Harry and Hermione are sitting facing each other on Hermione's bed. "Hermione, do you think Aunt Petunia would mind if I started calling her Mum."
"I don't see that as being a problem, why?"
"She doesn't feel like my Aunt before. My Aunt was an angry person who always snapped at me, belittled any of my achievements, and would find any excuse to make me do more work."
"I can't imagine your Aunt like that."
"She was, I found out just after I found the letter that she was being abused by Vernon, and worse than I was. I can easily see how if I wasn't being punished for even thinking about causing trouble, I could have so easily done the same to someone else. Even if I didn't want to hurt them.
"But once I found out and started protecting her too, it changed. She was happier when she came down in the mornings, we shared tea, and did the chores together. The one-time Vernon found out sounded like a bad night for her. But it didn't change who she was with me anymore. She even came to Diagon with me when before she wouldn't have ever countenanced doing anything that Vernon might disapprove of, and magic was high on that list."
"All that time we spent with you and your parents, she was different, happier and freer somehow. And then yesterday she doesn't even look like she used to, I mean it's still her, but not as old. I think I've been thinking about it for a while, and it only came together when I found out that she'd been badly hurt and was in hospital."
Feeling refreshed and normal once she wakes up early in the morning, Petunia decides that she shouldn't let her meditation fall by the wayside. Sinking into her trance she finds her magic easily and starts to work on how to control how active it is. It's still trial and error as she doesn't know what increases it's activity and what decreases it yet, but she feels like she's getting closer. She doesn't notice when Healers rush in, or when she surrounds herself with a clearly visible magical aura, or when her hair grows out to waist length again. She doesn't notice the recording charms and dictaquills going in the distance as the Healers are desperate to record this phenomena or when it suddenly flares into blinding light and goes dark again, leaving spots in the vision of all the watchers and all the unbound spells in the hospital dislodged, including those affecting the patients of long term care. Slowly her magic comes down to normal levels again and she opens her eyes before swearing softly, not noticing a couple of apprentice healers sweating in the corner.
She did notice an hour later when Amelia Bones walked in with a male healer both wearing very angry expressions on their faces.
"Of all the irresponsible things to do in a hospital, why on earth did you decide to practice channelling magic?" The man shouted at her.
Petunia struggled to defend herself, every instinct screaming to lower her head and accept the beating. Instead she said softly with her head lowered "I have no idea what you're talking about."
"That, meditating to channel magic and increase your own ability."
"I wasn't doing that."
"Then what do you think you were doing?"
"I was trying to control my own magic, to learn how to quieten it."
There was a pregnant pause as neither Amelia or the male healer expected that response.
Choosing her words carefully "Lily Potter left a letter for Harry that arrived on his birthday. In it she said that there was something different about his magic and he needed to use the beginning steps of something called Occulmancy to learn to control it before he grew up otherwise it would likely kill him. So I decided to learn alongside him to support him and give him someone to talk to about what he found."
Amelia reigned in her anger with great difficulty and tried to think about what she'd just been told rationally. She seemed to remember reading the letter from Lily, though it's clear that Petunia left a lot of it out. There was also the fact that she almost certainly wouldn't know about channelling as it was only something that was talked about in borderline dark defence books.
In a tightly controlled voice she bites out "I've seen the letter in question, I think she's telling the truth. Merlin knows what she's going to be like once she learns some control."
The Healer stalks over to the desk and picks up the results of her scans and looks them over. Draws his wand and casts a few diagnostic spells. "She's no Merlin or Dumbledore, so I have no idea how she was able to do this without channelling as no one has magic pure enough to even consider expelling that much magic without being a powerhouse like them."
As no one seems to be angry anymore and they're not paying attention to her, Petunia shrinks into the pillows on the bed and tries to look small and harmless.
Amelia conjures a chair and sits down heavily rubbing at her temples, "Let's assume that she's telling the truth is there anyway to check?"
"We have a teaching tool that Journeyman Healers have to show competence in before they can be accredited as full Healers. It's sometimes used in obscure cases where we need to calculate exactly how much magic someone has in reserve in order to treat a progressive spell or use a lifesaving potion."
The two apprentices start to pay rapt attention as they are getting a free lesson from a Master, possibly Grandmaster Healer.
"You, go and get a purity plate from the storage room and calibration stones, ask for help if you can't find them immediately."
The other apprentice cuts off a blank section of parchment and starts taking notes as the other one runs off.
"I'm sure you're aware of the Merlin scale of magic." Amelia nods.
"That goes from 0 to 1000, and is the absolute amount of magic that something contains. When measuring creature like dragons they expand the scale as size affects the absolute amount. Our diagnostic spells work off of an assumption of a certain range of densities as muscle mass and magical power are strongly correlated while fat is the inverse, so rather than needing to do calculations to work out just how their magic is distributed we instead take shortcuts for speed. 99% of the time this works out, as someone that's stronger but has lower magical density would have the same power as someone with a greater density but lower physical fitness."
Amelia nods thoughtfully as this explains some of the things about the Auror corps.
