"This sounds rich!" Gaius jibed.
"I must give you some help for your coming discussion," Timothy said. One of the advantages of being right was that you could afford to look generous, and give what were sometimes known as Greek gifts. "Remember the great Aristotle showed why the Earth was a sphere? We can prove that the Earth is a sphere, and you always fall towards the centre. If you travel far enough. ."
"You get back to where you started, although I am unaware anyone has tried."
"The Earth is simply too big," Timothy nodded. The young man was assertive, confident. Good! Now to be 'helpful'. "If you look at the Moon it has an image, right?"
"Yes."
"Carthaginians travelled south along the coast of Africa, where the desert changes to very hot jungle, to desert again, and then it starts to get cooler. What do you deduce?"
"The sun is over the middle part of the sphere," Gaius said, "and so the travellers went past the middle, and then to the corresponding part. . well. . down, or south."
"And the moon?"
"I presume it was about the same size, the same colour, the same image. What else?"
"The image is upside down," Timothy explained. "Of course the moon is the same. The traveller is the other way up."
Gaius stared at him, then said, "Of course!"
"Of course we don't know much more than that," Timothy added. "The noble Romans ploughed the Carthaginians into the soil, and destroyed any records they might have had."
"They were barbarians," Gaius shrugged. "They didn't leave records."
"On the contrary, the reason there are no records is because the noble Romans burned their great library to the ground. And why do you think they were barbarians?"
"They sacrificed little children to their Gods, just to get rain. And even then, it didn't rain!"
"So the noble Romans put an end to baby killing by killing everyone! They didn't do it out of greed? Your leading families didn't get hugely rich?"
"Yes, they did," Gaius admitted.
"And it wasn't as if they shared it out? Your senators got all the farmers to join the army and defeat the Carthaginians, and what did they do? They stole the peasants' land, so now they have a great landless class in Rome who have to be fed and entertained with barbaric games, all paid for by the taxes you impose."
"I agree the games are barbaric, however, they get rid of vicious criminals and make a bit of money doing it. Anyway, I'm not sure what that has to do with Aristarchus."
"You have to select your facts," Timothy nodded. "Some are irrelevant. Now, besides going south, you can go north, which is what the Greek Pytheas did. He sailed out of the sea you know, past the Pillars of Hercules, out to the great ocean and then sailed north, past Gaul, past Britain, and eventually reached the island of Thule, where in winter it is always dark."
"And cold," Gaius offered.
"And cold. Now, on the coasts of the great ocean, the water rises up and down in what are called tides, and Pytheas noted that these tides are related to where the moon is. The water is pulled up by the moon, which is providing a small contrary to the force of the Earth. Of course the Moon's force is much weaker than Earth's. Why?"
"Because the moon is smaller and further away?"
"Exactly. The tides are higher when the sun and moon pull together. The sun is huge, but it is much further away, so its effect is much smaller."
"He must have been observant to see this," Gaius muttered. "I've never noticed much."
"In our sea, tides are very small. But in the great ocean, with more water, they're much bigger, with the water level changing more than the height of a man in places. Now, that's enough for today." And with any luck, Timothy thought, he will waste a lot of time thinking about that.
* * *
Once again, it was pleasant to sit in the sun. By now Gaius was quite at home on Rhodes, and there was little about Rome that he missed, other than his family. His only concern was that these lessons, while quite pleasant, were not leading anywhere. Athene had implied they were important, but if they were, he could not see how. Wretched dream! It was so obviously a dream, but he could not put it out of his mind. Athene was so beautiful. . But that was the trouble. She looked different from any Greek girl he had ever seen, she had blonde hair and grey eyes, and that was more like what he had heard of those wretched Germans. And therein lay his problem. She looked like nothing he had seen before, particularly her clothes, but at the same time she did not look like a Goddess. She looked like a woman. Surely Gods would look different in some ways?
"Since you are basically anti-Greek, there are two other Greek theories," Timothy brought him back to reality, "which I presume you will also refute?"
"That depends on what they say. I should know what it is before I say it's wrong."
"Good!" Timothy seemed genuinely pleased. "And feel free to refute them, because both have been refuted by the great Aristotle. The one that actually came second was due to the Stoics. They said nature is continuous, and infused with a spirit called pneuma. If you take a cylinder and piston, such as we use for water pumps, with nothing but air in it, seal an end, and press the piston down as hard as you can, then let go, the piston bounces back. The air is springy. Now, if you fill the cylinder with water, you simply cannot compress it. The element water therefore cannot be compressed, but it will transmit pressure, for you can use a pump to force water uphill. Do you understand that?"
"I understand what you can do with a pump," Gaius said, "but I do not understand this pneuma. It could be just the air."
"Aristotle didn't agree with that either," Timothy continued, "and if you are right and air provides the contrary to motion, it is providing the contrary to this piston."
"Your Greek, Democritus, might have the answer here," Gaius offered. "If he is correct about heat being atoms moving about, and air pressure being the atoms striking the wall, then if you reduce the volume and keep the heat the same, then atoms will strike the wall of the pump more frequently, which presumably means more force on it."
"You might be right," Timothy replied, "Whatever causes it, you can make pumps to lift water, or blow air, and in Egypt Hero has built a device by which the sun's heat makes air blow to move water that opens the door of a temple. Now, I'm trying to spark creative thought, so go away and think of something useful that comes to you from this pneuma. You can use Democritus' theory if you like."
* * *
Once again Gaius walked, and eventually arrived at the temple. He had been there several times, but never again had he received the vision of the young woman. Still, this was as good a place as any to think. He ate his bread and cheese, took some water, and sat with his back to a stone column.
At first, nothing came. Then later, it seemed that only nonsense had come. Accordingly, he was apprehensive when he met Timothy again.
"Well?"
"Suppose you have a fire, and to make it go faster, you have bellows. The fire heats some air, and when you take it to Hero's device, it lifts the bellows up and down. So, and you'll be pleased to hear this," Gaius added sarcastically, "you don't need a slave to keep the fire going. Of course, if you never lit the fire in the first place, you also wouldn't need the slave."
"Ah, but you've improved the life of one slave," Timothy said.
"Not necessarily," Gaius shrugged. "The fire is going faster, so you need two more slaves to keep up the wood supply. Unless," he added with a grin, "we could get Hero's device to chop wood, but that's hardly likely, is it?"
"One of these days, if you wish, I can take you to Egypt to see this device open doors, but in answer to your question, no, this won't. I have heard there are some Egyptians who have found that if you heat water and get steam, the steam can be made to push against something. Go away again and think what could happen if you can give steam enough pneuma. Imagine you could do something more than blow your own bellows!"