Harry and Hagrid continue their journey down Diagon Alley, stopping at a pet shop for Hagrid to buy a snowy white owl for Harry, which he names Hedwig.
Leaving the apothecary where they bought a cauldron full of ingredients, they made their way to the book store. Moving passed the entrance, the interior seems bigger than the exterior.
There are book cases filled with books over twenty feet high, with multiple rows up and down the store. There are at least forty rows.
Harry goes down the aisles, peaking every now and then down, until he finds a shelf of torn books. Under the shelf is the label "DAMAGED".
Peering at the covers, none seemed to grab his attention. There are a few on wand waving, "Wands Wonderful Wrist by Agatha Athritis" and several on dueling "Entombing Enemies by Spye Duet".
Looking on, he notices a book with small lines and rectangles, before they wormed their way into words. "Avoiding the Mob: How To Overpower The Majority, by Heretica Gaunt".
Harry takes the book and opens it. Looking at the table of contents, he sees "Pushing Back - Expulsioritisima pp32".
Harry turned to the page, which reads "swishing and retracting the wand with the incantation will not only push back the attacker, the tip of the spear, but the entire crowd. This spell acts as a fulcrum where a large crowd can be pushed back.
Mind that the push back is not as powerful as it would be with the traditional expulsion of a single individual, but pushes back with a greater total force spread out of the entire crowd."
Harry flipped several of the pages into another chapter "Incidiorisma: pulling up and then down. This starts fires all over a large crowd. Not as powerful as a full on flaming tower of incendio maxima, but more fire power spread out over a larger group."
Flipping through the book, a common them emerged, where sickening, cuts, confusion, or cold is applied over a large group at significant effect.
Harry picks up the book and makes his way to another aisle, labelled "Hogwarts Books".
Harry takes out a list of books for Hogwarts and starts to collect each one. All these books are heavy, and it takes a while for Harry to walk to the counter where Hagrid is waiting.
Harry dumps the books on the counter and gets out his wallet, paying for the books. Hagrid picks up the supplies for Harry and announces "now the best for last. Your wand at Ollivander's."
They walked down the alley until they met a small, unobtrusive shop with the words "Ollivandeer's" emblazed on the front.
Entering, a thin man with wide white eyes looked up from the desk where a wand is split apart, and beckons them further in.
"Come in, come in. How may I help you?"
"Wer lookin fer a wannd fer Herry Porter."
The man's eyes widened a bit, but then beckoned him forward. "Yes of course, I have been expecting you."
He then continued to a shelf filled with boxes and slipped out a wand from the box. "Oak, twelve inches, unicorn core. Here, try it."
Harry took the wand. "Now move it around, see how it responds."
Harry moved it around, but nothing happened. Snatching the wand away, Ollivander continued. Taking out a box from the shelf and placing the wand in Harry's hand, but getting no reaction.
It is getting late, and around the hundredth or two hundredth time, Ollivander paused. "Maybe, no, but why not?"
He delicately took a wand from the back of his shop and placed it in Harry's hand. "Holly, phoenix feather".
Harry moved it around with his hand, and small red sparks appeared.
"Strange" he mumbled.
"What is so strange?"
"Why, just that the twin, of this wand, it has done great things, terrible but great."
This reminded Harry of that book.
"I have a question on spells actually. Is there a way to spread out the effect of a spell meant only for an individual. Like some curse, meant to hurt, but is spread out around a larger area, reducing the amount of pain someone would feel?"
Ollivander leaned out "Yes, of course, an old branch of magic. Fulcrunirism. It's defensive properties is to spread out an attack across a large area, diffusing the potential damage to the individual."
"So it can be used in defense."
"Yes of course. Why in fact, the Potters are infamous for that branch of magic. You may not know it Mr. Potter, but your family has stolen a large amount of Ministry property over the years. Even an entire citadel, in Kent I believe. The Potters are reknowned for using fulcrunirism magic to protect their holdings so that any orchestrated attack on them is in fact spread out over a great large area."
Harry looked down in contemplation.
"Well, tat's all fer terday Harry. Guess we ken go. Thanshk Ollivander."
Hagric took Harry out of the shop after paying for the wand and out of Diagon Alley towards the parked motorcycle.