‘In what way?’ asked Helena.

‘We might place different values on books.’ He shrugged off the problem, however. ‘It has never arisen.’

Clearly he was reluctant to continue. I then asked where Timosthenes was when Theon died.

‘Here in my own Library. My staff can confirm it. We were conducting a scroll count.’

‘Any particular reason for this inventory, or is it routine?’

‘Checks are carried out from time to time.’

‘Do you lose books?’ Helena asked him.

‘Sometimes.’

‘Many?’

‘No.’

‘Enough for concern?’

‘Not in my Library. Since works are available for public consultation, we have to be rigorous. Members of the public have been known to “forget” to return things, though of course we always know who has borrowed what, so we can remind them tactfully. We find scrolls mis-shelved occasionally, though I have a proficient staff.’ Timosthenes paused. He had been conversing with Helena, yet he looked at me: ‘You are interested in scroll numbers?’

I played bored. ‘Tallying and ticking off lists? Sounds dry as desert dust.’

Helena pursed her lips at this interruption. ‘And how did the count go, Timosthenes?’

‘Good. Very few were missing.’

‘Was that what you expected?’

‘Yes. Yes,’ replied Timosthenes. ’That was as I expected.’

XXV

Sometimes during an investigation, Helena and I just stopped. When the flow of information became overwhelming, we turned away. We fled the scene. We bunked off to the country for a few hours, without telling anybody. Students of rational science might find the fact odd but forgetting all about the case for a time could, by a mysterious process, clarify the facts. Besides, she was my wife. I loved her enough to spend time alone with her. This was not the traditional way to view a wife, but as the noble Helena Justina often said, I was a surly beggar who just loved to break the rules.

Of course I was never surly to her. That’s how traditional husbands let themselves down. We two had a union of lustrous tranquillity. If Helena Justina saw a moment of uncharacteristic surliness coming on, she would stalk from the room with a riffle of skirts and a sneer. She always knew how to get in first.

We both pursed our lips over Timosthenes. We agreed he was high quality and almost certainly ethical, but we thought he was keeping things back. ‘Men who take refuge in scrupulous good manners can be hard to break, Helena. I can’t put the Serapeion Librarian up against a wall and mutter threats in his ear.’

‘I hope you don’t generally work like that, Marcus.’

‘I do when it gets results.’

The Serapeion lay close to Lake Mareotis. We had picked up transport - a horse and cart, with its driver whom I had bargained with when I saw them sitting glumly in Canopus Street. Uncle Fulvius was using his conveyance today. You can’t blame a man for wanting to use his own palanquin. (I would blame him if I found out he had lent it to my father - an unpalatable thought, which was unfortunately probable.)

When we left the sanctuary, found our cart and faced that moment of having to decide where to go next, it took no time for us to choose a little afternoon trip. The driver was happy. Even his horse perked up. ‘Outside city’ had a higher rate.

He took us to the lake first. There, close to the city which it bordered, we marvelled at the size of the inland harbour. The driver claimed the lake itself stretched for a hundred miles east to west, cut off from the sea by a long, narrow spit of land that ran for miles, away towards Cyrenaica. Canals provided links with other parts of the delta, including a large canal at Alexandria. Here on the north lake shore we found a vast mooring pool that seemed even busier than the great Western and Eastern harbours on the sea side. The surrounding countryside was obviously fertile, swept annually by the Nile inundation with its burden of rich silt, and as a result everywhere close to the lake was well cultivated. They had grain, olives, fruit and vines so although at first this seemed an enormous, lonely area, we saw large numbers of oil presses, fermentation vats and breweries. Lake Mareotis was famously the home of endless papyrus beds, so it had all the necessities of the scroll-making industry. Boys paddled up to their knees in water as they cut the reeds, calling out to each other and stopping to stare at us. From the lake itself huge quantities of fish were caught. Then they had commercial quarrying and glass-blowing, plus numerous pottery kilns for the lamp industry and amphora-making for the wine trade.

It was one of the most frequented waterways I had ever seen. Outside the huge harbour, ferries plied both north-south to and from the towns on the southern edge of the lake, and also east-west. The fringes of the lake were extremely marshy, yet lined with jetties. Flat-bottomed punts were everywhere. Many people lived and worked from houseboats moored in the shallows - whole families, including infants who at crawling stage were tied on with a rope around the ankle that just gave them enough play to keep safe. ‘Hmmm. I wonder if it would be frowned upon if we tried short tethers with our own dear mites?’ ‘Julia and Favoma could undo a rope in about five minutes.’ The driver refused to stop among the marshes. He said the tall papyrus reeds were full of paths and dens used by gangs of criminals. This seemed at odds with the multitude of luxurious out-of-town villas to which rich Alexandrians migrated for leisure in the countryside. Playboys and tycoons don’t put up with brigands in their neighbourhood - well, not unless they themselves are brigands who have made their pile and settled in huge villas on the proceeds. The tycoons’ spreads here worked like the grand holiday homes in the coastal strip between Ostia and the Bay of Neapolis - close enough to be reached from town in the evening by weary businessmen, and close enough too for obsessive workers to feel they could nip back to the courts and to hear the news in the Forum without ever growing out of touch.

We had left the harbour behind us and driven out on the long narrow land spit between sea and lake. After a time the driver decided the reeds in these parts were not the dangerous kind out of which brigands might rush to steal his horse. They looked the same as the others to me, but you bow to expert local knowledge. The horse itself was game to plod on, since it made progress at an undemanding pace, allowing itself time to gaze around at the views. But the man needed to get down and fall asleep under an olive tree. He made it plain we required a rest stop, so we obediently took one.

Fortunately we had brought drinking-water and snacks to keep us occupied. Herons and ibises paraded themselves. Frogs and insects kept up low background noise. The sun was hot, though not sweltering. While the driver snored, we took advantage of the peaceful spot. He may have been acting and hoped for intimate behaviour to spy on, but I was alert to that. Besides, sometimes catching up on a case is even more alluring.

‘I had a long talk with Cassius this morning, when you abandoned me again,’ said Helena, who liked to be part of everything. Her complaint was light-hearted. She was used to me disappearing on interviews or surveillance. She never minded me doing the boring routines, so long as I let her play dice when the game hotted up.

‘I was with your dear brother part of the time, looking at the Pinakes.’

‘How commendably academic. Oddly enough, Cassius and I were talking about the catalogue.’

‘I hadn’t seen him as a scrollworm.’

‘Well, neither had I, Marcus, but we know very little about him. We just assume Cassius was once some beautiful, vacuous young boy Uncle Fulvius picked up in a gym or a bath house - but he is probably not that young.’

I laughed lazily. ‘So you think he’s an intellectual? Fulvius chose him for his mind? When nobody is looking, they sit together and intently discuss the finer points of Plato’s Republic?’