The hell with Vespasian! The twentieth would have the best manoeuvres, carried out the fastest, of any of the legions. As for Vespasian's brother, the hell with him too!
* * *
On his first meeting with Vespasian, Gaius was struck by the fact that everyone was deferring to him and trying to get his attention, which was a waste of time since Vespasian ignored them. Well, someone was going to be different. Claudii were not noted for being deferential! Vespasian noticed him, and strode towards him.
"Your men haven't got here yet?" Vespasian frowned. It was not until later that Gaius realized that Vespasian seemed to have a perpetual frown.
"They're camped about two hours march to the north," Gaius replied, then he kicked himself. Vespasian knew that anyway! He had been watching the training!
"Don't want to mix with the rest of us, huh?"
"Better forage there," Gaius shrugged.
Vespasian stared for a moment, then nodded as he said, "That's a good enough reason. Is there spare forage there?"
"A few miles to the east there's plenty."
"I'll tell my cavalry commander," he said, and turned away to deal with his next problem. If nothing else, Gaius noted, while Vespasian's social graces were slight, he was efficient.
* * *
Organizing the running of the cohorts was the Tribunes' job and Gaius felt it was more important that he showed he trusted them to do it than he spent time overseeing. The trick was to show he trusted them rather than to give the impression that he did not care. So, each morning he required reports as to what problems were being dealt with, what problems were solved, and any problems that might seem to be too difficult for the Tribune. No Tribune would permit anything into the last category unless it bordered on the insurmountable, so by about ten o'clock each morning he had time to deal with some of the more vexing problems facing him.
Gaius also felt that the Tribunes would prefer it if he was not watching while misunderstandings were sorted. As a reason to be out of their way, he decided to go for a walk along the coast. He had hardly gone any distance when he noticed that the reef he had seen previously was gone, and the beach was almost submerged.
"It's the tides," Timothy remarked. "You remember we discussed them. They were first discovered by Pytheas."
"If they're this big here," Gaius muttered, "it is fairly obvious that the locals would know about them well before Pytheas turned up."
Timothy was about to mutter something about a certain anti-Greek feeling, but decided against it. "They would know about them," he conceded.
"So the moon can actually pull this much water up?"
"Apparently. The sea definitely rises and falls, depending on where the moon is. It is obvious that the moon must be pulling the sea up."
Gaius was intrigued. If the Moon went around the Earth, it had to be falling around the Earth, but if the sea rose, was that not the sea "falling" towards the Moon? He vaguely recalled the lesson about Pytheas, but he had never imagined the tidal movement could be so great. A local fisherman told him that it was now high tide, and the water would not come any higher. So how far did it go down? He would come back twelve hours later.
He did, and found the water in the same place. Something was wrong. It was later he found out there were two tides a day, and so next time he went out six hours later, and there was his reef, the sea having sustained a remarkable drop. So, all was well, except. . Except the high tide was not caused by the Moon pulling water towards it, otherwise his original analysis would have been correct. The water faced the Moon once a day, so if the Moon pulled on it there would be one high tide. There were two!
The odd thing, he reflected as he sat on a rock and watched the waves, was that a few weeks ago he had this all sussed out. The Moon moved around the Earth because the Earth pulled on it; the Earth moved around the Sun because the Sun pulled on the Earth. He was prepared to believe the Moon could pull on the water, which meant one tide per day.
Wait a minute! Something was wrong! The water had to be falling towards the Moon faster than the rocks?? Light things falling slightly faster than heavy things?? He was missing something, but what? With regard to the rocks, perhaps they did not move because the solid earth was essentially rigid. No, that was not it, because sand was not rigid. Why did not sand rise towards the Moon? Because the net force was still directed towards the centre of the Earth; if the Moon was pulling, its pull was much weaker than that from the Earth. If the forces were added, everything still fell towards the Earth. Perhaps it fell slower, but it still fell only one way. Which left the question, why did water rise to form the tides?
A wave of despair passed over him. Yesterday he thought he had it all under control, and now, suddenly, he realized he knew nothing. Or did he?
What did he know? The tides did happen, and they were in phase, more or less, with the position of the Moon, but there was one directed towards the Moon, and one directed away. There were no tides in a cup of water, nor in lakes, nor, for that matter, any in the Mediterranean of any substance. Why not? There was pull from the Moon, but there was always a much greater net pull from the Earth, presumably because it was closer and bigger. The two forces were in direct opposition, and by adding them there was one, slightly weaker, directed towards the centre of the Earth. There should be no tides! Except there were.
Did that mean that the Moon had nothing to do with the tides, and it was all an accidental coincidence? As Aristotle said, the wrong premise could readily explain a correct observation. The Moon pulling on the water might well predict a tide, but the presence of the tide did not prove the Moon's action. Perhaps not, but there were not many options.
What was different between this ocean and a lake? Salt? No, the Mediterranean had that, and yes, it did have very small tides. The amount of water? Yes, that was most likely to be real. Strictly speaking, he did not know this, because he had no idea how big this ocean was, but it was generally accepted to be much bigger than other bodies of water. It was then that he saw it: geometry! The water directly under the Moon had a weak force going upwards, and a strong force equal and opposite, leaving a net force going straight down. But since the Earth was a sphere, if the ocean was big enough, water far away would receive the same two forces, but the force directed towards the Moon would not be exactly opposite to the force towards the centre. Accordingly, there would be a small force directed along the surface of the water and directed towards the line between the centres of the Moon and Earth. That small net tangential force was not cancelled out initially by anything else, and that would cause the water to flow tangentially towards the point directly under the Moon. The tides were caused by water flowing sideways, which, when he thought about it a bit further, was obvious because if all the water did was to fall towards the Moon, there had to be a space underneath. No! Water had to come from somewhere else.
Then what? One thing was obvious: the point under the Moon would follow the path of the Moon. On the big ocean the high tide would travel like a wave. Wait! He was slightly wrong. There was an opposing force to the water flowing sideways, which was the weight of the water in the crest of the wave that would try to flow back the other way to make the ocean flat.
That was why there were no tides in a cup of water, or in a lake, or in a small sea. The amount of water was not big enough to generate a sideways flow! Could that be right? Could he have made a mistake? Maybe, but right now he had one explanation that worked, so he would stick with it.
That also explained why the rocks did not form a tide. If the tides were caused by water flowing sideways, the rocks did not flow, hence there was no net effect. Of course, he suddenly realized, he did not know there was not a small effect, because he could not measure its presence or absence. If the rocks did move, he moved with them. Motion could only be measured with respect to something else. The rocks could be going up and down, but because he was always the same distance from them, he would be unaware of it. Which, of course, was required by Aristarchus' heliocentric theory. The Earth was going around the Sun, but since he was going around with it, at the same rate, there was no simple way to prove it.