It was some time before Frank could get an opportunity to use his musket; for if he exposed the smallest portion of his body, it was the signal for his watchful enemies, who sent the bullets about him in unpleasant proximity. In spite of his dangerous situation, he could not help thinking that the rebels were very proficient in "Indian fighting," for, with all his watchfulness, he could not get an opportunity to put in a shot. All he could see of his enemies would be, first, a rifle thrust carefully over the levee, then a very small portion of a head would appear, and the bullet would come straight to the mark. In the mean time the Milwaukee was working her way out into the stream, and the rebels, finding that their fire was not returned, grew bolder by degrees, and became less careful to conceal themselves. This was what Frank wanted; but he reserved his fire until a tall rebel rose to his full hight from behind the levee, fired his gun, and stood watching the effect of the shot. Frank's musket was at his shoulder in an instant, his finger pressed the trigger, and the rebel staggered for a moment, and disappeared behind the levee. "There," said Frank to himself, "that's what Simpson would call 'squaring the yards.' I'm even with the rascals now." The rebels answered the shot with load yells, and their bullets fell thicker than ever; but the Milwaukee was almost out of range, and, in a few moments, the firing ceased altogether. CHAPTER VII. On a Gun-boat. When the Milwaukee was fairly out of range of the bullets of the guerrillas, Frank put his gun back in the rack, and started in search of the doctor's steward. He ran into the cabin without ceremony, and was about to enter the steward's room, when he discovered a pair of patent-leather boots, which he thought he recognized, sticking out from under a mattress which lay on the cabin floor; and, upon examination, he found that it concealed the steward, who was as pale as a sheet, and shaking as though he had been seized with the ague. "What do you want here?" he asked, in a trembling voice, as Frank raised the mattress. "Simpson is shot," answered Frank, "and I would like to have you come down and see him." "Do you suppose I am fool enough to go out on deck, and run the risk of being shot? No, sir; I'll stay here, where I am safe;" and the steward made an effort to draw his head under the mattress again. "There's no danger now," said Frank; "the rebels have stopped firing. Besides, we are out of"-- "Go away, and let me alone," whined the steward. "I am not going to expose myself." "You're a coward," exclaimed Frank, now fairly aroused "But I guess the captain can"-- "Oh, don't," entreated the steward; "I haven't been here a minute. I started to get a gun, to pay the rebels back in their own coin; but the bullets came through the cabin so thick that I thought it best to retreat to a safe place;" and the steward threw off the mattress, and arose, tremblingly, to his feet.