"To measure magical density we use Thaums, this goes from 1 to 1000, where 1 is the lowest level needed to use a spell, while 1000 would be a being of pure magic. Most muggles have a level of around 1/100th of a Thaum, squibs clock in at above 1/10th a Thaum. The highest level ever recorded was Grindelwald who was measured at 40 ½ when he was imprisoned in Nuremburg. Given that magical quantity works out at around 0.1/lb we can calculate that he would have scored around a whopping 800 on the Merlin scale.
"Given our standard assumptions our medical spells, given a 1 hour recovery time, calculated her to be at around 300-350 on the Merlin scale at full capacity, and she was dangerously low with 30 when she came in. I won't take you through the arithmancy for this as we don't have time. But suffice to say, unless she has a magical density like a dragon, our spells are highly unlikely to be wrong. The reason they don't work on Dragons is that their magical density is over 100, and our spells shortcut and take a fractional reading and extrapolate out."
Amelia groans as she can see where this is going to end up.
"Would you be able to do the calculations for a creature that weighs around 1 ½ lbs and is made of pure magic?"
"1500" The doctor responds promptly.
"Merlin, I knew the day was going too well when my eggs were perfect, and I had no missives from Fudge on my desk when I got in. Petunia has a verifiably purely magical creature as a familiar that lives off magic. Healer Gosling verified it with me yesterday afternoon."
A panting apprentice came back with the equipment and handed it to the Head Healer before going to stand back beside the other Apprentice and scanning over their notes.
"Oh, she said that she'd got the title of her Mastery dissertation and that she'd have a summary ready for next week for me to sign of on. Anyway, lets get started."
He lays the plate on the bed and opens the box revealing the stones inside.
"We've got 5 stones, the first of which is magically inert, the others go up in grades of 100 Thaums each. We stop at 500 because of the difficulty of both making a higher one, and the fact that charging a larger one would exhaust most people. As you can see, we charge the stone until the rune on the top turns red, then once it turns green we place it on the plate here and the number appears above it. Once we've verified that all 5 stones have given the correct numbers we place our wand or finger on the plate here and once we've channelled enough magic the number will show."
The plate shows 8 1/3
"As you can see, I'm not a particularly strong wizard, so I've had to make it up with skill. Amelia if you would?"
Amelia does the same and it shows 18 17/100
"That's a very respectable score, certainly in the upper levels of the wizarding population."
"Now Petunia, would you be able to do the same. If you're not used to doing it without a wand, just imagine a stream of water coming out of your finger."
She does that and a stream of water comes out and splashes off the plate all over the other two.
"Ok, I think you took that a little too literally. Think back to what your magic felt like while you were meditating and imagine that coming out of your finger."
A soft white light came out of her finger and streamed into the plate and showed 819 1/5
Spluttering in disbelief he get's the two apprentices to test, they come out as 10 1/3 and 14 12/25 respectively. Calling Dixy he persuades him to do it 60 1/7. He calls in another Master Healer to check the calibration and test it 13 1/8. Finally, he interrupts Andromeda and gets her to verify that the plate is functioning correctly.
It was into this that Harry and the Grangers walked into.
A man barked at them "Right you four, I need you to push your magic into this plate."
Looking up Amelia sees who it is, "I don't think you want them to do that."
"They're magical, of course I want them to do it, the more data we have the easier it's going to be to work out what's wrong with the calibration."
Amelia mutters under her breath, "You asked for it."
Harry looked up at her Aunt who nodded back to her and says in a quiet voice "Just imagine the stuff you feel while you're meditating is coming out of your finger. Don't imagine water otherwise you'll get the bed wet again."
Shrugging she does as asked and the number 840 shows up, then he climbs onto the bed and hugs his aunt.
Hermione, Emma and Dan all go next – 803, 798, and 790 respectively.
Seeing those number Andromeda shouts "Bingo, Master Dagworth, cast the standard diagnostic charm on them and see what comes out. If the plate is correct it should feedback obscenely high numbers."
Dagworth casts the spells on Dan and Emma and goggles at the numbers, "Ok, they match up. What in Hades name is going on?"
Amelia gets up and gently bashes her head against a wall. Then sighs, turns around and leans against it. "Petunia, Dan, and Emma aren't witches or wizards. They were born muggles and until a few months ago they were still muggles. Harry accidently found a way to turn a muggle into a magical, and Hermione reproduced it a few weeks later and accidently converted her parents. They have a friend that knows about it and they have threatened to turn her magical if we try to enforce the statute against her. Finally, Petunia's familiar is a purely magical creature, a living spell if you will, that eats magic."
With Harry hugging her Petunia was able to voice a query "Can I go now?"
Dagworth waved at her absently "Oh yeah sure, your no longer in danger of magical exhaustion, just make sure you're not on your own for the next few days and you'll be fine. Sign out at the welcome witch."
With that they leave, Harry holding onto a clearly shaken Petunia. The welcome witch kindly transfigures her nightgown into day robes for the journey home, and they all head back to the Grangers.