What exactly does the Spell Drinker amulet Elder Scrolls do IV: Oblivion?

He says: "Absorption of spells" But, I mean, what the hell exactly does this mean? available after completion of this spell a few quests in the Mages Guild

Spell Absorption effect: The size of the spell (I think which one is 20 or 25) is the percent chance that you absorb a spell on her. Which means that instead of taking damage or other negative effects (eg Silence), you would add the amount of votes required to enter your own spell Magicka Magicka pool.

Oblivion Artifacts