"That same old ship-rat!" exclaimed the submarine boy. "I'll catch the
beast before he goes under your skirts, Miss Peddensen."

At the mention of a rat so dangerously close young woman almost shot out
of her seat in anxiety to get away.

As she bounded something dropped down out of the wide right sleeve of
her coat. It was a small memorandum book.

This was just what Jack Benson caught, in place of the pretended rat.
Moreover, the young skipper was clever enough to catch the book so that
it fell into his hands open.

"It wasn't a rat, after all, Miss Peddensen," smiled Jack, straightening
up and holding the open memorandum book so that both he and Kimball
could see what was traced on the two pages that lay exposed.

There were sketches of the compressors, sketches of the mechanism by
which the compressed air was forced into the tanks to drive the water
out--in fact, sketches of many vital features in the control of the
boat. Nor was more than a glance needed to make it plain that this
young woman artist possessed expert knowledge of machinery.

At the cry of "rat" three or four women jumped from their seats. The
one nearest Miss Peddensen moved hastily to the forward end of the cabin.

"My dear young woman," murmured the lieutenant commander, dropping into
the vacated seat beside the Swedish girl, "you won't mind, will you,
if I keep these little matters to look over at my convenience!"