When Salazar Slytherin invoked the Parselmouth curse upon himself and all his children, his true plan was to ensure his descendants could trust one another's words, whatever plots they wove against outsiders.

• You have two parents, four grandparents, eight grandparents, etc.
• A generation is 20-25 years (depending on how young people have children)
• Salazar Slytherin lived one thousand years ago.

In short, today either every wizard in Britain is a descendant of Salazar Slytherin or none is. It seems awfully convenient for Quirell to suddenly have a foolproof way to make Harry believe certain claims. It seems to me that the whole "snakes can't lie" thing would have been revealed when Quirell was trying to convince Harry he didn't want to kill Bahry in Azkaban. In fact, that would have shortened that particular discussion considerably, in a situation where time was essential.
It has already been established that ventriloquism and silencing charms exist and that Quirell can do silent and wandless spell casting, so the "two plus two" test could easily have been faked.

Broad science background specialising in biology. I've studied to be a highschool teacher for two years so a background in didactics as well. And most of the sequences and pieces of literature (Kanheman's 'Thinking Fast and Slow' comes to mind)

Mail sent I'm looking forward to meeting everyone.

How hard it is depends on what kind of meetup you’re running, in may case it’s very easy. The Brussels group is more of a social gathering. We start of with a topic for the day but go on wild tangents/play board games and generally just have fun. The only things I ever needed to do as an organizer were: pick a topic for the meetup, post the meetup on the site, arrive on time, make new members feel welcome and manage the mailing list. When I started out I honestly didn't have any expectations on how hard it would be, I had no idea how they would turn and had decided to just run with whatever happened.

Once the meetup had a core group of regulars some of them offered to help and I could delegate the stuff I’m not very good at (like the meetup posts on LW and coming up with topics) These days the only things I feel I have to do are put in an extra effort to involve new members and keep the atmosphere friendly (which, in two years of meetups, has only once been a problem, LW’ers are generally great people) and those are things I would do anyway.

I know there are other meetups were the organizer has more responsibility. For example, if you have a system where every month another person gives a short presentation you have to manage that as well. For larger groups (Brussels rarely has more then 4 people) an official moderator type person might be handy to make sure quieter people get a chance to speak up. There is no one “right” way to run a meetup, see why people enjoy coming to yours and try and make that part as awesome as you can. Just keep an open mind about trying new things every now and then.

In short, how hard it is to run a meetup depends the type (social, exercise focused, presentations, etc.) In my case, it’s very easy especially since I have other helping me out. If you’re thinking on starting one yourself don’t worry to much about what type you want it to be, just see how the first few meeting go and it'll point itself out from there.

I'm a 24-year-old guy looking for a job and have a great interest in science and game design. I read a lot of LW but I rarely feel comfortable posting. I wished there was a LW meetup group in Belgium and when nobody seemed to want to take the initiative I set one up my self. I didn't expect anyone to show, but now, two years later it's still going. Ask me anything you want, but I reserve the right not to answer.

Or it's the ritual to create dementors. Quirrel says that "the spell to dismiss Death is lost" and nobody knows how to destroy a dementor.

It ignored other humans, Filch was standing close enough to be spattered with his cat's remains, there is no way he could have outrun the troll. He was alone and it's stated that trolls go for isolated targets, the only reason the troll would have let him go is if it was commanded to.

I do retract my later claim that Lucius wouldn't care about other Hogwarts students, it should have occurred to me he wouldn't risk his allies' children.

Harry is the only one to witness the 'dying-soul-magic' and he has no idea what it is supposed to look like. Adding any sort of magical disturbance to the dying magicked!rat would have the same result from Harry's point of view.

It could just have been an excuse to list the professors present and note Dumbledore's absence.