It was on the morning of the third day. The two boys and Professor Henderson were in the pilot house, and Mr. Roumann was in the engine–room, adjusting the Etherium motor, for he expected to shortly put it in operation. Suddenly Jack, who was looking at one of the instruments on the front wall, uttered a cry.
"What's the matter?" asked Mark.
"We're approaching something!" was the answer. "Some sort of heavenly body. Look at that indicator!"
The hand or pointer on a peculiar dial was moving violently to and fro.
"Call Mr. Roumann," suggested the professor. "I don't know just what to do."
Mr. Roumann hurried into the pilot house, gave a quick glance at the indicator, and exclaimed:
"We are nearing a planetoid, or, as some call them, an asteroid!"
"Is there any danger?" asked Mark.
"No. Fortunately the instrument gave us timely warning. I shall simply steer to avoid it. It is a small, unnamed planet flying around in space. There are many of them."
"Can we go close enough to it to see it?" asked Jack, who was a curious lad.