Lily took it from him and perused the page for quite some time, taking in the different directions and trying to compose herself. "Oh! Yes, the other book doesn't say to stir counter-clockwise, or to lower the temperature when it's almost done. No wonder my potion never turned the correct turquoise color."
She opened her Potions book and hastily wrote down the right directions, scratching out the incorrect ones. Her hand was sweaty now. "Thank you," she told Severus, handing the worn book back and smiling at him. "What would I do without you?"