Often he heard his silver whistle directing his troop, but the man himself remained invisible.

In his eagerness the lad rose too high, but the sergeant pulled him down in time, a bullet whistling a second later through the air where his head had been.
"Careful, Mr.Mason! Careful!" said Sergeant Whitley.

"It won't do you much good for one of his men to get you while you are trying to get him!" Dick became more cautious.

At last he caught a glimpse of the great hat that he could not mistake, and, aiming very carefully, he fired.

Then he uttered an angry cry.