The Hunchback of Notre Dame by Book 9 Chapter 3 Page 8

you do not turn away your eyes. I shall go to some place where I can see you without your seeing me: it will be better so.”

He drew from his pocket a little metal whistle.

“Here,” said he, “when you have need of me, when you wish me to come, when you will not feel too ranch horror at the sight of me, use this whistle. I can hear this sound.”

He laid the whistle on the floor and fled.