orpedo-boat destroyer
and expected to take it to Washington within a few days. He was to show
his model boat to a committee of naval experts, who were to decide
whether his invention were of value.

Aside from the pleasure it gave him to tell the girls of his invention
he had another graver reason for doing so. He had decided to ask
Phyllis to do him a great favor. From the beginning of their
acquaintance the young man had been impressed with Phil's sterling
qualities. She was loyal to her friends and absolutely dependable. He
felt certain that she would respect a confidence and keep a secret. He
believed her to be the one person he could trust absolutely. Yet he did
not wish to draw her into a promise without the knowledge of at least
one of her friends. For this reason he had chosen to make Madge his
confidante also.

Just how to begin he hardly knew, and it was not until they had rowed
within close range of the houseboat, where Tom Curtis and Alfred
Thornton stood waving from the deck, that he said nervously:

"Won't you and Miss Morton stop rowing for a moment, Miss Alden? I
wouldn't have bored you with the story of my invention, except that I
wish to ask you a strange favor. If I go away in a few days, of course
my work-shop will be closely watched and guarded. Yet I shall not feel
it to be perfectly safe. I alone know that I am being spied upon, that
certain men are shadowing me ready to report every movement that I
make. If, after leaving here, I should fall ill unexpectedly,
or--disappear suddenly, the secret of my invention might never be
known. So I wish to ask you, Miss Alden, to keep a small, square box,
which I shall give you before I leave. I shall ask you not to examine
its contents unless some unusual circumstance should develop, when you
feel obliged to ascertain what the box contains. You may think it
strange that I do not ask one of my men friends to do this favor for
me. But I have a special reason for desiring to place the box in the
care of some one who will never be suspected of having it. Will you
keep it for me, say for a week, or until I ask you or write to you for
it?"

The skiff had nearly reached the houseboat. Madge and Phyllis were
allowing the "Water Witch" to drift in. Their friends on board had seen
them and were signaling for them to come aboard.

Madge's usually sunny face was clouded with disapproval. Why should
Lieutenant Lawton wish a young girl like Phyllis, a mere acquainta