Her dust cloth fell to the floor and was lost from sight.
She took a letter from her pocket and read it.

In the twilight the letter was the whitest thing in the world.

The double sheet trembled between her fingers, which held it carefully, like a dove in the air.
She put the trembling letter to her lips, and kissed it.

From whom was the letter?
Not from her family.

A servant girl is not likely to have so much filial devotion as to kiss a letter from her parents.