Bit of sidestory fodder, since the entry of the TSAB into the crossover is likely to inspire some thought on adjacent topics.
...
During the human struggle between the British and German Air Forces, between pilot and pilot, between A. A. batteries and aircraft, between ruthless bombing and the fortitude of the British people, another conflict was going on step by step, month by month. This was a secret war, whose battles were lost or won unknown to the public, and only with difficulty is it comprehended, even now, by those outside the small high scholarly circles concerned. No such warfare had ever been waged by mortal men. The terms in which it could be recorded or talked about were unreachable to ordinary folk. Yet if we had not mastered its profound meaning and used its mysteries even while we saw them only in the glimpse, all the efforts, all the prowess of the fighting airmen, all the bravery and sacrifices of the people, would have been in vain. Unless British science had proved superior to German, and unless its strange, sinister resources had been effectively brought to bear on the struggle for survival, we might well have been defeated, and, being defeated, destroyed.
-Winston Spencer Churchill, Their Finest Hour
The Wizards' War
July 1940
Danson House
London
"I'm guessing you're done with your crystal ball work."
"They... it's true. It's actually true. They have at least three hundred Polish doctors and schoolmasters and so on there. Penned up as... as...
sacrificial cattle. And with this kind of
schrecklichkeit going on all over Europe, they'll do it again if it doesn't go as planned this time. How- how do we
stop something like that? I- I-
Christ..."
"Here. Let's improve that cup for you."
[sounds of gurgling, long silence]
"You confirmed the location, at least?"
"Yes."
"And they can't pack up and move easily, not with these arrays and not unless someone's been whispering a lot of geomancy in their ear. Well then, the good news is that the Army's been forming commando units for raids onto the Continent. It's not hopeless. And just between you, me, and the wall... I do believe this location is within range of the coastal batteries they're running up. Some of them are spare battleship guns. On supercharge, maybe... And there's always the Air Force."
"Hard on the Poles, if it comes to that."
[pause]
"You're not wrong."
"And how do we stop them
next time?"
"I've read proposals to ward the entire coastline. Heavily."
[pause]
"
That heavily."
"Yes."
"We'd need ten thousand experienced sorcerors lining the cliffs of Dover in little bunkers, and we don't have them. Or we'd need rune arrays fifty yards wide and sticking up in the air like bloody flagpoles. That won't fly."
"Nonsense. That's the easy part. There's buildings with giant metal widgets on poles all over the south of England these days. Not one man in a hundred is cleared to know what they do or how they do it, anyway. Won't be hard to run up some more and keep anyone from asking questions."
"Not one in a hundred... let me guess, I'm in the ninety-nine."
[pause]
"I'm cleared to know about Jerry's veritable
black magic and I'm not cleared to know
this?"
"I can tell you a name. Chain Home. I may tell you more later, if we go through with this."
"We'll be tuning across an arc from Land's End to Lowestoft Ness. Dozens of ritual sites.
Big. Lined up to the inch. I'm not looking forward to the calculations, are you?"
"We'll have to think of something. Maybe summon a few thousand imps with slide rules..."
"Have you ever taught an imp to use a slide rule?"
"Actually, yes. It wasn't worth it."
"We need a proper mathematician. One who knows how to keep a secret."
Some Days Later
Alfred Stibbons saw on the mathematician's face an expression he'd seen before- usually on apprentices.
The young man who insisted that he
wasn't a professor was looking at something no one else could see. Something he must think powerful and wonderful, but something he barely dared to imagine was real.
But he hardly seemed interested in magic itself at all. His questions had been… directed. Focused. As if he was a very busy man who already had a plan and was trying to fit an entire new world into it in a hurry. Perhaps that was exactly it. The new Ministry of Defence had refused to say
anything about what this man did in his existing war work, and Stibbons knew better than to ask.
The mathematician's broad mouth twisted in a grimace of thought, then he spoke again.
"So let me see if I understand you. You can build… magical sigils up out of nothing but metal and effort. And you need a great many calculations done in a hurry. Tell me, can this wizardry of yours make a
switch?"
"How do you mean?"
"Something that, oh, let's say it had two paths running into it, and if something was, oh, what amounts to "on" on both of those two paths, it would turn off. Otherwise it would stay on."
Cautiously, Alfred nodded. "You mean 'on' and 'off' like a light switch?"
"Or something more like sending dots and dashes on a telegraph. On and off, yes and no, either-or, anything of that sort."
"You're not imagining a little telegraph made out of magic? Because I could arrange something, but..."
"Not quite. It'd have to be something strictly automatic. But simple. Like a thermostat or an electric relay. Preferably something very easy to make an awful lot of."
Alfred shrugged. "I can't say I know a way off the top of my head, but I'm sure I could knock something out in runework if you gave me a little while to tinker with it."
"Because if you can make a little switch out of magic and wire it up to enough other little switches, sir, and if the whole pile doesn't cost too many thousands of pounds to make and run... I can give you all the calculations you could
possibly imagine wanting. And I think- I think we just might be able to take that and win the war with it."
The mathematician's eyes positively blazed. Yes, Alan Turing was
definitely seeing something he didn't.
