Spellbook of levitation
| spellbook of |
|Base price||400 zm|
|Turns to read||12|
|Ink to write||20–39|
|Power cost||20 Pw|
|Equivalent||potion of levitation|
Allows you to learn the levitation spell. When you cast levitation at the Escape spells skill level of unskilled or basic, the effect is the same as an uncursed potion of levitation. When you cast it at skilled or expert, the effect is the same as a blessed potion of levitation, leaving you in the air for 250 to 299 turns; in particular, you can land at will, using the > command. Note that you must be at the appropriate skill-level at the time of casting; if you cast it while Basic and then train to Skilled, you will not be able to land at will.
A levitation source is a vital part of most ascension kits; the game is hard to complete without access to the effect. However, it is typically wiser to use some other levitation source; the ring of levitation and boots of levitation are both better sources than the spell, as they work in a much more predictable way.
Early-game, the only real use for the spell is to levitate above an Elbereth engraving in order to avoid eroding it; this can be incredibly powerful, but if the Elbereth wears off as you cast the spell, you will be stuck in midair and unable to try again. Using the spell for this purpose is also potentially unwise due to the time it can leave you stuck in midair (early-game, you are unlikely to be skilled at the spell), which can cause problems worse than the original combat.
Later in the game, the spell is typically used to cross water or lava (and required to be able to move full speed on the Plane of Air); there are numerous special levels where this is useful (the first typically being Medusa's Island). Unless you are skilled or better at the spell, never use it to cross more than a couple of squares, or else recast it very frequently (bearing in mind that you'll have a long wait in mid-air when you're finished unless you can find a sink above your current location to land), as you have no control over when it will wear off, potentially leading to an instadeath via drowning or burning.
Even uncontrolled levitation is unlikely to cause problems if cast in the Plane of Air, so long as you're mindful of the possibility of it wearing off, as there is no real need to land on the ground later in the game from there unless you plan to drop the Amulet of Yendor to reduce Pw costs.
Should you end up stuck in midair due to the use of this spell, you can land using a sink, blessed potion of levitation, or via raising the spell to skilled and casting it again (which can be accomplished via repeatedly re-casting it, so long as you have enough skill slots left).