But, slow as this process was, it served to teach Tom a lesson or rather to remind him of one he had learned and forgotten.

He found that a hatful of water thrown on the bottom of the fire did more good than two hatfuls thrown on top, and he remembered that when the soot in the chimney at home caught fire once, his father would not allow anybody to pour water down the chimney, but stood himself by the fireplace throwing a little water, not up the chimney but, on the blazing fire below.

This water, turned into steam, went up the chimney and soon extinguished the fire there.

In the same way Tom now discovered that when he threw a hatful of water on a burning log at the bottom of the pile it had a perceptible effect all the way to the top.

Thinking of the chimney fire he remembered also that his father had said at the time that a plank laid over the top of a burning chimney, or a screen fastened over the fireplace would stop the burning of the soot by stopping the air, and so smothering the fire.