Still she could not but hope that Mary would come in the course of the afternoon.

The hours of the afternoon, however, passed tediously away, and the sun began to decline toward the west; still there was no Mary Bell.

The cause of her detention will now be explained.
When Mary Bell came down to breakfast, on the morning after her mother's visit to Mary Erskine, her mother told her, as she came into the room, that she had an invitation for her to go out to Mary Erskine's that day.
"And may I go ?" asked Mary Bell.
"Yes," said her mother, "I think I shall let you go." "I am _so_ glad!" said Mary Bell, clapping her hands.
"Mary Erskine wishes to have you stay there several days," continued her mother.
Mary Bell began to look a little sober again.

She was not quite sure that she should be willing to be absent from her mother, for so many days.
"Could not I come home every night ?" said she.
"Why, she wishes," answered Mrs.Bell, "to have you stay there all the time, day and night, for several days.

It is an opportunity for you to do some good.