of a warlike roughness, forbidding and terrible, rivers of boiling pitch overflow their banks and envelop the country in thick and suffocating smoke. Saturn, as a planet, is particularly accursed; everything looks like a deserted grave. The planets are not inhabited by human beings, but by angels or genii who rule them.
(All these arguments of Kircher are not less infantile than those of Huygens, but they have left distinct traces in astrological literature, and even Victor Hugo reflects them eloquently.)
A contemporary of the two authors we have just mentioned is the Nestor of French writers, Fontenelle, who lived from 1657 to 1757, exactly a century. He described with much detail the inhabitants of the planets, and, like Huygens, he starts from the basis that they are all inhabited, and inhabited by beings formed according to the circumstances. On Mercury, according to him, the heat is so great that the rivers contain fused metals instead of water, particularly gold and silver; the inhabitants of this planet can therefore not imagine that there are worlds like the Earth, where gold and silver are solid and serve as money. Besides, the inhabitants of Mercury could not support the excessive heat if their planet was not animated by a movement of rotation so rapid that they are only exposed for a short time to the rays of the Sun. They are all inclined to be hot-heads and, like fools and infants, live without reflection and enjoy themselves in anticipation of the coolness of the night. Littrow remarks on this subject that Bode, the translator of Fontenelle and at one time Director of the Berlin Observatory, is seriously astonished by this opinion of Fontenelle and exclaims: “Very strange! for with us in Berlin we find that a great heat makes people lazy and sleepy instead of lively and active.”
The inhabitants of Venus only render homage to the goddess of love. They are not interested in philosophy or mathematics, read no books or journals, pass the whole day in their flirtations, and practise in a superior manner the arts which appertain to them, music, poetry, dance, etc., but they are not adept at cookery, for they live almost entirely on air. They are not beautiful, but their amorous character prevents them being influenced by their ugliness; they are Celadons and Sylvanders. Wieland certainly did not know the works of Fontenelle, or he would probably have located one of his romances or his love-stories on Venus as depicted by that author.
Fontenelle’s procedure with regard to Mars is rather singular. He declares that that planet does not merit any attention. Our imaginative savant hardly wants to say anything about Jupiter either. He gives a description of the aspect offered by the whole solar system as seen from that planet. He explains how Venus and Mercury are invisible there without the aid of a telescope, and that the Earth only appears as a point. The volume of Jupiter causes him some embarrassment, for whereas the inhabitants of Mercury on account of the small dimensions of that planet nearly all know each other, those of Jupiter cannot possibly do so.
On account of the extreme cold, the life on Saturn is still more disagreeable than that on Jupiter. If the Saturnians were brought to the Earth they would certainly die of heat even in Lapland. If the water on Saturn is of the same nature as ours, it must look like our polished stones, and spirits of wine must resemble diamond. In consequence the inhabitants of Saturn cannot but be slow and phlegmatic; they know no gaiety and remain like oysters in the place they were born in.
Fontenelle continues in this way without attaining any depth, under the impression that our planet is the type of the universe. Let us now pass to the nineteenth century.
Graithuisen, the Director of the Munich Observatory, published his chief works in the first thirty years of this century. His researches relative to the habitability of the planets were, therefore, made at an epoch when we already possessed important data on their physical constitution, an epoch when, thanks to the work of Bessel, the golden period of astronomy had already begun. One may therefore take it that the work of Graithuisen marks a real progress beyond his predecessors, as indeed he says himself without ceremony. But as a matter of fact he is rather fruitless, as is shown by the strange manner in which he deals with the earth-light on Venus.