Since this Tome is somewhat more powerful than the other 2, I’m proposing it separately and putting an additional restriction on it.

Add the following tome to the list in Rule 2.7.1:
Book of Water(3 copies)
Condensation
Circumstances:This spell may be cast if the Student casting it has a positive Thirst, has a nonzero mythos knowledge, and has not cast Alertness Ritual, Condensation or Douse in the last 72 hours.
Consequences:Decrease the Thirst of the Student who cast this spell by 2.

Douse
Circumstances: This spell may be cast if the Student casting it has a mythos knowledge of at least 7 and has not cast Alertness Ritual, Condensation or Douse in the last 72 hours.
Conequences:  The Student who cast this spell chooses another Student. Ten liters of ice water appear directly above their head.  That Student loses 1 Sanity, plus 2 more if this spell has never been cast on them before.

Alertness Ritual
Circumstances:This spell may be cast if the Student casting it has a mythos knowledge of at least 4 and has not cast Alertness Ritual, Condensation or Douse in the last 72 hours.
Consequences:The Student who cast this dunks eir face in a bucket of water. The Student who cast this spell is cured of Sleep or Drowsiness, if e had either.  If this is cast immediately after this Student lost 6 Sanity due to the Rule entitled “Theraputic Isolation”, e regains 3 of the lost Sanity.

Drink the Book
Circunstances:This spell may be cast if the Student casting it has a mythos knowledge of 20.
Consequences:The Student who cast this spell has eir Thirst set to -10.  The Student who cast this spell loses eir copy of this tome.  For the rest of the Dynasty, that Student casts spells from the Book of Water as if all instances of “72 hours” in the spells’ Circumstances were “48 hours” instead