Chapter IX.—Further Astronomic Calculations. The mutual distances of the circles and spheres, and the depths, are rendered by Archimedes. He takes the perimeter of the Zodiac at 447,310,000 stadii; so that it follows that a straight line from the centre of the Earth to the most outward superficies would be the sixth of the aforesaid number, but that the line from the surface of the Earth on which we tread to the Zodiac would be a sixth of the aforesaid number, less by four myriads of stadii, which is the distance from the centre of the Earth to its surface. And from the circle of Saturn to the Earth he says the distance is 2,226,912,711 stadii; and from the circle of Jupiter to Earth, 202,770,646 stadii; and from the circle of Mars to Earth, 132,418,581. From the Sun to Earth, 121,604,454; and from Mercury to the Earth, 526,882,259; and from Venus to Earth, 50,815,160.