"What's the matter?" asked Jack. "I hope I haven't made them mad."
"No; they appear to be delighted," said Mr. Roumann. And sure enough, the Martians showed evidences of pleasure. They pointed to the triangle on the head of their leader, and then to the one Jack had drawn.
Then, from somewhere in the rear of the crowd, there came another man. He was slightly larger than his companions, but that was not saying much, for, aside from their great heads, the Martians were all little people, not much more than up to Andy's shoulder, and Andy was not much over five feet in height.
But it was not the size of the newcomer that attracted the attention of the travelers so much as it was the device he had in the golden circle on his head. For this device was exactly the same as the one Jack had drawn in the sand to illustrate the problem. It was a triangle, with squares drawn out from the three sides. He looked at the drawing in the sand, and made a low bow to the newcomers.
"Well, that appears to have taken their fancy," said Mark. "I can't understand it."
"I can," spoke the professor quickly. "The Martians are a very learned people. That's why their heads are so large and their bodies so small. They make a special study of the sciences, and geometry and mathematics probably are their favorites. That is why they understand Jack's problem. Science is the same throughout the universe, though conditions may differ on different planets. I think we have arrived at a means of communicating with the Martians, at least until we have learned their language."
The Martian with the triangle and squares on his circlet of gold appeared to be a grade higher in authority than the one with the simple triangle. He now addressed the travelers, but they could not understand him.
Seeing this, he stooped and drew in the sand another geometrical problem, leaving it half completed.
"You finish it, Mark," said Jack, and the boy did so, much to the delight of the crowd.
"They all are well up in geometry," declared Mr. Roumann.