m had been
rarely more than a few seconds. Then again it was noticeable that he
took the utmost care that none of the others should see what was on his
slate. He did his work in a corner, hunched up over it so that it was
well concealed, and he snatched his slate away from the pile at the very
first opportunity.

Bert noticed all these things, and they perplexed him quite as much as
Cohen's rapid gain alarmed him. He soon became convinced that there was
something wrong, that Cohen was doing crooked work; but, puzzle his
brains as he might, he could not get at the bottom of the mystery. Frank
and Ernest fully shared his suspicions, and they had many a talk over
the matter. Frank thought that Cohen must have the answers written on a
piece of paper which he managed to peep at somehow while all the other
boys were absorbed in working out the problems; but although he on
several occasions purposely refrained from doing anything himself in
order to watch Cohen the more closely, he failed to find the slightest
ground for his suspicions in that direction. Then Bert put forward his
theory.

"I'll tell what it is Frank: Cohen must learn the answers off by heart,
and then he sets them down without working out the whole sum."

"Shouldn't wonder a bit," said Frank. "He's got a great memory, I know,
and we always can tell from what part of the arithmetic Dr. Johnston is
going to get the sums."

"But how can we make sure of it, Frank?" inquired Bert, anxiously.

"The only way is to get hold of his slate, and see how he works his sums
out," replied Frank.

"Yes; but he takes precious good care not to let anybody see how he does
them."

"So he does; but we've got to find out some way, and I'm going to do it,
so sure as my name's Frank Bowser."

"How'll you manage it, Frank?" asked Bert, brightening up; for he really
was a good deal troubled over Cohen's continued success, particularly as
he felt so strongly that there was something wrong at the bottom of it.

"I don't know yet, Bert; but I'll find out a way somehow. See if you
can't think of a plan yourself."

"I'll tell you what I'll do: I'll ask father about it," said Bert, in a
tone that implied perfect confidence in Mr. Lloyd's ability to furnish a
solution for any difficulty.

Accordingly, that evening, Bert laid the whole case before his father,
who listened with judicial gravity, and then proceeded to ask a question
or two:

"You feel quite sure that Cohen does no