Billy took back the book. ‘Well, I’ve been through it all three, four times, but I always find Book IX, Number Theory the best.’ He flicked forward to find the appropriate section.
Fortescue considered the boy. ‘How old are you, Billy?’
‘Twelve, Mr Wickins.’
The scientist took the book again and found the section on number theory. ‘OK.’ He ran a finger down the right-hand page. ‘Let’s see how much you know.’ He took a breath. ‘If a number multiplied by itself makes a cubic number, what can you say about that number?’
Billy looked into Fortescue’s eyes. ‘Ican see why you wouldn’t believe me, mister.’
Fortescue held the boy’s intense look. He could read so much pain there, years of neglect and filth. He could imagine how Billy had been treated all his life. He had probably been kicked from pillar to post, physically and mentally abused, and yet there was a light in those eyes, a light that was markedly absent from so many wealthy and celebrated people Fortescue had met. It was the light of a self-respect that had been hard won, battled for, squeezed from the dry sponge of the shabby life Billy O’Donnell had been allotted.
‘I’m sorry,’ Fortescue said and handed back the book.
‘That number would itself be cubic,’ Billy said, finally answering Fortescue’s question.
Fortescue bit his lip and tilted his head to one side. ‘Sit down.’
The kid glanced around nervously but did as he was told and Fortescue withdrew his papers, found a blank page and removed the top of his pen. On the paper he wrote out a simple equation, the meaning of which a clever fifteen-year-old at a decent private school should have grasped. ‘What does that tell you?’
Billy considered the expression. ‘It says that y is equal to three x squared minus five.’
‘All right, so, in your head, work out what y would be if x was two.’
‘Seven,’ Billy said immediately.
Fortescue took a deep breath. ‘Good.’ He wrote out a much more complex equation involving higher powers of x and square roots and handed the pen and paper to Billy. ‘What is z when x is four?’
Billy merely glanced at the paper. ‘Three.’
Fortescue was stunned, took back the piece of paper, wrote out an elaborate piece of calculus and handed it to Billy. ‘There’s nothing like this in Elements,’ the scientist commented. ‘What do you make of it?’
Billy studied the symbols and the figures. ‘It’s a quadratic equation that has to be integrated. I think it’s to work out the volume of rotation between the two points.’ He paused and ran a finger along the line of mathematical symbols. ‘The answer is 3.24 cubic inches.’
Fortescue was shaking his head and staring at the boy’s serious expression. ‘Well,’ he said excitedly, ‘that is truly remarkable. Come with me.’
‘Where to?’
‘My cabin. I want to see how much you know… I won’t bite!’
They saw no one on the way and when Fortescue found half a jug of barley water left over from the previous evening, poured a large glass and handed it to Billy, the boy relaxed a little.
‘Let’s see how far this talent of yours goes,’ the scientist said. ‘Is that OK with you?’
Billy shrugged. ‘What do I get out of it?’
Fortescue gave him a surprised look and went to reach into his pocket.
Billy was shaking his head and wore his affronted look again. ‘I didn’t mean money, Mr Wickins.’
‘What do you mean then?’
‘Just that you teach me something new that I can take away with me.’
Fortescue nodded. ‘Yes, yes, of course, Billy.’
Fortescue completely lost track of the time. This young boy was an astonishing prodigy. It had taken him an hour of questions, pushing further and further into advanced mathematics, before Billy hit a wall and could not solve a problem, and that was simply because he had never learned the technique. When Fortescue had then taught him how to unravel the question, the boy had the answer in a few seconds and was ready to move on.
The rap on the door came as a surprise. Fortescue glanced at his watch to see that it was nine o’clock and his breakfast must have arrived. He got up from the desk and walked to the door, opening it only a little. The steward was there with a tray.
‘I’ll take that,’ Fortescue said.
The steward looked puzzled for a second and then he understood his passenger must have a lady friend with him. He accepted the generous tip Fortescue gave him and retreated.
Billy was starving and Fortescue took great pleasure in watching the boy eat.
‘What is that?’ Billy asked.
‘Raspberry jam.’ Fortescue dipped a silver jam spoon into the basin and plucked a croissant from a basket, ran the jam over it and handed it to the boy.
‘And that?’ Billy pointed to the croissant.
‘A croissant. It’s French. Absolutely delicious.’
‘I’ll take your word for it, Mr Wickins,’ Billy retorted and took a big bite. ‘Um,’ he said, eyes wide, mouth full… ‘Good.’
‘You have an incredible talent, Billy. Has no one else ever realized?’
The kid shook his head. ‘Never told no one.’
‘Your parents?’
Billy looked down between his worn leather boots and ripped trouser bottoms. ‘Both dead.’
‘Oh, I’m sorry.’
‘No need, it was a long time ago. I live with me aunt. She don’t care two figs about me, though.’
‘So, how did you end up here?’
‘Me aunt — Mary’s her name — married a man called Bert, Bert Spindle. Me Uncle Tom, he died two years ago… bad lungs. He used to cough so loud we couldn’t sleep. Then one morning, the coughing suddenly stopped. My new uncle is all right, I s’pose, a bit rough sometimes. Don’t think he likes me much, but Mary made a promise to me mum and dad to look after me.’
‘Your uncle and aunt are hoping for a fresh new start in America.’
Billy nodded. ‘Uncle Bert’s a strong man. Been working on the roads in East London. He reckons there’ll be a lot of road building going on in New York and there’ll be jobs for the both of us.’