Mr. Roumann was anxiously looking at the apparatus to see what damage had been done by the bomb. "Can't we go to Mars?" inquired Jack. "I think so," was the reassuring reply of the scientist. "It is not damaged so much as I feared. The wheels and pipes are easily replaced, and as long as the generator and the distributing plates are not disturbed, I can easily repair the rest. But it was a fortunate chance that the bomb did not explode nearer the projectile. Otherwise we would have had to give up our journey." "And we would have had to if you had been killed," remarked the professor. "I thought the secret of the power was going to die with you!" "It will," replied Mr. Roumann, "but not just yet. I shall never disclose the source of the power until I reach Mars, get what I am after, and come back. Then I may bequeath it to you, Professor Henderson, in return for the kindness of yourself and your young assistants." "I will appreciate that. But you had better go to the house now and let me doctor you up." "No, I feel well. I want to get right to work repairing the damage. It will delay us several days, but we cannot avoid it. I wish I could catch the men responsible for this outrage." "Have you any idea who they were?" "No; but I suspect they were in the enemy of mine. A man who used to work for me, but whom I discharged because of dishonetesty. His name was Zeb Forker." "One of the men who threw the bomb was same one who was at the window one night," said Mark. "Do you suppose he could be Forker, Mr. Roumann?" "No, I do not believe so. But we will not discuss that now. I fancy the men will not bother us again." "I'll tell Andy to keep a better watch," said Mr. Henderson. "And we'll help him," added Mark. "There is little for us to do on the projectile now, and we can do guard duty, Jack and I together." It took Mr. Roumann several days to repair the damage done to the Etherium motor by the bomb. During that time Andy and the boys were constantly on guard about the shop, but the crazy machinist and his companion did not return. Washington White agreed to stand guard part of one night, and, as the others were tired, they agreed to it. But a fox or some animal got in among the colored man's chickens, and at the first sound of alarm from his favorite fowls, Washington deserted his post and rushed for the coop. Jack, who was awakened by the noise, looked out of the window. "It is some one trying to get in, Wash?" he asked. "Dat's what, Massa Jack." Jack awakened Mark, and the two hurried down with their guns. They found the colored maw making a circuit of his coop. "I thought you said some one was trying to get in," observed Jack. "So dey was, Massa Jack. I done heard de most, tremendousness conglomeration of disturbances in de direction ob my domesticoryian orinthological specimens, an' I runned ober to see what it were." "You mean that something was after your chickens?" asked Mark.