1On the island of Murano, in the lagoon of Venice, they have made glass for longer than anyone remembers. There was a boy of that island named Bepi, twelve years old, whose grandfather had been a master of the furnace until the heat took his sight. The old man could still tell good glass from bad by running his thumb across it.
2"Glass is a liar," the grandfather used to say. "Never forget it. A bubble, a wave, a thread in the melt, and it will show you a straight oar bent and a fat man thin. I have made mirrors for duchesses. I know what glass does to the truth."
3In the summer of his twelfth year Bepi was sent across the water to Padua, to a house full of noise near the church of the Saint. It was the house of the professor of mathematics. The boy carried a crate of clear glass rounds packed in straw, the best of the island, and a note from his uncle.
4The professor was a big red-haired man of forty-five named Galileo Galilei. He was a Florentine, and he talked without stopping. He had students boarding in every room, a workshop on the ground floor that made brass measuring tools for soldiers, three small children, and more debts than he could count.
5He broke open the crate himself, there in the yard. He held each round up to the sky and turned it. He threw four out of five on the cobbles.
6"Liars," he said. "This one will do. And this. Who taught you to pack glass, boy?"
7"My grandfather, sir. He says all glass is a liar."
8The professor laughed out loud. "Then your grandfather and I are the only two honest men in the Republic. Can you grind? No. Can you learn? Stay, then. I need small hands."
9Here is what the hurry was. Word had come down from Holland that a spectacle-maker there had put two lenses in a tube, one at each end, and that through it far things looked near. The professor had never seen one. He had only heard it described, and he had gone home and thought for a night about how light bends in glass, and by the next evening he had made one of his own out of a lead pipe.
10It made things three times nearer. That was the toy. He did not want the toy. He wanted to know how far it could be pushed.
11So all that summer he ground lenses. He did it himself, on a spinning iron dish with wet sand, hour after hour, his big hands as careful as a woman threading a needle. Bepi mixed the grit and held the lamp, and learned. A lens must curve the same everywhere, to the width of a hair, or it lies. Most of them lied.
12By the end of August he had a tube that brought things nine times nearer. He took it to Venice, and Bepi carried the case.
13They climbed the bell tower of Saint Mark with the old lords of the Senate puffing behind them in their red robes. From the top, one after another, the lords put an eye to the tube. They saw the dome of a church in Padua, more than twenty miles off. They saw people going in at the door of a chapel on Murano, and Bepi, when his turn came at last, saw his own aunt shaking a cloth from a window.
14Then they turned it to the sea. There were ships out there, coming in, that no one could see with the bare eye. Two hours later those ships rose over the edge of the water.
15The lords understood that. They doubled the professor's pay on the spot.
16But mark what else had happened on that tower, for the lords did not mark it. The glass had been tested. It showed a dome, and you could walk to Padua and find the dome. It showed ships, and the ships came. Whatever it showed on earth, you could go and put your hand on. So far, this glass was no liar.
17The professor went home and ground a better one. By the first frost he had a tube as long as a man's leg that made things twenty times nearer. And on a cold clear evening, with the moon four days old, he carried it out to the garden behind the house and turned it up.
18"Come here," the professor said at last, in a voice the boy had not heard from him. "Tell me what you see. Do not tell me what you think. What you see."
19Bepi put his eye to the glass.
20Everyone knew what the moon was. The priests taught it and the philosophers taught it. The earth was the place of mud and change and death. But from the moon upward all was perfect: smooth, shining, made of a finer stuff that never altered. The moon was a ball of pearl.
21It was not a ball of pearl. It was a country. There were mountains on it. He could see them along the line where the bright part met the dark, for their tops caught the sun while their feet were still in night, just as the peaks behind Venice catch the dawn. There were round valleys full of shadow, and the shadows lay all one way.
22"It is rough," Bepi whispered. "Like here."
23"Like here," said the professor. "Watch the shadows. Tomorrow they will be shorter."
24Bepi did not sleep that night. He was a boy who had been taught his prayers, and he was afraid. If heaven was not perfect, what was it? Had he sinned by looking? On Sunday he went to the priest of the Saint's church, an old friar who had known the professor for years, and told him all of it in a rush.
25The friar heard him out. "Did you make the mountains?" he asked.
26"No, father."
27"Did the professor make them? Then they were there before either of you looked, and the Lord who put them there knew it. He is not shamed by His own work, child. Go home."
28Now hear the nights of January, for they are the heart of this.
29On the seventh night of the new year the planet Jupiter stood high and bright in the east. The professor turned his best tube on it. Close beside the planet he saw three little stars, tiny and sharp, two on one side and one on the other. They lay in a straight line, like beads on a thread.
30The next night he looked again, by chance. The three little stars were still there, in their line. But now all three were on the same side of Jupiter.
31He stood in the frozen garden with his eye at the tube and his mouth open.
32A star cannot change sides. The stars are fixed; that is what they are. Jupiter moves among them, slowly. But Jupiter was moving the wrong way that week to make this picture. Either the tables of every astronomer were wrong, or those three points of light had moved by themselves.
