The Professor looked up wide-eyed at the symbol. "Yes, yes, yes, that! That, that, that symbol!"
He got to his feet and limped closer to it, all the while digging through his bag for a book. Opening it to a specific page, he double-checked and then turned toward the rest of the group, pointing to his book. "That, that is the symbol for Fire! This, this... I've, I've, I've only read about this! My, my, my m-master, my master had taught me about this. This, this is, this is a m-magic circle..."
He hurriedly thumbed through his book some more. "Now, now, now, the Precursors, the Precursors, they... used these circles to invoke the tetragrammaton, which, which, which would allow them... them... ah it's in here somewhere..."