What she carries away from the pedestal isn't exactly the book; as she lifts it away, it slips ethereally through her fingers and a ghostly copy rises in its place, open to the same page she was reading. The ghost book's weight is faint, but it follows very obligingly wherever she carries it, and its translucent glowing text is clear and legible.
The page on how to channel magic (written entirely by Magister Aspen) goes into the different mindsets, wand motions, and physical stances involved in channeling the seven elements. Unformed magic appears at the end of the list, with a note that it's paradoxically difficult to settle into the right channeling style without accidentally slipping into some specific element, but once you've mastered that, it has the lightest mana burden of all of them. To channel it, you clear your mind, stand in a neutral posture, and hold your wand steady.
With that plus the directions of the Repel Fog ritual, Sable can successfully cast the ritual at the Mana Font. A blue-white glow emanates from her wand and connects to the massive crystal formation in a thin line, and a pool of blue light begins spreading through its massive translucent base and then slowly, slowly filling it. The whole formation is about twelve feet tall at its highest jagged point, with a few scattered crystals floating in the air around it, ranging from fist-sized to head-sized; everywhere above the slowly rising waterline of the blue light, the dormant crystal is as clear as slightly frosted glass.
As the Mana Font fills, its glow begins the light the room, bringing more visibility to the spiral stair of floating stone slabs that wraps around the central figure of the Font, and the engraved mural at the back of the room depicting a crystal suffused with a crackling glow. At the top of the stairs where they meet the ceiling is a firmly closed hatch with a glass porthole in the middle showing ominously swirling darkness, and at the bottom where they meet the floor is another one.