33The ninth night was cloud from edge to edge. On the tenth it cleared. There were two little stars now, both on one side. The third was nowhere.
34On the eleventh, two again, but one was farther out and brighter. On the twelfth there were three. On the thirteenth night, for the first time, there were four.
35Bepi held the lamp while the professor drew. Night after night the little beads slid along their thread, now this side, now that, now hiding, now out again. They never left the line. They never left Jupiter. As the planet crept across the sky, they went with it like ducklings.
36"Do you see what they are doing?" the professor asked him. "They are going round him. Round and round. When one is in front of him or behind him, we lose it. They are moons. Jupiter has four moons."
37He sat down on the garden wall.
38"They told the old canon that if the earth flew round the sun, it would leave its moon behind." He pointed up with his pen. "There is a planet that everyone agrees is moving, and it has not left its moons behind. And there are four bodies in heaven that do not go round the earth at all. Any man can see it who will put his eye here."
39He wrote it all in a little book, in six weeks, with pictures of the moon cut in copper. He called it the Starry Messenger. Five hundred and fifty were printed in Venice, and they were gone in a week.
40And then the trouble began, and it was the trouble Bepi's grandfather could have foretold. Glass is a liar.
41It was not a foolish thing to say. Those first tubes were hard to use. The view was narrow as a keyhole and shook with every breath. And the learned asked a fair question. This thing shows truly on earth, they said, where we can check it. Who has gone up to check it in heaven? The stuff of heaven is not the stuff of earth. Perhaps a glass made of earthly sand deceives when it is pointed at what is not earthly.
42That was a fair doubt, and a man could answer it: come and look again, here is how to hold it. There was another kind he could not answer. There was a philosopher at Padua, the most famous in the school, a man named Cremonini. He had been the professor's friend for eighteen years. He had taught all his life that the heavens are perfect and unchanging.
43Bepi was sent to his house with the tube in its case and the professor's compliments. Would the learned doctor care to see the mountains of the moon? Tonight was clear.
44The philosopher came to the door himself. He was not angry. He looked at the leather case in the boy's arms the way a man looks at a letter he knows holds bad news.
45"Take it home, lad," he said. "Tell him I thank him. Tell him those glasses make my head swim, and I want no more of them."
46"It is only looking, sir," said Bepi, who did not know his place. "It takes no longer than an Our Father."
47"I know how long it takes." The old man put a hand on the door. "I am sixty years old. I have written a shelf of books. Go home."
48Bepi carried the case back through the dark streets. He had thought the philosopher a fool, and now he was not so sure. He had seen the man's face. It was not the face of one who believes the glass lies. It was the face of one who is afraid it does not.
49He remembered his own night without sleep, after the moon. It had cost him something to look, and he was twelve, with nothing to lose but a picture in his head. What would it cost a man who had built his house on that picture, and lived in it for forty years? He never looked. It is told that to the end of his life he never once put his eye to the tube.
50But far off in Prague, Kepler answered this time. He had no glass of his own; he was too poor, and his eyes too bad. But he read the little book, and he knew the kind of man who had written it, and within eleven days he put out a printed letter to all the world saying that he believed it. He risked his name on a thing he had not seen, because he could follow how it had been seen. When at last someone lent him a tube, he found the four moons where the book said they would be.
51And now hear who else looked, for it must not be left out.
52In Rome the Jesuit fathers had a college, and in it the best astronomers of the Church. Their chief was Father Clavius, an old German of seventy-three, who had mended the calendar for the whole Christian world. He had taught the unmoving earth all his life. He did not like what he heard from Padua, and he said so.
53But he sent for a glass. He and his fathers went up on the roof of the college and looked. Then a cardinal asked them, in writing, whether these new things were so.
54They wrote back that they were so. The moons of Jupiter, yes. The stars past counting, yes. Venus changing shape like a little moon, yes: that too they had seen. On the moon's mountains the old father was not ready to agree. But he did not say the glass lied. He had looked, and he wrote down what was there.
55The professor went to Rome that spring and the fathers gave a feast in his honour. By then he had left the free Republic of Venice, which had sheltered him for eighteen years, and gone home to Florence to serve his prince. His friends in Venice had begged him not to go. Here, they said, no one can touch you. There, you are nearer to Rome.
56He did not listen. He was sure the truth, once seen, would be enough.
57Bepi did not go with him. He went back to Murano with a small tube of his own making, three lenses he had ground himself, the only three out of forty that did not lie. On the first clear night he led his blind grandfather out to the edge of the water and told him what the moon was.
58The old man listened, with his face turned up to a light he could not see.
59"Mountains," he said. "Well. And you tested this glass first? On something you could walk to?"
60"On the bell tower, grandfather. And on the ships."
61"Then it is honest glass." He felt for the tube and ran his thumb slowly across the lens, as he had done ten thousand times. "I did not think to live to hear of any."
62Now leave the lagoon for a while, and go north over the mountains. For in those same years, in Kepler's own country, fear was looking for someone to burn, and it found an old woman. Now hear what came after.