The Moons of Mars
The following passage, from Voltaire’s “Micromegas Histoire Philosophique,” is curious in view of the discovery of the two moons of Mars, several years ago, by Professor Asaph Hall, of the National Observatory, Washington. The work describes a journey, throughout the solar system, of Micromegas, a philosopher of Sirius, and a being of enormous proportions, who is accompanied by an inhabitant of Saturn, the latter intermediate in size between the great Sirian and the inhabitants of our earth. The extract is from the third chapter:
“Departing from Jupiter, our voyagers traversed a space of a hundred millions of leagues, and coasted the planet Mars, which, as is well known, is about one-fifth of the dimensions of our little globe. They saw two moons which attend this planet, and which have escaped the observations of our astronomers. I know very well that Father Castel will write, good-humoredly, of course (et même assez plaisamment), against the existence of these two moons; but I am in accord with those who reason from analogy. Philosophers of this sort know how difficult it would be for Mars, which is so distant from the sun, to get on with less than two moons, at all events.”
Voltaire’s philosophical romance, published in 1752, was imitated from Swift’s “Gulliver’s Travels.” It is therefore easy to trace the quotation to the Voyage to Laputa (Chapter III.) in which Swift, writing in 1727, says,—
“Although their largest telescopes do not exceed three feet, they show the stars with great clearness. This advantage has enabled them to extend their discoveries much farther than our astronomers in Europe; for they have made a catalogue of ten thousand fixed stars, whereas the largest of ours do not contain above one-third part of that number. They have likewise discovered two lesser stars, or satellites, which revolve about Mars, whereof the innermost is distant from the centre of the primary planet exactly three of his diameters, and the outermost five; the former revolves in the space of ten hours, and the latter in twenty-one and a half; so that the squares of their periodical times are very near in the same proportion with the cubes of their distance from the centre of Mars; which evidently shows them to be governed by the same law of gravitation that influences the other heavenly bodies.”