son. Like every mother, her sympathies went out to him. When Nick told
his father that he was in error, the mother felt a thrill of delight;
she wanted Nick to get the better of her husband, much as she loved
both, and you and I can't blame her.

Nick leaned back in his chair, shoved his hands into his pockets, and
looked smilingly at his father and his pipe as he said:

"Suppose, to illustrate, that Philadelphia has just one hundred people.
Then, if New York has fifty per cent. more, it must have one hundred and
fifty people as its population; that is correct, is it not, father?"

Mr. Ribsam took another puff or two, as if to make sure that his boy was
not leading him into a trap, and then he solemnly nodded his head.

"Dot ish so,--dot am,--yaw."

"Then if Philadelphia has one hundred people for its population, New
York has one hundred and fifty?"

"Yaw, and Pheelatelphy has feefty per cent. less--yaw, yaw, yaw!"

"Hold on, father,--not so fast. I'm teacher just now, and you mustn't
run ahead of me. If you will notice in this problem the per cent. in the
first part is based on Philadelphia's population, while in the second
part it is based on the population of New York, and since the
population of the two cities is different, the per cent. cannot be the
same."

"How dot is?" asked Mr. Ribsam, showing eager interest in the reasoning