ther,
examining the topography of the city's environs as once they had
studied the city itself. Marked to show altitudes, roads, byways,
rivers, streams, marshes, woodlands, and even the buildings themselves,
these maps enabled the little group of scouts to see, through their
imaginations, every foot of the country about New York.

They visualized the great, flat, low-lying stretches of southern Long
Island and New Jersey; the abrupt bluffs of Long Island's northern
coast by the shore of the Sound; the various watery arms that encircle
the American metropolis, permitting ships to sail in every direction;
the majestic Hudson leading straight north through a wonderful country
of rocks and hills, the impressive Palisades flanking its western bank
with their towering perpendicular walls of stone; and the rocky,
rolling country lying west of them, interspersed with streams and
swamps and woodlands and open fields and clustered villages. And when
they had finished their study of the maps, they knew more about the
topography of the country they had studied, its roads and paths and
groves and elevations and other physical characteristics, than half the
people who lived in the region. So they were prepared, if need be, to
find their way about with little difficulty. And it was well they were
so prepared. In the dangerous days to come they were to need all this
knowledge.

When they had studied the maps to their hearts' content--and each of
the four boys again and again examined them--Captain Hardy folded the
maps and thrust them into a waterproof cover. They made a neat little
packet like a thin book.

"You will be interested to learn what the secret service has found
out," said Captain Hardy, as he stowed the maps in his pocket. "When I
left here, I reported immediately to the man in charge of this
particular investigation. Our discovery seems to me so important that
I ventured to ask why the secret service men didn't take the case up
themselves, as they would no doubt get along much faster than we
possibly can. For it seems to me message sending ought to be stopped
at once. The agent said that all this was true, but that the secret
service was so crowded with work it had to take up the most important
matters first."

"Most important matters!" cried Roy, in indignation. "Doesn't the
secret service consider the guarding of our troops important?"

"Yes, Roy. But whether the Germans know exactly when our ships le