Answer: A Mr. Bixby asks, “Didn’t you know there was no bottom in that crossing?”
Step-by-step explanation:
Samuel had lots of confidence when offered to manage a crossing by himself, but after Mr. Bixby asks him "You think so, do you?", he became unsure and his confidence faded away. That´s why Samuel gets pranked while doing that task, and therefore Mr. Bixby asked him "Didn't you know there was no bottom in that crossing?", to show that he doubted himself when there was no reason to do so. He should have just trusted himself instead of allowing others to shook his confidence.