2) When Harry burried Lasciel's coin (Death Masks); why didn't the wet cement disrupt the circle? Harry broke the Shadowmans circle with a film canister.
Thanks
First I'll give the WoJ on the subject, which is quite good.
In SF p.66, Harry draws the circle to contain Toot, memorizes it's exact location, then covers it with leaves and twigs to hide it from view. Toot eats, the circle closes - everything works. However, on p.175 (when he and Susan are being attacked by the demon), Harry goes nuts ensuring that every scrap of paper is clear from the circle in his lab (the copper circle he installed in the floor - he should remember where it is... ) prior to activating it. I've gotten the impression that a circle's perimeter needs to be clear before activating it. Is this an inconsistancy, or am I missing something?
Something to do with the environment here, too. You can't have any foreign objects interrupt the circle. But since the circle was being made out of earth and twigs and leaves, it isn't going to be disrupted by earth and twigs and leaves. It still could have been /broken/ by one of them, if any of them had actually marred the circle drawn in the earth, so that it wasn't a complete shape any more (not just fallen over it). For that matter, if Toot had scuffed his foot through the circle on accident on the way in, that could have blown the trap, too.
Different situation with a big copper circle in a smooth concrete floor. I mean, I suppose Harry could have made a circle out of, I dunno, dirty laundry or something, and other dirty laundry laying across it could obscure it without breaking it. But then if the wrong sock gets shifted, pift, no circle any more. Much safer to go with the big metal circle in the floor that you know isn't going to be broken, and just take extra pains to make sure nothing falls across it.
Jim
Ok with the obligitory (for me) WoJ quote out of the way, I will give my interpretation of this situation.
It's actually quite a good question. The way I look at it though, is that the physical circle is a mental aid. I get the idea that if a wizard went through the effort of imagining the circle in his mind, that can get the job done... it's just easier to draw it and then his mind knows it's actually there and that mental effort can then go towards the actual spell's working... IMO, each physical object that is used for Harry's magic, be it his staff, or a complex multi stage circle with lots of ritual objects, is in itself not magical, it just gives him physical constructs that he can support his own mental workings onto like a firm foundation or chanel to contain it with and shape what he wants out of his magic...
Intent is key here. The prison was intended to be encased in cement. Every circle we have seen has had some medium that it passes through. Typically air, but in this case, the circle was intended to be emersed in cement. In fact, the cement was a deliberate part of the... prison constructed in Harry's mind. So in this case, pouring cement on top of an already activated circle that is intended to serve as a prision, does not interfere with it, but rather makes it stronger, since the spell is fundamentally mental construct on his mind. The cement serves as a seal on the vault both physically and metaphysically.
Of course that's just my opinion/interpretation.
Another related question that I have pondered a few times though, is why can the prison spell withstand so many sunrises and sunsets that typically degrade Harry's workings? The best answer I can come up with for that is that somehow an empowered circle is a different kind of magic than the workings that are degraded by passing of the day, or somehow Harry is actively maintaining the prison in his mind through some effort...