Cosima

Cosima is an elderly woman living in Moonglow during Ultima IV.

Description
Cosima was a skilled but tired alchemist, who could be found loitering outside of the Honest Inn. Should the Stranger speak to her of her trade, she would boast that she knew the best methods of mixing reagents, and would inform the hero that the Sleep spell required but one portion of spider silk, rather than the double portion listed in the Book of Mystic Wisdom.

Trivia

 * Seanna of Buccaneer's Den offers similar advice regarding the Sleep spell, which had had its formula misprinted in the Book of Mystic Wisdom.
 * In the Master System port of Ultima IV, Cosima reveals the full recipe for the Sleep spell, which had had its formula completely omitted from the Book of Mystic Wisdom.
 * In the Nintendo remake of Ultima IV (where most character names were omitted and dialogue was significantly modified), Cosima can be identified with the white mage in the apothecary shop, who gives the same information.