AND THE ASTRONOMER ushered Leibniz onto the three-legged stool, and with a firm hand on the back of the young philosopher’s skull he pressed Leibniz’s eye to the eyepiece. And Leibniz looked through it. The astronomer cried: “It is dark, yes? Absolutely dark, yes? You see that, do you not? You confirm it?” And though Leibniz, who’d grown oddly fond of the lonely old lunatic, had decided to tell him (“What would be the harm?”) that he saw the eclipse whether or not he did in fact see it, he was amazed to see that it really was dark, the Moon really had come between the Sun and the Earth, he would not have to lie. “I see it!” Leibniz exclaimed. “Yes, I see it, I see the eclipse, it is pitch-black! Oh, how strange it is, and how beautiful!” And very near his ear the astronomer said: “And just like that, it is over.” But although the forecasted four seconds had indeed elapsed, and then five seconds, and then six, it was still dark through the telescope, absolutely dark. And Leibniz (“I am not crazy,” he wrote, “but I am slow”) now realized the obvious, which is that the telescope was broken. He lifted his eyes from it and looked at the sliver of sky visible through the warped slat of the window blind. It was bright and blue. Then he peered through the telescope again. There it was still dark, and absolutely so. “I decided to say nothing to the old man.” But when Leibniz turned to the astronomer, he wasn’t there. Then Leibniz noticed that the candle had gone out, smoke now rose from it, it had been snuffed out it seems by a breeze blowing through one of the little windows overlooking the void, which had been shut until now but which now was wide open, and through which, it was not hard to deduce, the astronomer had just flung himself. It seemed he had leapt with his ledger in hand, and for a moment Leibniz thought he had taken Linus with him also. But, as Leibniz illustrates in a final diagram on the final page, the cat lay under the armillary sphere still, in the same position as before, though he had lifted his head a little, “not to look at the window out of which his master had fallen” (so the caption reads) “but to sniff with interest at the smoke from the candle.”