But what arguments, said he, were alleged after this? The moon, answered I then, suffered the same eclipse. You have done well, replied he, to put me in mind of it. But would you have me go on and prosecute the rest of the discourse, as if you had already supposed and granted that the moon is eclipsed, being intercepted within the shadow of the earth? Or shall I take for the subject of a declamation the making a demonstration of it, by rehearsing to you all the arguments, one after another? Nay, by Jove, said Theon, let this be the argument of your discourse. For I indeed stand in need of some persuasion, having only heard that when these three bodies, the earth, the moon, and the sun, are in a direct line, then eclipses happen; for that either the earth takes the sun from the moon, or the moon takes him from the earth. For the sun suffers an eclipse when the moon, and the moon when the earth, is in the midst of the three; of which the one happens in the conjunction or new moon, and the other in the opposition or when the moon is full. Then said Lucius: These are the principal points, and the summary of what is said. But in the first place, if you please, take the argument drawn from the form and figure of the shadow. For this is a cone, as it must be when a great fire or light that is spherical encompasses a mass that is also globular but less; whence it comes that, in the eclipses of the moon, the circumscriptions of the black and dark from the clear and luminous have their sections always round. For the sections given or received by one round body applied to another, which way soever they go, do by reason of the similitude always keep a circular form. Now as for the second argument, I suppose you understand that the first part which is eclipsed in the moon is always that which looks towards the east, and in the sun that which regards the west. Now the shadow of the earth moves from the east to the west, but the sun and moon from the west eastward. The experience of the appearances gives us a visible knowledge of this, nor is there need of many words to make us fully understand it; and from these suppositions the cause of the eclipse is confirmed. For, inasmuch as the sun is eclipsed by being overtaken, and the moon by meeting that which makes the eclipse, it probably or rather necessarily follows that the one is surprised behind, and the other before. For the obstruction begins on that side whence that which causes it first approaches. Now the moon comes upon the sun from the west, as striving in course with him and hastening after him; but the shadow of the earth comes from the east, as that which has a contrary motion. The third argument is taken from the time and greatness of the eclipses. For the moon, if she is eclipsed when she is on high in her apogee (or at her farthest distance from the earth), continues but a little while in her defect or want of light; but when she suffers the same accident being low and in her perigee (or near the earth), she is very much oppressed, and slowly gets out of the shadow; and yet, when she is low, she moves swifter, and when high, slower. But the cause of the difference is in the shadow, which is, like pyramids, broadest at the bottom or basis; and, growing still narrower by little and little, terminates in a sharp point at the top. Whence it comes, that when she is low, she is embarrassed within greater circles, traversing the bottom of the shadow and what is most obscure and dark; but when she is high, being through the narrowness of the shadow (as it were) but in a shallow puddle, by which she is sullied, she immediately gets out again. I omit what was said particularly about the bases and disposition of parts, for these admit of a rational explanation, so far as this is possible; but I return to the subject properly before us, which has its foundation in our senses. For we see that fire shines forth and appears brighter out of a dark and shady place, through the thickness of the caliginous air, which admits no effluxions or diffusions of the fire’s virtue, but keeps in and contains its substance within itself. Or rather,—if this is a passion of the senses,—as hot things, when near to cold ones, are felt to be hotter, and pleasures immediately after pains are found more vehement, so things that are bright appear better when they are near to such as are obscure, the imagination being more strained and extended by means of different passions. But there seems to be a greater appearance of probability in the first reason. For in the sun, all the nature of fire not only loses its faculty of illuminating, but is also rendered duller and more unapt to burn, because the heat of the sun dissipates and scatters all its force. If it were then true that the moon, being, as the Stoics say, a muddy and troubled star, has a weak and duskish fire, it would be meet that she should suffer none of these accidents which she is now seen to suffer, but altogether the contrary; to wit, that she should be seen when she is hidden, and absconded when she appears; that is, she should be concealed all the rest of the time, being obscured by the environing air, and again shine forth and become apparent and manifest for six months together, and afterwards disappear again five months, entering into the shadow of the earth. For of four hundred and sixty-five revolutions of ecliptic full moons, four hundred and four are of six months’ duration, and the rest of five. The moon then should all this time appear shining in the shadow; but on the contrary we see, that in the shadow she is eclipsed and loses her light, and recovers it again after she is escaped and got forth of the shadow. Nay, she appears often in the daytime, so that she is rather any thing else than a fiery and starry body.