'I have made observations concerning the nature of Light that contradict the theories of Descartes, Boyle, and Huygens,' Isaac said. 'I have divided the white light of the Sun into colors, and then recombined these rays to make white light again. I have done the experiment many times, changing the apparatus to rule out possible sources of error. But there is one I have yet to eliminate: the Sun is not a point source of light. Its face subtends a considerable arc in the heavens. Those who will seek to find fault with my work, and to attack me, will claim that this – the fact that the light entering my prism, from different parts of the Sun's disk, strikes it from slightly different angles – renders my conclusions suspect, and therefore worthless. In order to defeat these objections I must repeat the experiments using light, not from the Sun, but from Venus – an almost infinitely narrow point of light. But the light from Venus is so faint that my burned eyes cannot see it. I need you to make the observations with your good eyes, Daniel. We begin tonight. Perhaps you'd care to take a nap?'