‘Only if you do it wrong,’ said Nightingale. ‘I’m going to make a demonstration and you must pay close attention – as you did when searching for vestigia. Do you understand?’

‘Vestigia,’ I said. ‘Got it.’

Nightingale held out his right hand palm upwards and made a fist. ‘Watch my hand,’ he said and opened his fingers. Suddenly, floating a few centimetres above his palm was a ball of light. Bright, but not so bright that I couldn’t stare right at it.

Nightingale closed his fingers and the globe vanished. ‘Again?’ he asked.

Up until then I think a bit of me had been waiting for the rational explanation, but when I saw how casually Nightingale produced that werelight I realised that I had the rational explanation – magic worked. The next question of course was – how did it work?

‘Again,’ I said.

He opened his hand and the light appeared. The source seemed to be the size of a golf ball with a smooth pearlescent surface. I leaned forward but I couldn’t tell whether the light emanated from inside the globe or from its skin.

Nightingale closed his palm. ‘Be careful,’ he said. ‘You don’t want to damage your eyes.’

I blinked and saw purple blotches. He was right – I’d been fooled by the soft quality of the light into staring too long. I splashed some water in my eyes.

‘Ready to go again?’ asked Nightingale. ‘Try and focus on the sensation as I do it – you should feel something.’

‘Something?’ I asked.

‘Magic is like music,’ said Nightingale. ‘Everyone hears it differently. The technical term we use is forma, but that’s no more helpful than “something”, is it?’

‘Can I close my eyes?’ I asked.

‘By all means,’ said Nightingale.

I did feel a ‘something’, like a catch in the silence at the moment of creation. We repeated the exercise until I was sure I wasn’t imagining it. Nightingale asked me if I had any questions. I asked him what the spell was called.

‘Colloquially it’s known as a werelight,’ he said.

‘Can you do it underwater?’ I asked.

Nightingale plunged his hand into the sink and despite the awkward angle, demonstrated forming a werelight without any apparent difficulty.

‘So it’s not a process of oxidisation, is it,’ I said.

‘Focus,’ said Nightingale. ‘Magic first, science later.’

I tried to focus, but on what?

‘In a minute,’ said Nightingale, ‘I’m going to ask you to open your hand in the same manner as I have demonstrated. As you open your hand I want you to make a shape in your mind that conforms to what you sensed when I created my werelight. Think of it as a key that opens a door. Do you understand?’

‘Hand,’ I said. ‘Shape, key, lock, door.’

‘Precisely,’ said Nightingale. ‘Start now.’