day to day.

When the car returned from the grocer's, Henry jumped to his
motor-cycle and made his way to the ferry by a route different from the
roadster's. He knew he was taking a chance, but he also knew that an
accomplice might be trailing the roadster to see if the latter were
watched. Henry could follow the spy to the ferry once without arousing
much suspicion; but if he were twice seen to do so, his usefulness
might be ended. He knew when the ferry-boat would leave its slip and
he made his way aboard just before the gate closed.

At once he had a feeling that he had acted wisely. The roadster was
again in the forward part of the boat, but this time the driver did not
sit placidly looking out over the Bay. He seemed nervous, and every
little while turned sharp around and looked about him. Fortunately
Henry had concealed his wheel behind a truck and was himself where the
spy could not see him. When he noted the spy's restlessness, it
flashed into his mind that perhaps the secret service men who had been
investigating this spy had not been so careful as they should have
been, and that the spy had taken alarm. It was a discouraging thought,
for it made Henry's task vastly more difficult. Wisely, therefore, he
went into the cabin and sat down. The spy could not see him, and if
the latter should stroll about the boat, there was nothing to indicate
to whom the motor-cycle belonged.

As the gate opened and the roadster rolled from the ferry-boat, Henry
prudently remained well behind it. Up Broadway they went, as fast as
the traffic would allow, their pace gradually quickening as they drew
away from the congested lower end of the island. The spy drove
straight up Broadway. He circled Union Square and continued north. He
passed Madison Square and still held to Broadway. Past the shopping
district, past Longacre Square, past Columbus Circle, the roadster
continued, still on the city's main highway. And at a discreet
distance Henry followed.

Now they reached the apartment-house district and slid past block after
block of bulky living apartments. And so they continued past Columbia
University and down the grade beyond. And here Henry's troubles began.
The roadster turned to the left, and Henry knew the driver was making
for the Fort Lee ferry.

How should he gain the boat unnoticed? How should he follow,
undetected, along the Jersey roads? For after they had crossed the
Hudson there would be an end