In the same spirit, but more literally perhaps than these, are we to understand the music of Dante’s spheres, which accompanies the singing of the angels:— “Il cantar di quei che notan sempre Dietro alle note degli eterni giri.”[656] ------------------------------------------------------------------------ [654] _Hymn on the Nativity._ [655] _Merchant of Venice._ [656] “The song of those who sing for ever After the music of the eternal spheres.” _Purg._ xxx. 92, 93. (_Longfellow_). ------------------------------------------------------------------------ 3. DIMENSIONS AND PHYSICAL NATURE OF THE UNIVERSE. We have seen that Dante believed the circling of the nine moving spheres and their epicycles to be the immediate cause of the movements which he saw in stars and planets. If we ask what were his ideas with regard to their sizes and distances the question is easily answered. It is a curious fact that although our ideas about the size of anything we see depend upon the distance at which it appears to be, and no one can say how far away the sun looks, most of us nevertheless have a quite definite idea as to how large it looks, about the size of a dinner-plate, a cart-wheel, &c. Cleomedes, in the days of Augustus, quotes Lucretius and the Epicureans as believing that the sun is no larger than it looks, _that is a foot in diameter_; and he rightly remarks, amongst other arguments to the contrary, that if it were only that size it would be invisible unless nearer than the tops of the mountains, yet we see islands and hills projected against it when rising, which shows that its distance is greater. Dante twice quotes the same fallacy, as an instance of the folly of trusting to the impression of our senses, when not corrected by reason, and he tells us what he believes the true size of the sun to be. In _Conv._ IV.[657] he says:— “Thus we know that to most people the sun appears to be a foot wide in diameter; and this is so utterly false that according to the investigation and discovery made by human reason with her attendant arts, the diameter of the sun’s body is five times that of the earth’s, and a half besides. For whereas the earth has a diameter of six thousand five hundred miles, the diameter of the sun, which when measured by sense-impressions seems to be a foot in extent, is thirty-five thousand, seven hundred and fifty miles.” (See also _Ep._ x. 42-46). When speaking of the planet Venus he says she is “far off from us, being distant even when she is nearest to us one hundred and sixty-seven times the distance of the distance of the centre of the earth from us, which is three thousand two hundred and fifty miles.”[658] ------------------------------------------------------------------------ [657] _Conv._ IV. viii. 51-64.