And the effect was instant. The room became suffused with power, a field of intense magical energy unlike anything Hermione had ever experienced. It heaved and throbbed around them like a turbulent sea, igniting runes and alchemical symbols carved into the floor, walls and ceiling of the domed chamber. They flashed in electrifying multi-colour and vibrated with a power all of their own, joining with the swell of energy already swirling fiercely around them. Hermione felt the effect physically in her body. It was akin to standing next to a giant speaker at a concert and having the music pound into your bones. She was a little afraid of the sensation, and grabbed at Harry's arm on reflex.