“When you and Nightingale write reports, I’m the one who reads them,” he said. “At least those portions that are relevant.”

“So are you Nightingale’s governor?” I asked.

Postmartin chuckled. “No,” he said. “I’m the archivist. I’m in charge of the great man’s papers and the papers of all lesser beings that have stood on his shoulders since. Even Nightingale and you.”

After all that history it was quite nice to turn onto Broad Street, which at least had a few Victorian terraces and an Oxfam.

“This way,” said Postmartin.

“Newton was a Cambridge man,” I said. “Why are his papers here?”

“The same reason they didn’t want his alchemistical works there,” said Postmartin. “Once he was safely dead old Isaac became their shining star of science and reason—I doubt they wanted that picture complicated by what was, let’s face it, a complicated man at the best of times.”

Oxford continued to be solidly Tudor with sudden bursts of Georgian exuberance until we reached the Eagle and Child pub on St. Giles.

“Good,” said Postmartin as we sat down in what he called a “nook.” “Thomas isn’t here yet. One finds it so much easier to have a certain kind of conversation with a sherry in one’s hand.”

When you’re a boy your life can be measured out as a series of uncomfortable conversations reluctantly initiated by adults in an effort to tell you things that you either already know or really don’t want to know.

He had his sherry, I had a lemonade.

“I take it you understand how unprecedented it was for Thomas to take on an apprentice?” asked Postmartin.

“People have made that pretty clear,” I said.

“I think perhaps he should have taken that step earlier,” said Postmartin. “Once it was clear that reports of the death of magic had been greatly exaggerated.”

“What gave the magic away?”

“Thomas aging backward was a bit of a clue,” said Postmartin. “I archive Dr. Walid’s reports and the bits that I understand are … strange.”

“Should I be worried?” I asked. I’d only recently gotten used to the idea that my governor was born in 1900 and had, according to him, been getting young again since the early 1970s. Nightingale thought it might be linked to the general increase in magical activity since the ’60s, but didn’t really want to look a gift horse in the mouth. I didn’t blame him.

“I wish I knew,” said Postmartin. He reached into his pocket and handed me a card. It had Postmartin’s number, email, and, I was surprised to see, Twitter address. “If you have any concerns you can contact me.”

“And if I contact you,” I said. “What will you do?”

“I’ll listen to your concerns,” he said. “And I’ll be very sympathetic.”