The dormitory was not one of the coldest places of the castle, but Lucy liked to sleep in the heat. She suffered much from the cold. So she decided to start from the room in which she slept ..
She sat facing the wall next to her bed and pulled out her wand.
She was silent for a few minutes to concentrate and said:" caelum sepio! "
Lucy made a sweeping movement with her wand in the shape of 8!
When she went near to the wall it seemed a bit warmer!