ome!" exclaimed Bob from his post of observation, and,
looking out for a moment, Ralph saw six men riding into the clearing
directly toward the house.

Almost before he had time to regain his seat, and just as Bob held up
his hand as a signal for silence, a knock was heard at the door, as if
some one was pounding with the butt-end of a whip.

No one made any reply, and it seemed to Ralph as if he could hear the
pulsations of his own heart, so oppressive was the silence.

Again the summons was repeated, and a gruff voice cried:

"Open the door a moment. I wish to speak with Mr. Robert Hubbard."

Then there was a long silence, and, seeing the look of anxiety on
Ralph's face, George said, in a low whisper:

"Don't look so distressed, my boy. Those men have got no more right to
enter here than you have to go into another man's dwelling. If they
should succeed in getting in, however, they would find sufficient to
prove that Bob was about to infringe their patent; but, as it is, they
have no authority to do anything, although Bob will hardly get a chance
to shoot the Hoxie well to-night."

"That's just what I will do," whispered Bob, who had heard George's
remark. "I will put in that charge if they camp where they are all
night."

The men on the outside waited some moments in silence, and then the
request was repeated, while at the same time footsteps could be heard as
if some of them had gone toward the stable.

"They might easily batter in one of the windows," said Ralph, as the
pounding at the door was continued.

"They would hardly try that plan," replied George, with a meaning smile.
"There are a hundred or two quarts of nitro-glycerine stored here,
needing only the necessary concussion to explode them. Those men know
quite as well as we do how unpleasant such liquid may become, and I
assure you that they will strike no very heavy blows on the building."

It was a singular position for any one to be in, and Ralph was far from
being comfortable in his mind, as he awaited the result of this visit to
the cabin of the moonlighters.

CHAPTER IV.

A REGULAR SIEGE.

Ralph, simply a visitor to the cabin of the moonlighters, felt far more
uncomfortable than did his hosts, to whom alone there was any danger.

As the party waited silently for any move by those outside, Ralph had
plenty of time to review his own position, and this review was far from
pleasant or reassuring.

In that section of the country