Some things are known about its structure and how it connects to the keystones of the building, but it is not known how to cast it.

Fine. Is there a list of all the places in the world with anti-lightning wards? He will go on a trip trying to build voltaic piles.

Not in this book, but the library has a few examples.

Father,

We got midterm results back. I am the top of the year but am still not allowed to go to Hogsmeade because of cheating on my essays. I do not regret cheating on my essays but acknowledge the predictability of this consequence. I missed a question in Charms, the professor asked about examples of injuries resulting from miscasting the spells we've learned so far and instead I wrote about what constitutes miscasting in Charms and how we could do faster spell development with thinner safety margins and this would be worth the additional risk. I did mention examples of the thing he wanted but he said he didn't want to read through pages of irrelevant content to get to the relevant bits. I could never be a Hogwarts teacher, you have to spend so much time grading stupid students' work. 

...

There are, as far as I can determine, twenty-seven publicly accessible sites with variants on the lightning ward that I think must be responsible for voltaic piles not working at Hogwarts. I want to visit all of them this summer as part of the trip to China. The sites are attached. Everybody's talking about the goings-on in France so visiting the ones there might be challenging, not sure, I haven't actually been paying attention to the content of the goings-on in France beyond that they're causing all this stir. 

...

I find it very deeply upsetting that we don't know how to cast all the wards that went into Hogwarts. I want to reconstruct them all, starting with the lightning one, but it occurred to me you'd have felt the same way. Did you get anywhere on that? Do you have advice on where I can productively start?

With loving regard, your son,

Minor Finis Way

Minor -

Except with respect to the opportunity to build a voltaic pile you are not missing much - Hogsmeade is an unremarkable village except for its proximity to Hogwarts, and if you want to buy things you can ask one of your brothers. Michael in particular has somehow already exhausted his pocket money for the year and I take it would run you errands in exchange for some of yours. (You have also exhausted your pocket money for the year, eels and copper and zinc are expensive, but you are spending it well and so can have as much as you require.) Not all of those sites have the same kind of ward, is that why you think you'll need to see more than twenty of them to make the appropriate extrapolations? Either way, it is very doable, we have all summer and much of my work can travel with us.

I did, like you, decide to reconstruct a lot of ancient magic my first year in Hogwarts. Surpassing it might come ahead of reconstructing it, honestly - the former only requires superior knowledge of the subject, while the latter also requires an understanding of what the ancients were doing and what constraints they were under. I do not know if I can make a Philosopher's Stone but I am very certain I can make men immortal. Someday. 

Your first-year scores don't matter. Learn things and don't worry about anything else. If you get expelled I will just teach you myself, don't let them threaten you.

- Finis

Father, 

Attached are more language notes, and a few attempts at translating some poetry into Igbo. Swan did not think I'd done particularly badly. There are conventions for the translation of poetry from Latin; I found myself at something of a loss trying to do the translation without the convention. I know this means I should practice more and I certainly will do so. I have answers to three of your four syntax questions, fourth one I have some examples and an attempt at an intensional definition. 

...

Ravenclaw beat Hufflepuff and the common room's tediously loud, so I went up to the Owlery. Which smells. Have we not devised a better form of communication? Or a spell to make owls defecate less? That'd be a very popular one, maybe I will suggest it to Michael who is apparently out of pocket money. (His girlfriend has a lot of elaborate new jewelry. I think this is because he enjoys having a reputation for wasting his money on jewelry more than because he thinks the jewelry itself is valuable, or the girlfriend, but it's not a question to which I've devoted extensive consideration because people are confusing and I could always consult Timothy on them if it actually mattered. You didn't have a Timothy, how did you do people things?)

...

The Transfiguration professor said something interesting today. We were talking about Gamp's laws - Gamp is a Slytherin first year and has been very smug for the last several weeks of lessons, even though she's no more closely related to Ulik Gamp than I am - and the smallest unit from which you can make more of something through transfiguration. Someone said very gravely that it was one of those questions the Greeks disagreed on, which is fine as far as it goes but hardly means the question is inherently unanswerable or something. Professor Litwick thinks it might be, but I have a list of experiments I want to try to check...

Eagerly awaiting your reply, your devoted son,

Minor Finis Way

OWLs are approaching, and the workload is getting ridiculous. He starts a number of study groups, since he's never been particularly good at studying alone. They spend all their time in the library. He asks Michael to look after everybody and to his surprise Michael does this, well and without any complaining.

A study group member, present to trade her Runes expertise for help with Charms, is sidetracked talking political logistics with someone who's there to cram for Arithmancy. "No, there can't exist any position higher than Minister of Magic, it's literally impossible - if it's private, it's not really higher, and if it's public, somebody just Imperiuses you and then you're a figurehead and they're the private operator behind it -"

"That just means they'd need lots of security."

"Even the Minister of Magic needs lots of security, the best that can be had, and if the target were any juicier that wouldn't do for more than a week."

"It's supposed to be possible to learn to resist the Imperius."

"Not from a cold start," says the first student. "And by the time you've been under it for a week they've got all the blackmail they could ever want, don't they, and plenty of chances to Memory Charm you -"

"You seem to think it's so easy, why don't you think someone's doing it to the Minister -"

"Minister doesn't have enough power to make it worth Azkaban if you get caught."

"This still just seems like an argument that no one who hasn't dabbled in dark magic could rule anything larger than Britain."

"They can't, that's the point. Not unless the power's spread around a few people like how they have it in Belgium. Or at least they have to have associated with people who do. Dabble."

"I sort of assumed most people with real power did. Or do."

"Maybe they do."

"Now there's a depressing thought. Warps the soul."

"Aren't we here to study," says another boy.

Sure, he doesn't say, but what are we studying for?

They get back on topic.

The topic meanders again but in softer voices, later:

"Who do you think dabbles? I reckon Mullins."

"He just looks it, nobody with sense does it and looks it."

"Who do you reckon then."

"Lyons."

"She does not," says a girl.

"How do you know?"

"I just know."

"There, you see, you're clearly Imperiused to say that -"

"Shut your mouth -"

"Merlin's arse I just want an O in Charms will you all shut up."

Muffling charm for that kid, why not. "Accusing people of dark arts without evidence seems unkind if you're wrong and unwise if you're right."

"He asked what I reckoned!"

"Don't be such a child."

They subside.

To the benefit of all of their charms scores.

The girl who defended Lyons lingers a little after the group disperses and remarks casually, "It is possible."

"Know someone?"

"You'd owe me a favor."

"People tend to find it advantageous for me to owe them favors."

"Yup." Smile. "You'll owe somebody else a favor, too, I just know they went somewhere, not where."

"Someone I can look up for study help, or do I need to wait for summer?"