It has been a favourite idea with those who delight in the argument from design, that the moons of the remoter planets have been provided for the express purpose of making up for the small amount of sunlight which reaches those planets. Jupiter receives only about one twenty-seventh part of the light which we receive from the sun; but then, has he not four moons to make his nights glorious? Saturn is yet farther away from the sun, and receives only the ninetieth part of the light we get from the sun; but then he has eight moons and his rings, and the nocturnal glory of his skies must go far to compensate the Saturnians for the small quantity of sunlight they receive. The Saturnian spirits who visited Swedenborg were manifestly indoctrinated with these ideas. For they informed him that the nocturnal light of Saturn is so great that some Saturnians worship it, calling it the Lord. These wicked spirits are separated from the rest, and are not tolerated by them. 'The nocturnal light,' say the spirits, 'comes from the immense ring which at a distance encircles that earth, and from the moons which are called the satellites of Saturn.' And again, being questioned further 'concerning the great ring which appears from our earth to rise above the horizon of that planet, and to vary its situations, they said that it does not appear to them as a ring, but only as a snow-white substance in heaven in various directions.' Unfortunately for our faith in the veracity of these spirits, it is certain that the moons of Saturn cannot give nearly so much light as ours, while the rings are much more effective as darkeners than as illuminators. One can readily calculate the apparent size of each of the moons as seen from Saturn, and thence show that the eight discs of the moons together are larger than our moon's disc in about the proportion of forty-five to eight. So that if they were all shining as brightly as our full moon and all full at the same time, their combined light would exceed hers in that degree. But they are not illuminated as our moon is. They are illuminated by the same remote sun which illuminates Saturn, while our moon is illuminated by a sun giving her as much light as we ourselves receive. Our moon then is illuminated ninety times more brightly than the moons of Saturn, and as her disc is less than all theirs together, not as one to ninety, but as sixteen to ninety, it follows that all the Saturnian moons, if full at the same time, would reflect to Saturn one-sixteenth part of the light which we receive from the full moon.[29] As regards the rings of Saturn, nothing can be more certain than that they tend much more to deprive Saturn of light then to make up by reflection for the small amount of light which Saturn receives directly from the sun. The part of the ring which lies between the planet and the sun casts a black shadow upon Saturn, this shadow sometimes covering an extent of surface many times exceeding the entire surface of our earth.