MY DEAR LITTLE FRIENDS: --You can never guess how much I have enjoyed writing these stories of the night-time, and I must tell you how I first came to think of doing so. I once knew a girl--and she was not a very little girl, either, who was afraid of the dark. And I have known three boys who were as brave as could be by daylight, but who would not run on an errand alone after the lamps were lighted