Private Message to Professor Dolohov

[alt_ron]

Sir, I was wondering whether there are any spells a person could use to keep someone else from casting a blood lock on an object. For instance, if I had something that I wouldn't want to lock, but it would be really annoying if someone else came along and charmed it closed. Is there anything I could do to keep them from locking it to themselves?

Sorry if that sounds like making up stuff to worry about. Only, I've got brothers who do things like that all the time because they think it's a laugh. I could totally see them locking me out of my room that way. Because you could do, couldn't you? With a wooden door and doorframe.

So, yeah. Sorry to bother you. Just, it was interesting today, and got me thinking, I guess.

Comments

[alt_antonin]

My apologies, Mr Weasley; I did not see this message before today's class ended, or I would have answered it then. Do feel free to bring questions such as this up in class, particularly since our lunchtime class together will necessarily be slightly more informal; of course, I'm equally happy to answer via journal.

You could possibly lock someone out of a room if the door and doorframe were all wood, as well as all the walls that made up the room, but it is very rare these days that doors alone don't have metal hinges, much less the walls themselves. Even a single nail driven into the wall would likely cause the magic to fail. (I say 'likely' because the boundaries and requirements of this particular spell are somewhat nonspecific, and rely a great deal on how both you and the magic think of "boundaries" and "edges". We will discuss many of those questions later in the year, though I promise I will not make you sit through all the lessons on philosophy my own teacher made me work through! But the Arts are ever mutable, and different people will often get different results based on how they conceptualise the world around them.)

Too, the spell I taught you does not scale well at all: in the case of a room, the protection of the lock would spread out over the entire volume of the room, and the small amount of power you put behind it would be much easier to break if spread over such a large area. For protecting a room, a house, or any large area, you would want wards, not this lock. Wards are much more complex, and take much greater time and care to set up and cast, but they are far more stable. (We will be studying warding in NEWT-level classes; however, if you're interested in knowing more now, I do have some introductory texts I could lend you, as long as you gave me your word that you would not try any of its exercises without my supervision.)

The more "yours" a particular item is, meanwhile, the more likely it is that the spell will fail if someone else tries to claim it and lock it. The reason I had to borrow a box from Professor Lestrange's stores was because all the ones I had have been mine for so long I would not have been able to lift ownership enough to allow you all to try the spell if you wanted! (There is a way to sever ownership for magical purposes -- just giving something to someone often is not enough, depending on the degree of ownership -- but it, too, is slightly more complex, and deals with the extremely messy question of intent. It is how I was able to transfer 'ownership' for purposes of demonstration before class, however.) If someone tries to use the blood-lock on an object that they do not have some form of claim upon, and that belongs to and is claimed by another, it is likely to fail -- your dorm-mates almost certainly would not be able to claim your trunk and lock it, for instance, unless they were able to establish some form of ownership over it.

But if you wish to ease your mind, there is indeed a way you can establish a stronger magical claim over your possessions if you do not have a strong emotional attachment to them: using the spell I taught you to draw your blood, lift one drop of your blood to the surface of your finger and touch it to the underside (it must be the underside, bottom, or place where the thing rests against a surface when it is set down) of the object. Take your wand and tap the top of the object three times in equal intervals; as your wand touches the object, each time, repeat Res mea. This establishes a very basic "ownership" claim over the object: that claim is relatively weak, and can be broken in many ways, including by making a sincere and wholly-meant gift of the object to someone else, but it will ensure most attempts to exert ownership over the object by another will fail.

Another five points to Gryffindor, for your thoughtfulness and interest. And do allow me to say, I have been quite impressed thus far by your critical reasoning skills. From what I have seen so far, you have the knack -- quite rare in the population at large, in my experience -- of taking a fact, and from there seeing many of its practical implications that others would wholly miss. I would like to encourage you to continue asking whatever question comes to mind throughout the year: from what I have seen thus far, they are certain to be useful and relevant.

Regards,
Professor Dolohov