ns. Inside, the play had
hardly begun. Gambling does not reach its frantic height until
midnight.

"We shall feel out of place," mused Dave aloud. "Dan, we really should
have known better than to come here in anything but evening dress. You
see that every one else is in full regalia."

"Perhaps we'd better keep on the edge of the crowd," responded Danny
Grin. "There is enough to be seen here, for one evening, without
entering the Casino."

Though Dave intended to enter the Casino later, he decided, for the
present, to take in the full beauty of the night in the gardens. There
were electric lights everywhere, which outshone the brilliance of the
moon.

"Hello!" whispered Dan, suddenly. "There's an old friend of ours."

"Who?"

"Mr. Green Hat," Dan whispered impressively.

Instantly Dave Darrin became intensely interested, though he had no
intimation of what this second meeting portended. That Mr. Green Hat
was destined to play a highly tragic role in his life, Darrin, of
course, had no inkling at that moment.

"There he is!" whispered Dalzell, pointing, as the chums stood
screened by a flowering bush.

"We'll watch that rascal!" Dave proposed promptly. "I wonder if he has
followed the 'Hudson' here with a view to attempting more mischief
against our Government. Whatever his game is, I am going to take a
peep at the inside of it if a chance comes my way!"

CHAPTER IV

MR. GREEN HAT'S NEW ROLE

Mr. Green Hat, on this occasion, had discarded the article of headwear
that had given him that nickname with the young ensigns.

Instead, Gortchky wore an opera hat, with evening dress of the most
fashionable description. On his broad white expanse of vest there
glittered a foreign decoration.

Though he walked alone, and affected an air of indifference to his
surroundings, Darrin was of the impression that the spy was looking
alertly for some one.

"Of course it may happen," said Dave to his friend, "that the fellow
is foolish enough to come here for the purpose of throwing away at the
gaming tables the money he earns by his questionable services to some
plotting international ring. Yet that seems hardly likely, either, for
Gortchky must be a man of tremendous energy, to render the thrilling
services that are demanded of a spy or an international trouble-maker."

Now the two chums left the place where they had been standing behind
the bush, to stroll along slowly, all the while keeping Gortchky in
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