on
foot."

"You had better keep ahead of her on your horse about a quarter of a
mile, or more; but your main duty will be here. I have brought with me
half a dozen Roman candles, and I am going to fix them in the ground on
this spot. Here is a bunch of matches," said Christy, handing it to him.

The steward watched the midshipman while he planted the fireworks in the
sand, and particularly marked the spot where they were located, for his
companion told him he was to fire them, and he must be ready to do so
without any delay.

"A boy could do that and like the fun of it," said Mr. Watts, laughing
at the simple duty he was to perform.

"But it is the time that you are to do it, and the boy might be
skylarking, or become impatient. This signal of the fireworks is to
assure us at the right moment that the Vampire, if it should be she,
is in the place where I expect her to be."

"I understand it perfectly."

"After I leave you, another steamer may come along, and get to this
point ahead of the Vampire; and I should be very sorry to blow her out
of the water, or sink her under it. You are to let us know by this
signal that it is the Vampire, and no other, that is coming round the
bend. You had better leave your horse a short distance from the river,
for that gun will make every pane of glass within a mile of it shake
when it is discharged."

"You may be sure that I will not be on his back at that time."

"Still further: I have planted six candles in the sand. You will light
only one of them when the steamer begins to round the bend. That will be
enough to inform us of the fact on board of the Bellevite."

"What are the others for?" asked the steward, taking a memorandum-book
from his pocket as though he intended to write his instructions.

"It is not necessary to write it. We shall not be able to see what
effect the shot produces after we fire. If the Vampire, always supposing
she is the one, is not hurt, light a second candle--only one of them. If
she should be disabled, you will light two candles."

Christy repeated what he had said, and was careful not to give the
steward too much to remember. As soon as the matter was fully
understood, the middy mounted his horse, and they proceeded on their
mission down the river. After they had ridden about three miles, Mr.
Watts insisted that the steamer was coming, and that it was the Vampire.

"I don't see anything," added Christy.

"Neither do I; but I know that the